ML102430462: Difference between revisions

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| number = ML102430462
| number = ML102430462
| issue date = 08/30/2010
| issue date = 08/30/2010
| title = Response to Request for Additional Information, Proposed License Amendment Request Regarding Risk-Informed Justification for the Relocation of Specific Surveillance Frequency Requirements to a Licensee Controlled Program..
| title = Response to Request for Additional Information, Proposed License Amendment Request Regarding Risk-Informed Justification for the Relocation of Specific Surveillance Frequency Requirements to a Licensee Controlled Program
| author name = Hartz L
| author name = Hartz L
| author affiliation = Dominion, Virginia Electric & Power Co (VEPCO)
| author affiliation = Dominion, Virginia Electric & Power Co (VEPCO)
Line 18: Line 18:


=Text=
=Text=
{{#Wiki_filter:10 CFR 50.90 VIRGI NI A ELECTRI C A N D POWER COM P A N Y RICHMOND, VIRGI N I A 23261 August 30, 2010 U.S. Nuclear Regulatory Commission                               Serial No. 10-122A Attention: Document Control Desk                                  NL&OS/ETS RO Washington , D.C. 20555                                          Docket Nos. 50-338/339 License Nos. NPF-4/7 VIRGINIA ELECTRIC AND POWER COMPANY (DOMINION)
{{#Wiki_filter:10 CFR 50.90 VIRGINI A ELECTRIC A N D POWER COM PA N Y RICHMOND, VIRGI N I A 23261 August 30, 2010 U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555 Serial No.
10-122A NL&OS/ETS RO Docket Nos. 50-338/339 License Nos. NPF-4/7 VIRGINIA ELECTRIC AND POWER COMPANY (DOMINION)
NORTH ANNA POWER STATION UNITS 1 AND 2 RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION PROPOSED LICENSE AMENDMENT REQUEST REGARDING RISK-INFORMED JUSTIFICATION FOR THE RELOCATION OF SPECIFIC SURVEILLANCE FREQUENCY REQUIREMENTS TO A LICENSEE CONTROLLED PROGRAM (ADOPTION OF TSTF-425, REVISION 3)
NORTH ANNA POWER STATION UNITS 1 AND 2 RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION PROPOSED LICENSE AMENDMENT REQUEST REGARDING RISK-INFORMED JUSTIFICATION FOR THE RELOCATION OF SPECIFIC SURVEILLANCE FREQUENCY REQUIREMENTS TO A LICENSEE CONTROLLED PROGRAM (ADOPTION OF TSTF-425, REVISION 3)
In a March 30, 2010 letter (Serial NO.1 0-050), Dominion requested amendments, in the form of changes to the Technical Specifications (TS) to Facility Operating License Numbers NPF-4 and NPF-7, for North Anna Power Station Units 1 and 2, respectively.
In a {{letter dated|date=March 30, 2010|text=March 30, 2010 letter}} (Serial NO.10-050), Dominion requested amendments, in the form of changes to the Technical Specifications (TS) to Facility Operating License Numbers NPF-4 and NPF-7, for North Anna Power Station Units 1 and 2, respectively.
The proposed amendments would modify North Anna TS by relocating specific surveillance frequencies to a licensee-controlled program with the implementation of Nuclear Energy Institute (NEI) 04-10, "Risk-Informed Technical Specifications Initiative 5b, Risk-Informed Method for Control of Surveillance Frequencies."               In an August 6, 2010 e-mail from Dr. V. Sreenivas, the NRC requested additional information to complete the review of the license amendment request. The attachment to this letter provides the information requested in the August 6, 2010 e-mail.
The proposed amendments would modify North Anna TS by relocating specific surveillance frequencies to a licensee-controlled program with the implementation of Nuclear Energy Institute (NEI) 04-10, "Risk-Informed Technical Specifications Initiative 5b, Risk-Informed Method for Control of Surveillance Frequencies."
The information provided in this letter does not affect the conclusion of the significant hazards consideration discussion provided in Dominion letter dated March 30, 2010 (Serial NO.10-050) for North Anna.
In an August 6, 2010 e-mail from Dr. V. Sreenivas, the NRC requested additional information to complete the review of the license amendment request. The attachment to this letter provides the information requested in the August 6, 2010 e-mail.
The information provided in this letter does not affect the conclusion of the significant hazards consideration discussion provided in Dominion {{letter dated|date=March 30, 2010|text=letter dated March 30, 2010}} (Serial NO.10-050) for North Anna.
Dominion continues to request approval of the proposed license amendments by April 1, 2011, with the amendments being implemented within 120 days.
Dominion continues to request approval of the proposed license amendments by April 1, 2011, with the amendments being implemented within 120 days.
In accordance with 10 CFR 50.91, "Notice for Public Comment; State Consultation," a copy of this response, with attachments, is being provided to the designated State Officials.
In accordance with 10 CFR 50.91, "Notice for Public Comment; State Consultation," a copy of this response, with attachments, is being provided to the designated State Officials.


Serial No. 10-122A Docket Nos. 50-338/339 LAR - Relocate Surveillance Frequencies from TS Page 2 of 3 If you have any questions or require additional . information,                       please contact Mr. Thomas Shaub at (804) 273-2763.
Serial No. 10-122A Docket Nos. 50-338/339 LAR - Relocate Surveillance Frequencies from TS Page 2 of 3 If you have any questions or require additional. information, please contact Mr. Thomas Shaub at (804) 273-2763.
Sincerely,
Sincerely,
~1:cJ Vice President - Nuclear Support Services Attachments:
~1:cJ Vice President - Nuclear Support Services Attachments:
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: 2. Response To Request For Additional Information - Revised Insert for TS Bases Changes Commitments made in this letter: Dominion will assess the PRA model gaps for each surveillance frequency change until the PRA model of record is updated.
: 2. Response To Request For Additional Information - Revised Insert for TS Bases Changes Commitments made in this letter: Dominion will assess the PRA model gaps for each surveillance frequency change until the PRA model of record is updated.
COMMONWEALTH OF VIRGINIA COUNTY OF HENRICO The foregoing document was acknowledged before me, in and for the County and Commonwealth aforesaid, today by Leslie N. Hartz, who is Vice President - Nuclear Support Services, of Virginia Electric and Power Company. She has affirmed before me that she is duly authorized to execute and file the foregoing document in behalf of that Company, and that the statements in the document are true to the best of her knowledge and belief.
COMMONWEALTH OF VIRGINIA COUNTY OF HENRICO The foregoing document was acknowledged before me, in and for the County and Commonwealth aforesaid, today by Leslie N. Hartz, who is Vice President - Nuclear Support Services, of Virginia Electric and Power Company. She has affirmed before me that she is duly authorized to execute and file the foregoing document in behalf of that Company, and that the statements in the document are true to the best of her knowledge and belief.
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                                                          .., ConInIiAion ExpIrn Mar 31.2014
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Serial No. 10-122A Docket Nos. 50-338/339 LAR - Relocate Surveillance Frequencies from TS Page 3 of 3 cc: U.S. Nuclear Regulatory Commission Region II Marquis One Tower 245 Peachtree Center Avenue, NE Suite 1200 Atlanta, Georgia 30303-1257 Mr. J. E. Reasor, Jr.
cc:
U.S. Nuclear Regulatory Commission Region II Marquis One Tower 245 Peachtree Center Avenue, NE Suite 1200 Atlanta, Georgia 30303-1257 Mr. J. E. Reasor, Jr.
Old Dominion Electric Cooperative Innsbrook Corporate Center 4201 Dominion Blvd.
Old Dominion Electric Cooperative Innsbrook Corporate Center 4201 Dominion Blvd.
Suite 300 Glen Allen, Virginia 23060 State Health Commissioner Virginia Department of Health James Madison Building - 7th floor 109 Governor Street Suite 730 Richmond, Virginia 23219 NRC Senior Resident Inspector North Anna Power Station Ms. K. R. Cotton NRC Project Manager U. S. Nuclear Regulatory Commission One White Flint North Mail Stop 08 G9A 11555 Rockville Pike Rockville, Maryland 20852 Dr. V. Sreenivas NRC Project Manager U. S. Nuclear Regulatory Commission One White Flint North Mail Stop 08 G9A 11555 Rockville Pike Rockville, Maryland 20852
Suite 300 Glen Allen, Virginia 23060 State Health Commissioner Virginia Department of Health James Madison Building - 7th floor 109 Governor Street Suite 730 Richmond, Virginia 23219 NRC Senior Resident Inspector North Anna Power Station Ms. K. R. Cotton NRC Project Manager U. S. Nuclear Regulatory Commission One White Flint North Mail Stop 08 G9A 11555 Rockville Pike Rockville, Maryland 20852 Dr. V. Sreenivas NRC Project Manager U. S. Nuclear Regulatory Commission One White Flint North Mail Stop 08 G9A 11555 Rockville Pike Rockville, Maryland 20852 Serial No. 10-122A Docket Nos. 50-338/339 LAR - Relocate Surveillance Frequencies from TS Page 3 of 3


