ML20237A761
| ML20237A761 | |
| Person / Time | |
|---|---|
| Site: | Seabrook  |
| Issue date: | 08/12/1998 |
| From: | Harrison J NRC (Affiliation Not Assigned) |
| To: | Feigenbaum T, Harpster T NORTH ATLANTIC ENERGY SERVICE CORP. (NAESCO) |
| References | |
| GL-96-06, GL-96-6, TAC-M96864, NUDOCS 9808170082 | |
| Download: ML20237A761 (6) | |
Text
"
. August 12, 1998 s
Mr. Ted C. Feigenbaum Executive Vice President and Chief Nuclear Officer North Atlantic Energy Seivice Corporation clo Mr. Terry L. Harpster P.O. Box 300 -
' Seabrook, NH 03874
SUBJECT:
' REQUEST FOR ADDITIONAL INFORMATION RELATED TO THE GENERIC LETTER (GL) 96-06 RESPONSE FOR THE SEABROOK STATION, UNIT NO.1
' (TAC NO. M96864)
Dear Mr. Feigenbaum:
. By letters dated October 30,1996, and January 28,1997, you provided information related to GL 96-06, " Assurance of Equipment Operability and Containment integrity During Design-Basis Accident Conditions," dated September 30,1996.
GL 96-06 included a request for licensees to evaluate cooling water systems that serve containment air coolers to assure that they are not vulnerable to waterhammer and two-phase flow conditions. In order to complete our review of these issues, additional information is necessary. Please provide the additionalinformation requested by the enclosure to this letter by October 30,1998, to support the review schedule for GL 96-06.
If you should have any questions regarding this request, please contact me at (301) 415-3199.
Sincerely,
/S/
John Harrison, Project Manager Project Directorate 1-3 Division of Reactor Projects 8/11 Office of Nuclear Reactor Regulation Docket No. 50-443
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August 12, 1998 Mr. Ted C. Feigenbaum Executive Vice President and Chief Nuclear Officer North Atlantic Energy Service Corporation c/o Mr. Terry L. Harpster P.O. Box 300 Seabrook, NH 03874
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION RELATED TO THE GENERIC LETTER (GL) 96-06 RESPONSE FOR THE SEABROOK STATION UNIT NO.1 (TAC NO. M96864)
)
Dear Mr. Feigenbaum:
l By letters dated October 30,1996, and January 28,1997, you provided information related to GL 96-06, " Assurance of Equipment Operability and Containment integrity During Design-Basis Accident Conditions," dated September 30,1996.
GL 96-06 included a request for licensees to evaluate coo ling water systems that serve containment air coolers to assure that they are not vulnerable to waterhammer and two-phase flow conditions. In order to complete our review of these issues, additional information is necessary. Please provide the additional information requested by the enclosure to this letter by October 30,1998, to support the review schedule for GL 96-06.
If you should have any questions regarding this request, please contact me at (301) 415-3199.
Sincerely, I
ohn Harrison, Project Manager Project Directorate 1-3 Division of Reactor Projects - 1/11 Office of Nuclear Reactor Regulation Docket No. 50-443
Enclosure:
Request for Additionalinformation ec w/ encl: See next page t
L_---------------_--_--------__-------------.
t North Atlantic Energy Service Corporation Seabrook Station, Unit No.1 cc:
Lillian M. Cuoco, Esq. '
Mr. Peter LaPorie, Director Senior Nuclear Counsel ATTH: James Muckerheide Northeast Utilities Service Ccmpe.ny Massachusetts E.mergency Management P.O. Box 270 Agency Hartford, CT 06141-0270 400 Worcester Road P.O. Box 1496 Mr. Peter Brann Framingham, MA 01701-0317 Assistant Attomey General State House, Station #6 Jeffrey Howard, Attomey General Augusta, ME 04333 G. Dana Bisbee, Deputy Attomey General Resident inspector 33 Capitol Street U.S. Nuclear Regulatory Commission Concord, NH 03301 Seabrook Nuclear Power Station P.O. Box 1149 Mr. Woodbury Fogg, Director Seabrook, NH 03874 New Hampshire Office of Emergency Management Jane Spector State Office Park South Federal Energy Regulatory Commission 107 Pleasant Street 825 North Capital Street, N.E.
Concord, NH 03301 Room 8105 Washington, DC 20426 Mr. Roy E. Hickok Nuclear Training Manager Town of Exeter Seabrook Station 10 Front Street North Atlantic Energy Service Corp.
Exeter, NH 03823 P.O. Box 300 Seabrook, NH 03874 Regional Administrator, Region i U.S. Nuclear Ragulatory Commission Mr. Terry L. Harpster i
475 Allendale / toad Director of Licensing Services King of Prussia, PA 19406 Seabrook Station North Atlantic Energy Service Corp.
