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g               g                           UNITED STATES g               g         NUCLEAR REGULATORY COMMISSION
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UNITED STATES g
  ,                                      WASHINGTON. D.C. 30NH001 V. m . /*                                       September 5, 1997 MEETING PARTICIPANT:     NUCLEAR ENERGY INSTITUTE
g NUCLEAR REGULATORY COMMISSION
,E WASHINGTON. D.C. 30NH001 V. m. /*
September 5, 1997 MEETING PARTICIPANT:
NUCLEAR ENERGY INSTITUTE


==SUBJECT:==
==SUBJECT:==
==SUMMARY==
==SUMMARY==
OF APRIL 30, 1997. MEETING WITH THE NUCLEAR ENERGY INSTITUTE (NEI) REGARDING GENERIC LETTER (GL) 96 06. " ASSURANCE OF EQUIPMENT OPERABILITY AND CONTAINMENT INTEGRITY DURING DESIGN BASIS ACCIDENT CONDITIONS" On April 30. 1997, representatives of NEl met with representatives of the Nuclear Regulatory Comission (NRC) at the NRC's offices in Rockville.         '
OF APRIL 30, 1997. MEETING WITH THE NUCLEAR ENERGY INSTITUTE (NEI) REGARDING GENERIC LETTER (GL) 96 06. " ASSURANCE OF EQUIPMENT OPERABILITY AND CONTAINMENT INTEGRITY DURING DESIGN BASIS ACCIDENT CONDITIONS" On April 30. 1997, representatives of NEl met with representatives of the Nuclear Regulatory Comission (NRC) at the NRC's offices in Rockville.
Maryland   Attachment 1 provides a list of meeting attendees.
Maryland provides a list of meeting attendees.
The meeting was requested by NEl representatives to discuss issues pertaining to GL 96 06. " Assurance of Equipment Operability and Containment _ Integrity During Design Basis Accident Conditions." Prior to the meeting NEI sent NRC a proposed agenda and a list of questions that it wanted the staff to address during the meeting. The staff's response to these questions is summarized in this meeting summary. The agenda is contained in Attachment 2.
The meeting was requested by NEl representatives to discuss issues pertaining to GL 96 06. " Assurance of Equipment Operability and Containment _ Integrity During Design Basis Accident Conditions."
The NRC staff began the meeting by making a preser.tation that included an overview of the GL, a summary of the industry responses to the GL received by the NRC to date, and a brief discussion on each of the technical issues in the GL,   Attachment 3 contains the overhead slides that were used during the NRC presentation. The NRC staff stated that it has been disappointed with the 120 day responses to the Gt. because of some licensees' questionable schedules for resolving the problems identified in the GL. Also, some of the responses submitted were incomplete. The staff has been contacting individual licensees in an attem schedules. pt to obtain a better understanding of licensee responses and An industry representative stated that in order to plan outages, modification packages must be completed at least 6 months prior to the beginning of an outage; therefore, if the GL 96 06 modifications cannot be installed during the upcoming outages, the modifications will not be installed until 18 to 24 months later (a refuel cycle), which may put implementation of some plant modifications into the year 1999. The staff stated that licensees became aware of the issues on September 30, 1996, when the GL was issued and guidance in GL 91-18 ("Information to Licensees Regarding Two NRC Inspection Manual Sections on Resolution of Degraded and Nonconforming Conditions and on Operability") suggests that degraded systems should be restored to within the original criteria during the next refueling outage.
Prior to the meeting NEI sent NRC a proposed agenda and a list of questions that it wanted the staff to address during the meeting. The staff's response to these questions is summarized in this meeting summary. The agenda is contained in Attachment 2.
OV /15 The NEl representatives next made their formal presentation which included a restatement and clarification of the questions that were given to the NRC to address during the meeting. The NEl presentation materials are 3rovided as Attachment 4. which includes the formal questions given to the NRC prior to the meeting. The NRC staff addressed NEl's questions as each was presented.           l
The NRC staff began the meeting by making a preser.tation that included an overview of the GL, a summary of the industry responses to the GL received by the NRC to date, and a brief discussion on each of the technical issues in the GL, contains the overhead slides that were used during the NRC presentation. The NRC staff stated that it has been disappointed with the 120 day responses to the Gt. because of some licensees' questionable schedules for resolving the problems identified in the GL. Also, some of the responses submitted were incomplete. The staff has been contacting individual licensees in an attem schedules. pt to obtain a better understanding of licensee responses and An industry representative stated that in order to plan outages, modification packages must be completed at least 6 months prior to the beginning of an outage; therefore, if the GL 96 06 modifications cannot be installed during the upcoming outages, the modifications will not be installed until 18 to 24 months later (a refuel cycle), which may put implementation of some plant modifications into the year 1999.
                                                                                              ,7
The staff stated that licensees became aware of the issues on September 30, 1996, when the GL was issued and guidance in GL 91-18 ("Information to Licensees Regarding Two NRC Inspection Manual Sections on Resolution of Degraded and Nonconforming Conditions and on Operability") suggests that degraded systems should be restored to within the original criteria during the next refueling outage.
(..a CONTACT:   Beth Wetzel. NRR
OV /15 The NEl representatives next made their formal presentation which included a restatement and clarification of the questions that were given to the NRC to address during the meeting.
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The NEl presentation materials are 3rovided as. which includes the formal questions given to the NRC prior to the meeting. The NRC staff addressed NEl's questions as each was presented.
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                                                -2                             September 5, 1997 Individual answers to each NEl question have not been provided in this meeting sumary since the staff believes the discussions in this summary and its attachments cover the basic issues of the questions.
-2 September 5, 1997 Individual answers to each NEl question have not been provided in this meeting sumary since the staff believes the discussions in this summary and its attachments cover the basic issues of the questions.
During the meeting, the staff discussed some of the issues associated with waterhamer and two phase flow. In general, plants were licensed assuming single phase flow conditions in the service water and component cooling water systems. The staff expects that licensees will make modifications as                     ,
During the meeting, the staff discussed some of the issues associated with waterhamer and two phase flow.
necessary to conform to the original system design basis, or seek NRC review               i and approval for any proposed changes to the design basis as appropriate. The staff also cautioned that some system modifications (e.g.. changing a closed   loop)may pressurized    cooling waternew introduce  system   from oneor vulnerabilities that is vented warrant      to one that is new Technical Specification requirements, and prior NRC review and ap>roval may be required.
In general, plants were licensed assuming single phase flow conditions in the service water and component cooling water systems.
Finally, the staff emphasized that evaluations of water 1 amer and two phase flow conditions must include worst-case design basis assumptions, such as-single failure considerations.
The staff expects that licensees will make modifications as necessary to conform to the original system design basis, or seek NRC review i
and approval for any proposed changes to the design basis as appropriate.
The staff also cautioned that some system modifications (e.g.. changing a closed loop) cooling water system from one that is vented to one that is pressurized may introduce new vulnerabilities or warrant new Technical Specification requirements, and prior NRC review and ap>roval may be required.
Finally, the staff emphasized that evaluations of water1 amer and two phase flow conditions must include worst-case design basis assumptions, such as-single failure considerations.
The staff discussed the use of American Society of Mechanical Engineers (ASME)
The staff discussed the use of American Society of Mechanical Engineers (ASME)
Section Ill Appendix F-criteria for the evaluation of thermal overpressure events. Appendix F provides rules for the evaluation of components for ASME Code Level D service loadings. These service loadings are typically specified for plant faulted design conditions. The staff has endorsed the use of the Appendix F criteria for operability evaluations in GL 91-18.
Section Ill Appendix F-criteria for the evaluation of thermal overpressure events.
Appendix F contains criteria for inelastic analysis of components. Licensees may be able to @monstrate the long term acceptability of some piping runs between containment isolation valves for the thermal overpressure event using the inelastic criteria of Appendix F. If licensees decide to use Appendix F criteria by adding it to their current-licensing basis and they determine that use of the criteria creates an unreviewed safety question through a 10 CFR 50.59 evaluation, then NRC prior review and approval would be required.
Appendix F provides rules for the evaluation of components for ASME Code Level D service loadings.
The staff notes that the Appedix F criteria apply only-to load combinations associated with plant faulted conditions. Licensees would have to describe the applicable load combinations used in the Appendix F evaluation and the basis for determining the applicable load combination associated with the thermal overpressure event.
These service loadings are typically specified for plant faulted design conditions. The staff has endorsed the use of the Appendix F criteria for operability evaluations in GL 91-18.
Another topic of discussion involved the a>propriate set point pressure for thermal relief valves. The staff stated tlat the set point pressure should be determined such that the applicable design criteria are not exceeded.
Appendix F contains criteria for inelastic analysis of components.
Representatives from the Electric Power Research Institute (EPRI) made a presentation on two projects (one for-the overpressurization of piping and one for waterhamer) that it is overseeing to su the technical issues identified in GL-96 06.pport The the EPRIindustry in resolving presentation is provided in Attachment 5. NEl and the staff discussed the use of the EPRI test results to verify the adequacy of piping for thermal overpressure events.
Licensees may be able to @monstrate the long term acceptability of some piping runs between containment isolation valves for the thermal overpressure event using the inelastic criteria of Appendix F.
If licensees decide to use Appendix F criteria by adding it to their current-licensing basis and they determine that use of the criteria creates an unreviewed safety question through a 10 CFR 50.59 evaluation, then NRC prior review and approval would be required.
The staff notes that the Appedix F criteria apply only-to load combinations associated with plant faulted conditions.
Licensees would have to describe the applicable load combinations used in the Appendix F evaluation and the basis for determining the applicable load combination associated with the thermal overpressure event.
Another topic of discussion involved the a>propriate set point pressure for thermal relief valves.
The staff stated tlat the set point pressure should be determined such that the applicable design criteria are not exceeded.
Representatives from the Electric Power Research Institute (EPRI) made a presentation on two projects (one for-the overpressurization of piping and one for waterhamer) that it is overseeing to su the technical issues identified in GL-96 06.pport the industry in resolving The EPRI presentation is provided in Attachment 5.
NEl and the staff discussed the use of the EPRI test results to verify the adequacy of piping for thermal overpressure events.
The staff expressed its view that it would be difficult to design a bounding
The staff expressed its view that it would be difficult to design a bounding
        -test configuration: however, the use of testing on piping configurations that A
-test configuration: however, the use of testing on piping configurations that A


