B17590, Application for Amend to License DPR-65,removing TS 3/4.6.4.3, Containment Systems,Hydrogen Purge Sys, from Plant TS
| ML20199L027 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 01/18/1999 |
| From: | Bowling M NORTHEAST NUCLEAR ENERGY CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20199L030 | List: |
| References | |
| B17590, NUDOCS 9901270109 | |
| Download: ML20199L027 (13) | |
Text
,_ . ... _ _ _ . _ _ . _ .. . . . _ _ _ _ _ _._ _ _ ___ ___.
>g #* t .,
Northeast ' R Pe Feny Bd. (Rouw 156), %wrford, CT 06385 Nuclear Energy mu. tone Nuclear Power Station Northeast Nuclear Energy Company P.O. Bos 128 Waterford, CT 06385-0128
- l' (860) 447-1791 Fax (860) 444-4277 ;
'lhe Northeast Utahties System ,
c JAN 181999 f I Docket No. 50-336 B17590 Re: 10 CFR50.90 :
U. S. Nuclear Regulatory Commission :
Attention: Document Control Desk Washington, DC 20555
, Millstone Nuclear Power Station, Unit No. 2 !
Proposed Revision to Technical Specifications ;
Deletion of The Technical Specification Related to The Hydroaen Purae System j Pursuant to 10 CFR 50.90, Northeast Nuclear Energy Company (NNECO) hereby
- proposes to amend Operating License DPR-65 by incorporating the attached proposed changes into the Millstone Unit No. 2 Technical Specifications. The proposed changes '
will remove the Technical Specification'related to Hydrogen Purge System from the Millstone Unit No. 2 Technical Specifications. ;
The proposed changes affect Technical Specifications 3/4.6.4.3, " Containment Systems, Hydrogen Purge System." The Bases of the associated Technical :
Specification will be modified to address the proposed changes. ;
Attachment 1 provides a discussion of the proposed changes and the Safety Summary.
Attachment 2 provides the Significant Hazards Consideration. Attachment 3 provides L the marked-up version of the appropriate pages of the current Technical Specifications. >
Attachment 4 provides the retyped pages of the Technical Specifications and associated Bases.
Environmental Considerations 'l l
NNECO has reviewed the proposed License Amendment Request against the criteria !
of 10 CFR 51.22 for environmental considerations. The proposed changes will remove
\
- Technical- Specifications 3/4.6.4.3, and revise index Page Vll. The Bases of the associated Technical Specification will be modified to address the proposed changes.
f0 These changes will not significantly increase the type arid amounts of effluents that j may be' released offsite. In addition, this amendment request will not significantly increase individual or cumulative occupational radiation exposures. Therefore, ,
NNECO has determined that the proposed changes will not have a significant effect on 4
the quality of human environment.
9901270109 990118 7 jDR ADOCK O
U.S. Nucl=r R:gulatory Commission B17590/Pcge 2 Conclusions The proposed changes were evaluated utilizing the criteria of 10 CFR 50.59 and were determined not to be an unreviewed safety question. Additionally, we have concluded that the proposed changes are safe.
The proposed changes do not involve a significant impact on public health and safety (see the Safety Summary provided in Attachment 1) and do not involve a Significant Hazards Consideration pursuant to the provisions of 10 CFR 50.92 (see the Significant Hazards Consideration provided in Attachment 2).
Plant Operations Review Committee and Nuclear Safety Assessment Board The Plant Operations Review Committee and Nuclear Safety Assessment Board have reviewed and concurred with the determinations.
Schedule We request issuance at your earliest convenience, with the amendment to be implemented within 60 days of issuance.
State Notification in accordance with 10 CFR50.91(b), a copy of this License Amendment Request is being provided to the State of Connecticut.
t . . _ _ _ .
U.S. Nucle:r R:gul: tory Commission B17590/Page 3 If you should have any questions on the above, please contact Mr. Ravi Joshi at (860) 440-2080l Very truly yours NORIHEAST NUCLEAR ENERGY COMPANY M. L. Bowling, Jr. v/ !
