ML19322A471
| ML19322A471 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 09/20/1979 |
| From: | Swanson D NRC OFFICE OF THE EXECUTIVE LEGAL DIRECTOR (OELD) |
| To: | Foster R, Gambardella A AFFILIATION NOT ASSIGNED, VIRGINIA, COMMONWEALTH OF |
| References | |
| NUDOCS 7911010530 | |
| Download: ML19322A471 (1) | |
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Anthony Gambardella, Esq.
Richard Foster, Esq.
Office of the Attorney General 1230 A Pearl Street 11 South 12th Street Denver, CO 80203 Room 308 Richmond, VA 23219 In the Matter of Virginia Electric and Power Company (North Anna Nuclear Power Station, Units 1 and 2)
Docket Nos. 50-338 OL and 50-339 OL Gentlemen:
Enclosed for your information is a copy of a letter from S. Brown of VEPC0 to J. O'Reilly of the NRC's Office of Inspection and Enforcement, Region II, dated August 20, 1979. A copy of the letter was previously sent to the Appeal Board members. The letter contains a discussion 'of the analyses per-formed by VEPC0 regarding potential over stressing of the service water system piping and piping supports during post-LOCA conditions for North Anna 2 due to an increased temperature range of the service water system.
Although this matter is not directly related to the service, water pumphouse (SWPH) settlement issue, it does concern stressing ef the service water pip-ing, which was discussed during the recent hearing (See VEPCO SWPH Testimony, pp. 60-62, and Tr. 214-218).
Expansion joint movement and piping stresses resulting from maximum service water temperature in a post-LOCA condition were considered by VEPC0 in its testimony at the referenced pages, and were found to be within the allowable limits.
To guard against overstressing, how-ever, VEPC0 in its letter indicated that it had modified certain pump-to-soleplate connections on the service water and auxiliary pumps.
Sincerely, O & J.
Daniel T. Swanson Counsel for NRC Staff
Enclosure:
As stated cc w/ enclosure:
Service List 791101'O 530
VepCO
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I August 20, 1979 Mr. Ja:es P. O'Railly, Directer Serial No. 556C Offica of Inspection & Enforces:ent PSEIC/CSC:adw:mc U. 5. Nuclear Ragulatory Ccsmission Region II Docket No. 50-333 101 Marietta Street. Suita 31CO Atlanta, Georgia 30203
Dear Mr. O'Reilly:
Under the pr:visiens o# ICCFR50.55(e), MRC Region II was notified on Novembep17,1978 of tas potenttal over stresiiEg oftNe~ Sinfer-
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Water System m1 ping and piping supports curing pcst-LCCA conditions for' Marth Anna lhtt E cce to an increased taccerature range of the serrice water sys*em. Cur last interb report (SN. 6563 of January 25,1979) described the prcblem and cutlined the analytical parz=etars and =eth-ocology to be used in solving it. This report will cutline the specific analyses perfor.ned and the results cf these analyses. The secpe of this effort included the Servica Water (S'd) and Cecipenent Cooling Watar (CCA)
Systems on Units 1 and 2.
This problem has been addressed in two phases.
Phase I was an anaTysis of the affected piping in the SW System fcr both units, the Unit 2 CCA Systam, and those portiens of the Unit 1 CCW system which are an integral part of the SW cr Unit 2 CCW Systas; the
, portiens of the CCA water system analyzed in phase 1 can be isolatad fr6n those analyzed in phase 2. and conprise all portiens ' required for the operation of Unit 2.
This analysis indicated that one branch ccnnec.
tion in the servica water system required additicnal reinforhet to maintain pipe stresses within allewables. A total of 427 pipe supports were reviewed,147 ef which required either r.odt ficatien to sat-isfy support allowables or remcyal to satisfy. pipe stress allcwables.
The review of the revised nozzle 1 cads and equi;,ent suppcrt loads which resulted fms tne pipe stress analysis in phase 1 indicatad the followir,g wort was required:
1.
Modification of the ptarp-to-soleplata ecnnections on each of the fcur SW and two auxiliary SW pucps.
C 2.
Modification of sane end connections < cn the menn
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support frame for the four CCW heat exchangers, m
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Mqdificatien of the CCW piping and/or pipe succorts to and frcm taa Unit 2 ructcr coolant pcp (RCP) motor u~pper hearing oil c clers to reduce loads on four of the six cooler noules.
4.
'Mo'.ificatica of the CCW piping to and from the Unit
, 2 RCP motor air ecclers to raduca loads en all twelve cooler no ules.
i All of the physical rework required by the phase 1 analysis, as describ-ed in the above two paragraphs, has been completed.
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Phase 21s"ai asilysTs of eie-affektsi pTpfng istaunit 1W sysTam-~~~
not covered by Phase 1.. The pips stress analysis is cespleta and requires no modification to piping. The pipe support analysi7 is c:spleta, and of 252 supports reviewed 114 require reworic.
The review of the revised nonle loads and equipment support loads which, _
resulted free the pipe stress analysis in phase 2 is empleta and requires no rework, excapt for the folicwing it.:::Is:
1.
The spent fuel pool coolers.
2.
The Unit 1 RCP motor upper bearing oil cooler nonie loads.
3.
The Unit 1 RCP motor air eccler nonia leads.
4 The boron recovery evaporator overhead condansers.
The engineering review to data indicatas a minor equipment support modification is required for item 1; for ite:ss 2 and 3, modificatiens similar to Unit 2 are required; for itan 4, the review ta data indicates no rework.
With the phy'sical completion of all rewcrk required by phase 1, all North Anna Unit 2 systans are now capable of cperating witnin their de-sign limits for the elevated Servica Watar temperature. Therefore, the issue of service watar %sperature excursion saculd no longer be a re-straint to any mode of operatica for North Anna Unit 2.
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Mr. James P, O'Pailly 3
I ila consider this to be cur final n;;crt undar the previsiens of 10CFR50.55(,s). If you have any questions, please contact this offica.
truly ursi
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Senior Vice Pnsident-Power /
g Station Engineering and Constnction Mr. Victer Stallo, Director om e. e z=,ect4c. unfc - n Mr. Harold N. Denten, Directer f
Offica of.1uclear Reacter Ragulatica 1
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