3-                       sept. ember 5,1997 ing layouts might be useful.                 NEI are and representative the staff also discussedof somethe  common      plant pip' ting to verify an analytical use of tes procedure that could be used to evaluate unique plant configurations.                                     The staff considers the ute of such an approach to be reasonable.
3-sept. ember 5,1997 are representative of some common plant pip' ting to verify an analytical ing layouts might be useful.
During the meeting there was considerable discussion regarding 10 CFR 50.59 and USQs (unreviewed safety guestions) with respect to GL 96-06. The industry is concerned with the GL 95-06 issues and whether the staff considers potential resolutions of GL 96-061ssues to involve US0s or not, particularly with respect to the use of ASME Section 111 Appendix F criteria for piping loads for other than interim operability evaluations. Industry representatives went as far as to say that if lonc-term use of Appendix F criteria pipingwas          determined to susceptible          tobeoveroressurization,y a US0. the                 i would            )nstall relief      valves then request use.of         the Appendix         F criteria and remove the relief valves after use of Appendix F was granted.
NEI and the staff also discussed the use of tes procedure that could be used to evaluate unique plant configurations.
NRC policy has been that if a plant has a USQ and it shuts down, the plant cannot restart until the USQ has been reviewed and a) proved by the NRC However, some of the modifications associated with G 96-06 issues could take a considerable amount of time to design, procure, schedule,and im
The staff considers the ute of such an approach to be reasonable.
;              thereby being impractical to implement prior to the next startup.plement.                           The staff acknowledged the industry representatives' concerns with respect to USQs but
During the meeting there was considerable discussion regarding 10 CFR 50.59 and USQs (unreviewed safety guestions) with respect to GL 96-06.
'              was not able to answer their specific questions at the meeting because they were associated with policy decisions. The staff has been considering a
The industry is concerned with the GL 95-06 issues and whether the staff considers potential resolutions of GL 96-061ssues to involve US0s or not, particularly with respect to the use of ASME Section 111 Appendix F criteria for piping loads for other than interim operability evaluations.
;              possible revision to the existing policy which, among other changes, would eliminate the restriction on plant restart with a USO provided that the system structure, or component in question is operable and the applicable regulations and the technical specification requirements are being met. A final determination on this policy issue has not been reached-ORIGINAL SIGNED BY Beth A. Wetzel. Project Manager Project Directorate III 1 Division of Reactor Projects - III/IV Office of Nuclear Reactor Regulation Attachments:         1. List of Attendees
Industry representatives went as far as to say that if lonc-term use of Appendix F piping susceptible to overoressurization,y would )nstall relief valve criteria was determined to be a US0. the i
: 2. Meeting Agenda
then request use.of the Appendix F criteria and remove the relief valves after use of Appendix F was granted.
: 3. NRC Handouts
NRC policy has been that if a plant has a USQ and it shuts down, the plant cannot restart until the USQ has been reviewed and a) proved by the NRC However, some of the modifications associated with G 96-06 issues could take a considerable amount of time to design, procure, schedule,and im thereby being impractical to implement prior to the next startup.plement.
: 4. NEI Handouts
The staff acknowledged the industry representatives' concerns with respect to USQs but was not able to answer their specific questions at the meeting because they were associated with policy decisions.
: 5. EPRI Handouts c      N@         OGC         PUBLIC                   ACRs             PD# 3 1 Reading R: N     h                           b$aW                         $        l   k na pg                               K. Manoly                 J. Fair         B. McCabe DOCUMENT NAME: G:\WPDOCS\GL9606\MTGSUM.497 To receive a copy of this document, indicate in the box C= Copy w/o attachment / enclosure E= Cop _y with attachment / enclosure N = No copy                   *SEE PREVIOUS CONCURRENCE OFFICE     PM:PD31         E   LA:PD31       E     D:PD31   )       BC:SPlB       E     BC:EMEB*           E   obr /
The staff has been considering a possible revision to the existing policy which, among other changes, would eliminate the restriction on plant restart with a USO provided that the system structure, or component in question is operable and the applicable regulations and the technical specification requirements are being met.
NAME       BWetzel:db*         CJamersonk JHannonkI                   LMarsh*             RWessman                   b DATE'         NYd               9 /6 M7               9 / [97         7 /11 /97         7/9/97                 [/     /97       .
A final determination on this policy issue has not been reached-ORIGINAL SIGNED BY Beth A. Wetzel. Project Manager Project Directorate III 1 Division of Reactor Projects - III/IV Office of Nuclear Reactor Regulation Attachments:
OFFICE     (A)[M ir                 M ADT               h             /         C NAME       MSloNoM M               TMar h               RZi M DATE         F/6/97                   / [   /97 h                 /97 \
1.
List of Attendees 2.
Meeting Agenda 3.
NRC Handouts 4.
NEI Handouts 5.
EPRI Handouts N@
OGC PUBLIC ACRs PD# 3 1 Reading c
R: N h
b$aW l
k na pg K. Manoly J. Fair B. McCabe DOCUMENT NAME: G:\\WPDOCS\\GL9606\\MTGSUM.497 To receive a copy of this document, indicate in the box C= Copy w/o attachment / enclosure E= Cop _y with attachment / enclosure N = No copy
*SEE PREVIOUS CONCURRENCE OFFICE PM:PD31 E
LA:PD31 E
D:PD31 )
BC:SPlB E
BC:EMEB*
E obr /
NAME BWetzel:db*
CJamersonk JHannonkI LMarsh*
RWessman b
DATE' NYd 9 /6 M7 9 / [97 7 /11 /97 7/9/97
[/
/97 OFFICE (A)[M ir M ADT h
/
C NAME MSloNoM M TMar h RZi M DATE F/6/97
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/97 h
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OFFICIAL RECORD COPY
OFFICIAL RECORD COPY
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MEETING ATTENDEES Name                           -Oraanization L Marsh-                                 NRC G. Hubbard                               NRC G, Hammer                                 NRC K, Manoly                                 NRC-R. Weseman                               NRC B. Wetzel                                 NRC R. Lobel                                 NRC J. Fair                                   NRC J. Tatum                                 NRC C, Saadu -                               NRC-E. McKenna                               NRC S. Greco                                 Wisconsin Electric T.'Wroblewski-                           Wisconsin Electric S. Denny                                 PEC0 Nuclear R. Randels                               Comed R.-Gamberg:                               Duke Power Co.
MEETING ATTENDEES Name
D. Murphy                                 Bechtel A Singh-                                 EPRI B. Demars                                 Virginia Power T. Sutter                                 Bechtel E. May-                                   Virginia Power
-Oraanization L Marsh-NRC G. Hubbard NRC G, Hammer NRC K, Manoly NRC-R. Weseman NRC B. Wetzel NRC R. Lobel NRC J. Fair NRC J. Tatum NRC C, Saadu -
                        -D.     Stellfox                         Inside NRC P. Tamburro                               GPU Nuclear S. Mixon                                 M 'S
NRC-E. McKenna NRC S. Greco Wisconsin Electric T.'Wroblewski-Wisconsin Electric S. Denny PEC0 Nuclear R. Randels Comed R.-Gamberg:
                        - D. McGuigan                               Scientech P. Okas                                   NYPA W. Birely.                               NYPA J. del Mazo Pacific Gas & Electric-G. Davant                                 Entergy--
Duke Power Co.
T. Esselman-                             Altran Corporation S. Gosselin                               EPRI D. Modeen                             - NEl--
D. Murphy Bechtel A Singh-EPRI B. Demars Virginia Power T. Sutter Bechtel E. May-Virginia Power
J. Minichello                             Comed S, Plymaie             ,
-D. Stellfox Inside NRC P. Tamburro GPU Nuclear S. Mixon M 'S
GPU Nuclear G. Gyrkan                                 GPU Nuclear AlTACHMENT 1
- D. McGuigan Scientech P. Okas NYPA W. Birely.
NYPA J. del Mazo Pacific Gas & Electric-G. Davant Entergy--
T. Esselman-Altran Corporation S. Gosselin EPRI D. Modeen
- NEl--
J. Minichello Comed S, Plymaie GPU Nuclear G. Gyrkan GPU Nuclear AlTACHMENT 1


PROPOSED AGENDA NRC/NEI MEETING ON GL 9646 APa!L 80,1997 123g     Tggic -                                                 rib!IPONSIBLE Ran
PROPOSED AGENDA NRC/NEI MEETING ON GL 9646 APa!L 80,1997 rib!IPONSIBLE 123g Tggic -
: 1.     Welcomo and Opening Rs. marks                           NRC NEI
Ran 1.
: 2.     GL 96 06 Suhmittah: Status and Observations             WRC
Welcomo and Opening Rs. marks NRC NEI 2.
: 3.  -
GL 96 06 Suhmittah: Status and Observations WRC GL 96 06: Questions and Responnes NEI 3.
GL 96 06: Questions and Responnes                     -  NEI NRC
NRC 4.
: 4.     EPRI GL 96 06 programs on Over Pressurization and         EPRI Waterhammer (Tentative)
EPRI GL 96 06 programs on Over Pressurization and EPRI Waterhammer (Tentative) 5.
: 5.     Concluding Remarks                                       NRC NEI
Concluding Remarks NRC NEI 6.
: 6.     Adjournment                       .
Adjournment O
O e
e e
e                                                                                     -
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S 9
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4 9
1 Attachment 2
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                                  . MEETING WITH XEI REGARDING GEXERIC LETTER 96-06 APRIL 30,1997 GL 96-06, " ASSURANCE OF EQUIPMENT OPERABILITY AND CONTAINMENT INTEGRITY DURING DESIGN-BASIS ACCIDENT CONDITIONS" TECHNICAL BRANCHES: SPLB, EMEB AND SCSB LEAD PM: BETH WETZEL 5
. MEETING WITH XEI REGARDING GEXERIC LETTER 96-06 APRIL 30,1997 GL 96-06, " ASSURANCE OF EQUIPMENT OPERABILITY AND CONTAINMENT INTEGRITY DURING DESIGN-BASIS ACCIDENT CONDITIONS" TECHNICAL BRANCHES: SPLB, EMEB AND SCSB LEAD PM: BETH WETZEL 5
5                                                           -
5 8
8


                                                                                            ~
~
PRESENTATION
PRESENTATION
  +               OVERVIEW OF GENERIC LErrER - BETH WETZEL
+
  +               INDUSTRY RESPONSES - CORETTA SAADU
OVERVIEW OF GENERIC LErrER - BETH WETZEL
  +               CONTAINMENT FAN COOLER ISSUES - JIM TATUM
+
  +               THERMAL OVERPRESSURE - KAMAL MANOLY
INDUSTRY RESPONSES - CORETTA SAADU
  +               NEI DISCUSSION QUESTIONS - ALL 2
+
CONTAINMENT FAN COOLER ISSUES - JIM TATUM
+
THERMAL OVERPRESSURE - KAMAL MANOLY
+
NEI DISCUSSION QUESTIONS - ALL 2


SCOPE OF GL 96-06 (1) POTENTIAL WATERHAMMER IN THE COOLING WATER SYSTEMS SERVING THE CONTAINMENT AIR COOLERS DURING A LOSS-OF-COOLANT ACCIDENT (LOCA) OR A MAIN STEAM LINE BREAK (MSLB) o DIABLO CANYON o HADDEM NECK (2) POTENTIAL TWO-PHASE FLOW IN THE COOLING WATER SYSTEMS SERVING THE CONTAINMENT AIR COOLERS DURING POSTULATED LOCA AND MSLB SCENARIOS o PT. BEACH o SALEM (3) THERMALLY INDUCED OVERPRESSURIZATION OF       ~
SCOPE OF GL 96-06 (1)
ISOLATED PIPING INSIDE CONTAINMENT o BEAVER VALLEY                                     j o MAINE YANKEE 3
POTENTIAL WATERHAMMER IN THE COOLING WATER SYSTEMS SERVING THE CONTAINMENT AIR COOLERS DURING A LOSS-OF-COOLANT ACCIDENT (LOCA) OR A MAIN STEAM LINE BREAK (MSLB) o DIABLO CANYON o
HADDEM NECK (2)
POTENTIAL TWO-PHASE FLOW IN THE COOLING WATER SYSTEMS SERVING THE CONTAINMENT AIR COOLERS DURING POSTULATED LOCA AND MSLB SCENARIOS o
PT. BEACH o
SALEM (3)
THERMALLY INDUCED OVERPRESSURIZATION OF ISOLATED PIPING INSIDE CONTAINMENT
~
o BEAVER VALLEY j
o MAINE YANKEE 3