Recovery Officer - Technical Services Subscribed and sworn to before me this /f day ofI4 met V.1998 H W LORETTA F.GOODSON Date Comm.ission Expires:
MOT.'.RY PUBllC Canaission Empires November 30,2001 cc: H. J. Miller, Region i Administrator S. Dembek, NRC Project Manager, Millstone Unit No. 2 D. P. Beaulieu, Senior Resident inspector, Millstone Unit No. 2 E. V. Imbro, Director, Millstone ICAVP inspections Director Bureau of Air Management Moni'.oring and Radiation Division Department of Environmental Protection 79 Elm Street Hartford, CT 06106-5127 l
l 1
1
Docket No. 50-336 B17590 l
Attachment 1 Millstone Nuclear Power Station, Unit No. 2 Proposed Revision to Technical Specifications i Deletion of The Technical Specification Related to The Hydrogen Purge System Discussion of Proposed Changes l
l l
l.
l ,
i l
i
~
January 1999 4
4 4
w -
p .,
. . 1 U. S. Nucl:ar Regulttory Commission B17590/ Attachment 1/Page 1 l
Proposed Revision to Technical Specifications Deletion of The Technical Specification Related to The Hydrogen Purge System l Discussion of Proposed Changes Introduction l Northeast Nuclear Energy Company (NNECO) is proposing to delete the Technical l Specification related to the Hydrogen Purge system from Millstone Unit No. 2 Technical Specifications.
The proposed changes affect Technical Specification 3/4.6.4.3, " Containment Systems, Hydrogen Purge System," and index Page Vll. The Bases of the associated Technical Specification are being modified to address the proposed change. Each proposed change is discussed below. Additbnal background information is included, as necessary, to exp!sh. 2 a ges.
Current Desian and Licensina Bases The design and licensing bases for the hydrogen control system are contained in the Millstone Unit No. 2 FSAR sections 1.2.7, " Summary Description, Engineered Safety Features System," 1.8.2.2, " Hydrogen Control," 6.6, " Containment Post-Accident Hydrogen Control System," 6.7.3.1, " Enclosure Building Filtration System, Emergency ,
Conditions," and 14.8.3, " Hydrogen Accumulation in Containment," and in Technical l Specifications (TS) section 3/4.6.4.3, " Containment Systems, Hydrogen Purge System."
The post-accident hydrogen control system includes independent and fully redundant I subsystems to (a) measure the hydrogen concentration in the containment, (b) mix the atrnosphere in the containment, and (c) control combustible gas concentrations without !
relying on purging of the containment atmosphere following a loss-of-coolant accident.
These subsystems function to maintain the concentration of locally accumulated l i hydrogen below four volume percent. The post-accident hydrogen control system meets the recommendations of Safety Guide 7.
Control of hydrogen concentration is achieved using two full capacity electric recombiners which meet the recommendations of Safety Guide 7. The recombiner system incorporates several design features that are intended to assure the capability of the system to be operable in the event of an accident. Among these are:
- 1. Seismic Category I design.
- 2. IEEE requirements for the wiring and electrical equipment are satisfied.
- 3. Protection from missiles and jet impingement from a broken pipe.
1
U. S. Nuclear R:gulttory Commission B17590/ Attachment 1/Page 2
- 4. Redundancy to the extent that no single component failure disables both recombiners.
A controlled containment hydrogen purge system is also provided, as a backup to the recombiner system, in accordance with the recommendations of Safety Guide 7.
Proposed chanaes in the Licensina Bases Northeast Nuclear Energy Company (NNECO) is proposing the following changes in the licensing bases to down grade the hydrogen purge system to a non safety-related system:
- 1. Delete Technical Specification 3/4.6.4.3, " Containment Systems, Hydrogen Purge '
System." The Bases of the associated Technical Specification will be modified to I address the proposed changes. This item is the subject of this correspondence.
- 2. Revise a number of sections in Millstone Unit No. 2 FSAR to include the effects of down grading the hydrogen purge system to a non safety-related system. These changes include the deletion of the discussion on radiological consequences of the l purge. The FSAR changes, which are not discussed in this correspondence, are performed in accordance with the FSAR change process which is subject to 10CFR50.59 requirements.
The hydrogen purge system will be down graded to a non safety-related system based on the following reasons.
1
- 1. The NRC regulatory position given in Regulatory Guide (RG) 1.7, Rev. 2, Section l (C), " Regulatory Position," Item (4), states that the system need not be redundant or i be designed Seismic Category I as stated below:
"All water-cooled power reactors should also have the installed capability for a controlled purge of the containment atmosphere to aid in cleanup. The purge or ventilation system may be a separatt system or part of an existing system. It need not be redundant or be designated Seismic Category I (see Regulatory Guide 1.29),
except insofar as portions of the system constitute part of the primary containment boundary or containment filters."
l Therefore, the hydrogen purge system can be down graded to a non safety-related system except portions of the system which constitute part of the primary containment bounchry. The non safety-related part of the hydrogen purge system Ere the parts located in the enclosure building down stream from the second containment isolation valves 2-EB-92 and 2-EB-99.
