ML20150C612

Requests Addl Info Re Backup Nitrogen Supply Sys & Drywell Spray Sys in Safety Enhancement Program as Detailed in Encl

ML20150C612
Person / Time
Site:	Pilgrim
Issue date:	06/29/1988
From:	Mcdonald D Office of Nuclear Reactor Regulation
To:	Bird R BOSTON EDISON CO.
References
TAC-65356, NUDOCS 8807120557
Download: ML20150C612 (4)

Text

P

- s June 29, 1988 Docket No. 50-293- DISTRIBUTION iDocRet NRC & Local PDRs

< Mr. Ralph G. Bird PDI-3 RF

{ Senior Vice President - Nuclear SAVarga ACRS(10) l Boston Edison Company. BABoger Gray File j Pilgrim Nuclear Power Station-- MRushbrook RFD #1, Rocky Hill Road DGMcDonald I Plymouth, Massachusetts 02360 OGC-WF E. Jordan

Dear Mr. Bird:

B. Grimes

SUBJECT:

PILGRIM SAFETY ENHANCEMENT PROGRAM - REQUEST FOR ADDITIONAL INFORMATION l

REFERENCE:

TAC NUMBER 65356 1

By letter dated February 22,1!18 you responded to our initial assessment of the Pilgrim Safety Enhancement Program (SEP) dated August 21, 1987. We

! indicated in our initial assessment that additional information and i clarification were needed in some specific areas of the SEP. The information requested was provided in your response.

The staff has reviewed your response and needs additional information relating to the Backup Nitrogen Supply System and the Drywell Spray System which are detailed in the enclosure to this letter.

The reporting and/or reccrdkeeping requirements contained in this letter affect fewer than ten respondents; therefore, OMB clearance is not required under P.L.96-511.

Sincerely, Original Signed by:

Daniel G. Mcdonald, Jr., Senior Project Manager Project Directorate I-3 Division of Reactor Projects I/II 1

Enclosure:

Request for ,',dditional l Information i cc w/ enclosure:

See next page

-3  ?

DIR:PDI-37,fgy MRushbrook n d:ah RHWessman M Y 06/g.T88 /88 06/$88 8807120557 880629 PDR ADOCK 05000293 P PDR

4 I June 29, 1988 Docket No. 50-293 DISTRIBUTION Docket NRC & Local PDRs Mr. Ralph G. Bird PDI-3 RF Senior Vice President - Nuclear SAVarga ACRS(10)

Boston Edison Company BABoger Gray File Pilgrim Nuclear Power Station MRushbrook RFD #1, Rocky Hill Road DGMcDonald Plymouth, Massachusetts 02360 OGC-WF E. Jordan

Dear Mr. Bird:

B. Grimes

SUBJECT:

PILGRIM SAFETY ENHANCEMENT PROGRAM - REQUEST FOR ADDITIONAL INFORMATION

REFERENCE:

TAC NUMBER 65356 By letter dated February 29.; 1988 you responded to our initial assessment of the Pilgrim Safety Enhancement Program (SEP) dated August 21, 1987. We indicated in our initici assessment that additional information and clarification were needed in some specific areas of the SEP. The informatSn requested was provided in youi response.

The staff has reviewed your response and needs additional infonnation relating to the Backup Nitrogen Supply System and the Drywell Spray System which are detailed in the enclosure to this letter.

The reporting and/or recordkeeping requirements contained in this letter affect fewer than ten respondents; therefore, OMB clearance is not required under P.L.96-511.

Sincerely, Original Signed by:

Daniel G. Mcdonald, Jr., Senior Project Manager Project Directorate I-3 Division of Reactor Projects I/II

Enclosure:

Request for Additional Information cc w/ enclosure:

See next page

-3 .