REASONS FOR ISSUANCE OF GENERIC LEITER
REASONS FOR ISSUANCE OF GENERIC LEITER
!      + THE PROBLEMS IDENTIFIED IN THE LEITER ARE COMPLIANCE ISSUES     .
+
      + THESE PROBLEMS WERE IDENTIFIED AT SEVERAL PLANTS AND ALL PLANTS ARE POTENTIALLY SUSCEPTIBLE
THE PROBLEMS IDENTIFIED IN THE LEITER ARE COMPLIANCE ISSUES
      + TWO OPERATING PLANTS SHUT DOWN BECAUSE OF THE ISSUES AND HARDWARE MODIFICATIONS WERE REQUIRED
+
      + NRC WAS DEALING WITH THESE ISSUES ON A CASE-BY-CASE BASIS 4
THESE PROBLEMS WERE IDENTIFIED AT SEVERAL PLANTS AND ALL PLANTS ARE POTENTIALLY SUSCEPTIBLE
+
TWO OPERATING PLANTS SHUT DOWN BECAUSE OF THE ISSUES AND HARDWARE MODIFICATIONS WERE REQUIRED
+
NRC WAS DEALING WITH THESE ISSUES ON A CASE-BY-CASE BASIS 4


                                                    ~
~
REQUESTED INFORMATION l   +   GL ISSUED SEPTEMBER 30,1996
REQUESTED INFORMATION l
[   + 30 DAY RESPONSES
+
      + ~ 120 DAY RESPONSES DUE JANUARY 28,1997 o IF SUSCEPTIBLE o ACTIONS TAKEN o   BASIS FOR OPERABILITY o   CORRECTIVE ACTIONS AND SCHEDULE 5
GL ISSUED SEPTEMBER 30,1996
[
+
30 DAY RESPONSES
+
~ 120 DAY RESPONSES DUE JANUARY 28,1997 o
IF SUSCEPTIBLE o
ACTIONS TAKEN o
BASIS FOR OPERABILITY o
CORRECTIVE ACTIONS AND SCHEDULE 5
l
l


                                                                ~
~
REVIEW PLAN
REVIEW PLAN
                + TIMELINE
+
                    ~'
TIMELINE SCREENING REVIEW
SCREENING REVIEW o   ISSUE MAJORITY OF SEs BY 18 MONTHS o   CONSIDERING TI
~'
                + REVIEW RESPONSIBILITIES SPLB - CFCU ISSUES EMEB - OVERPRESSURIZATION OF PIPING ISSUES SCSB - CONTAINMENT PARAMETERS 6
o ISSUE MAJORITY OF SEs BY 18 MONTHS o
CONSIDERING TI
+
REVIEW RESPONSIBILITIES SPLB - CFCU ISSUES EMEB - OVERPRESSURIZATION OF PIPING ISSUES SCSB - CONTAINMENT PARAMETERS 6


a
a
  ~
~
PRELIMINARY GL RESPONSE  
PRELIMINARY GL RESPONSE  


==SUMMARY==
==SUMMARY==
 
+
+  7 PLANTS NOT SUSCEPTIBLE TO ANY OF THE ISSUES
7 PLANTS NOT SUSCEPTIBLE TO ANY OF THE ISSUES
+   2 PLANTS SUSCEPTIBLE ONLY TO WATERHAMMER AND TWO PHASE FLOW                                           ,
+
+   45 PLANTS SUSCEPTIBLE ONLY TO THERMAL OVERPRESSURIZATION
2 PLANTS SUSCEPTIBLE ONLY TO WATERHAMMER AND TWO PHASE FLOW
+   51 PLANTS SUSCEPTIBLE TO BOTH CONTAINMENT FAN COOLER ISSUES AND THERMAL OVERPRESSURIZATION 7
+
45 PLANTS SUSCEPTIBLE ONLY TO THERMAL OVERPRESSURIZATION
+
51 PLANTS SUSCEPTIBLE TO BOTH CONTAINMENT FAN COOLER ISSUES AND THERMAL OVERPRESSURIZATION 7


OUTLIERS / STAFF FOLLOWUP ACTIONS i
OUTLIERS / STAFF FOLLOWUP ACTIONS i
,!      +   ADDITIONAL SUBMIrrALS:
+
i O JUNE SUBMITTAL - 6 PLANTS o JULY SUBMIrrAL - 7 PLANTS o AUGUST SUBMITTAL - 3 PLANTS o OCTOBER AND BEYOND - 5 PLANTS
ADDITIONAL SUBMIrrALS:
        +   MODIFICATION SCHEDULES EXTENDING INTO SPRING 1998 AND BEYOND: 7 PLANTS 8
i O
JUNE SUBMITTAL - 6 PLANTS o
JULY SUBMIrrAL - 7 PLANTS o
AUGUST SUBMITTAL - 3 PLANTS o
OCTOBER AND BEYOND - 5 PLANTS
+
MODIFICATION SCHEDULES EXTENDING INTO SPRING 1998 AND BEYOND: 7 PLANTS 8


                                                                  ~
~
WATER HAMMER /TWO-PHASE FLOW ISSUES
WATER HAMMER /TWO-PHASE FLOW ISSUES
                  + ANALYTICAL ACCEPTANCE OF THE CONDITION o NEW ANALYSIS / METHODOLOGY / UNCERTAINTIES o NOT PREVIOUSLY REVIEWED / ACCEPTED BY NRC
+
                  + SYSTEM MODIFICATIONS o SATISFY DESIGN BASIS o NEW VULNERABILITIES & FAILURE MODES o TS CONSIDERATIONS l
ANALYTICAL ACCEPTANCE OF THE CONDITION o
                  + SINGLE FAILURE /FMEA CONSIDERATIONS o WORST-CASE / BOUNDING CONDITIONS
NEW ANALYSIS / METHODOLOGY / UNCERTAINTIES o
                  + POST-ACCIDENT USE OF NON-ESSENTIAL CFCs
NOT PREVIOUSLY REVIEWED / ACCEPTED BY NRC
                  + IMPACT ON PLANT OPERATION o USQ DETERMINATION / LICENSE SUBhBTTAL o COMPLEX REVIEW / LIMITED RESOURCFJ 9
+
SYSTEM MODIFICATIONS o
SATISFY DESIGN BASIS o
NEW VULNERABILITIES & FAILURE MODES o
TS CONSIDERATIONS l
+
SINGLE FAILURE /FMEA CONSIDERATIONS o
WORST-CASE / BOUNDING CONDITIONS
+
POST-ACCIDENT USE OF NON-ESSENTIAL CFCs
+
IMPACT ON PLANT OPERATION o
USQ DETERMINATION / LICENSE SUBhBTTAL o
COMPLEX REVIEW / LIMITED RESOURCFJ 9


THERMAL OVERPRESSURIZATION
THERMAL OVERPRESSURIZATION
  +             OVERPRESSURIZATION OF ISOLATED PIPING IS ADDRESSED IN ANSI B31.1 AND ASME DESIGN CODES
+
  +             AFFECTED PIPING RANGES FROM 3/8-INCH TO 20-INCH O.D.
OVERPRESSURIZATION OF ISOLATED PIPING IS ADDRESSED IN ANSI B31.1 AND ASME DESIGN CODES
  +           SOME MEMBERS OF THE ASME CODE DISAGREE THAT THE PHENOMENON IS A FAULTED DESIGN CONDITION
+
  +           PROPOSED ASME CODE CHANGE TO DECLARE AFFECTED PIPING SYSTEMS MEET THE CODE WITHOUT FURTHER ANALYSIS FOR TEMPERATURE INCREASE UP TO 250 F 10 1
AFFECTED PIPING RANGES FROM 3/8-INCH TO 20-INCH O.D.
+
SOME MEMBERS OF THE ASME CODE DISAGREE THAT THE PHENOMENON IS A FAULTED DESIGN CONDITION
+
PROPOSED ASME CODE CHANGE TO DECLARE AFFECTED PIPING SYSTEMS MEET THE CODE WITHOUT FURTHER ANALYSIS FOR TEMPERATURE INCREASE UP TO 250 F 10 1


THERMAL OVERPRESSURIZATION (cont'd) a
THERMAL OVERPRESSURIZATION (cont'd) a
          + STAFF DOES NOT ENDORSE PROPOSED CHANGE SINCE IT IS BASED ON SIMPLISTIC ANALYSIS OF IDEAL PIPING CONFIGURATION
+
          + APPENDIX F TO SECTION III OF ASME CODE EMPLOYED IN SOME OPERABILITY DETERMINA-TIONS. LICENSE AMENDMENT MAY BE REQUIRED FOR LONG-TERM RESOLUTION AT SOME FACILITIES
STAFF DOES NOT ENDORSE PROPOSED CHANGE SINCE IT IS BASED ON SIMPLISTIC ANALYSIS OF IDEAL PIPING CONFIGURATION
          + PROPOSED SOLUTIONS INCLUDE THERMAL RELIEF I
+
APPENDIX F TO SECTION III OF ASME CODE EMPLOYED IN SOME OPERABILITY DETERMINA-TIONS. LICENSE AMENDMENT MAY BE REQUIRED FOR LONG-TERM RESOLUTION AT SOME FACILITIES
+
PROPOSED SOLUTIONS INCLUDE THERMAL RELIEF I
VALVE, RUPTURE DISK WITH EXPANSION CHAMBER, DRAINAGE OF LINE DURING NORMAL OPERATION, PERFORM INELASTIC ANALYSIS OF PIPING (APPLICATION OF APPENDIX F), FAILURE HAS NO SAFETY CONSEQUENCES, AND DETAILED HEAT TRANSFER ANALYSIS TO DEMONSTRATE THAT PRESSURE DOES NOT EXCEED ALLOWABLE 11 1
VALVE, RUPTURE DISK WITH EXPANSION CHAMBER, DRAINAGE OF LINE DURING NORMAL OPERATION, PERFORM INELASTIC ANALYSIS OF PIPING (APPLICATION OF APPENDIX F), FAILURE HAS NO SAFETY CONSEQUENCES, AND DETAILED HEAT TRANSFER ANALYSIS TO DEMONSTRATE THAT PRESSURE DOES NOT EXCEED ALLOWABLE 11 1


P   .
P INDUSTRY -- NRC STAFF MEETING ON GENERIC LETTER 96-06 l
INDUSTRY -- NRC STAFF MEETING ON GENERIC LETTER 96-06 l
presented by:
presented by:
NEl GL 96-06 ISSUE TASK FORCE Dave Modeen, NEl Raub Randels, COMED John Minichiello, COMED Steve Greco, WEPCo Avtar Singh, EPRI April 30,1997 Rockville, MD 1
NEl GL 96-06 ISSUE TASK FORCE Dave Modeen, NEl Raub Randels, COMED John Minichiello, COMED Steve Greco, WEPCo Avtar Singh, EPRI April 30,1997 Rockville, MD hi 1
hi ATTACHMENT 4
ATTACHMENT 4


MEETING OBJECTIVES Discuss status of licensee responses to GL 96-06 and NRC staff concerns and resolution plan
MEETING OBJECTIVES Discuss status of licensee responses to GL 96-06 and NRC staff concerns and resolution plan
        - Generic Communication?
- Generic Communication?
        - Formal letters to licensees? When?
- Formal letters to licensees? When?
        - Other?
- Other?
l Obtain clarification on NRC staff views regarding application of ASME Section 111, B31.1 and B31.7 requirements and guidance in resolving nonconformances identified c uring licensee review of Generic Letter 96-06 issues.
l Obtain clarification on NRC staff views regarding application of ASME Section 111, B31.1 and B31.7 requirements and guidance in resolving nonconformances identified c uring licensee review of Generic Letter 96-06 issues.