- 2. The safety-related hydrogen recombiner system is designed to the extent that: (a) it is Seismic Category I design, (b) IEEE requirements for the wiring and electrical i
U. S. Nucirr Regulatory Commission B17590/ Attachment 1/Page 3 equipment are satisfied, (c) protected from missiles and jet impingement from brokeri pipe, (d) redundant to the extent that no single component failure disables both recombiners, and (e) is intended to provide 100% of the required hydrogen '
removal capacity using only one recombiner. Therefore, the hydrogen recombiner system can alone provide the required hydrogen removal capacity without relying on purging as recommended in Regulatory Guide (RG) 1.7, Rev. 2, Section (C),
" Regulatory Position," item (1), which states that:
"Each boiling or pressurized light-water nuclear power reactor fueled with uranium oxide pellets within cylindrical zircaloy cladding should have the capability to (a) measure the hydrogen concentration in the containment, and (b) mix the atmosphere in the containment, and (c) control combustible gas concentrations without relying on purging and/or repressurization of the containment atmosphere following a LOCA."
- 3. The Hydrogen Purge System is significant and credited only in Severe Accident Management scenarios. These scenarios are beyond the design basis. The l Technical Specifications are derived from analyses and evaluations included in the j safety analysis report. Neither Severe Accident analyses nor evaluations are !
included in the safety analysis report or its amendments. I i
The purge system will still be available, as necessary, to mitigate severe accident scenarios and will continue to be operated and maintained in accordance with RG 1.7, Rev. 2 recommendations and the station procedures.
Description of The Proposed Chanoes The proposed changes are described below.
- 1. Technical Specification 3/4.6.4.3 will be removed. The text on the corresponding page will be deleted and replaced with "This page intentionally left blank."
The two trains of hydrogen recombiners provide 100% redundancy, as only one recombiner and its associated power supply and control panel is intended to provide 100% of the required hydrogen removal capacity. Each train is capable of performing its functional requirement using onsite or offsite power. No single failure of an active component in either train will affect the functional capability of the other train or the other subsystems. Therefore, the two treins of hydrogen recombiners completely fulf!!! the requirements of (RG) 1.7, Rev. 2, General Design Criterion (GDC) 41 on containment atmospheric cleanup systems, and 10 CFR 50.44 on standards for combustible gas control system in light-water-cooled power reactors. The hydrogen purge system is provided as a backup to the hydrogen recombiners system and needs not be redundant or be designated Seismic Category I (in accordance with RG 1.7, Rev 2) except those portions of the system which constitute part of the primary containment boundary or containment filters.
I l
! l l
U. S. Nuckar Regulttory Commission B17590/ Attachment 1/Page 4 Therefore, the hydrogen purge system can be down graded to a non safety-related tystani. Furthermore, the Hydrogen Purge System does not meet any one of the following criteria of 10 CFR 50.36, " Technical Specifications," Section c(2)(ii). The criteria and the reason (s) for not meetmg the criteria are as follows:
l Cdterion 1 :
"(ii) A technical specification limiting condition for operation of a nuclear reactor I must be established for each item meeting one or more of the following criteria:
i (A) Criterion 1. Installed instrumentation that is used to detect, and indicate in the control room, a significant abnormal degradation of the reactor coolant pressure -
boundary."
Reason (s):
i . The Hydrogen Purge System provides a backup means to manually control the hydrogen concentration in containment given the multiple failure of the redundant, Seismic Category I Hydrogen Recombiner System. It is not installed instrumentation. As such, it cannot be used to detect a "significant abnormal degradation of the reactor coolant pressure boundary."
Criterion 2 :
"(B) Criterion 2. A process variable, design feature, or operating restriction that is an initial condition of a design basis accident or transient analysis that either assumes the failure of or presents a challenge to the integrity of a fission product barrier."
Reason (s):
. The Hydrogen Purge System is a standby purge system which is not in service during normal operations as a hydrogen purge system (i.e., Charcoal Filter Heaters de-energized). The purge system, however, is periodically used for controlling the containment pressure in accordance with the technical specifications. Operation of the purge system does not present a challenge to the integrity of a fission product barrier because the valves which are operated are containment isolation valves which are controlled by Technical Specification 3.6.3.1. Thus, operation of the purge system is not an initial condition of a design basis accident.