Office of the Attomey General P.O. Box 300 One Ashburton Place Seabrook, NH 03874 20th Floor Boston, MA 02108 Mr. D. M. Goebel Vice President-Nuclear Oversight Board of Selectmen Northeast Utilities Service Company Town of Amesbury P.O. Box 270 Town Hall Hartford, CT 06141-0270 Amesbury, MA 01g13 Mr. W. A. DiProfio Mr. Dan McElhinney Station Director Federal Emergency Management Agency Seabrook Station Region l North Atlantic Energy Service Corporation
'J.W. McCormack P.O. &
P.O. Box 300 Courthouse Building, Room 401 Seabrook, NH 03874 Boston, MA 02109
t Mr. Frank W. Getman, Jr.
Great Bay Power Corporation Cochsco Falls Millworks 100 Main Street, Suite 201 Dover, NH 03820 Mr. B. D. Kenyon President - Nuclear Group Northeast Utilities Service Group P.O. Box 128 Waterford, CT 06385 Mr. David E. Carriere Director, Production Services Canal Electric Company
' 2421 Cranberry Highway Wareham, MA 02571 i
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REQUEST FOR ADDITIONAL INFORMATION FOR RESOLUTION OF GL 96-06 ISSUES AT SEABROOK (TAC NO. M96864)
Generic Letter (GL) 96-06, " Assurance of Equipment Operability and Containment integrity During Design-Basis Accident Conditions," dated September 30,1996, included a request
' for licensees to evaluate cooling water systems that serve containment air coolers to assure that they are not vulnerable to waterhammer and two-phase flow conditions. North Atlantic Energy Service Corporation (the licensee) provided its assessment of the waterhammer and two phase flow issues for Seabrook in a letter dated January 28,1997. The licensee indicated that the containment air coolers at Seabrook Station are cooled by the primary component coo!!ng water (PCCW) system and are not required for accident mitigation. The PCCW system is automatically isolated on a Phase B isolation signal (containment pressure greater than 18 psig) or on a low-low level in the PCCW head tank. For situations where Phase B isolation does not occur, the licensee indicated that the PCCW head tank will provide sufficient over-
. pressure to prevent boiling in the PCCW system.~ In order to assess the licensee's resolution of these issues, the following additional information is requested:
- 1. The licensee's response indicated that the PCCW system will be isolated and the containment air coolers will not be used following a Phase B isolation. Describe measures that exist, including guidance provided in emergency operating procedures, to assure that plant operators will not use the containment air coolers as an option following Phase B isolation.
- 2. The licensee's response indicated that for accident scenarios where Phase B isolation does not occur (containment pressure less than 18 psig), the PCCW head tank provides sufficient overpressure to prevent the occurrence of waterhammer and two-phase f!ow conditions.
Discuss specific system operating parameters and other operating restrictions that must be maintained to assure that the waterhammer and two-phase flow analyses remain valid (e.g., head tank level, pressures, temperatures), and explain why it would not be appropriate to establish Technical Specification requirements to acknowledge the i nportance of these parameters and operating restrictions. Also, describe and justify reliance on any non-safety related instrumentation and controls in this regard.
- 3. Implementing measures to assure that waterhammer and two-phase flow conditions will not occur, such as proriibiting post-accident operation of the affected system and maintaining l
specific PCCW head tank conditons, is an acceptable approach for addressing the waterhammer and two-phase flow concems. However, all scenarios must be considered to assure that the vulnerability to waterhammer and twc-phase flow has been eliminated.
Confirm that all scenarios have been consider 40, such that the measures that have been established are adequate to prevent the occurrence of waterhammer and two-phase flow.
- 4. Describe and justify all assumptions and input parameters that were credited in the t
waterhammer and two-phase flow analyses. Also, explain and justify all uses of
" engineering judgement."
ENCLOStJRE
_--___--_____O
i 2
- 5. Confirm that the waterhammer and two-phase flow analyses included a complete failure modes and effects analysis (FMEA) for all components (including electrical and pneumatic failures) that could impact performance of the cooling water system and confirm that the FMEA is documented and avaliable for review, or explain why a complete and fully documented FMEA was not performed.
- 6. Provide a detailed description of the "wcrst case" scenarios that were identified for the situations where Phase B isolation does, and does not, occur, taking into consideration the comoteta range of event possibilities, system configurations, and parameters (e.g., temperatures, pressures, flow rates, load combinations, potential component failures).
Discuss the minimum margin to boiling that will exist, taking into consideration instrumentation and analytical uncertainties.
- 7. Provide a simplified diagram of the affected system, showing major components, active components, relative elevations, lengths of piping runs, and the location of any oridces and flow restrictions.
- 8. Describe in detail any plant modifications or procedure changes that have been made or are planned to be made to resolve the waterhammer and two-phase flow issues, o
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