MEETING OBJECTIVES (contd.)
MEETING OBJECTIVES (contd.)
Obtain NRC staff views on the scope of, and schedule of, any licensee-specific and EPRI-sponsored collaborative experimental and analytical efforts to assess:
Obtain NRC staff views on the scope of, and schedule of, any licensee-specific and EPRI-sponsored collaborative experimental and analytical efforts to assess:
          - Piping and valve integrity during overpressurization caused by LOCA
- Piping and valve integrity during overpressurization caused by LOCA
          - Conservatisms in bounding waterhammer i
- Conservatisms in bounding waterhammer i
analyses and their impact on fan cooler system operability evaluations For example, if a plant performs a waterhammer Loss of Offsite Power test and if results show that mocs are required, can these mods be postponed to the following outage, provided that system meets operability?
analyses and their impact on fan cooler system operability evaluations For example, if a plant performs a waterhammer Loss of Offsite Power test and if results show that mocs are required, can these mods be postponed to the following outage, provided that system meets operability?
s h              i
h s
i


QUESTION ONE A number of NRC staff communications on near and long term use of ASME Section 111 Appendix F," Analysis Methodology & Limits," have been provided to industry, but some confusion remains with regards to its use. The NRC staff is requested to provide clarification about the following:
QUESTION ONE A number of NRC staff communications on near and long term use of ASME Section 111 Appendix F," Analysis Methodology & Limits," have been provided to industry, but some confusion remains with regards to its use. The NRC staff is requested to provide clarification about the following:
      - If Appendix F is within a plant's licensing basis, is it acceptable for use as a long-term, over-pressurization solution?
- If Appendix F is within a plant's licensing basis, is it acceptable for use as a long-term, over-pressurization solution?
      - If the answer to (a)is yes, can a plant without Appendix F as a part of its licensing basis restart from a planned or unplanned outage while pursuing a license amendment to make Appendix F a part of the plant's licensing basis?
- If the answer to (a)is yes, can a plant without Appendix F as a part of its licensing basis restart from a planned or unplanned outage while pursuing a license amendment to make Appendix F a part of the plant's licensing basis?
      - If a plant is processing a licensing change to add Appendix F to its licensing basis, what types of considerations should be included in the submittal?
- If a plant is processing a licensing change to add Appendix F to its licensing basis, what types of considerations should be included in the submittal?
      - If a plant has committed to a schedule for making modifications and/or procedural changes as a long-term over-pressurization solution, is it permitted, prior to making the scheduled modification, to pursue a license amendment to make Appendix F a part of the o' ant's licensina 3 asis?
- If a plant has committed to a schedule for making modifications and/or procedural changes as a long-term over-pressurization solution, is it permitted, prior to making the scheduled modification, to pursue a license amendment to make Appendix F a part of the o' ant's licensina 3 asis?
4                  cd,i
cd,i 4
  -      __ ____ rm_r_ __ _ __ _ . --
__ ____ rm_r_ __ _ __ _.


QUESTIONS (contd.)
QUESTIONS (contd.)
Line 193: Line 301:
the use of ASME lil, Appendix F as a licensing basis for piping sys+"ms designed to ANSI B31.17 QUESTION THREE Is the following considered an acceptable justification for evaluating the failure mode effect of a stuck open relief valve, occurring post accident, located between two closed containment isolations valves?
the use of ASME lil, Appendix F as a licensing basis for piping sys+"ms designed to ANSI B31.17 QUESTION THREE Is the following considered an acceptable justification for evaluating the failure mode effect of a stuck open relief valve, occurring post accident, located between two closed containment isolations valves?
The reason a relief valve opens is because the pressure has increased between the two containment isolation valves. Consequently, due to the tightness of the subject isolation valves, the opening of the relief valve confirms the containment integrity is provided by the isolation valves and associated piping.
The reason a relief valve opens is because the pressure has increased between the two containment isolation valves. Consequently, due to the tightness of the subject isolation valves, the opening of the relief valve confirms the containment integrity is provided by the isolation valves and associated piping.
s hi
hi s


QUESTION FOUR Set Pressure (LOCA ONLYh The design codes used by licensees are silent on " provisions" to be taken for relieving the excess pressure. The 1967 edition of ANSI B31.1 does not address set pressure requirements. Newer editions do by reference to ASME Section Vlli, paragraphs UG-126 through UG-133. The newer versions of ASME Section 111 (W 1979 and forward) also do not address set pressure / relief capacity for faulted conditions.
QUESTION FOUR Set Pressure (LOCA ONLYh The design codes used by licensees are silent on " provisions" to be taken for relieving the excess pressure. The 1967 edition of ANSI B31.1 does not address set pressure requirements. Newer editions do by reference to ASME Section Vlli, paragraphs UG-126 through UG-133. The newer versions of ASME Section 111 (W 1979 and forward) also do not address set pressure / relief capacity for faulted conditions.
Line 203: Line 311:
The NRC staff is also requested to respond to the following specific questions:
The NRC staff is also requested to respond to the following specific questions:
ANSI B31.1 Applications:
ANSI B31.1 Applications:
            - Does the NRC staff agree that it is permissible to use a relief valve set pressure equal to 1.09 Pa, where Pa equals the pipe or valve rated pressure, assuming all components subjected to that pressure are shown acceptable under the faulted condition l               loading?
- Does the NRC staff agree that it is permissible to use a relief valve set pressure equal to 1.09 Pa, where Pa equals the pipe or valve rated pressure, assuming all components subjected to that pressure are shown acceptable under the faulted condition l
loading?
ASME Code Applications:
ASME Code Applications:
            - Does the NRC staff agree it is permissible to use a relief valve set pressure equal to 0.91 P*, where P*
- Does the NRC staff agree it is permissible to use a relief valve set pressure equal to 0.91 P*, where P*
equals the lower of 2 Pa (Pipe) or 1.5 Pa (Valve),
equals the lower of 2 Pa (Pipe) or 1.5 Pa (Valve),
assuming all components subjected to that pressure are shown acceptable under the faulted condition loading?
assuming all components subjected to that pressure are shown acceptable under the faulted condition loading?
            - The basis of the 1.09 and 0.91 factors is a 10%
- The basis of the 1.09 and 0.91 factors is a 10%
accumulation, bringing the maximum pressure to 1.09 x 1.1 = 1.2 Pa (permitted by B31.1 and Section Vill) and 1.1 (.91) = P* (permitted by Section Ill).
accumulation, bringing the maximum pressure to 1.09 x 1.1 = 1.2 Pa (permitted by B31.1 and Section Vill) and 1.1 (.91) = P* (permitted by Section Ill).
7                             I
7 I


QUESTlONS QUESTION FIVE If waterhammer and/or two-phase flow were not specifically addressed during initial plant / system design and licensing, can an analytical approach be used without introducing an unreviewed safety question (USQ) per 10CFR50.59, provided that the analysis shows that applicable code allowables are met once the necessary piping support modifications have been installed?
QUESTlONS QUESTION FIVE If waterhammer and/or two-phase flow were not specifically addressed during initial plant / system design and licensing, can an analytical approach be used without introducing an unreviewed safety question (USQ) per 10CFR50.59, provided that the analysis shows that applicable code allowables are met once the necessary piping support modifications have been installed?
QUESTION SIX If tests confirm that piping and valves exposed to an external temperature increase of up to 250 F are not challenged structurally, will the NRC staff consider accepting the test results as a basis for endorsing an ASME Code Case (relief protection is not necessary when the temperature increase is less than or equal to 250 F) being developed?
QUESTION SIX If tests confirm that piping and valves exposed to an external temperature increase of up to 250 F are not challenged structurally, will the NRC staff consider accepting the test results as a basis for endorsing an ASME Code Case (relief protection is not necessary when the temperature increase is less than or equal to 250 F) being developed?
8 hi
hi 8


  '.                                                                                      l l'
l' EPRl/NPG EPRl/ Industry Collaborative Project 4
EPRl/NPG 4
to Support Resolution of GL 96-06 Technical issues i
EPRl/ Industry Collaborative Project to Support Resolution of GL 96-06 Technical issues i
l Avtar Singh S. Gosselin Mati Merilo H.T. Tang NRC/NEl/ industry Meeting on GL 96-06 Rockville, MD April 30,1997
l Avtar Singh S. Gosselin Mati Merilo H.T. Tang NRC/NEl/ industry Meeting on GL 96-06 Rockville, MD April 30,1997


===Background===
===Background===
EPRI project (1994-96) on waterhammer prevention, mitigation, and accommodation
EPRI project (1994-96) on waterhammer prevention, mitigation, and accommodation
              - EPRI reports: TR 106438 and NP 6766 EPRI analysis efforts (early 1996) to predict fan cooler system boiloff and voiding Preliminary plan of the EPRl/ Industry collaborative project presented to NRC on December 19,1996 Two collaborative projects to address piping overpressurization and waterhammer/two phase flow issues
- EPRI reports: TR 106438 and NP 6766 EPRI analysis efforts (early 1996) to predict fan cooler system boiloff and voiding Preliminary plan of the EPRl/ Industry collaborative project presented to NRC on December 19,1996 Two collaborative projects to address piping overpressurization and waterhammer/two phase flow issues
              - Two industry meetings (2/25 and 4/9,1997) to review scope of testing and analysis ATTACHMENT 5   '1
- Two industry meetings (2/25 and 4/9,1997) to review scope of testing and analysis ATTACHMENT 5
'1


l EPRuNeo Overpressurization of isolated Piping Sections Under Postulated LOCA Objectives
l EPRuNeo Overpressurization of isolated Piping Sections Under Postulated LOCA Objectives
Line 234: Line 343:
* Phase 1 focuses on scoping (simple' pipe) tests and analysis to show piping and valve integrity evaluation meeting Appendix F criteria Phase 2 provides more quantitative (typical in-plant configuration) tests and evaluations for generic applications by utilities SARA EPRl/NPG Overpressurization of isolated Piping Sections Under Postulated LOCA Phase 1
* Phase 1 focuses on scoping (simple' pipe) tests and analysis to show piping and valve integrity evaluation meeting Appendix F criteria Phase 2 provides more quantitative (typical in-plant configuration) tests and evaluations for generic applications by utilities SARA EPRl/NPG Overpressurization of isolated Piping Sections Under Postulated LOCA Phase 1
* Utility survey on piping configurations and containment temperature profiles
* Utility survey on piping configurations and containment temperature profiles
                = 3 sample piping segments of different D/t (i.e. sch 10,80
= 3 sample piping segments of different D/t (i.e. sch 10,80
                    & 160)
& 160)
* Bounding steady state temperature profile
* Bounding steady state temperature profile
* Pressure, temperature and piping response history measurement Appendix F evaluation based on measured pressure loading
* Pressure, temperature and piping response history measurement Appendix F evaluation based on measured pressure loading
                    - 3 piping segments
- 3 piping segments
                      - 2 typical valves: gate and globe 3
- 2 typical valves: gate and globe 3