Serial No. 10-122A Docket Nos. 50-338/339 Response To Request For Additional Information LAR - Relocate Surveillance Frequencies from TS ATTACHMENT 1 RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION PROPOSED LICENSE AMENDMENT REQUEST REGARDING RISK-INFORMED JUSTIFICATION FOR THE RELOCATION OF SPECIFIC SURVEILLANCE FREQUENCY REQUIREMENTS TO A LICENSEE CONTROLLED PROGRAM PRA QUALITY CONCERNS VIRGINIA ELECTRIC AND POWER COMPANY (DOMINION)
Serial No. 10-122A Docket Nos. 50-338/339 Response To Request For Additional Information LAR - Relocate Surveillance Frequencies from TS ATTACHMENT 1 RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION PROPOSED LICENSE AMENDMENT REQUEST REGARDING RISK-INFORMED JUSTIFICATION FOR THE RELOCATION OF SPECIFIC SURVEILLANCE FREQUENCY REQUIREMENTS TO A LICENSEE CONTROLLED PROGRAM PRA QUALITY CONCERNS VIRGINIA ELECTRIC AND POWER COMPANY (DOMINION)
NORTH ANNA POWER STATION UNITS 1 AND 2
NORTH ANNA POWER STATION UNITS 1 AND 2


Serial No. 10-122A Docket Nos. 50-338/339 Response To Request For Additional Information LAR - Relocate Surveillance Frequencies from TS Page 1 of 11 NRC Question 1 and 2 Table 1 of Attachment 2 has been updated to address the NRC's Request for Additional Information. Specifically, questions 1 and 2:                       .
Serial No. 10-122A Docket Nos. 50-338/339 Response To Request For Additional Information LAR - Relocate Surveillance Frequencies from TS Page 1 of 11 NRC Question 1 and 2 Table 1 of Attachment 2 has been updated to address the NRC's Request for Additional Information. Specifically, questions 1 and 2:
: 1. In Table 1 of Attachment 2 of the submittal, the importance of each gap to this application in many instances is dispositioned simply by referring to the Nuclear Energy Institute (NEI) 04-10 requirement to assess deficiencies with sensitivity analyses. This statement alone is insufficient for the staff to find the probabilistic risk assessment (PRA) model adequate to support the application. The licensee is requested to provide its assessment of the significance of each gap to the calculation of risk increases associated with changes to surveillance frequency. This is requested for the following items in Table 1: #1, #2, #3(1), #4(1), #5, #7, #9, #10, and #17.
: 1. In Table 1 of Attachment 2 of the submittal, the importance of each gap to this application in many instances is dispositioned simply by referring to the Nuclear Energy Institute (NEI) 04-10 requirement to assess deficiencies with sensitivity analyses.
This statement alone is insufficient for the staff to find the probabilistic risk assessment (PRA) model adequate to support the application.
The licensee is requested to provide its assessment of the significance of each gap to the calculation of risk increases associated with changes to surveillance frequency. This is requested for the following items in Table 1: #1, #2, #3(1), #4(1), #5, #7, #9, #10, and #17.
: 2. In Table 1 of Attachment 2 of the submittal, several gaps (#3, #4(1), #5, #7,
: 2. In Table 1 of Attachment 2 of the submittal, several gaps (#3, #4(1), #5, #7,
          #9) identify missing logic in the PRA model (inadequate scope). It is not clear to the staff how missing scope in a PRA can be addressed by sensitivity analyses. The licensee is requested to discuss how it would conduct such analyses for this application. This is requested for the following items in Table 1: #3, #4(1), #5, #7, and #9.
#9) identify missing logic in the PRA model (inadequate scope). It is not clear to the staff how missing scope in a PRA can be addressed by sensitivity analyses.
Dominion Response Table 1 has been revised to address the above RAls. The revisions are included in column titled, Importance to Application. Specifically, the responses to question #1 start off with "Significance" and the responses to question #2 begin with "Inadequate Scope."
The licensee is requested to discuss how it would conduct such analyses for this application.
This is requested for the following items in Table 1: #3, #4(1), #5, #7, and #9.
Dominion Response Table 1 has been revised to address the above RAls.
The revisions are included in column titled, Importance to Application. Specifically, the responses to question #1 start off with "Significance" and the responses to question #2 begin with "Inadequate Scope."
For each surveillance test interval change, missing logic gaps (inadequate scope) will be addressed via the use of sensitivity studies. The model used for the sensitivity study will account for the specific logic gaps as shown in Table 1. In addition, the PRA input to the expert panel will include a documented discussion on each of the aforementioned gaps. The use of gap sensitivity studies will no longer be required once the gaps have been incorporated into the NAPS PRA model of record. The Dominion PRA models are usually updated around every 3 to 5 years
For each surveillance test interval change, missing logic gaps (inadequate scope) will be addressed via the use of sensitivity studies. The model used for the sensitivity study will account for the specific logic gaps as shown in Table 1. In addition, the PRA input to the expert panel will include a documented discussion on each of the aforementioned gaps. The use of gap sensitivity studies will no longer be required once the gaps have been incorporated into the NAPS PRA model of record. The Dominion PRA models are usually updated around every 3 to 5 years
* Serial No. 10-122A Docket Nos. 50-338/339 Page 2 of 11 Table 1 Status of identified Gaps to NEI 00-02 and Capability Category II of the ASME PRA Standard Title    Description              NEI Element I  Current Status I Comment                Importance to Application ASMESR Gap #1    ATWS modeling of          AS-9 ,          ATWS Failure Relief Probability is      Conservative modeling of the A1VVS Failure potentially dominate      QU-11,          conservatively modeled based on          Probabilities 'Nill be addressed by sensitivities per NEI dominant sequences        ST-13          a UET (Unfavorable Exposure              04 10, Revision 1 if applioable to the speoific STI and data traceability                    Time) of 27%.                            evaluation .
Significance: The NAPS ATWS model uses a conservative simplification that assumes that pressure relief is always insufficient whenever the unit is in the UET period, which is assumed to be 27%. This is a conservative bias since there is a probability that pressure relief is successful given the availability of the pressurizer PORVs , safeties and AFW. The sensitivity studies will include an ATWS assessment in accordance with WCAP-15831, WOG Risk-Informed A TWS Assessment and Licensing Implementation Process using the generic methodology and values.
Gap #2    For initiating event    IE-C8          The current NAPS system-level            Support system level initiating event fault trees will be fault-tree modeling,                    initiating event fault trees uses a      addressed by sensitivities per NEI 04 10, Revision 1 if capture all relevant                    365*Capacity Factor multiplier in        applioable to the speoifio STI evaluation.
combinations of events                  all of the initiating event fault trees, involving the annual                    which needs to be replaced with          Significance: This issue is important for any potential frequency of one                        the new methodology described in        Surveillance Test Interval (STI) change impacting component failure                        EPRI TR-1013490, "Support              support system initiating events . Therefore, the combined with the                        System Initiating Events:                system-level initiating events will be revised using the unavailability of other                  Identification and Quantification      methodology in EPRI TR-1 013490 methodology.
components                              Guideline", EPRI, December 2006.


Serial No. 10-122A Docket Nos. 50-338/339 Page 3 of 11 Table 1 Status of identified Gaps to NEI 00-02 and Capability Category II of the ASME PRA Standard Title     Description               NEI Element I   Current Status I Comment           Importance to Application ASMESR Gap #3     For key safety functions AS-A4           SR is NOT MET until : 1) an HEP is 1) HEP for restoring of EGGS during SBO will be (e.g., power                             added to the SBO nodes for         addressed by sensitivities per NEI 04 10, Revision 1 if restoration) identify                   restoring the EGGS functions; and   applioable to the speoifio STI evaluation.
Serial No. 10-122A Docket Nos. 50-338/339 Page 2 of 11 Table 1 Status of identified Gaps to NEI 00-02 and Capability Category II of the ASME PRA Standard Title Description NEI Element I Current Status I Comment Importance to Application ASMESR Gap #1 ATWS modeling of AS-9, ATWS Failure Relief Probability is Conservative modeling of the A1VVS Failure potentially dominate QU-11, conservatively modeled based on Probabilities 'Nill be addressed by sensitivities per NEI dominant sequences ST-13 a UET (Unfavorable Exposure 04 10, Revision 1 if applioable to the speoific STI and data traceability Time) of 27%.
operator actions to                       2) text in seotion 2.3.3.1 is the achieve the defined                       accident sequence documentation     Significance: Non-consideration of this operator action success criteria.                         needs to be revised to clarify the results in a small non-conservatism in the Station need for operator action to restart Black-Out (SBO) accident sequences results. The EGGS functions.                     overall impact on the results is small.
evaluation.
Significance: The NAPS ATWS model uses a conservative simplification that assumes that pressure relief is always insufficient whenever the unit is in the UET period, which is assumed to be 27%. This is a conservative bias since there is a probability that pressure relief is successful given the availability of the pressurizer PORVs, safeties and AFW. The sensitivity studies will include an ATWS assessment in accordance with WCAP-15831, WOG Risk-Informed ATWS Assessment and Licensing Implementation Process using the generic methodology and values.
Gap #2 For initiating event IE-C8 The current NAPS system-level Support system level initiating event fault trees will be fault-tree modeling, initiating event fault trees uses a addressed by sensitivities per NEI 04 10, Revision 1 if capture all relevant 365*Capacity Factor multiplier in applioable to the speoifio STI evaluation.
combinations of events all of the initiating event fault trees, involving the annual which needs to be replaced with Significance: This issue is important for any potential frequency of one the new methodology described in Surveillance Test Interval (STI) change impacting component failure EPRI TR-1013490, "Support support system initiating events. Therefore, the combined with the System Initiating Events:
system-level initiating events will be revised using the unavailability of other Identification and Quantification methodology in EPRI TR-1013490 methodology.
components Guideline", EPRI, December 2006.
 
