ML17059B537
| ML17059B537 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 05/08/1997 |
| From: | Milano P NRC (Affiliation Not Assigned) |
| To: | Boulette E BOSTON EDISON CO. |
| References | |
| TAC-M97789, NUDOCS 9705130193 | |
| Download: ML17059B537 (10) | |
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UNITED STATES NUCLEAR REGULATORY COMMISSiON WASHINGTON, D.C. 20555-0001 May 8, 1997 Go-2ZO Mr. E. Thomas Boulette, Ph.D Senior Vice President Nuclear Boston Edison Company Pilgrim Nuclear Power Station RFD.Pl Rocky Hill Road
- Plymouth, MA 02360
SUBJECT:
REQUEST TO CREDIT CONTAINMENT OVERPRESSURE TO SATISFY NET POSITIVE SUCTION HEAD (NPSH)
REQUIREMENTS, AND SUBSEQUENT DEFERRAL OF REVIEW REQUEST BASED ON 10 CFR 50.59 EVALUATION PILGRIM NUCLEAR POWER STATION (TAC NO. M97789)
Dear Mr. Boulette:
By submittals dated January 20 and January 30, 1997, the Boston Edison Company (BECo/the licensee) submitted an amendment request for the Pilgrim Nuclear Power Station (PNPS).
The licensee requested to update the Updated Final Safety Analysis Report (UFSAR) to credit containment overpressure to satisfy Emergency Core Cooling System (ECCS) pump NPSH requirements, and also requested approval of revised, containment pressure and suppression pool temperature analyses for an increased ultimate heat sink temperature of 75 'F, versus the current 65 F.
The NRC staff had determined that the licensee's need for containment overpressure constituted an Unreviewed Safety Question (USQ) and approval of the amendment request was needed to support plant startup.
The licensee subsequently determined that because of the reduced head losses associated with new ECCS suction strainers installed during the refueling outage ll, credit for containment overpressure, assuming a 65 'F ultimate heat g
sink temperature, is no longer necessary to satisfy low-pressure coolant injection and core spray pump NPSH requirements.
By letter dated April ll,,
1997, the licensee submitted a 10 CFR 50.59 safety evaluation supporting this conclusion and committed to enter a "loss of containment cooling" limiting condition for operation when the ultimate heat sink temperature exceeds 65 'F.
We find the licensee's conclusion that adequate NPSH will exist without credit for overpressure, as determined in the 10 CFR 50.59 evaluation, to be consistent with the plant's licensing basis.
Because overpressure is no longer necessary to satisfy NPSH requirements, there is no longer a
USQ involving the use of containment over pressure, However, while the amendment for credit for overpressure is not necessary with lower strainer head losses and a 65 'F ultimate heat sink temperature, it is anticipated that the amendment will be needed by the summer as the service water temperature typically will exceed 65 'F during this time.
The licensee had performed the containment design basis accident loss-of-coolant accident analysis and NPSH analysis with the assumption of a 75 'F ultimate heat sink E3003P 9705l30193 970508 PDR ADQCK 05000220 P
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P' I
E. Thomas Boulette temperature and the ANS 5.1 Decay Keat curve.
The staff has informed BECo that a 2-sigma adder needs to be included to the ANS standard curve to provide a 95 percent confidence for that curve.
The licensee has stated that this reanalysis will be submitted shortly.
In a separate action, the NRC deferred resolution of Pilgrim's final response to Bulletin 96-03, "Potential Plugging of Emergency Core Cooling Suction Strainers By Debris in Boiling Mater Reactors," until no later than the end of 1998.
This deferral is documented in a letter dated Harch 11, 1997.
Based on the NRC staff's review of the April 11, 1997, letter the staff has concluded that the need for containment overpr essure is not a restart issue for PNPS.
If you have any questions in this matter, please contact Mr. Alan Mang at (301) 415-1445.
Sincerely, Docket No. 50-220 cc:
See next page Patrick D. Hilano, Acting Director Project Directorate I-3 Division of Reactor Projects I/II Office of Nuclear Reactor Regulation
P'
0 E.
Thomas Boulette May 8, 1997 temperature and the ANS 5. 1 Decay"Heat curve.
