ML20138L246

Forwards Rev 2 to TR-6121-4, Fluid Analysis to Determine If Standby Gas Treatment Sys Purge...Overpressurized During DBA LOCA, Technical Rept,Per 850829 Request for Addl Info. Supporting Calculations Also Encl

ML20138L246
Person / Time
Site:	Pilgrim
Issue date:	10/23/1985
From:	Harrington W BOSTON EDISON CO.
To:	Vassallo D Office of Nuclear Reactor Regulation
Shared Package
ML20138L251	List: BECO-85-193, Forwards Rev 2 to TR-6121-4, Fluid Analysis to Determine If Standby Gas Treatment Sys Purge...Overpressurized During DBA LOCA, Technical Rept,Per 850829 Request for Addl Info. Supporting Calculations Also Encl ML20138L260
References
BECO-85-193, NUDOCS 8510310240
Download: ML20138L246 (3)

Text

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• e BOSTON EDISON COMPANY 800 50YLETON ETMEET EDETON, MABBACHUBErrin 02199 WILLIAM D. HARRINETON semieswees pneeseew?

October 23, 1985 BECo 85-193 Mr. Domenic B. Vassallo, Chief Operating Reactors Branch #2 Division of Licensing Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, D. C. 20555 License DPR-35 Docket 50-293 Request for Information Relative to Containment Purge and Vent

Dear Str:

By letter of August 29, 1985, the NRC requested that Boston Edison Company (BEco) provide additional information to that which was provided in our April 1, 1985 response relative to minimizing purging / venting of the primary containment during operation of Pilgrim Station. The following narrative addresses the questions contained in the August 29, 1985 letter, and the attachments provide the supporting calculations for your information and review.

Request

! In the submittal (Aprl1 1, 1985) it is stated that 17 seconds was used as the valve closure time in the radiation release calculation, even though the Tech.

Spec, requires valve closure in 10 seconds. In the Tech. Spec, (Amendment 42, 12 May 80) the valve closure time is given as 15 seconds. In our telecon of l 31 July 1985 you stated the following: (1) the 10-second valve closure time

! was incorrect, (2) 15 seconds is the correct Tech. Spec. value; and (3) a 2-second delay is assumed for pressure bulldup plus electronic delay to account for the difference between 15 seconds and 17 seconds, and that this time will be changed. Please verify that the above information is correct.

Response

s At the time of the July telecon the Information was correct relative to Technical Specifications. Currently the required operating times for the 8" containment purge and vent valves are:

Valve Maximum Operating Time (Seconds)

A0-5035A 5.0 A0-50358 5.0 A0-5044A 5.0 A0-50448 8510310240 DR 851023 p ADOCK 05000293 PDR hOOl Ifg i

BOSTON EDISON COMPANY Mr. Domenic B. Vassallo, Chief October 23, 1985 l Page 2 These operating times are from Pilgrim Station (PNPS) Operating Procedure No.

l 2.2.125, " Containment Isolation System", which governs the testing of containment valves. Technical Specifications still state 15 seconds for valve closure, a value based on the 20" valves formerly used in this application.

l By letter of June 21, 1985, BECo submitted Proposed Technical Specification

Change 85-08, which, in addition to satisfying Appendix J of 10CFR50, removes l Table 3.7.1 and transfers control of the valve times to Procedure 2.2.125.

Therefore 5 seconds is now the maximum operating time allowed for the purge

~

and vent valves.

Request Provide the analyses which show that the ductwork, filters, fans, and any

other safety equipment outboard of the purge / vent valves will survive a DBA-LOCA. Describe any equipment (moisture separators, heaters, coolers) in the purge / vent Ilnes that may reduce the damage potential of the air-steam effluent due to a LOCA.

l

Response

Teledyne Engineering Services Technical Report TR-6121-4, " Fluid Analysis to i Determine if the SGTS Purge and Vent Ductwork is Overpressurized During DBA-LOCA" is provided for your review as Attachment "A" of this submittal.

l TR-6121-4 demonstrates that the ductwork, filters, fans and other safety equipment outboard of the purge / vent valves is not overpressurized and will safely withstand the pressure effects of a DBA-LOCA.

Request On Page 2 of your submittal you quote a release rate of 161,000 lbm/hr.

Please provide either the calculations or the assumptions and methodology in sufficient detall to allow verification of this value.

Response

"BECo Calculation N3" is provided for your review as Attachment "B" of this l submittal. This calculation determines that 161,000 lbm/hr is the release rate for a DBA-LOCA at PNPS.

1 We believe this submittal provides the Information requested in your letter of August 29, 1985. Should you wish any further Information on this issue,

, please contact us.

l' r r ly yours, l W. D. Harringt i Attachments: (A) Teledyne Engineering Services Technical Report TR-6121-4 l (B) Boston Edison Calculation N3 l

t l

y ATTACHMENT A