Serial No. 10-122A Docket Nos. 50-338/339 Page 3 of 11 Table 1 Status of identified Gaps to NEI 00-02 and Capability Category II of the ASME PRA Standard Title Description NEI Element I Current Status I Comment Importance to Application ASMESR Gap #3 For key safety functions AS-A4 SR is NOT MET until: 1) an HEP is
: 1) HEP for restoring of EGGS during SBO will be (e.g., power added to the SBO nodes for addressed by sensitivities per NEI 04 10, Revision 1 if restoration) identify restoring the EGGS functions; and applioable to the speoifio STI evaluation.
operator actions to
: 2) text in seotion 2.3.3.1 is the achieve the defined accident sequence documentation Significance: Non-consideration of this operator action success criteria.
needs to be revised to clarify the results in a small non-conservatism in the Station need for operator action to restart Black-Out (SBO) accident sequences results. The EGGS functions.
overall impact on the results is small.
Inadequate Scope: An Human Error Probability (HEP) will be added to the sensitivity PRA model when quantifying the effect of a proposed individual STI revision for comparison to acceptance criteria in NEI 04-10. Revision 1.
Inadequate Scope: An Human Error Probability (HEP) will be added to the sensitivity PRA model when quantifying the effect of a proposed individual STI revision for comparison to acceptance criteria in NEI 04-10. Revision 1.
: 2) None. This is judged to be a documentation consideration only and does not affect the technical adequacy of the PRA model.
: 2) None. This is judged to be a documentation consideration only and does not affect the technical adequacy of the PRA model.


Serial No ."10-122A Docket Nos. 50-338/339 Page 4 of 11 Table 1 Status of identified Gaps to NEI 00-02 and Capability Category II of the ASME PRA Standard Title     Description               NEI Element I   Current Status I Comment           Importance to Application ASME SR Gap #4   Delineate accident       AS-A?           SR is NOT MET until: 1) inclusion 1) Consequential loss of RCP seal cooling for sequence (e.g., Loss of                   of consequential loss of RCP seal transients will be addressed by sensitivities per NEI 04 RCP seal cooling) for                     cooling for transients, and 2)     10, Revision 1 if applicable to the specific STI each initiating event                     documentation enhancement of       evaluation.
Serial No."10-122A Docket Nos. 50-338/339 Page 4 of 11 Table 1 Status of identified Gaps to NEI 00-02 and Capability Category II of the ASME PRA Standard Title Description NEI Element I Current Status I Comment Importance to Application ASME SR Gap #4 Delineate accident AS-A?
(e.g., transients).                       the U1-RCPSL nodes.
SR is NOT MET until: 1) inclusion
: 1) Consequential loss of RCP seal cooling for sequence (e.g., Loss of of consequential loss of RCP seal transients will be addressed by sensitivities per NEI 04 RCP seal cooling) for cooling for transients, and 2) 10, Revision 1 if applicable to the specific STI each initiating event documentation enhancement of evaluation.
(e.g., transients).
the U1-RCPSL nodes.
Significance: Consequential loss of RCP seal cooling is not specifically considered in the event trees, as both the CC and CH systems would need to fail within the 24 hours of an initiating event. The model does include consequential pressurizer PORV failing to reclose, which is transferred to the small LOCA event tree. The consequential PORV LOCA has a relatively low risk importance. The consequential loss of RCP seal cooling is expected to have a comparable or lower risk impact.
Significance: Consequential loss of RCP seal cooling is not specifically considered in the event trees, as both the CC and CH systems would need to fail within the 24 hours of an initiating event. The model does include consequential pressurizer PORV failing to reclose, which is transferred to the small LOCA event tree. The consequential PORV LOCA has a relatively low risk importance. The consequential loss of RCP seal cooling is expected to have a comparable or lower risk impact.
Inadeguate Scope: A consequential loss of RCP seal cooling for transients will be addressed in sensitivity studies when quantifying the effect of a proposed individual STI revision for comparison to acceptance criteria in NEI 04-10, Revision 1.
Inadeguate Scope: A consequential loss of RCP seal cooling for transients will be addressed in sensitivity studies when quantifying the effect of a proposed individual STI revision for comparison to acceptance criteria in NEI 04-10, Revision 1.
: 2) None. This is judged to be a documentation consideration only and does not affect the technical adequacy of the PRA model.
: 2) None. This is judged to be a documentation consideration only and does not affect the technical adequacy of the PRA model.


Serial No. 10-122A Docket Nos. 50-338/339 Page 5 of 11 Table 1 Status of identified Gaps to NEI 00-02 and Capability Category II of the ASME PRA Standard Title     Description             NEI Element I   Current Status I Comment           Importance to Application ASME SR Gap #5     Define and model plant   AS-B5a         Cross-tie unavailability due to     Cross tie electrioal bus unavailability due to refuel ing configurations and                       outages is accounted for with the   outages will be addressed by sensitivities per NEI 04 alignments that reflect                   exception of electrical buses where 10, Revision 1 if applioable to the specific STI dependencies.                             the unavailability during at power evaluation.
Serial No. 10-122A Docket Nos. 50-338/339 Page 5 of 11 Table 1 Status of identified Gaps to NEI 00-02 and Capability Category II of the ASME PRA Standard Title Description NEI Element I Current Status I Comment Importance to Application ASME SR Gap #5 Define and model plant AS-B5a Cross-tie unavailability due to Cross tie electrioal bus unavailability due to refuel ing configurations and outages is accounted for with the outages will be addressed by sensitivities per NEI 04 alignments that reflect exception of electrical buses where 10, Revision 1 if applioable to the specific STI dependencies.
operation is essentially 0 versus one or two days during refueling   Significance: Significance will be addressed by outages.                           modeling electrical bus cross-tie unavailability for each sensitivity study.
the unavailability during at power evaluation.
operation is essentially 0 versus one or two days during refueling Significance: Significance will be addressed by outages.
modeling electrical bus cross-tie unavailability for each sensitivity study.
Inadequate Scope: The sensitivity studies will address the electrical bus cross-tie unavailability before quantifying the effect of a proposed individual STI revision for comparison to acceptance criteria in NEI 04-10, Revision 1.
Inadequate Scope: The sensitivity studies will address the electrical bus cross-tie unavailability before quantifying the effect of a proposed individual STI revision for comparison to acceptance criteria in NEI 04-10, Revision 1.
Gap #6     Include a discussion of SC-A6           Some of the success criteria       None. This is jUdged to be a documentation operator actions                         discussion includes general         consideration only and does not affect the technical assumed as part of the                   operator actions, but the           adequacy of the PRA model.
Gap #6 Include a discussion of SC-A6 Some of the success criteria None. This is jUdged to be a documentation operator actions discussion includes general consideration only and does not affect the technical assumed as part of the operator actions, but the adequacy of the PRA model.
success criteria                         discussion does not include development, and how                     procedures and not all event tree those actions are                       sections contain the discussion consistent with plant procedures and practices
success criteria discussion does not include development, and how procedures and not all event tree those actions are sections contain the discussion consistent with plant procedures and practices


Serial No . 10-122A Docket Nos. 50-338/339 Page 6 of 11 Table 1 Status of identified Gaps to NEI 00-02 and Capability Category II of the ASME PRA Standard Title     Description               NEI Element /   Current Status / Comment           Importance to Application ASME SR Gap #7   Incorporate the effect of SY-A11         The ourrent NAPS PRA does not       Inadvertent SI Aotuation will be addressed by variable success         SY-A13         inolude inadvertent SI Aotuation . sensitivities per NEI 04 10, Revis ion 1 if applioable to criteria (i.e., success                   Inadvertent Safety Injection (SI)   the speoifio STI evaluation.
Serial No. 10-122A Docket Nos. 50-338/339 Page 6 of 11 Table 1 Status of identified Gaps to NEI 00-02 and Capability Category II of the ASME PRA Standard Title Description NEI Element /
criteria that change as                   Actuation has been included in the a function of plant                       NAPS PRA model of record,           Significance: The NAPS PRA model, N009A. has status) into the system                   N009Aa.                             been updated since the RITS 5b subm ittal and before modeling. Include                                                             receiving the Request for Additional Information. The consideration of all                                                         latest NAPS PRA model, N009Aa, includes Inadvertent failure modes,                                                               SI Actuation , Significance has been addressed by consistent with                                                               incorporating the issue into the PRA model of record ,
Current Status / Comment Importance to Application ASME SR Gap #7 Incorporate the effect of SY-A11 The ourrent NAPS PRA does not Inadvertent SI Aotuation will be addressed by variable success SY-A13 inolude inadvertent SI Aotuation.
available data and                                                           N009Aa.
sensitivities per NEI 04 10, Revision 1 if applioable to criteria (i.e., success Inadvertent Safety Injection (SI) the speoifio STI evaluation.
criteria that change as Actuation has been included in the a function of plant NAPS PRA model of record, Significance: The NAPS PRA model, N009A. has status) into the system N009Aa.
been updated since the RITS 5b submittal and before modeling. Include receiving the Request for Additional Information. The consideration of all latest NAPS PRA model, N009Aa, includes Inadvertent failure modes, SI Actuation, Significance has been addressed by consistent with incorporating the issue into the PRA model of record,
available data and N009Aa.
model level of detail Inadeauate Scope: As stated above, Inadvertent SI Actuation was integrated into the latest NAPS PRA model, N009Aa.
model level of detail Inadeauate Scope: As stated above, Inadvertent SI Actuation was integrated into the latest NAPS PRA model, N009Aa.
Gap #8     Use results of plant     SY-A2           The Dom inion PRA staff has         Not Significant. This is judged to be a documentation walkdowns and plant       SY-A4           performed many system               conside ration only and does not affect the technical personnel interviews     SY-B8           walkdowns during the               adequacy of the PRA model.
Gap #8 Use results of plant SY-A2 The Dominion PRA staff has Not Significant. This is judged to be a documentation walkdowns and plant SY-A4 performed many system conside ration only and does not affect the technical personnel interviews SY-B8 walkdowns during the adequacy of the PRA model.
(system engineers and     SY-C1           development and maintenance of operators) as a source                   the models. In addition , Dominion of information for                       PRA staff works closely with North modeling the as-built,                   Anna system engineers and as-operated plant.                       operators on nearly a daily basis while supporting the various risk informed programs. However, no formal documentation exists at this time to allow closure of these SRs.
(system engineers and SY-C1 development and maintenance of operators) as a source the models.
In addition, Dominion of information for PRA staff works closely with North modeling the as-built, Anna system engineers and as-operated plant.
operators on nearly a daily basis while supporting the various risk informed programs. However, no formal documentation exists at this time to allow closure of these SRs.
It is NOT anticipated that not meeting this requirement will have a siqnificant impact on the model.
It is NOT anticipated that not meeting this requirement will have a siqnificant impact on the model.