Criterion 3 :
"(C) Criterion 3. A structure, system, or component that is part of the primary success path End which functions or actuates to mitigate a design basis accident or transient that either assumes the failure of or presents a challenge to the integrity of a fission product barrier."
Reason (s):
L e The primary success path for hydrogen control is the Hydrogen Recombiner System. The Hydrogen Recombiner System has redundant trains and is fully
e U. S. Nuclxr R:gul;. tory Commission B17590/ Attachment 1/Page 5 qualified to maintain hydrogen control following a design basis accident. The Hydrogen Purge System is the backup success path for hydrogen control.
. Regulatory Guide 1.7, Revision 2 , Section (C), " Regulatory Position" states that the Hydrogen Purge System need not be redundant or designed to Seismic Category I except for those portions of the system which constitute part of the primary containment boundary. The non safety-related portion of the Hydrogen Purge System are the parts located in the enclosure building down stream of the second containment isolation valves, 2-EB-92 and 2-EB-99. These valves, along with their inboard counterparts,2-EB-91 and 2-EB-100 are controlled by Technical Specification 3.6.3.1.
Criterion 4 :
"(D) Criterion 4. A structure, system, or component which operating experience or probabilistic risk assessment has shown to be significant to public health and safety."
Reason (s):
. The Hydrogen Purge System is not considered a Maintenance Rule Risk Significant System. The list of maintenance rule risk significant systems was developed, in part, using an expert panel which equates to the operating experience criteria.
. MP2 probabilistic risk assessment analyses do not consider the Hydrogen Purge System.
. The Hydrogen Purge System is significant and credited only in Severe Accident Management scenarios. These scenarios are beyond design basis. From 10 CFR 50.36(b):
l "The technical specifications will be derived from the analyses and evaluation l included in the safety analysis report, and amendments thereto, submitted l pursuant to S 50.34."
. Severe accident analyses are not included in either the safety analysis report or its amendments.
[ Therefore, Technical Specification 3/4.6.4.3 does not fulfill any one or more of the
! requirements of 10 CFR 50.36c(2)(ii) on items for which Technical Specifications must be established and can be deleted from Millstone Unit No. 2 Technical Specifications.
- 2. Index Page Vil is being revised by eliminating the section corresponding to hydrogen purge system (page 3/4 6-23). This change is administrative in nature.
U. S. Nucl::cr Regulatory Commission B17590/ Attachment 1/Page 6
- 3. The proposed change to Bases section 3/4.6.4 deletes reference to "the purge system" since Technical Specification 3/4.6.4.3 is being removed.
Safety Summary The proposed changes will delete the Technical Specification related to the Hydrogen Purge system from Millstone Unit No. 2 Technical Specifications. The proposed changes sffect Technical Specification 3/4.6.4.3, " Containment Systems, Hydrogen Purge System," and Index Page Vll. The Bases of the associated Technical Specification are being modified to address the proposed change.
The Hydrogen Purge System provides a backup means to manually control the hydrogen concentration in contair. ment given the multiple failure of the redundant, Seismic Category I Hydrogen Recombiner System. The primary success path for hydrogen control is the Hydrogen Recombiner System. The Hydrogen Recombiner System has redundant trains and is fully qualified to maintain hydrogen control following a design basis accident. Removal of the Technical Specification is justified since:
. Regulatory Guide 1.7, Revision 2 has categorized the Hydrogen Purge System as a non safety-relatec. backup to the Hydrogen Recombiners, and a containment cleanup system.
. The Hydrogen Purge System is credited only for beyond design basis events.
. The system does not satisfy one or more of the criteria specified in 10 CFR 50.36.
Revision of Index Page Vil is an administrative change. The proposed change to Bases section 3/4.6.4 by deleting reference to "the purge system" is required since Techtical Specification 3/4.6.4.3 is being removed. Therefore, the proposed changes will have no adverse effect on plant safety.
I i
~ __ _. . _ _ . _ _ _ . - . . . _ _ . . _ . . _ . _ . - _ . . _ -_._.. _ - _ -_- _
I I
Docket No. 50-336 B17590 i
l l
l Attachment 2
)
l Millstone Nuclear Power Station, Unit No. 2 !
Proposed Revision to Technical Specifications Delet:on of The Technical Specification Related to The Hydrogen Purge System Significant Hazards Consideration l
l !
l 1
l l
I
!- i i
l l
l l
January 1999 4
4
~
U. S. Nucl:ar R::gulatory Commission B17590/ Attachment 2/Page 1 Proposed Revision to Technical Specifications Deletion of The Technical Specification Related to The Hydrogen Purge System Significant Hazards Consideration Sianificant Hazards Consideration In accordance with 10 CFR 50.92, NNECO has reviewed the proposed changes and has concluded that they do not involve a Significant Hazards Consideration (SHC).