Th'e staff has informed BECo that a 2-sigma adder needs to be included to the ANS standard curve to provide a 95 percent confidence for that curve.
The licensee has stated that this reanalysis will be submitted shortly.
,In a separate
- action, the NRC deferred resolution of Pilgrim's final response to Bulletin 96-03, "Potential Plugging of Emergency Core Cooling Suction Strainers By Debris in Boiling Water Reactors," until no later than the end of 1998.
This deferral is documented in a letter dated March 11, 1997.
Based on the NRC staff's review of the April 11, 1997, letter the staff has concluded that the need for containment overpressure is not a restart issue for PNPS.
If you have any questions in this matter, please contact Hr. Alan Wang at (301) 415-1445.
Sincerely, (Original Signed By)
Patrick D. Milano, Acting Director Project Directorate I-3 Division of Reactor Projects I/II Office of Nuclear Reactor Regulation Docket No. 50-220 cc:
See next page Distribution Docket File PUBLIC PDI-3 RF SVarga JZwolinski
'PHilano AWang OGC ACRS GCarpenter HDawson JKudrick CBerlinger
- RConte, RI DOCUMENT NAME:
G: iP ILGRIMiNPSH.59 To receive e copy of thle document, Indicate In the boau "C
a Copy without attechment/enclosure E
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E. Thomas Boulette.
CC:
Hr. Leon J. Olivier Vice President of Nuclear Operations 5 Station Director Pilgrim Nuclear Power Station 1FD tl Rocky Hill Road
- Plymouth, HA 02360 Resident Inspector U. S. Nuclear Regulatory Comnission Pilgrim Nuclear Power Station Post Office Box 867
- Plymouth, HA 02360
- Chairman, Board of Selectmen 11 Lincoln Street
- Plymouth, HA 02360
~ Chairman, Duxbury Board of Selectmen Town Hall 878 Tremont Street
- Duxbury, HA 02332 Office of the Commissioner Massachusetts Department of Environmental Protection One Winter Street
- Boston, HA 02108 Office of the Attorney General One Ashburton Place 20th Floor
- Boston, HA 02108 Mr. Robert H. Hallisey, Director Radiation Control Program Hassachusetts Department of Public Health 305 South Street
'Boston,. MA 02130 Regional Administrator, Region I U. S. Nuclear Regulatory Commission 475 Allendale Road King of Prussia, PA 19406 Hs. Jane Fleming 8 Oceanwood Drive
- Duxbury, HA 0233 Pilgrim Nuclear Power Station Hr. Jeffery Keene Licensing Division Manager Boston Edison Company 600 Rocky Hill Road
- Plymouth, MA 02360-5599 Hs.
Nancy Desmond
- Hanager, Reg. Affairs Dept.
Pilgrim Nuclear Power Station RFD tl Rocky Hill Road
- Plymouth, HA 02360 Hr. David F. Tarantino Nuclear Information Manager Pilgrim Nuclear Power Station RFD fl, Rocky Hill Road
- Plymouth, MA 02360 Ms. Kathleen H. O'oole Secretary of Publ,ic Safety Executive Office of Public Safety One Ashburton Place
- Boston, HA 02108 Mr. Peter LaPorte, Director Attn:
James Huckerheide Hassachusetts Emergency Management Agency 400 Worcester Road P.O.
Box 1496 Framingham, HA 01701-0317
- Chairman, Citizens Urging Responsible Energy P.O.
Box 2621
- Duxbury, HA 02331 Citizens at Risk P.O.
Box 3803
- Plymouth, HA 02361 W.S. Stowe, Esquire Boston Edison Company 800 Boylston St.,'6th Floor
- Boston, HA 02199
cc:
(cont.)
Chairman Nuclear Hatters Committee Town Hall II Lincoln Street
- Plymouth, HA 02360 Mr. Milliam D. Heinert Nuclear Engineer Massachusetts Municipal wholesale Electric Company P.O.
Box 426 Ludl ow, HA 01056-0426
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