Serial No. 10-122A Docket Nos. 50-338/339 Page 7 of 11 Table 1 Status of identified Gaps to NEI 00-02 and Capability Category II of the ASME PRA Standard Title     Description               NEI Element /   Current Status / Comment           Importance to Application ASME SR Gap #9     Identify SSCs that may   SY-B15         Currently, the NAPS PRA model     PZR PORVs failing to reolose on water relief will be be required to operate                   does not distinguish between PZR   addressed by sensitivities per NEI 04 10, Revision 1 if in conditions beyond                     PORVs failing to reclose on water applioable to the speoifio STI evaluation.
Serial No. 10-122A Docket Nos. 50-338/339 Page 7 of 11 Table 1 Status of identified Gaps to NEI 00-02 and Capability Category II of the ASME PRA Standard Title Description NEI Element /
their environmental                       relief and steam qualifications.                                                             Significance: Currently, the NAPS PRA model does not distinguish between PZR PORVs failing to reclose on steam or water relief. EPRI TR-1011047
Current Status / Comment Importance to Application ASME SR Gap #9 Identify SSCs that may SY-B15 Currently, the NAPS PRA model PZR PORVs failing to reolose on water relief will be be required to operate does not distinguish between PZR addressed by sensitivities per NEI 04 10, Revision 1 if in conditions beyond PORVs failing to reclose on water applioable to the speoifio STI evaluation.
                                                                                      'Probability of Safety Valve Failure-to-Reseat Following Steam and Liquid Relief' provides guidance for evaluating the increase in failure probability associated with passing water. Significance will be addressed by incorporating the issue into the sensitivity study model.
their environmental relief and steam qualifications.
Significance: Currently, the NAPS PRA model does not distinguish between PZR PORVs failing to reclose on steam or water relief. EPRI TR-1011047
'Probability of Safety Valve Failure-to-Reseat Following Steam and Liquid Relief' provides guidance for evaluating the increase in failure probability associated with passing water. Significance will be addressed by incorporating the issue into the sensitivity study model.
Inadequate Scope: Probability of PZR PORV failing to reclose on water relief will be addressed in the sensitivity PRA model when quantifying the effect of a proposed individual STI revision for comparison to acceotance criteria in NEI 04-10 Revision 1.
Inadequate Scope: Probability of PZR PORV failing to reclose on water relief will be addressed in the sensitivity PRA model when quantifying the effect of a proposed individual STI revision for comparison to acceotance criteria in NEI 04-10 Revision 1.
Gap #10   Base the time available HR-G4           Time windows for successful       Several HEP M/\AP runs need to be updated and, to complete actions on                   completion of actions in some     therefore, these 'Nill be addressed by sensitivities per appropriate realistic                     instances may need to be updated NEI 04 10, Revision 1 if applioable to the speoifio STI generic thermal-                         (for example, those that are based evaluation. Note not all neoessary MAAP runs 'Nere hydraulic analyses, or                   on estimates made for the IPE)     updated for N009/\ model.
Gap #10 Base the time available HR-G4 Time windows for successful Several HEP M/\\AP runs need to be updated and, to complete actions on completion of actions in some therefore, these 'Nill be addressed by sensitivities per appropriate realistic instances may need to be updated NEI 04 10, Revision 1 if applioable to the speoifio STI generic thermal-(for example, those that are based evaluation. Note not all neoessary MAAP runs 'Nere hydraulic analyses, or on estimates made for the IPE) updated for N009/\\ model.
simulation from similar plants                                                                     Significance: This gap is not considered significant since most of the NAPS time windows are similar to the Surry Power Station (SPS) time windows, which are based on updated MAAP runs. NAPS and SPS systems are similar enough that the timings aren't expected to be significantly different. For those HEPs that don't have NAPS-specific MAAP analyses (which is most of them), the HEP probabilities will be increased bv factor of 2.
simulation from similar plants Significance: This gap is not considered significant since most of the NAPS time windows are similar to the Surry Power Station (SPS) time windows, which are based on updated MAAP runs. NAPS and SPS systems are similar enough that the timings aren't expected to be significantly different. For those HEPs that don't have NAPS-specific MAAP analyses (which is most of them), the HEP probabilities will be increased bv factor of 2.


Serial No. 10-122A Docket Nos. 50-338/339 Page 8 of 11 Table 1 Status of identified Gaps to NEI 00-02 and Capability Category II of the ASME PRA Standard Title     Description             NEI Element /   Current Status I Comment             Importance to Application ASME SR Gap #11 Base the required time     HR-G5           No formal documentation currently     Not Significant. This is judged to be a documentation to complete actions for                   exists and this SR will remain NOT consideration only and does not affect the technical significant HFEs on                       MET. As a footno te the timings       adequacy of the PRA model.
Serial No. 10-122A Docket Nos. 50-338/339 Page 8 of 11 Table 1 Status of identified Gaps to NEI 00-02 and Capability Category II of the ASME PRA Standard Title Description NEI Element /
action time                               are not expected to change measurements in either                   significantly as they are based on walkthroughs or talk-                     comparisons with similar actions at throughs of the                           Surry .
Current Status I Comment Importance to Application ASME SR Gap #11 Base the required time HR-G5 No formal documentation currently Not Significant. This is judged to be a documentation to complete actions for exists and this SR will remain NOT consideration only and does not affect the technical significant HFEs on MET. As a footnote the timings adequacy of the PRA model.
procedu res or simulator observations.
action time are not expected to change measurements in either significantly as they are based on walkthroughs or talk-comparisons with similar actions at throughs of the Surry.
Gap #12 Check the consistency       HR-G6           Document a review of the HFEs         Not Significant. This is judged to be a documentation of post-initiator HEPs.                 and their final HEPs relative to     consideration only and does not affect the technical each other to confirm their           adequacy of the PRA model.
procedures or simulator observations.
reasonableness given the scenario context, plant history , procedures, operational practices, and experience Gap #13 When using expert           DA-D2           Documentation needs to be             Not Significant. This is judged to be a documentation judgment document the                   enhanced for the several cases       consideration only and does not affect the techn ical rationale behind the                     where expert opinion is used. The adequacy of the PRA model choice of parameter                     expert opinion is reasonable and values .                                 should not chance.
Gap #12 Check the consistency HR-G6 Document a review of the HFEs Not Significant. This is judged to be a documentation of post-initiator HEPs.
Gap #14 Identify method-specific QU-B1             Although key assumptions are         Not Significant. This is judged to be a documentation limitations and features QU-F5           documented, these do not include     consideration only and does not affect the technical that could impact the                   limitations of the quantification     adequacy of the PRA model.
and their final HEPs relative to consideration only and does not affect the technical each other to confirm their adequacy of the PRA model.
results and                             method or features that impact applications.                             results (aside from references to code limitations, guidance documents and procedures) .
reasonableness given the scenario context, plant history, procedures, operational practices, and experience Gap #13 When using expert DA-D2 Documentation needs to be Not Significant. This is judged to be a documentation judgment document the enhanced for the several cases consideration only and does not affect the technical rationale behind the where expert opinion is used. The adequacy of the PRA model choice of parameter expert opinion is reasonable and values.
Gap #15 Identify key sources of     QU-E1           Each PRA element notebook (IE,       Not Significant. The PRA documentation has identified model uncertainty.                       AS ,SC,SY,DA,HR,LE)has               potential sources of modeling uncertainty. The identified potential sources of     potential sources of uncertainty will be addressed by model uncertainty. A                 sensitivities per NEI 04-10 , Revision 1 if applicable to characterization of those sources   the specific STI evaluation.
should not chance.
Gap #14 Identify method-specific QU-B1 Although key assumptions are Not Significant. This is judged to be a documentation limitations and features QU-F5 documented, these do not include consideration only and does not affect the technical that could impact the limitations of the quantification adequacy of the PRA model.
results and method or features that impact applications.
results (aside from references to code limitations, guidance documents and procedures).
Gap #15 Identify key sources of QU-E1 Each PRA element notebook (IE, Not Significant. The PRA documentation has identified model uncertainty.
AS,SC,SY,DA,HR,LE)has potential sources of modeling uncertainty. The identified potential sources of potential sources of uncertainty will be addressed by model uncertainty. A sensitivities per NEI 04-10, Revision 1 if applicable to characterization of those sources the specific STI evaluation.
of uncertainty and evaluation of the generic sources of uncertainty has not yet been completed however.
of uncertainty and evaluation of the generic sources of uncertainty has not yet been completed however.