                                                                                                                  .. 4 o   6 4
4 6
l EPRl/NPG                                                               -
o 4
i Overpressurization of Isolated Piping Sections Under Postulated LOCA Phase 2 Example of Expanded Test Matrix Configuration         Material       T1"           T2"       Coupon                     i Group
EPRl/NPG i
* CG1                   CS/SS     1             1             1 CG2                   CS/SS     1             1             1                     l CG3                   CS/SS     1             1             1                     i CG4                   CS/SS     1             1             1 CG6                   CS/SS     1             1             1 CG6                   CS/SS     1             1     ,
Overpressurization of Isolated Piping Sections Under Postulated LOCA Phase 2 Example of Expanded Test Matrix Configuration Material T1" T2" Coupon i
Group
* CG1 CS/SS 1
1 1
CG2 CS/SS 1
1 1
CG3 CS/SS 1
1 1
i CG4 CS/SS 1
1 1
CG6 CS/SS 1
1 1
CG6 CS/SS 1
1 1
Specific test configurations designed to address geometric leeues identifd in the Phase 1 survey T1 & T2 represent bounding steady state and transient temperature profiles SARA
-, r EPRl/NPG Overpressurization of Isolated Piping Sections Under Postulated LOCA Phase 2 (cont.)
* Appendix F evaluation Valve leakage evaluation If leakage potential exists, test to demonstrate leakage and ability to reseal M ate rial 11 T2 Straight Pipe with Globe Valve CS or SS i
1 Straight Pipe with Gate Valve CS or SS 1
1 1
1 1
Specific test configurations designed to address geometric leeues identifd in the Phase 1 survey
SAM 4
                        "  T1 & T2 represent bounding steady state and transient temperature profiles SARA
                -, r EPRl/NPG Overpressurization of Isolated Piping Sections Under Postulated LOCA Phase 2 (cont.)
* Appendix F evaluation Valve leakage evaluation If leakage potential exists, test to demonstrate                                    .
l leakage and ability to reseal M ate rial  11      T2 Straight Pipe with Globe Valve        CS or SS      i      1 Straight Pipe with Gate Valve        CS or SS      1      1 I
1 4
SAM l
1
1
                                                                                                                      )
)
4
4
_ ::'' _ _ _ _ _ - . .        ~~: :
~~: :


t EPRl/NPG Overpressurization of isolated Piping Sections Under Postulated LOCA Jochnical Products Appendix F analysis methodology Actual safety margins by comparison of analysis and test data Analysis and evaluation guidelines Screening criteria for analysis and evaluation of afiected in-plant systems SARA
t EPRl/NPG Overpressurization of isolated Piping Sections Under Postulated LOCA Jochnical Products Appendix F analysis methodology Actual safety margins by comparison of analysis and test data Analysis and evaluation guidelines Screening criteria for analysis and evaluation of afiected in-plant systems SARA
                        - .m. .
-.m..
EPRt/NPG Overpressurization of Isolated Piping Sections Under Postulated LOCA Deliverables Technical report
EPRt/NPG Overpressurization of Isolated Piping Sections Under Postulated LOCA Deliverables Technical report
                                  - Testing report including testing data
- Testing report including testing data
                                  - Analysis guidelines
- Analysis guidelines
                                  - Screening criteria
- Screening criteria
                                  - Inelastic models
- Inelastic models
                                  - Appendix F calculations
- Appendix F calculations
                                  - LonD-term integrity criteria
- LonD-term integrity criteria
                              - Quick look summary reports
- Quick look summary reports
* Input to ASME code committees 5   \
* Input to ASME code committees 5
\\


EPRl/NPG Overpressurization of isolated Piping Sections Under Postulated LOCA Preliminary Schedule
EPRl/NPG Overpressurization of isolated Piping Sections Under Postulated LOCA Preliminary Schedule
* Phase 1: 2 months after Phase i start
* Phase 1: 2 months after Phase i start
* Phase 2: 8 months after Phase 2 start
* Phase 2: 8 months after Phase 2 start
              . Final technical report: 12 months after Phase 2 start l   _ _ . .
. Final technical report: 12 months after Phase 2 start l
EPRl/NPG Overpressurization of Isolated Piping l
EPRl/NPG Overpressurization of Isolated Piping Sections Under Postulated LOCA l
Sections Under Postulated LOCA Proposed NRC -Industry Meetinas -
Proposed NRC -Industry Meetinas -
                + Review Phase 1 Results (7/97)
+ Review Phase 1 Results (7/97)
Phase 2 Planning Meeting with the Staff Phase 2 Progress Review Meeting with Staff
Phase 2 Planning Meeting with the Staff Phase 2 Progress Review Meeting with Staff
* Review Phase 2 Results and Conclusions (7/98)                 -
* Review Phase 2 Results and Conclusions (7/98) 6
6


apRvNeo Waterhammer Assessment
apRvNeo Waterhammer Assessment
                                      . For some plants, waterhammer is expected to occur in the containment air cooler cooling water system during a LOCA/ LOOP scenario
. For some plants, waterhammer is expected to occur in the containment air cooler cooling water system during a LOCA/ LOOP scenario
                                      . The severity of waterhammer, in terms of the loads imposed on the piping system, is not well understood
. The severity of waterhammer, in terms of the loads imposed on the piping system, is not well understood
                                    . Analytical methods can give overly conservative results EPRl/NPo Potential Mitigative Factoru for Waterhammer Loads
. Analytical methods can give overly conservative results EPRl/NPo Potential Mitigative Factoru for Waterhammer Loads
                                        . Low system pressure results in small driving forces
. Low system pressure results in small driving forces
                                        . Bubble vapor pressure opposes acceleration of water slug
. Bubble vapor pressure opposes acceleration of water slug
                                        . Heatup and possible bolln.g in the water slugs prior to impact
. Heatup and possible bolln.g in the water slugs prior to impact
                                        . Air coming out of solution
. Air coming out of solution
                                              - cushioning
- cushioning
                                              - sound speed
- sound speed
                                              - pressure wave absorption 7
- pressure wave absorption 7


                                                                                              ~.
~.
EPRl/NPG General Project Objectives 4
EPRl/NPG General Project Objectives
                                    . Relax conservatisms related to developing thermal-hydraulic forcing functions
. Relax conservatisms related to developing 4
                                    . Provide thermal hydraulle boundary and initial conditions for waterhammer analysis
thermal-hydraulic forcing functions
                                    . Assess fan cooler operability with two-phase flow and its ability to transition to design flow conditions SARA EPRl/NPG Proposed Experimental Objectives
. Provide thermal hydraulle boundary and initial conditions for waterhammer analysis
. Assess fan cooler operability with two-phase flow and its ability to transition to design flow conditions SARA EPRl/NPG Proposed Experimental Objectives
: 1. Determine the external and internal heat transfer coefficients for the fan cooler coils.
: 1. Determine the external and internal heat transfer coefficients for the fan cooler coils.
: 2. Determine the rate and extent of voiding in the fan cooler unit and headers during the LOCA LOOP transient.
: 2. Determine the rate and extent of voiding in the fan cooler unit and headers during the LOCA LOOP transient.
Line 305: Line 426:


t EPRl/NPO Proposed Experimental Objectives (cont'd.)
t EPRl/NPO Proposed Experimental Objectives (cont'd.)
i I                   5. Characterize the effects of the pump startup translents.
i I
: 5. Characterize the effects of the pump startup translents.
: 6. Characterize the effects of the parallel channels.
: 6. Characterize the effects of the parallel channels.
: 7. Characterize the effects of different header geometries.
: 7. Characterize the effects of different header geometries.
Line 311: Line 433:
: 9. Determine the effects of system components such as throttling valves, surge tanks, loop seals, check valves etc.
: 9. Determine the effects of system components such as throttling valves, surge tanks, loop seals, check valves etc.
SARA EPRl/NPG Proposed Analysis Objectives
SARA EPRl/NPG Proposed Analysis Objectives
                              . Provide a method to apply the results of a testing program to prototypic conditions
. Provide a method to apply the results of a testing program to prototypic conditions
                                      - e.g. recommendations for heat transfer and fluid flow correlations, as well as system nodalization
- e.g. recommendations for heat transfer and fluid flow correlations, as well as system nodalization
                              . Support development of experimental facility design, scaling, test definition, and prioritization
. Support development of experimental facility design, scaling, test definition, and prioritization of the test matrix through transient analysis and sensitivity studies.
,                                    of the test matrix through transient analysis and sensitivity studies.
SARA 9
SARA 9


4 4 Conceptual Test Facility OPEN LocP                                 CLOSED LOOP J4i             it                         ;4i                 it IJ                   Lr               1.{                           ;f-1                   F                       l                     F r                   4                       r                     4
4 4 Conceptual Test Facility OPEN LocP CLOSED LOOP J4i it
              %            -p,EJ_ ...             $                           aE w
;4i it IJ Lr 1.{
l       q
;f-1 F
                                                                              ,,  g EPRl/NPG Deliverables
l F
                . Validated thermal-hydraulic models/ correlations applicable to Containment Fan Cooler calculations
r 4
                . Recommendations / guidance on how to set up fan cooler system calculations for thermal-hydraulic codea
r 4
                  . Experimentaldata SARA 10
-p,EJ_... $
aE w
l q
g EPRl/NPG Deliverables
. Validated thermal-hydraulic models/ correlations applicable to Containment Fan Cooler calculations
. Recommendations / guidance on how to set up fan cooler system calculations for thermal-hydraulic codea
. Experimentaldata SARA 10


~
~
EPRIMPG Status l
EPRIMPG Status l
        . Participation interest survey
. Participation interest survey
            - Approximately twelve to fifteen utilities for the overpressurization project
- Approximately twelve to fifteen utilities for the overpressurization project
            - Approximately four to six utilities for the waterhammer project
- Approximately four to six utilities for the waterhammer project
        . Contractual agreements for funding authorization sent to interested utilities
. Contractual agreements for funding authorization sent to interested utilities
            - Approval contingent on resuhs being timely in addressing regulatory issues
- Approval contingent on resuhs being timely in addressing regulatory issues
        . Anticipated start date - May 1997 SARA e
. Anticipated start date - May 1997 SARA e
11
11