The basis for this conclusion is that the three criteria of 10 CFR 50.92(c) are not compromised. The proposed changes do not involve an SHC because the changes would not:
- 1. Involve a significant increase in the probability or consequences of an accident previously evaluated.
The Hydrogen Purge System provides a backup means to manually control the hydrogen concentration in containment given the multiple failure of the redundant, Seismic Category I Hydrogen Recombiner System. The primary success path for hydrogen control is the Hydrogen Recombiner System. The Hydrogen Recombiner System has redundant trains and is fully qualified to maintain hydrogen control following a design basis accident. FSAR Section 14.8.3.5, " Radiological Consequences of Purging" is being removed from the FSAR since it is no longer required. Since thn hydrogen recombiners are fully redundant, it is not necessary to postulate offsite doses for purge during a design basis accident. Thus, the deletion of consequences does not represent a change in the consequences of a design basis event. Therefore, this change will not significantly increase the probability or consequences of an accident previously evaluated.
Revision of Index Page Vil is an administrative change. The proposed change to Bases section 3/4.6.4 by deleting reference to "the purge system" is required since Technical Specification 3/4.6.4.3 is being removed. Therefore, these changes will not significantly increase the probability or consequences of an accident previously evaluated.
The proposed changes do not alter how any structure, system, or component functions. There will be no effect on equipment important to safety. The proposed changes have no effect on any of the design basis accidents previously evaluated. Therefore, this License Amendment Request does not impact the probability of an accident previously evaluated, nor does it involve a significant increase in the consequences of an accident previously evaluated.
- 2. Create the possibility of a new or different kind of accident from any accident previously evaluated.
U. S. Nucl:ar R:gulatory Commission B17590/ Attachment 2/Page 2 The purge system is a standby purge system which is not in service during normal operations as a hydrogen purge system (i.e., Charcoal Filter Heaters de-energized). Therefore, no new accident is created either by system unavailability or actuation. The FSAR will still address the use of the purge system as a backup to the recombiner system. Revision of Index Page Vil is an administrative change. The proposed change to Bases section 3/4.6.4 by deleting reference to "the purge system" is required since Technical Specification 3/4.6.4.3 is being removed. Therefore, the proposed changes will not create the possibility of a new or different kind of accident from any accident previously evaluated.
- 3. Involve a significant reduction in a margin of safety.
The margin of safety is defined in the Bases 3/4.6.4 which states that the
" hydrogen control systems are consistent with the recommendations of Regulatory Guide 1.7.. " Regulatory Guide 1.7 describes methods that would )
be acceptable in meeting the standards for a combustible gas control system, i 10 CFR 50.44, " Standards for combustible gas control systems in light-water- ;
cooled power reactors." Regulatory Guide 1.7 acknowledges that purging is a 1 means of reducing the hydrogen concentration but it should not be the primary ,
means because of the release of radioactivity to the environment. The regulatory guide does advise that there be an " installed capability for a controlled purge of the containment atmosphere to aid in cleanup." Removal of the Hydrogen Purge System Technical Specification is consistent with Regulatory Guide 1.7. Additionally, the capability to purge is still documented in l the FSAR. Revision of Index Page Vil is an administrative change. The proposed change to Bases section 3/4.6.4 by deleting reference to "the purge system" is required since Technical Specification 3/4.6.4.3 is being removed.
Therefore, the proposed changes will not result in a significant reduction in the
! margin of safety as defined in the Bases for Technical Specifications covered in this License Amendment Request.
The NRC has provided guidance concerning the application of standards in 10 CFR l
50.92 by providing certain examples (March 6,1986,51 FR 7751) of amendments that are considered not likely to involve an SHC. The changes proposed herein to delete ;
the Technical Specification related to the Hydrogen Purge system from Millstone Unit i l
No. 2 Technical Specifications are not covered by any specific example. l l l l As described above, this License Amendment Request does not involve a significant increase in the probability of an accident previously evaluated, does not involve a significant increase in the consequences of an accident previously evaluated, does not create the possibility of a new or different kind of accident from any accident previously evaluated, and does not result in a significant reduction in a margin of safety.
Therefore, NNECO has concluded that the proposed changes do not involve an SHC.