Serial No. 10-122A Docket Nos. 50-338/339 Page 9 of 11 Table 1 Status of identified Gaps to NEI 00-02 and Capability Category II of the ASME PRA Standard Title     Description               NEI Element I   Current Status I Comment             Importance to Application ASME SR Gap #16 Provide a detailed         QU-F3           Significant contributors (based on   Not Significant. This is judged to be a documentation description of                           F-V and RAW) have been               consideration only and does not affect the technical significant accident                     identified and evaluated . A detailed adequacy of the PRA model.
Serial No. 10-122A Docket Nos. 50-338/339 Page 9 of 11 Table 1 Status of identified Gaps to NEI 00-02 and Capability Category II of the ASME PRA Standard Title Description NEI Element I Current Status I Comment Importance to Application ASME SR Gap #16 Provide a detailed QU-F3 Significant contributors (based on Not Significant. This is judged to be a documentation description of F-V and RAW) have been consideration only and does not affect the technical significant accident identified and evaluated. A detailed adequacy of the PRA model.
sequences or functional                   description has been provided for failure groups.                           the top 5 accident sequences, but not for all significant accident sequences or functional failure qroups.
sequences or functional description has been provided for failure groups.
Gap #17 Perform realistic           LE-D4           Secondary     side isolation during a The effeat of additional relief valve demands '""ill be secondary side                           SGTR should also consider the         addressed by sensitivity studies per NEI 04 10, revision isolation capability                     additional number of demands on       1, if appliaable to the speaifia STI evaluation.
the top 5 accident sequences, but not for all significant accident sequences or functional failure qroups.
analysis for the                         the relief valves in the progression significant accident                     to core damage.                       Significance: This is a Level 2 issue involving the progression sequences                                                         progression of core damage. The model currently does caused by SG tube                                                             not consider the additional steam generator relief valve release.                                                                       demands associated with SGTR resulting in core damage. The water relief PORV issue will be addressed in the sensitivity studies by evaluating the impact on the proposed surveillance test interval change. Therefore, significance will be addressed by incorooratina the issue into the sensitivitv studv model.
Gap #17 Perform realistic LE-D4 Secondary side isolation during a The effeat of additional relief valve demands '""ill be secondary side SGTR should also consider the addressed by sensitivity studies per NEI 04 10, revision isolation capability additional number of demands on 1, if appliaable to the speaifia STI evaluation.
analysis for the the relief valves in the progression significant accident to core damage.
Significance: This is a Level 2 issue involving the progression sequences progression of core damage. The model currently does caused by SG tube not consider the additional steam generator relief valve release.
demands associated with SGTR resulting in core damage. The water relief PORV issue will be addressed in the sensitivity studies by evaluating the impact on the proposed surveillance test interval change. Therefore, significance will be addressed by incorooratina the issue into the sensitivitv studv model.


Serial No. 10-122A Docket Nos. 50-338/339 Page 10 of 11 NRC Question 3 In Attachment 1, Section 2.2, Item 3 identified a deviation from Technical Specification Task Force-425 associated with the proposed Bases. Subsequent to the submittal, the U. S. Nuclear Regulatory Commission issued additional guidance on acceptable Bases (ADAMSML100990099) which addressed the specific issue.
Serial No. 10-122A Docket Nos. 50-338/339 Page 10 of 11 NRC Question 3 In Attachment 1, Section 2.2, Item 3 identified a deviation from Technical Specification Task Force-425 associated with the proposed Bases. Subsequent to the submittal, the U. S. Nuclear Regulatory Commission issued additional guidance on acceptable Bases (ADAMSML100990099) which addressed the specific issue.
"The insert provided in TSF-425 to replace text in the TS Bases describing the basis for each frequency relocated to the SFCP has been revised from, 'The Surveillance Frequency (SF) is based on operating experience, equipment reliability, and plant risk and is controlled under the Surveillance Frequency Control Program,' to read 'The Frequency may be based on factors such as operating experience, equipment reliability, or plant risk, and is controlled under the Surveillance Frequency Control Program.' This deviation is necessary to reflect the NAPS basis for frequencies which do not, in all cases, base frequency on operating experience, equipment reliability and plant risk."
"The insert provided in TSF-425 to replace text in the TS Bases describing the basis for each frequency relocated to the SFCP has been revised from, 'The Surveillance Frequency (SF) is based on operating experience, equipment reliability, and plant risk and is controlled under the Surveillance Frequency Control Program,' to read 'The Frequency may be based on factors such as operating experience, equipment reliability, or plant risk, and is controlled under the Surveillance Frequency Control Program.' This deviation is necessary to reflect the NAPS basis for frequencies which do not, in all cases, base frequency on operating experience, equipment reliability and plant risk."
TSTF-425 , Revision 3, "Relocate Surveillance Frequencies to Licensee Control-RITSTF Initiative 5b," (ADAMS Accession Nos. ML090850627 , ML090850630, ML090850638, and ML090850640) was approved by Notice of Availability published in the Federal Register on July 6, 2009. TSTF-425, Rev. 3 involves the relocation of most time-based surveillance frequencies to a licensee controlled program, called the Surveillance Frequency Control Program (SFCP), and adds the SFCP to the administrative controls section of TS. The SFCP does not include surveillance frequencies that are event driven, controlled by an existing program, or are condition-based.
TSTF-425, Revision 3, "Relocate Surveillance Frequencies to Licensee Control-RITSTF Initiative 5b," (ADAMS Accession Nos. ML090850627, ML090850630, ML090850638, and ML090850640) was approved by Notice of Availability published in the Federal Register on July 6, 2009. TSTF-425, Rev. 3 involves the relocation of most time-based surveillance frequencies to a licensee controlled program, called the Surveillance Frequency Control Program (SFCP), and adds the SFCP to the administrative controls section of TS.
The SFCP does not include surveillance frequencies that are event driven, controlled by an existing program, or are condition-based.
Part of the TSTF-425 change to NUREGs 1430-1434 (Standard Technical Specifications) provides an optional insert (INSERT 2) to the existing Technical Specification (TS) Bases to facilitate adoption of the TSTF while retaining the existing NUREG TS Surveillance Frequency TS Bases for licensees not choosing to adopt TSTF-425. The TSTF-425 TS Bases INSERT 2 states:
Part of the TSTF-425 change to NUREGs 1430-1434 (Standard Technical Specifications) provides an optional insert (INSERT 2) to the existing Technical Specification (TS) Bases to facilitate adoption of the TSTF while retaining the existing NUREG TS Surveillance Frequency TS Bases for licensees not choosing to adopt TSTF-425. The TSTF-425 TS Bases INSERT 2 states:
"The Surveillance Frequency is based on operating experience, equipment reliability, and plant risk and is controlled under the Surveillance Frequency Control Program."
"The Surveillance Frequency is based on operating experience, equipment reliability, and plant risk and is controlled under the Surveillance Frequency Control Program."
Several licensees requesting license amendments to adopt TSTF-425 have identified a need to deviate from this statement because it only applies to frequencies that have been changed in accordance with the Surveillance Frequency Control Program (SFCP) and does not apply to frequencies that are relocated but not changed.
Several licensees requesting license amendments to adopt TSTF-425 have identified a need to deviate from this statement because it only applies to frequencies that have been changed in accordance with the Surveillance Frequency Control Program (SFCP) and does not apply to frequencies that are relocated but not changed.
The NRC staff agrees that the TSTF-425 TS Bases insert applies only to relocated SFs that are subsequently evaluated and changed in accordance with the SFCP, and that the current insert does not apply to SFs relocated to the SFCP but remain unchanged.
The NRC staff agrees that the TSTF-425 TS Bases insert applies only to relocated SFs that are subsequently evaluated and changed in accordance with the SFCP, and that the current insert does not apply to SFs relocated to the SFCP but remain unchanged.
Line 114: Line 151:


Serial No. 10-122A Docket Nos. 50-338/339 Page 11 of 11 One option to address this concern for those instances where the licensee used TSTF-425 Insert 2, is to modify the wording used in the application as follows:
Serial No. 10-122A Docket Nos. 50-338/339 Page 11 of 11 One option to address this concern for those instances where the licensee used TSTF-425 Insert 2, is to modify the wording used in the application as follows:
"The Surveillance Frequency is controlled under the Surveillance Frequency Control Program" In addition, the following statement should be included regarding SF Bases relocated to the SFCP:
"The Surveillance Frequency is controlled under the Surveillance Frequency Control Program" In addition, the following statement should be included regarding SF Bases relocated to the SFCP:
"The existing Bases information describing the basis for the Surveillance Frequency will be relocated to the licensee-controlled Surveillance Frequency Control Program."
"The existing Bases information describing the basis for the Surveillance Frequency will be relocated to the licensee-controlled Surveillance Frequency Control Program."
It should be noted that only the Bases for the Surveillance Frequency can be relocated to the SFCP. The Bases for the TS Surveillance will remain in the TS Bases and should not be relocated to the SFCP. The licensee is requested to provide a revision to its proposed Bases changes consistent with this guidance.
It should be noted that only the Bases for the Surveillance Frequency can be relocated to the SFCP. The Bases for the TS Surveillance will remain in the TS Bases and should not be relocated to the SFCP.
The licensee is requested to provide a revision to its proposed Bases changes consistent with this guidance.
VEPCO's application dated March 30, 2010, included the aforementioned deviations from the proposed language in TSTF-425, Revision 3. The NRC staff has reviewed the proposed deviation from TSTF-425 and requests that the licensee modify the application, as described above, or develop an alternate resolution to the issue with Insert 2 as described in item 3, and including appropriate justifications.
VEPCO's application dated March 30, 2010, included the aforementioned deviations from the proposed language in TSTF-425, Revision 3. The NRC staff has reviewed the proposed deviation from TSTF-425 and requests that the licensee modify the application, as described above, or develop an alternate resolution to the issue with Insert 2 as described in item 3, and including appropriate justifications.
Dominion Response Dominion was aware of the NRC guidance provided in the April 2010 letter. In addition, to the letter, several discussions have taken place between the NRC and Technical Specification Task Force (TSTF) to develop the appropriate wording of the Bases.
Dominion Response Dominion was aware of the NRC guidance provided in the April 2010 letter. In addition, to the letter, several discussions have taken place between the NRC and Technical Specification Task Force (TSTF) to develop the appropriate wording of the Bases.
Dominion has reviewed this additional guidance and is providing a revision to its proposed Bases changes consistent the latest guidance from the NRC and TSTF.
Dominion has reviewed this additional guidance and is providing a revision to its proposed Bases changes consistent the latest guidance from the NRC and TSTF.
The following Bases words will be used to discuss the basis for surveillance frequencies consistent with the NRC guidance:
The following Bases words will be used to discuss the basis for surveillance frequencies consistent with the NRC guidance:
        'T he Surveillance Frequency is controlled under the Surveillance Frequency Control Program."
'The Surveillance Frequency is controlled under the Surveillance Frequency Control Program."
A corrected Insert 1 for the Bases changes is included. Please use the revised Insert 1 to complete the review of the proposed March 30, 2010 LAR Bases changes.
A corrected Insert 1 for the Bases changes is included. Please use the revised Insert 1 to complete the review of the proposed March 30, 2010 LAR Bases changes.
After NRC approval of the LAR and as part of the LAR implementation , the existing North Anna Bases information describing the basis for the relocated Surveillance Frequencies will also be relocated to the North Anna Surveillance Frequency Control Program.
After NRC approval of the LAR and as part of the LAR implementation, the existing North Anna Bases information describing the basis for the relocated Surveillance Frequencies will also be relocated to the North Anna Surveillance Frequency Control Program.


Serial No. 10-122A Docket Nos. 50-338/339 ATTACHMENT 2 RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION PROPOSED LICENSE AMENDMENT REQUEST REGARDING RISK-INFORMED JUSTIFICATION FOR THE RELOCATION OF SPECIFIC SURVEILLANCE FREQUENCY REQUIREMENTS TO A LICENSEE CONTROLLED PROGRAM REVISED INSERT FOR TS BASES CHANG ES VIRGINIA ELECTRIC AND POWER COMPANY (DOMINION)
Serial No. 10-122A Docket Nos. 50-338/339 ATTACHMENT 2 RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION PROPOSED LICENSE AMENDMENT REQUEST REGARDING RISK-INFORMED JUSTIFICATION FOR THE RELOCATION OF SPECIFIC SURVEILLANCE FREQUENCY REQUIREMENTS TO A LICENSEE CONTROLLED PROGRAM REVISED INSERT FOR TS BASES CHANG ES VIRGINIA ELECTRIC AND POWER COMPANY (DOMINION)

Latest revision as of 03:10, 14 January 2025

Response to Request for Additional Information, Proposed License Amendment Request Regarding Risk-Informed Justification for the Relocation of Specific Surveillance Frequency Requirements to a Licensee Controlled Program
ML102430462
Person / Time
Site: North Anna  Dominion icon.png
Issue date: 08/30/2010
From: Hartz L
Dominion, Virginia Electric & Power Co (VEPCO)
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
10-122A
Download: ML102430462 (17)
v • d • e


Text

10 CFR 50.90 VIRGINI A ELECTRIC A N D POWER COM PA N Y RICHMOND, VIRGI N I A 23261 August 30, 2010 U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555 Serial No.

10-122A NL&OS/ETS RO Docket Nos. 50-338/339 License Nos. NPF-4/7 VIRGINIA ELECTRIC AND POWER COMPANY (DOMINION)

NORTH ANNA POWER STATION UNITS 1 AND 2 RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION PROPOSED LICENSE AMENDMENT REQUEST REGARDING RISK-INFORMED JUSTIFICATION FOR THE RELOCATION OF SPECIFIC SURVEILLANCE FREQUENCY REQUIREMENTS TO A LICENSEE CONTROLLED PROGRAM (ADOPTION OF TSTF-425, REVISION 3)

In a March 30, 2010 letter (Serial NO.10-050), Dominion requested amendments, in the form of changes to the Technical Specifications (TS) to Facility Operating License Numbers NPF-4 and NPF-7, for North Anna Power Station Units 1 and 2, respectively.

The proposed amendments would modify North Anna TS by relocating specific surveillance frequencies to a licensee-controlled program with the implementation of Nuclear Energy Institute (NEI) 04-10, "Risk-Informed Technical Specifications Initiative 5b, Risk-Informed Method for Control of Surveillance Frequencies."

In an August 6, 2010 e-mail from Dr. V. Sreenivas, the NRC requested additional information to complete the review of the license amendment request. The attachment to this letter provides the information requested in the August 6, 2010 e-mail.

The information provided in this letter does not affect the conclusion of the significant hazards consideration discussion provided in Dominion letter dated March 30, 2010 (Serial NO.10-050) for North Anna.

Dominion continues to request approval of the proposed license amendments by April 1, 2011, with the amendments being implemented within 120 days.

In accordance with 10 CFR 50.91, "Notice for Public Comment; State Consultation," a copy of this response, with attachments, is being provided to the designated State Officials.

Serial No. 10-122A Docket Nos. 50-338/339 LAR - Relocate Surveillance Frequencies from TS Page 2 of 3 If you have any questions or require additional. information, please contact Mr. Thomas Shaub at (804) 273-2763.

Sincerely,

~1:cJ Vice President - Nuclear Support Services Attachments:

1. Response To Request For Additional Information - PRA Quality Concerns
2. Response To Request For Additional Information - Revised Insert for TS Bases Changes Commitments made in this letter: Dominion will assess the PRA model gaps for each surveillance frequency change until the PRA model of record is updated.

COMMONWEALTH OF VIRGINIA COUNTY OF HENRICO The foregoing document was acknowledged before me, in and for the County and Commonwealth aforesaid, today by Leslie N. Hartz, who is Vice President - Nuclear Support Services, of Virginia Electric and Power Company. She has affirmed before me that she is duly authorized to execute and file the foregoing document in behalf of that Company, and that the statements in the document are true to the best of her knowledge and belief.

Acknowledged before me thisdf)7l'day ofd (just

,2010.

My Commission Expires:9 31, dO 1'1-.,;[..

~ IclL(. X, \\.j..} U. QQ _

Notary Public V1CKll. HUll fCotary Public Commonwtallt ofVIrgilIa 140542

.., ConInIiAion ExpIrnMar 31.2014

cc:

U.S. Nuclear Regulatory Commission Region II Marquis One Tower 245 Peachtree Center Avenue, NE Suite 1200 Atlanta, Georgia 30303-1257 Mr. J. E. Reasor, Jr.

Old Dominion Electric Cooperative Innsbrook Corporate Center 4201 Dominion Blvd.

Suite 300 Glen Allen, Virginia 23060 State Health Commissioner Virginia Department of Health James Madison Building - 7th floor 109 Governor Street Suite 730 Richmond, Virginia 23219 NRC Senior Resident Inspector North Anna Power Station Ms. K. R. Cotton NRC Project Manager U. S. Nuclear Regulatory Commission One White Flint North Mail Stop 08 G9A 11555 Rockville Pike Rockville, Maryland 20852 Dr. V. Sreenivas NRC Project Manager U. S. Nuclear Regulatory Commission One White Flint North Mail Stop 08 G9A 11555 Rockville Pike Rockville, Maryland 20852 Serial No. 10-122A Docket Nos. 50-338/339 LAR - Relocate Surveillance Frequencies from TS Page 3 of 3

Serial No. 10-122A Docket Nos. 50-338/339 Response To Request For Additional Information LAR - Relocate Surveillance Frequencies from TS ATTACHMENT 1 RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION PROPOSED LICENSE AMENDMENT REQUEST REGARDING RISK-INFORMED JUSTIFICATION FOR THE RELOCATION OF SPECIFIC SURVEILLANCE FREQUENCY REQUIREMENTS TO A LICENSEE CONTROLLED PROGRAM PRA QUALITY CONCERNS VIRGINIA ELECTRIC AND POWER COMPANY (DOMINION)

NORTH ANNA POWER STATION UNITS 1 AND 2

Serial No. 10-122A Docket Nos. 50-338/339 Response To Request For Additional Information LAR - Relocate Surveillance Frequencies from TS Page 1 of 11 NRC Question 1 and 2 Table 1 of Attachment 2 has been updated to address the NRC's Request for Additional Information. Specifically, questions 1 and 2:

1. In Table 1 of Attachment 2 of the submittal, the importance of each gap to this application in many instances is dispositioned simply by referring to the Nuclear Energy Institute (NEI) 04-10 requirement to assess deficiencies with sensitivity analyses.

This statement alone is insufficient for the staff to find the probabilistic risk assessment (PRA) model adequate to support the application.

The licensee is requested to provide its assessment of the significance of each gap to the calculation of risk increases associated with changes to surveillance frequency. This is requested for the following items in Table 1: #1, #2, #3(1), #4(1), #5, #7, #9, #10, and #17.

2. In Table 1 of Attachment 2 of the submittal, several gaps (#3, #4(1), #5, #7,
  1. 9) identify missing logic in the PRA model (inadequate scope). It is not clear to the staff how missing scope in a PRA can be addressed by sensitivity analyses.

The licensee is requested to discuss how it would conduct such analyses for this application.