                                                                                                .    .R
.R
                                                                                                      .- 1 EPRI INDUSTRY COLLACORATIVE PROJECT                                                   4 '
.- 1 EPRI INDUSTRY COLLACORATIVE PROJECT 4 '
l TO SUPPORT RESOLUTION OF GL 96-06                                                     .,  ,
l TO SUPPORT RESOLUTION OF GL 96-06 OVERPRESSURI7sATION OF ISOLATED PIPING UTII.ITY SURVEY Piping Configurations Valve Descriptions Containment Temperature Profiles V
OVERPRESSURI7sATION OF ISOLATED PIPING UTII.ITY SURVEY Piping Configurations Valve Descriptions Containment Temperature Profiles V                                                                       V Prototypical                                                     Hounding Containment Configuration Groups                                                   Temperature Profiles Piping & Valves                                                         PWR Designs BWR Designs PliASE 1 TESTING 3 Straight Pipe Segment
V Prototypical Hounding Containment Configuration Groups Temperature Profiles Piping & Valves PWR Designs BWR Designs PliASE 1 TESTING 3 Straight Pipe Segment Tests a
                              >                Tests Steady State Bounding a
Steady State Bounding Temperature Profile V
Temperature Profile V
Burst?
Burst?             Yes     > Stop No Y
Yes
> Stop No Y
PIPE LOADS P(t), T(t), E(t)
PIPE LOADS P(t), T(t), E(t)
If                                                                 V PIPE INTEGRITY                                               VALVE INTEGRITY Scoping Appendix F Evaluation                                 Scoping Appendix F Evaluation y                   (Sample Two Valve Types)
If V
Pil ASE 1 REPORT Survey & Test Results Prototypical Configuration Groups Temperature Profiles m              Model vs Test Data r          Pipe & Valve Evaluations       '
PIPE INTEGRITY VALVE INTEGRITY Scoping Appendix F Evaluation Scoping Appendix F Evaluation y
                                  . Phase 2 Test Matrix & Scope 4 Input to ASME Working                                       Presentation Group on Piping Design                         lf           to NRC w         LA          '
(Sample Two Valve Types)
Pil ASE 1 REPORT Survey & Test Results Prototypical Configuration Groups Temperature Profiles Model vs Test Data m
Pipe & Valve Evaluations r
. Phase 2 Test Matrix & Scope 4
Input to ASME Working Presentation Group on Piping Design lf to NRC LA w


a   .
a ea EPRI-INDUSTRY COLLABORATIVE PROJECT 1
ea               EPRI-INDUSTRY COLLABORATIVE PROJECT                         '
TO SUPPORT RESOLUTION OF GL 96-06 OVERPRESSURIZATION OF ISOLATED PIPING I PIIASE 2 V
1 TO SUPPORT RESOLUTION OF GL 96-06 OVERPRESSURIZATION OF ISOLATED PIPING I PIIASE 2 V
Comnlete Test Matrix Pipe Configuration Oroups Steady State and Transient Temperature Profiles V
Comnlete Test Matrix Pipe Configuration Oroups Steady State and Transient Temperature Profiles V
                                  / PIPE LOADS !
/ PIPE LOADS
V
/
                                /        Pm.Tm.cm /
Pm.Tm.cm /
V p
V p
VALVE INTEGRITY                                           VALVE LEARAGE Appendix F Evaluation     PIPE INTEGRITY                   internals Evaluation Appendix T Evaluation V                           V Non Linear Model L AKAGE (Clos d o       o ution)
V VALVE INTEGRITY VALVE LEARAGE Appendix F Evaluation PIPE INTEGRITY internals Evaluation Appendix T Evaluation V
V Apply to Other Piping 3,Es Configurations V                           Y Configuration               Coupled Pipe and App F Evaluation                   Valve Test (Pipe and Valve) y           NO Screening Criteria Proposed Code Changes                 Limited Valve Leakage & Resea FINAL REPORT Phase I and 2 Results Non Linear Model Validation
V Non Linear Model L AKAGE (Clos d o o ution)
                              >      Screening Criteria       y Pipe Integrity Assessments Valve Integrity Assessments Valve Leakage Astessments
V Apply to Other Piping 3,Es Configurations V
                ..}}
Y Configuration Coupled Pipe and App F Evaluation Valve Test (Pipe and Valve)
NO y
Screening Criteria Proposed Code Changes Limited Valve Leakage & Resea FINAL REPORT Phase I and 2 Results Non Linear Model Validation Screening Criteria y
Pipe Integrity Assessments Valve Integrity Assessments Valve Leakage Astessments
..}}

Latest revision as of 10:34, 3 December 2024

Summary of 970430 Meeting W/Licensee in Rockville,Md Re GL-96-06, Assurance of Equipment Operability & Containment Integrity During Design-Basis Accident Conditions. Listed Attendees & Meeting Handouts Encl
ML20216E524
Person / Time
Issue date: 09/05/1997
From: Wetzel B
NRC (Affiliation Not Assigned)
To:
NRC (Affiliation Not Assigned)
References
GL-96-06, GL-96-6, NUDOCS 9709100220
Download: ML20216E524 (38)
v • d • e


Text

.

  • g g

UNITED STATES g

g NUCLEAR REGULATORY COMMISSION

,E WASHINGTON. D.C. 30NH001 V. m. /*

September 5, 1997 MEETING PARTICIPANT:

NUCLEAR ENERGY INSTITUTE

SUBJECT:

SUMMARY

OF APRIL 30, 1997. MEETING WITH THE NUCLEAR ENERGY INSTITUTE (NEI) REGARDING GENERIC LETTER (GL) 96 06. " ASSURANCE OF EQUIPMENT OPERABILITY AND CONTAINMENT INTEGRITY DURING DESIGN BASIS ACCIDENT CONDITIONS" On April 30. 1997, representatives of NEl met with representatives of the Nuclear Regulatory Comission (NRC) at the NRC's offices in Rockville.

Maryland provides a list of meeting attendees.

The meeting was requested by NEl representatives to discuss issues pertaining to GL 96 06. " Assurance of Equipment Operability and Containment _ Integrity During Design Basis Accident Conditions."

Prior to the meeting NEI sent NRC a proposed agenda and a list of questions that it wanted the staff to address during the meeting. The staff's response to these questions is summarized in this meeting summary. The agenda is contained in Attachment 2.

The NRC staff began the meeting by making a preser.tation that included an overview of the GL, a summary of the industry responses to the GL received by the NRC to date, and a brief discussion on each of the technical issues in the GL, contains the overhead slides that were used during the NRC presentation. The NRC staff stated that it has been disappointed with the 120 day responses to the Gt. because of some licensees' questionable schedules for resolving the problems identified in the GL. Also, some of the responses submitted were incomplete. The staff has been contacting individual licensees in an attem schedules. pt to obtain a better understanding of licensee responses and An industry representative stated that in order to plan outages, modification packages must be completed at least 6 months prior to the beginning of an outage; therefore, if the GL 96 06 modifications cannot be installed during the upcoming outages, the modifications will not be installed until 18 to 24 months later (a refuel cycle), which may put implementation of some plant modifications into the year 1999.

The staff stated that licensees became aware of the issues on September 30, 1996, when the GL was issued and guidance in GL 91-18 ("Information to Licensees Regarding Two NRC Inspection Manual Sections on Resolution of Degraded and Nonconforming Conditions and on Operability") suggests that degraded systems should be restored to within the original criteria during the next refueling outage.

OV /15 The NEl representatives next made their formal presentation which included a restatement and clarification of the questions that were given to the NRC to address during the meeting.

The NEl presentation materials are 3rovided as. which includes the formal questions given to the NRC prior to the meeting. The NRC staff addressed NEl's questions as each was presented.

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Beth Wetzel. NRR 301-415-1355 y 7 /2 c ;

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-2 September 5, 1997 Individual answers to each NEl question have not been provided in this meeting sumary since the staff believes the discussions in this summary and its attachments cover the basic issues of the questions.

During the meeting, the staff discussed some of the issues associated with waterhamer and two phase flow.

In general, plants were licensed assuming single phase flow conditions in the service water and component cooling water systems.

The staff expects that licensees will make modifications as necessary to conform to the original system design basis, or seek NRC review i

and approval for any proposed changes to the design basis as appropriate.

The staff also cautioned that some system modifications (e.g.. changing a closed loop) cooling water system from one that is vented to one that is pressurized may introduce new vulnerabilities or warrant new Technical Specification requirements, and prior NRC review and ap>roval may be required.

Finally, the staff emphasized that evaluations of water1 amer and two phase flow conditions must include worst-case design basis assumptions, such as-single failure considerations.

The staff discussed the use of American Society of Mechanical Engineers (ASME)

Section Ill Appendix F-criteria for the evaluation of thermal overpressure events.

Appendix F provides rules for the evaluation of components for ASME Code Level D service loadings.

These service loadings are typically specified for plant faulted design conditions. The staff has endorsed the use of the Appendix F criteria for operability evaluations in GL 91-18.

Appendix F contains criteria for inelastic analysis of components.

Licensees may be able to @monstrate the long term acceptability of some piping runs between containment isolation valves for the thermal overpressure event using the inelastic criteria of Appendix F.

If licensees decide to use Appendix F criteria by adding it to their current-licensing basis and they determine that use of the criteria creates an unreviewed safety question through a 10 CFR 50.59 evaluation, then NRC prior review and approval would be required.

The staff notes that the Appedix F criteria apply only-to load combinations associated with plant faulted conditions.

Licensees would have to describe the applicable load combinations used in the Appendix F evaluation and the basis for determining the applicable load combination associated with the thermal overpressure event.

Another topic of discussion involved the a>propriate set point pressure for thermal relief valves.

The staff stated tlat the set point pressure should be determined such that the applicable design criteria are not exceeded.

Representatives from the Electric Power Research Institute (EPRI) made a presentation on two projects (one for-the overpressurization of piping and one for waterhamer) that it is overseeing to su the technical issues identified in GL-96 06.pport the industry in resolving The EPRI presentation is provided in Attachment 5.

NEl and the staff discussed the use of the EPRI test results to verify the adequacy of piping for thermal overpressure events.

The staff expressed its view that it would be difficult to design a bounding

-test configuration: however, the use of testing on piping configurations that A

3-sept. ember 5,1997 are representative of some common plant pip' ting to verify an analytical ing layouts might be useful.

NEI and the staff also discussed the use of tes procedure that could be used to evaluate unique plant configurations.

The staff considers the ute of such an approach to be reasonable.

During the meeting there was considerable discussion regarding 10 CFR 50.59 and USQs (unreviewed safety guestions) with respect to GL 96-06.

The industry is concerned with the GL 95-06 issues and whether the staff considers potential resolutions of GL 96-061ssues to involve US0s or not, particularly with respect to the use of ASME Section 111 Appendix F criteria for piping loads for other than interim operability evaluations.

Industry representatives went as far as to say that if lonc-term use of Appendix F piping susceptible to overoressurization,y would )nstall relief valve criteria was determined to be a US0. the i

then request use.of the Appendix F criteria and remove the relief valves after use of Appendix F was granted.

NRC policy has been that if a plant has a USQ and it shuts down, the plant cannot restart until the USQ has been reviewed and a) proved by the NRC However, some of the modifications associated with G 96-06 issues could take a considerable amount of time to design, procure, schedule,and im thereby being impractical to implement prior to the next startup.plement.

The staff acknowledged the industry representatives' concerns with respect to USQs but was not able to answer their specific questions at the meeting because they were associated with policy decisions.

The staff has been considering a possible revision to the existing policy which, among other changes, would eliminate the restriction on plant restart with a USO provided that the system structure, or component in question is operable and the applicable regulations and the technical specification requirements are being met.

A final determination on this policy issue has not been reached-ORIGINAL SIGNED BY Beth A. Wetzel. Project Manager Project Directorate III 1 Division of Reactor Projects - III/IV Office of Nuclear Reactor Regulation Attachments:

1.

List of Attendees 2.

Meeting Agenda 3.

NRC Handouts 4.

NEI Handouts 5.