DIR:PDI-3 W p y MRushbrook ,n d:ah RHWessman /^, '

hM06/g.%88 /88 06/2/88

i Mr. Ralph G. Bird Boston Edison Company Pilgrim Nuclear Power Station cc:

Mr. K. L. Highfill Mr. Ralph G. Bird Station Director Senior Vice President - Nuclear Pilgrim Nuclear Power Station Boston Edison Company RFD #1 Rocky Hill Road Pilgrim Nuclear Power Station Plymouth, Massachusetts 02360 RFD#1, Rocky Hill Roac Plymouth, Massachusetts 02360 Resident Inspector's Office Mr. Richard N. Swansori, Manager V. S. Nuclear Regulatory Corrmission Nuclear Engineering Department Post Office Box 867 Boston Edison Company Plymouth, Massachusetts 02360 25 Braintree Hill Park Braintree, Massachusetts 02184 Chainnan, Board of Selectmen 11 Lincoln Street Ms. Elaine D. Robinsen Plymouth, Massachusetts 02360 Nuclear Information Panager Pilgrim Nuclear Power Staticn Office of the Coninissioner RF0 #1, Rocky Hill Road Massachusetts Department of Plymouth, Massachusetts 02360 Environmental Quality Engineering One Winter Street Charles V. Barry Boston, Massachusetts 02108 Secretary of Public Safety Executive Office of Public Safety Office of the Attorney General One Ashburton Place 1 Ashburton Place Boston, Massachusetts 02108 20th Floor Boston, Massachusetts 02108 "r. Robert M. Hallisey, Director Radiation Control Program Massachusetts Department of Public Health 150 Treinont Street, 2nd Floor Boston, Passachusetts 02111 Regional Administrator, Region I U. S. Nuclear Regulatory Commission 475 Allendale Road King of Prussia, Pennsylvania 19406 Mr. James D. Keyes Regulatory Affairs and Programs Group leader Boston Edison Company 25 Braintree Hill Park Braintree, Massachusetts 02184

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6 ENCLOSURE PILGRIM NUCLEAR POWER STATION DOCKET NO. 50-293 REQUEST FOR %DDITIONAL INFORMATION PILGRIM SAFETY ENHANCEMENT PROGRAM i 1. Check valve 31-CK-167 has been identified as the containment isolation valve far the Backup Nitrogen Supply System. The use of a simple check valve is, in general, unacceptable for purposes of containment isolation.

Identify any other valve (s) that could provide inlation capability for the system and details relating to the valve (s) 16entified including the associated piping.

2. BEco reanalysis of a spectrum of MSLB accidents was performed to address the effect on the drywell response and in particular the thermal response of the drywell liner. BEco should confinn that the effect of spray nozzle modifications has similarly been considered for the relevant spectrum of accidents used for determining the equipment qualification environmental envelope. Sumarize the analysis and results of the evaluation of the effects of reduced spray flow on equipment qualification.

3. In the reanal calculation (ysis of the drywell described briefly inresponse to MSLB BECo Safety accidents, Evaluation 2133)the reviseda assumed spray droplet size of Imm. Discuss the basis for this assumption and describe how water impingement on drywell walls and other surfaces is accounted for in the calculation of the drywell atmosphere temperature.

Discuss any differences between the revised calculation and that analysis which served as the licensing basis for Pilgrim.

4 While not the sole mitigating feature in reducing the consequences of pool bypass, drywell sprays do influence the plants response to drywell pipe breaks with pool bypass, especially in limiting the break sizes of interest. Discuss the effect of reducing drywell spray flow rates on pool bypass capability. *

5. Discuss the effect of reduced drywell sprsy flow capacity on the capcbility to limit or terminate pool chugging loads.

6. It is noted that Pilgrim has experienced a problem with clogging of drywell spray nozzles and that the propcsed modification would dramatically reduce the number of nozzles. The revised design is inherently more vulnerable to such an issue. Therefore, it is our view that BECo should provide for additional surveillance to assure that corrective actions have been successful in addressing the problem of rusting in the spray header and potential nozzle clogging. Describe the measures that will be taken to confirm clogging of dr;vell spray nozzles will not impair spray operability.

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