This is requested for the following items in Table 1: #3, #4(1), #5, #7, and #9.

Dominion Response Table 1 has been revised to address the above RAls.

The revisions are included in column titled, Importance to Application. Specifically, the responses to question #1 start off with "Significance" and the responses to question #2 begin with "Inadequate Scope."

For each surveillance test interval change, missing logic gaps (inadequate scope) will be addressed via the use of sensitivity studies. The model used for the sensitivity study will account for the specific logic gaps as shown in Table 1. In addition, the PRA input to the expert panel will include a documented discussion on each of the aforementioned gaps. The use of gap sensitivity studies will no longer be required once the gaps have been incorporated into the NAPS PRA model of record. The Dominion PRA models are usually updated around every 3 to 5 years

Serial No. 10-122A Docket Nos. 50-338/339 Page 2 of 11 Table 1 Status of identified Gaps to NEI 00-02 and Capability Category II of the ASME PRA Standard Title Description NEI Element I Current Status I Comment Importance to Application ASMESR Gap #1 ATWS modeling of AS-9, ATWS Failure Relief Probability is Conservative modeling of the A1VVS Failure potentially dominate QU-11, conservatively modeled based on Probabilities 'Nill be addressed by sensitivities per NEI dominant sequences ST-13 a UET (Unfavorable Exposure 04 10, Revision 1 if applioable to the speoific STI and data traceability Time) of 27%.

evaluation.

Significance: The NAPS ATWS model uses a conservative simplification that assumes that pressure relief is always insufficient whenever the unit is in the UET period, which is assumed to be 27%. This is a conservative bias since there is a probability that pressure relief is successful given the availability of the pressurizer PORVs, safeties and AFW. The sensitivity studies will include an ATWS assessment in accordance with WCAP-15831, WOG Risk-Informed ATWS Assessment and Licensing Implementation Process using the generic methodology and values.

Gap #2 For initiating event IE-C8 The current NAPS system-level Support system level initiating event fault trees will be fault-tree modeling, initiating event fault trees uses a addressed by sensitivities per NEI 04 10, Revision 1 if capture all relevant 365*Capacity Factor multiplier in applioable to the speoifio STI evaluation.

combinations of events all of the initiating event fault trees, involving the annual which needs to be replaced with Significance: This issue is important for any potential frequency of one the new methodology described in Surveillance Test Interval (STI) change impacting component failure EPRI TR-1013490, "Support support system initiating events. Therefore, the combined with the System Initiating Events:

system-level initiating events will be revised using the unavailability of other Identification and Quantification methodology in EPRI TR-1013490 methodology.

components Guideline", EPRI, December 2006.

Serial No. 10-122A Docket Nos. 50-338/339 Page 3 of 11 Table 1 Status of identified Gaps to NEI 00-02 and Capability Category II of the ASME PRA Standard Title Description NEI Element I Current Status I Comment Importance to Application ASMESR Gap #3 For key safety functions AS-A4 SR is NOT MET until: 1) an HEP is

1) HEP for restoring of EGGS during SBO will be (e.g., power added to the SBO nodes for addressed by sensitivities per NEI 04 10, Revision 1 if restoration) identify restoring the EGGS functions; and applioable to the speoifio STI evaluation.

operator actions to

2) text in seotion 2.3.3.1 is the achieve the defined accident sequence documentation Significance: Non-consideration of this operator action success criteria.

needs to be revised to clarify the results in a small non-conservatism in the Station need for operator action to restart Black-Out (SBO) accident sequences results. The EGGS functions.

overall impact on the results is small.

Inadequate Scope: An Human Error Probability (HEP) will be added to the sensitivity PRA model when quantifying the effect of a proposed individual STI revision for comparison to acceptance criteria in NEI 04-10. Revision 1.

2) None. This is judged to be a documentation consideration only and does not affect the technical adequacy of the PRA model.

Serial No."10-122A Docket Nos. 50-338/339 Page 4 of 11 Table 1 Status of identified Gaps to NEI 00-02 and Capability Category II of the ASME PRA Standard Title Description NEI Element I Current Status I Comment Importance to Application ASME SR Gap #4 Delineate accident AS-A?

SR is NOT MET until: 1) inclusion

1) Consequential loss of RCP seal cooling for sequence (e.g., Loss of of consequential loss of RCP seal transients will be addressed by sensitivities per NEI 04 RCP seal cooling) for cooling for transients, and 2) 10, Revision 1 if applicable to the specific STI each initiating event documentation enhancement of evaluation.

(e.g., transients).

the U1-RCPSL nodes.

Significance: Consequential loss of RCP seal cooling is not specifically considered in the event trees, as both the CC and CH systems would need to fail within the 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of an initiating event. The model does include consequential pressurizer PORV failing to reclose, which is transferred to the small LOCA event tree. The consequential PORV LOCA has a relatively low risk importance. The consequential loss of RCP seal cooling is expected to have a comparable or lower risk impact.

Inadeguate Scope: A consequential loss of RCP seal cooling for transients will be addressed in sensitivity studies when quantifying the effect of a proposed individual STI revision for comparison to acceptance criteria in NEI 04-10, Revision 1.

2) None. This is judged to be a documentation consideration only and does not affect the technical adequacy of the PRA model.

Serial No. 10-122A Docket Nos. 50-338/339 Page 5 of 11 Table 1 Status of identified Gaps to NEI 00-02 and Capability Category II of the ASME PRA Standard Title Description NEI Element I Current Status I Comment Importance to Application ASME SR Gap #5 Define and model plant AS-B5a Cross-tie unavailability due to Cross tie electrioal bus unavailability due to refuel ing configurations and outages is accounted for with the outages will be addressed by sensitivities per NEI 04 alignments that reflect exception of electrical buses where 10, Revision 1 if applioable to the specific STI dependencies.

the unavailability during at power evaluation.

operation is essentially 0 versus one or two days during refueling Significance: Significance will be addressed by outages.

modeling electrical bus cross-tie unavailability for each sensitivity study.

Inadequate Scope: The sensitivity studies will address the electrical bus cross-tie unavailability before quantifying the effect of a proposed individual STI revision for comparison to acceptance criteria in NEI 04-10, Revision 1.

Gap #6 Include a discussion of SC-A6 Some of the success criteria None. This is jUdged to be a documentation operator actions discussion includes general consideration only and does not affect the technical assumed as part of the operator actions, but the adequacy of the PRA model.

success criteria discussion does not include development, and how procedures and not all event tree those actions are sections contain the discussion consistent with plant procedures and practices

Serial No. 10-122A Docket Nos. 50-338/339 Page 6 of 11 Table 1 Status of identified Gaps to NEI 00-02 and Capability Category II of the ASME PRA Standard Title Description NEI Element /

Current Status / Comment Importance to Application ASME SR Gap #7 Incorporate the effect of SY-A11 The ourrent NAPS PRA does not Inadvertent SI Aotuation will be addressed by variable success SY-A13 inolude inadvertent SI Aotuation.

sensitivities per NEI 04 10, Revision 1 if applioable to criteria (i.e., success Inadvertent Safety Injection (SI) the speoifio STI evaluation.

criteria that change as Actuation has been included in the a function of plant NAPS PRA model of record, Significance: The NAPS PRA model, N009A. has status) into the system N009Aa.

been updated since the RITS 5b submittal and before modeling. Include receiving the Request for Additional Information. The consideration of all latest NAPS PRA model, N009Aa, includes Inadvertent failure modes, SI Actuation, Significance has been addressed by consistent with incorporating the issue into the PRA model of record,

available data and N009Aa.

model level of detail Inadeauate Scope: As stated above, Inadvertent SI Actuation was integrated into the latest NAPS PRA model, N009Aa.

Gap #8 Use results of plant SY-A2 The Dominion PRA staff has Not Significant. This is judged to be a documentation walkdowns and plant SY-A4 performed many system conside ration only and does not affect the technical personnel interviews SY-B8 walkdowns during the adequacy of the PRA model.

(system engineers and SY-C1 development and maintenance of operators) as a source the models.

In addition, Dominion of information for PRA staff works closely with North modeling the as-built, Anna system engineers and as-operated plant.

operators on nearly a daily basis while supporting the various risk informed programs. However, no formal documentation exists at this time to allow closure of these SRs.

It is NOT anticipated that not meeting this requirement will have a siqnificant impact on the model.

Serial No. 10-122A Docket Nos. 50-338/339 Page 7 of 11 Table 1 Status of identified Gaps to NEI 00-02 and Capability Category II of the ASME PRA Standard Title Description NEI Element /

Current Status / Comment Importance to Application ASME SR Gap #9 Identify SSCs that may SY-B15 Currently, the NAPS PRA model PZR PORVs failing to reolose on water relief will be be required to operate does not distinguish between PZR addressed by sensitivities per NEI 04 10, Revision 1 if in conditions beyond PORVs failing to reclose on water applioable to the speoifio STI evaluation.

their environmental relief and steam qualifications.

Significance: Currently, the NAPS PRA model does not distinguish between PZR PORVs failing to reclose on steam or water relief. EPRI TR-1011047

'Probability of Safety Valve Failure-to-Reseat Following Steam and Liquid Relief' provides guidance for evaluating the increase in failure probability associated with passing water. Significance will be addressed by incorporating the issue into the sensitivity study model.

Inadequate Scope: Probability of PZR PORV failing to reclose on water relief will be addressed in the sensitivity PRA model when quantifying the effect of a proposed individual STI revision for comparison to acceotance criteria in NEI 04-10 Revision 1.