EPRI Handouts N@

OGC PUBLIC ACRs PD# 3 1 Reading c

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k na pg K. Manoly J. Fair B. McCabe DOCUMENT NAME: G:\\WPDOCS\\GL9606\\MTGSUM.497 To receive a copy of this document, indicate in the box C= Copy w/o attachment / enclosure E= Cop _y with attachment / enclosure N = No copy

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MEETING ATTENDEES Name

-Oraanization L Marsh-NRC G. Hubbard NRC G, Hammer NRC K, Manoly NRC-R. Weseman NRC B. Wetzel NRC R. Lobel NRC J. Fair NRC J. Tatum NRC C, Saadu -

NRC-E. McKenna NRC S. Greco Wisconsin Electric T.'Wroblewski-Wisconsin Electric S. Denny PEC0 Nuclear R. Randels Comed R.-Gamberg:

Duke Power Co.

D. Murphy Bechtel A Singh-EPRI B. Demars Virginia Power T. Sutter Bechtel E. May-Virginia Power

-D. Stellfox Inside NRC P. Tamburro GPU Nuclear S. Mixon M 'S

- D. McGuigan Scientech P. Okas NYPA W. Birely.

NYPA J. del Mazo Pacific Gas & Electric-G. Davant Entergy--

T. Esselman-Altran Corporation S. Gosselin EPRI D. Modeen

- NEl--

J. Minichello Comed S, Plymaie GPU Nuclear G. Gyrkan GPU Nuclear AlTACHMENT 1

PROPOSED AGENDA NRC/NEI MEETING ON GL 9646 APa!L 80,1997 rib!IPONSIBLE 123g Tggic -

Ran 1.

Welcomo and Opening Rs. marks NRC NEI 2.

GL 96 06 Suhmittah: Status and Observations WRC GL 96 06: Questions and Responnes NEI 3.

NRC 4.

EPRI GL 96 06 programs on Over Pressurization and EPRI Waterhammer (Tentative) 5.

Concluding Remarks NRC NEI 6.

Adjournment O

e e

S 9

4 9

1

-.--~--= Sew--%.,--,wm

. MEETING WITH XEI REGARDING GEXERIC LETTER 96-06 APRIL 30,1997 GL 96-06, " ASSURANCE OF EQUIPMENT OPERABILITY AND CONTAINMENT INTEGRITY DURING DESIGN-BASIS ACCIDENT CONDITIONS" TECHNICAL BRANCHES: SPLB, EMEB AND SCSB LEAD PM: BETH WETZEL 5

5 8

~

PRESENTATION

+

OVERVIEW OF GENERIC LErrER - BETH WETZEL

+

INDUSTRY RESPONSES - CORETTA SAADU

+

CONTAINMENT FAN COOLER ISSUES - JIM TATUM

+

THERMAL OVERPRESSURE - KAMAL MANOLY

+

NEI DISCUSSION QUESTIONS - ALL 2

SCOPE OF GL 96-06 (1)

POTENTIAL WATERHAMMER IN THE COOLING WATER SYSTEMS SERVING THE CONTAINMENT AIR COOLERS DURING A LOSS-OF-COOLANT ACCIDENT (LOCA) OR A MAIN STEAM LINE BREAK (MSLB) o DIABLO CANYON o

HADDEM NECK (2)

POTENTIAL TWO-PHASE FLOW IN THE COOLING WATER SYSTEMS SERVING THE CONTAINMENT AIR COOLERS DURING POSTULATED LOCA AND MSLB SCENARIOS o

PT. BEACH o

SALEM (3)

THERMALLY INDUCED OVERPRESSURIZATION OF ISOLATED PIPING INSIDE CONTAINMENT

~

o BEAVER VALLEY j

o MAINE YANKEE 3

REASONS FOR ISSUANCE OF GENERIC LEITER

+

THE PROBLEMS IDENTIFIED IN THE LEITER ARE COMPLIANCE ISSUES

+

THESE PROBLEMS WERE IDENTIFIED AT SEVERAL PLANTS AND ALL PLANTS ARE POTENTIALLY SUSCEPTIBLE

+

TWO OPERATING PLANTS SHUT DOWN BECAUSE OF THE ISSUES AND HARDWARE MODIFICATIONS WERE REQUIRED

+

NRC WAS DEALING WITH THESE ISSUES ON A CASE-BY-CASE BASIS 4

~

REQUESTED INFORMATION l

+

GL ISSUED SEPTEMBER 30,1996

[

+

30 DAY RESPONSES

+

~ 120 DAY RESPONSES DUE JANUARY 28,1997 o

IF SUSCEPTIBLE o

ACTIONS TAKEN o

BASIS FOR OPERABILITY o

CORRECTIVE ACTIONS AND SCHEDULE 5

l

~

REVIEW PLAN

+

TIMELINE SCREENING REVIEW

~'

o ISSUE MAJORITY OF SEs BY 18 MONTHS o

CONSIDERING TI

+

REVIEW RESPONSIBILITIES SPLB - CFCU ISSUES EMEB - OVERPRESSURIZATION OF PIPING ISSUES SCSB - CONTAINMENT PARAMETERS 6

a

~

PRELIMINARY GL RESPONSE

SUMMARY

+

7 PLANTS NOT SUSCEPTIBLE TO ANY OF THE ISSUES

+

2 PLANTS SUSCEPTIBLE ONLY TO WATERHAMMER AND TWO PHASE FLOW

+

45 PLANTS SUSCEPTIBLE ONLY TO THERMAL OVERPRESSURIZATION

+

51 PLANTS SUSCEPTIBLE TO BOTH CONTAINMENT FAN COOLER ISSUES AND THERMAL OVERPRESSURIZATION 7

OUTLIERS / STAFF FOLLOWUP ACTIONS i

+

ADDITIONAL SUBMIrrALS:

i O

JUNE SUBMITTAL - 6 PLANTS o

JULY SUBMIrrAL - 7 PLANTS o

AUGUST SUBMITTAL - 3 PLANTS o

OCTOBER AND BEYOND - 5 PLANTS

+

MODIFICATION SCHEDULES EXTENDING INTO SPRING 1998 AND BEYOND: 7 PLANTS 8

~

WATER HAMMER /TWO-PHASE FLOW ISSUES

+

ANALYTICAL ACCEPTANCE OF THE CONDITION o

NEW ANALYSIS / METHODOLOGY / UNCERTAINTIES o

NOT PREVIOUSLY REVIEWED / ACCEPTED BY NRC

+

SYSTEM MODIFICATIONS o

SATISFY DESIGN BASIS o

NEW VULNERABILITIES & FAILURE MODES o

TS CONSIDERATIONS l

+

SINGLE FAILURE /FMEA CONSIDERATIONS o

WORST-CASE / BOUNDING CONDITIONS

+

POST-ACCIDENT USE OF NON-ESSENTIAL CFCs

+

IMPACT ON PLANT OPERATION o

USQ DETERMINATION / LICENSE SUBhBTTAL o

COMPLEX REVIEW / LIMITED RESOURCFJ 9

THERMAL OVERPRESSURIZATION

+

OVERPRESSURIZATION OF ISOLATED PIPING IS ADDRESSED IN ANSI B31.1 AND ASME DESIGN CODES

+

AFFECTED PIPING RANGES FROM 3/8-INCH TO 20-INCH O.D.

+

SOME MEMBERS OF THE ASME CODE DISAGREE THAT THE PHENOMENON IS A FAULTED DESIGN CONDITION

+

PROPOSED ASME CODE CHANGE TO DECLARE AFFECTED PIPING SYSTEMS MEET THE CODE WITHOUT FURTHER ANALYSIS FOR TEMPERATURE INCREASE UP TO 250 F 10 1

THERMAL OVERPRESSURIZATION (cont'd) a

+

STAFF DOES NOT ENDORSE PROPOSED CHANGE SINCE IT IS BASED ON SIMPLISTIC ANALYSIS OF IDEAL PIPING CONFIGURATION

+

APPENDIX F TO SECTION III OF ASME CODE EMPLOYED IN SOME OPERABILITY DETERMINA-TIONS. LICENSE AMENDMENT MAY BE REQUIRED FOR LONG-TERM RESOLUTION AT SOME FACILITIES

+

PROPOSED SOLUTIONS INCLUDE THERMAL RELIEF I

VALVE, RUPTURE DISK WITH EXPANSION CHAMBER, DRAINAGE OF LINE DURING NORMAL OPERATION, PERFORM INELASTIC ANALYSIS OF PIPING (APPLICATION OF APPENDIX F), FAILURE HAS NO SAFETY CONSEQUENCES, AND DETAILED HEAT TRANSFER ANALYSIS TO DEMONSTRATE THAT PRESSURE DOES NOT EXCEED ALLOWABLE 11 1

P INDUSTRY -- NRC STAFF MEETING ON GENERIC LETTER 96-06 l

presented by:

NEl GL 96-06 ISSUE TASK FORCE Dave Modeen, NEl Raub Randels, COMED John Minichiello, COMED Steve Greco, WEPCo Avtar Singh, EPRI April 30,1997 Rockville, MD hi 1

ATTACHMENT 4

MEETING OBJECTIVES Discuss status of licensee responses to GL 96-06 and NRC staff concerns and resolution plan

- Generic Communication?

- Formal letters to licensees? When?

- Other?

l Obtain clarification on NRC staff views regarding application of ASME Section 111, B31.1 and B31.7 requirements and guidance in resolving nonconformances identified c uring licensee review of Generic Letter 96-06 issues.

MEETING OBJECTIVES (contd.)

Obtain NRC staff views on the scope of, and schedule of, any licensee-specific and EPRI-sponsored collaborative experimental and analytical efforts to assess:

- Piping and valve integrity during overpressurization caused by LOCA

- Conservatisms in bounding waterhammer i

analyses and their impact on fan cooler system operability evaluations For example, if a plant performs a waterhammer Loss of Offsite Power test and if results show that mocs are required, can these mods be postponed to the following outage, provided that system meets operability?

h s

i

QUESTION ONE A number of NRC staff communications on near and long term use of ASME Section 111 Appendix F," Analysis Methodology & Limits," have been provided to industry, but some confusion remains with regards to its use. The NRC staff is requested to provide clarification about the following:

- If Appendix F is within a plant's licensing basis, is it acceptable for use as a long-term, over-pressurization solution?

- If the answer to (a)is yes, can a plant without Appendix F as a part of its licensing basis restart from a planned or unplanned outage while pursuing a license amendment to make Appendix F a part of the plant's licensing basis?

- If a plant is processing a licensing change to add Appendix F to its licensing basis, what types of considerations should be included in the submittal?

- If a plant has committed to a schedule for making modifications and/or procedural changes as a long-term over-pressurization solution, is it permitted, prior to making the scheduled modification, to pursue a license amendment to make Appendix F a part of the o' ant's licensina 3 asis?

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__ ____ rm_r_ __ _ __ _.

QUESTIONS (contd.)

QUESTION TWO What information does the NRC need to approve l

the use of ASME lil, Appendix F as a licensing basis for piping sys+"ms designed to ANSI B31.17 QUESTION THREE Is the following considered an acceptable justification for evaluating the failure mode effect of a stuck open relief valve, occurring post accident, located between two closed containment isolations valves?

The reason a relief valve opens is because the pressure has increased between the two containment isolation valves. Consequently, due to the tightness of the subject isolation valves, the opening of the relief valve confirms the containment integrity is provided by the isolation valves and associated piping.

