ML20037D299
| ML20037D299 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 06/29/1981 |
| From: | Clark R Office of Nuclear Reactor Regulation |
| To: | Counsil W NORTHEAST NUCLEAR ENERGY CO. |
| References | |
| TAC-10468, NUDOCS 8107090342 | |
| Download: ML20037D299 (3) | |
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JUN 2 01981 Docket No. 50-336 Mr. W. G. Counsil, Vice President Nuclear Engineering & Operations Northeast Nuclear Energy Company P. O. Box 270 Hartford, Connecticut 06101
Dear Mr. Counsil:
We have completed the review of your submittals dated June 27, 1975, October 31, 1977 and May 10, 1978 concerning long term cooling following a loss of coolant accident (LOCA). These submittals were to address the staff's concern, presented in our September 19, 1977 letter, related to the possibility of the boric acid concentration reaching the solubility limit for the reactor coolant system parameters during long term cooling following a LOCA and result in boron precipitation in the reactor pressure vessel thereby limiting the emergency core cooling system (ECCS) flow rates.
10, 1978 letter proposed a new procedure to provide hot leg in-Your May jection from a low pressure safety injection (LPSI) pump, taking suction from the sump and injecting through the 2 inch warmup line (GCB-2) and the 12 inch shutdown cooling line KCA-10).
You also provided preliminary pperating procedures for this injection mode and proposed that this method replace the existing hot leg suction mode. The method offsimultaneous high pressure safety injection (HPSI) hot and cold leg injection would be retained as a backup method.
In addition, your iday 10, 1978 letter provides qualitative information that tests indicate satisfactory results, identification of acequate flow instrumentation for both injection paths and addresses the other staff Concerns.
We find that your new method of LPSI hot leg injection will enhance the ECCS cooling capabilities and thereby reduces the probability of boron precipitation. We also find that since these modifications do not involve a significant increase in the probability or consequences of an accident and do not involve a significant decrease in a safety margin, they suawaury
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3 E WASHINGTON. D. C. 20555 JUN 2 01981 Docket No. 50-336 Mr. W. G. Counsil, Vice President Nuclear Engineering & Operations Northeast Nuclear Energy Company P. O. Box 270 Hartford, Connecticut 06101
Dear Mr. Counsil:
We have completed the review of your submittals dated June 27, 1975, October 31, 1977 and May 10, 1978 concerning long term cooling following a loss of coolant accident (LOCA).
These submittals were to address the staff's concerr., presented in our September 19, 1977 letter, related to the possibility of the boric acid concentration reaching the solubility limit for the reactor coolant system parameters during long term cooling folicwing a LOCA and result in boron precipitation in the reactor pressure vessel thereby limiting the emergency core cooling system (ECCS) flow rates.
'/ cur May 10, 1973 latter proposed a new precedure to provide hot leg in-jection from a low pressure safety injection (LPSI) pump, taking suction from the sump and injecting througn the 2 inch warmuc line (GC3-2) and the 12 inch shutdown cooling line (CCA-10). You also provided oreliminary cperating procedures for tnis injection moce and proposed that this method replace tne existing hot leg suct;on mode.
The method of simultaneous high pressure safety injection (HPSI) hot and cold leg injection would be retained as a backup method.
In addition, your May 10, 1978 letter provides qualitative information that flow tests indicate satisfactory results, identification of adequate flow instrumentation for both injection paths and addresses the other staff concerns.
We find that your new method of LPSI hot leg injection will enhance the ECLS cooling capabilities and thereby reduces the probability of boron precipitation. We also find that since these modifications do not involve a significant increase in the probability or consequences of an accident and do not involve a significant decrease in a safety margin, they
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2-do not involve a significant hazards consideration. Therefore, we consider the multi-plant issue " Boron Solubility During Long Term Cooling Following a LOCN' closed for Millstone, Unit No. 2.
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Robert A. Clark, Chief
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Northeast Nuclear Energy Company cc:
William H. Orddy, Esquire Mr. John Shedlosky Day, Berry & Howard Resident Inspector / Millstone Ccunselors at Law c/o U.S.N.R.C.
One Ccnstitution Plaza P. O. Drawer KK Hartford, Connecticut 06103 Niantic, CT 06357 Anthony Z. Roisman Mr. Charles Brinkman Natural Resources Defense Council Manager - Washington Nuclear 91715th Street, N.W.
Operations Washington, D. C.
20005 C-E Pcwer Systems Combustion Engineering. Inc.
Mr. Lawrence Bettencourt, First Selec' man 4853 Cerdell Aven., Suite A-1 Town of Waterford Bethesda, MD 20014 Hall of Records - 200 Boston Post Road Waterford, Cennecticut 06385 Rcrtheast Nucidar Energy Company ATTN: Superintendent Millstene Plant Connecticut Energy Agency Fest Cffica Box 123 ATTN: Assistant Director, Researen Waterf:rd, 0:nnecticut 06255 and Policy Develepren:
Department of Planning and Energy Waterfer: Puclic Library Policy Repe Perry Rcad, Reuce 156 20 Grand Stree:
Waterford, ::nnecticut C6335 Hartferd, CT 06106 Director, Criteria and Standards Division Office of Radiation Programs (ANR-460)
U.S. Environmental Protection Agency Bashing:cn, O. C.
20460 U. S. En/f renmental Protection Agnecy Regien I Office ATTN: EIS COORDINATOR John F. Kennedy Federal Building Boston, Massachusetts 02203 Northeast Utilities Service Conpany ATTN: Mr. Janus R. Himmelwright Nuclear Engineering and Operations P. O. Box 270 Hartford, Connecticut 06101 0
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Sincerely, Original signed uj Robert A. Clark Robert A. Clark, Chief Operating Reactors Branch #3 Division of Licensing cc: See next page DISTR T AltT TON -
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