Gap #10 Base the time available HR-G4 Time windows for successful Several HEP M/\\AP runs need to be updated and, to complete actions on completion of actions in some therefore, these 'Nill be addressed by sensitivities per appropriate realistic instances may need to be updated NEI 04 10, Revision 1 if applioable to the speoifio STI generic thermal-(for example, those that are based evaluation. Note not all neoessary MAAP runs 'Nere hydraulic analyses, or on estimates made for the IPE) updated for N009/\\ model.

simulation from similar plants Significance: This gap is not considered significant since most of the NAPS time windows are similar to the Surry Power Station (SPS) time windows, which are based on updated MAAP runs. NAPS and SPS systems are similar enough that the timings aren't expected to be significantly different. For those HEPs that don't have NAPS-specific MAAP analyses (which is most of them), the HEP probabilities will be increased bv factor of 2.

Serial No. 10-122A Docket Nos. 50-338/339 Page 8 of 11 Table 1 Status of identified Gaps to NEI 00-02 and Capability Category II of the ASME PRA Standard Title Description NEI Element /

Current Status I Comment Importance to Application ASME SR Gap #11 Base the required time HR-G5 No formal documentation currently Not Significant. This is judged to be a documentation to complete actions for exists and this SR will remain NOT consideration only and does not affect the technical significant HFEs on MET. As a footnote the timings adequacy of the PRA model.

action time are not expected to change measurements in either significantly as they are based on walkthroughs or talk-comparisons with similar actions at throughs of the Surry.

procedures or simulator observations.

Gap #12 Check the consistency HR-G6 Document a review of the HFEs Not Significant. This is judged to be a documentation of post-initiator HEPs.

and their final HEPs relative to consideration only and does not affect the technical each other to confirm their adequacy of the PRA model.

reasonableness given the scenario context, plant history, procedures, operational practices, and experience Gap #13 When using expert DA-D2 Documentation needs to be Not Significant. This is judged to be a documentation judgment document the enhanced for the several cases consideration only and does not affect the technical rationale behind the where expert opinion is used. The adequacy of the PRA model choice of parameter expert opinion is reasonable and values.

should not chance.

Gap #14 Identify method-specific QU-B1 Although key assumptions are Not Significant. This is judged to be a documentation limitations and features QU-F5 documented, these do not include consideration only and does not affect the technical that could impact the limitations of the quantification adequacy of the PRA model.

results and method or features that impact applications.

results (aside from references to code limitations, guidance documents and procedures).

Gap #15 Identify key sources of QU-E1 Each PRA element notebook (IE, Not Significant. The PRA documentation has identified model uncertainty.

AS,SC,SY,DA,HR,LE)has potential sources of modeling uncertainty. The identified potential sources of potential sources of uncertainty will be addressed by model uncertainty. A sensitivities per NEI 04-10, Revision 1 if applicable to characterization of those sources the specific STI evaluation.

of uncertainty and evaluation of the generic sources of uncertainty has not yet been completed however.

Serial No. 10-122A Docket Nos. 50-338/339 Page 9 of 11 Table 1 Status of identified Gaps to NEI 00-02 and Capability Category II of the ASME PRA Standard Title Description NEI Element I Current Status I Comment Importance to Application ASME SR Gap #16 Provide a detailed QU-F3 Significant contributors (based on Not Significant. This is judged to be a documentation description of F-V and RAW) have been consideration only and does not affect the technical significant accident identified and evaluated. A detailed adequacy of the PRA model.

sequences or functional description has been provided for failure groups.

the top 5 accident sequences, but not for all significant accident sequences or functional failure qroups.

Gap #17 Perform realistic LE-D4 Secondary side isolation during a The effeat of additional relief valve demands '""ill be secondary side SGTR should also consider the addressed by sensitivity studies per NEI 04 10, revision isolation capability additional number of demands on 1, if appliaable to the speaifia STI evaluation.

analysis for the the relief valves in the progression significant accident to core damage.

Significance: This is a Level 2 issue involving the progression sequences progression of core damage. The model currently does caused by SG tube not consider the additional steam generator relief valve release.

demands associated with SGTR resulting in core damage. The water relief PORV issue will be addressed in the sensitivity studies by evaluating the impact on the proposed surveillance test interval change. Therefore, significance will be addressed by incorooratina the issue into the sensitivitv studv model.

Serial No. 10-122A Docket Nos. 50-338/339 Page 10 of 11 NRC Question 3 In Attachment 1, Section 2.2, Item 3 identified a deviation from Technical Specification Task Force-425 associated with the proposed Bases. Subsequent to the submittal, the U. S. Nuclear Regulatory Commission issued additional guidance on acceptable Bases (ADAMSML100990099) which addressed the specific issue.

"The insert provided in TSF-425 to replace text in the TS Bases describing the basis for each frequency relocated to the SFCP has been revised from, 'The Surveillance Frequency (SF) is based on operating experience, equipment reliability, and plant risk and is controlled under the Surveillance Frequency Control Program,' to read 'The Frequency may be based on factors such as operating experience, equipment reliability, or plant risk, and is controlled under the Surveillance Frequency Control Program.' This deviation is necessary to reflect the NAPS basis for frequencies which do not, in all cases, base frequency on operating experience, equipment reliability and plant risk."

TSTF-425, Revision 3, "Relocate Surveillance Frequencies to Licensee Control-RITSTF Initiative 5b," (ADAMS Accession Nos. ML090850627, ML090850630, ML090850638, and ML090850640) was approved by Notice of Availability published in the Federal Register on July 6, 2009. TSTF-425, Rev. 3 involves the relocation of most time-based surveillance frequencies to a licensee controlled program, called the Surveillance Frequency Control Program (SFCP), and adds the SFCP to the administrative controls section of TS.

The SFCP does not include surveillance frequencies that are event driven, controlled by an existing program, or are condition-based.

Part of the TSTF-425 change to NUREGs 1430-1434 (Standard Technical Specifications) provides an optional insert (INSERT 2) to the existing Technical Specification (TS) Bases to facilitate adoption of the TSTF while retaining the existing NUREG TS Surveillance Frequency TS Bases for licensees not choosing to adopt TSTF-425. The TSTF-425 TS Bases INSERT 2 states:

"The Surveillance Frequency is based on operating experience, equipment reliability, and plant risk and is controlled under the Surveillance Frequency Control Program."

Several licensees requesting license amendments to adopt TSTF-425 have identified a need to deviate from this statement because it only applies to frequencies that have been changed in accordance with the Surveillance Frequency Control Program (SFCP) and does not apply to frequencies that are relocated but not changed.

The NRC staff agrees that the TSTF-425 TS Bases insert applies only to relocated SFs that are subsequently evaluated and changed in accordance with the SFCP, and that the current insert does not apply to SFs relocated to the SFCP but remain unchanged.

For SFs relocated to the SFCP but not subsequently changed in accordance with the program, the existing TS Bases description remains a valid Bases for these SFs.

Serial No. 10-122A Docket Nos. 50-338/339 Page 11 of 11 One option to address this concern for those instances where the licensee used TSTF-425 Insert 2, is to modify the wording used in the application as follows:

"The Surveillance Frequency is controlled under the Surveillance Frequency Control Program" In addition, the following statement should be included regarding SF Bases relocated to the SFCP:

"The existing Bases information describing the basis for the Surveillance Frequency will be relocated to the licensee-controlled Surveillance Frequency Control Program."

It should be noted that only the Bases for the Surveillance Frequency can be relocated to the SFCP. The Bases for the TS Surveillance will remain in the TS Bases and should not be relocated to the SFCP.

The licensee is requested to provide a revision to its proposed Bases changes consistent with this guidance.

VEPCO's application dated March 30, 2010, included the aforementioned deviations from the proposed language in TSTF-425, Revision 3. The NRC staff has reviewed the proposed deviation from TSTF-425 and requests that the licensee modify the application, as described above, or develop an alternate resolution to the issue with Insert 2 as described in item 3, and including appropriate justifications.

Dominion Response Dominion was aware of the NRC guidance provided in the April 2010 letter. In addition, to the letter, several discussions have taken place between the NRC and Technical Specification Task Force (TSTF) to develop the appropriate wording of the Bases.

Dominion has reviewed this additional guidance and is providing a revision to its proposed Bases changes consistent the latest guidance from the NRC and TSTF.

The following Bases words will be used to discuss the basis for surveillance frequencies consistent with the NRC guidance:

'The Surveillance Frequency is controlled under the Surveillance Frequency Control Program."

A corrected Insert 1 for the Bases changes is included. Please use the revised Insert 1 to complete the review of the proposed March 30, 2010 LAR Bases changes.

After NRC approval of the LAR and as part of the LAR implementation, the existing North Anna Bases information describing the basis for the relocated Surveillance Frequencies will also be relocated to the North Anna Surveillance Frequency Control Program.

Serial No. 10-122A Docket Nos. 50-338/339 ATTACHMENT 2 RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION PROPOSED LICENSE AMENDMENT REQUEST REGARDING RISK-INFORMED JUSTIFICATION FOR THE RELOCATION OF SPECIFIC SURVEILLANCE FREQUENCY REQUIREMENTS TO A LICENSEE CONTROLLED PROGRAM REVISED INSERT FOR TS BASES CHANG ES VIRGINIA ELECTRIC AND POWER COMPANY (DOMINION)

NORTH ANNA POWER STATION UNITS 1 AND 2

Serial No. 10-122A Docket Nos. 50-338/339 REVISED INSERT FOR TECHNICAL SPECIFICATIONS BASES INSERT 1 The Surveillance Frequency is controlled under the Surveillance Frequency Control Program.

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