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QUESTION FOUR Set Pressure (LOCA ONLYh The design codes used by licensees are silent on " provisions" to be taken for relieving the excess pressure. The 1967 edition of ANSI B31.1 does not address set pressure requirements. Newer editions do by reference to ASME Section Vlli, paragraphs UG-126 through UG-133. The newer versions of ASME Section 111 (W 1979 and forward) also do not address set pressure / relief capacity for faulted conditions.

Does the NRC staff agree that it is acceptable for a plant to set thermal relief valves at a pressure high enough to prevent unnecessary actuation during normal operation, but low enough to meet current ASME Section Vlli (ANSI B31.1) or ASME Section til guidance? This option does not propose revising system design pressures, but does propose reevaluating the components for the maximum (set plus accumulation) faulted condition pressure.

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O QUESTION FOUR (contd.)

The NRC staff is also requested to respond to the following specific questions:

ANSI B31.1 Applications:

- Does the NRC staff agree that it is permissible to use a relief valve set pressure equal to 1.09 Pa, where Pa equals the pipe or valve rated pressure, assuming all components subjected to that pressure are shown acceptable under the faulted condition l

loading?

ASME Code Applications:

- Does the NRC staff agree it is permissible to use a relief valve set pressure equal to 0.91 P*, where P*

equals the lower of 2 Pa (Pipe) or 1.5 Pa (Valve),

assuming all components subjected to that pressure are shown acceptable under the faulted condition loading?

- The basis of the 1.09 and 0.91 factors is a 10%

accumulation, bringing the maximum pressure to 1.09 x 1.1 = 1.2 Pa (permitted by B31.1 and Section Vill) and 1.1 (.91) = P* (permitted by Section Ill).

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QUESTlONS QUESTION FIVE If waterhammer and/or two-phase flow were not specifically addressed during initial plant / system design and licensing, can an analytical approach be used without introducing an unreviewed safety question (USQ) per 10CFR50.59, provided that the analysis shows that applicable code allowables are met once the necessary piping support modifications have been installed?

QUESTION SIX If tests confirm that piping and valves exposed to an external temperature increase of up to 250 F are not challenged structurally, will the NRC staff consider accepting the test results as a basis for endorsing an ASME Code Case (relief protection is not necessary when the temperature increase is less than or equal to 250 F) being developed?

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l' EPRl/NPG EPRl/ Industry Collaborative Project 4

to Support Resolution of GL 96-06 Technical issues i

l Avtar Singh S. Gosselin Mati Merilo H.T. Tang NRC/NEl/ industry Meeting on GL 96-06 Rockville, MD April 30,1997

Background

EPRI project (1994-96) on waterhammer prevention, mitigation, and accommodation

- EPRI reports: TR 106438 and NP 6766 EPRI analysis efforts (early 1996) to predict fan cooler system boiloff and voiding Preliminary plan of the EPRl/ Industry collaborative project presented to NRC on December 19,1996 Two collaborative projects to address piping overpressurization and waterhammer/two phase flow issues

- Two industry meetings (2/25 and 4/9,1997) to review scope of testing and analysis ATTACHMENT 5

'1

l EPRuNeo Overpressurization of isolated Piping Sections Under Postulated LOCA Objectives

  • Develop a credible technical approach to resolve the GL 96-06 containment penetration overpressurization issue and minimize unwarranted hardware modifications
  • Develop simplified elastic-plastic methods that can be applied by utilities to evaluate these loading conditions without the need for FEA EPRl/NPG Overpressurization of isolated Piping Sections Under Postulated LOCA Anoroach Conduct industry survey to define piping configurations, materials, etc.
  • Conduct tests to simulate overpressurization conditions Demonstrate piping and valve integrity Benchmark analysis methodology against test data Perform analysis to show how ASME Appendix F critarM can be met 2

i EPRl/NPO Overpressurization of isolated Piping Sections Under Postulated LOCA Prolect Scope Two-phase project

  • Phase 1 focuses on scoping (simple' pipe) tests and analysis to show piping and valve integrity evaluation meeting Appendix F criteria Phase 2 provides more quantitative (typical in-plant configuration) tests and evaluations for generic applications by utilities SARA EPRl/NPG Overpressurization of isolated Piping Sections Under Postulated LOCA Phase 1
  • Utility survey on piping configurations and containment temperature profiles

= 3 sample piping segments of different D/t (i.e. sch 10,80

& 160)

  • Bounding steady state temperature profile
  • Pressure, temperature and piping response history measurement Appendix F evaluation based on measured pressure loading

- 3 piping segments

- 2 typical valves: gate and globe 3

4 6

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EPRl/NPG i

Overpressurization of Isolated Piping Sections Under Postulated LOCA Phase 2 Example of Expanded Test Matrix Configuration Material T1" T2" Coupon i

Group

  • CG1 CS/SS 1

1 1

CG2 CS/SS 1

1 1

CG3 CS/SS 1

1 1

i CG4 CS/SS 1

1 1

CG6 CS/SS 1

1 1

CG6 CS/SS 1

1 1

Specific test configurations designed to address geometric leeues identifd in the Phase 1 survey T1 & T2 represent bounding steady state and transient temperature profiles SARA

-, r EPRl/NPG Overpressurization of Isolated Piping Sections Under Postulated LOCA Phase 2 (cont.)

  • Appendix F evaluation Valve leakage evaluation If leakage potential exists, test to demonstrate leakage and ability to reseal M ate rial 11 T2 Straight Pipe with Globe Valve CS or SS i

1 Straight Pipe with Gate Valve CS or SS 1

1 1

SAM 4

1

)

4

~~: :

t EPRl/NPG Overpressurization of isolated Piping Sections Under Postulated LOCA Jochnical Products Appendix F analysis methodology Actual safety margins by comparison of analysis and test data Analysis and evaluation guidelines Screening criteria for analysis and evaluation of afiected in-plant systems SARA

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EPRt/NPG Overpressurization of Isolated Piping Sections Under Postulated LOCA Deliverables Technical report

- Testing report including testing data

- Analysis guidelines

- Screening criteria

- Inelastic models

- Appendix F calculations

- LonD-term integrity criteria

- Quick look summary reports

  • Input to ASME code committees 5

\\

EPRl/NPG Overpressurization of isolated Piping Sections Under Postulated LOCA Preliminary Schedule

  • Phase 1: 2 months after Phase i start
  • Phase 2: 8 months after Phase 2 start

. Final technical report: 12 months after Phase 2 start l

EPRl/NPG Overpressurization of Isolated Piping Sections Under Postulated LOCA l

Proposed NRC -Industry Meetinas -

+ Review Phase 1 Results (7/97)

Phase 2 Planning Meeting with the Staff Phase 2 Progress Review Meeting with Staff

  • Review Phase 2 Results and Conclusions (7/98) 6

apRvNeo Waterhammer Assessment

. For some plants, waterhammer is expected to occur in the containment air cooler cooling water system during a LOCA/ LOOP scenario

. The severity of waterhammer, in terms of the loads imposed on the piping system, is not well understood

. Analytical methods can give overly conservative results EPRl/NPo Potential Mitigative Factoru for Waterhammer Loads

. Low system pressure results in small driving forces

. Bubble vapor pressure opposes acceleration of water slug

. Heatup and possible bolln.g in the water slugs prior to impact

. Air coming out of solution

- cushioning

- sound speed

- pressure wave absorption 7

~.

EPRl/NPG General Project Objectives

. Relax conservatisms related to developing 4

thermal-hydraulic forcing functions

. Provide thermal hydraulle boundary and initial conditions for waterhammer analysis

. Assess fan cooler operability with two-phase flow and its ability to transition to design flow conditions SARA EPRl/NPG Proposed Experimental Objectives

1. Determine the external and internal heat transfer coefficients for the fan cooler coils.
2. Determine the rate and extent of voiding in the fan cooler unit and headers during the LOCA LOOP transient.
3. Determine the thermal stratification and mixing in the headers.
4. Determine the void / liquid interface temperatures and/or the void vapor pressures.

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t EPRl/NPO Proposed Experimental Objectives (cont'd.)

i I

5. Characterize the effects of the pump startup translents.
6. Characterize the effects of the parallel channels.
7. Characterize the effects of different header geometries.
8. Assess the evolution of noncondensible gases and their effect on waterhammer pressure spikes.
9. Determine the effects of system components such as throttling valves, surge tanks, loop seals, check valves etc.

SARA EPRl/NPG Proposed Analysis Objectives

. Provide a method to apply the results of a testing program to prototypic conditions

- e.g. recommendations for heat transfer and fluid flow correlations, as well as system nodalization

. Support development of experimental facility design, scaling, test definition, and prioritization of the test matrix through transient analysis and sensitivity studies.

SARA 9

4 4 Conceptual Test Facility OPEN LocP CLOSED LOOP J4i it

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f-1 F

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g EPRl/NPG Deliverables

. Validated thermal-hydraulic models/ correlations applicable to Containment Fan Cooler calculations

. Recommendations / guidance on how to set up fan cooler system calculations for thermal-hydraulic codea

. Experimentaldata SARA 10

~

EPRIMPG Status l

. Participation interest survey

- Approximately twelve to fifteen utilities for the overpressurization project

- Approximately four to six utilities for the waterhammer project

. Contractual agreements for funding authorization sent to interested utilities

- Approval contingent on resuhs being timely in addressing regulatory issues

. Anticipated start date - May 1997 SARA e

11

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.- 1 EPRI INDUSTRY COLLACORATIVE PROJECT 4 '

l TO SUPPORT RESOLUTION OF GL 96-06 OVERPRESSURI7sATION OF ISOLATED PIPING UTII.ITY SURVEY Piping Configurations Valve Descriptions Containment Temperature Profiles V

V Prototypical Hounding Containment Configuration Groups Temperature Profiles Piping & Valves PWR Designs BWR Designs PliASE 1 TESTING 3 Straight Pipe Segment Tests a

Steady State Bounding Temperature Profile V

Burst?

Yes

> Stop No Y

PIPE LOADS P(t), T(t), E(t)

If V

PIPE INTEGRITY VALVE INTEGRITY Scoping Appendix F Evaluation Scoping Appendix F Evaluation y

(Sample Two Valve Types)

Pil ASE 1 REPORT Survey & Test Results Prototypical Configuration Groups Temperature Profiles Model vs Test Data m

Pipe & Valve Evaluations r

. Phase 2 Test Matrix & Scope 4

Input to ASME Working Presentation Group on Piping Design lf to NRC LA w

a ea EPRI-INDUSTRY COLLABORATIVE PROJECT 1

TO SUPPORT RESOLUTION OF GL 96-06 OVERPRESSURIZATION OF ISOLATED PIPING I PIIASE 2 V

Comnlete Test Matrix Pipe Configuration Oroups Steady State and Transient Temperature Profiles V

/ PIPE LOADS

/

Pm.Tm.cm /

V p

V VALVE INTEGRITY VALVE LEARAGE Appendix F Evaluation PIPE INTEGRITY internals Evaluation Appendix T Evaluation V

V Non Linear Model L AKAGE (Clos d o o ution)

V Apply to Other Piping 3,Es Configurations V

Y Configuration Coupled Pipe and App F Evaluation Valve Test (Pipe and Valve)

NO y

Screening Criteria Proposed Code Changes Limited Valve Leakage & Resea FINAL REPORT Phase I and 2 Results Non Linear Model Validation Screening Criteria y

Pipe Integrity Assessments Valve Integrity Assessments Valve Leakage Astessments

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