ML17299A758

Provides Updated & Addl Info Re 851113 Request for Partial Schedular Exemption to GDC 4.Partial Exemption Requested for Period Ending W/Completion of Second Refueling Outage or Adoption of Proposed Rulemaking for Mod of GDC 4

ML17299A758
Person / Time
Site:	Palo Verde
Issue date:	11/15/1985
From:	Van Brunt E ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR
To:	Harold Denton Office of Nuclear Reactor Regulation
References
ANPP-34020-EEVB, TAC-60476, NUDOCS 8511250154
Download: ML17299A758 (8)

Text

REGULATOR "INFORMATION DISTRIBUTION > LITEM (RIDS)

ACCEScSION'~%BR ~ 651 1250 150 DOC ~ DATE 85/ 1 1 / 15 NOTARIZED ~ NO . DOCKET FACIL;STN-50 528 Palo Verde Nuclear Stationi Unit 1i Arizona Publi 05000528 AUTH, NAME AUTHOR AFFILIATION VAN BRUNTiE,E, Ar izona Nuclear Power Project (formerly Arizona Public Serv REC IP ~ NAME*'ECIPIENT AFFILIATION DENTONiH. Office. of Nuclear Reactor Regulationi Director (pre 851125)

SUBJECT; Provides updated 5 addi info re 651113 request for partial schedular exemption. to GDC 0 Partial exemption requested for

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period ending w/completion- of second refueling outage- or acloption of proposed rulemaking for mod of GDCQ ~

DISTRIBUTION CODE: A001D COPIES RECEIVED:LTR ENCL 0 SIZE:

TITLE: OR Submittal: General Distr ibution NOTES:Standardized plant. 05000528 OL 12/31/64 RECIPIENT COPIES REC IPIENT COPIES ID CODE/NAME. LTTR ENCL ID CODE/NAME LTTR ENCL:

PNR B PD7 PD 01 INTERNAL: ACRS 09 6 ADM/LFMB ELD/HDS3 1 0 NRR BNR EB NRR PWR A EB 1 NRR PNR B EB NRR/DHFT/TSCB 1- 1 NRR/DS I/METB NRR/DSRO DIR 1 1 R/DSRO/RRAB NRR/ORAS 1 0 EG F ILt- 04 RGN5 1 EXTERNAL: 20X 1 EG8,G BRUSKEpS LPDR 03 1 NRC PDR 02 NSIC 05 1 TOTAL NUMBER OF COPIES REQUIRED: LTTR 28 ENCL

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Arizona Nuclear Power Project P.O. BOX 52034 ~ PHOENIX, ARIZONA85072-2034 Mr. Harold Denton November 15, 1985 Director of Nuclear Reactor Regulation ANPP-34020-EEVB/WFQ/PGN U. S. Nuclear Regulatory Commission Washington D.C. -20555

Subject:

Palo Verde Nuclear Generating Station (PVNGS)

Unit 1 Docket No. STN-50-528 (License NPF-41)

Update to Request for Partial Schedular Exemption to GDC 4 File: 85-056-026 '.l.01.10

References:

(A) Letter from E. E. Van Brunt, Jr. (APS), to H. Denton (NRC) dated November 13, 1985 (ANPP-33985)

(B) Letter from E. E. Van Brunt, Jr. (APS), to G. W. Knighton (NRC) dated June 7, 1984 (ANPP-29684)

(C) Letter from E. E. Van Brunt, Jr. (APS), to G. W. Knighton (NRC) dated December 10, 1984 (ANPP-31417)

(D) NRR Report "Safety Evaluation Report on the Elimination of Large Primary Loop Responses as a Design Basis", dated October ll, 1984, Docket No. STN-50-470

Dear Mr. Denton:

Reference (A) requested and'rovided justification for a partial schedular exemption to General Design Criterion (GDC) 4. This letter provides updated and additional information relative to the request.

On November 8, 1985, APS was notified by Bechtel of a,deficiency in the Unit 1 Reactor Coolant System (RCS) pipe whip restraints. Corrective action was initiated immediately. As currently installed, the bolts in some of the restraints were not properly tensioned, or of the correct material, such that some of the pipe whip restraints may not be able to perform their intended function in the event of a pipe break. Under those circumstances, PVNGS Unit 1 does not meet the requirement of GDC 4 for protection of structures, systems, and components against certain dynamic effects associated with postulated RCS main loop pipe breaks. As a result, PVNGS Unit 1 cannot return to power until bolts of suitable material in the pipe whip restraints are properly tensioned.

As provided by 10CFR50.12(a), Arizona Public Service Company requests for PVNGS Unit 1 a partial exemption from the provisions of GDC 4, as requested and justified for PVNGS Units 2 and 3 in Reference (B)', for a period ending with the completion of the second refueling outage, or the ~adoption of the proposed rulemaking for modification of GDC 4, whichever occurs first.

F'DR 8511250154 8511.15 PDR ADOCK 05000528 py/

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Mr. Harold Denton Director of Reactor Regulation Update to Request for Partial Schedular Exemption to GDC 4 Page Two ANPP-34020 The justification for this partial schedular exemption that was presented in Reference (B) included a radiation exposure reduction to plant maintenance personnel of 560 man-rem per unit. This assumes that each restraint is removed once for Inservice Inspection (ISI). The personnel radiation exposure estimates for the current work that needs to be performed is 3 man-rem/day.

This estimate is higher than the estimate of 10 man-rem over an 18 day period which was previously reported in Reference (A). This is due to increased dose rates once the insulation is removed from the stops, and a crew size increase from 2 to 5 people for the D stops, which are located inside the primary shield wall. The estimate is based on actual dosimetry readings from the personnel working on the stops.

The cost benefit of this exemption is 530,000/day for labor and engineering.

Assuming the exemption is granted on November 22, 1985, a cost savings of 4240,000 and a radiation exposure reduction to personnel of 24 man-rem would be realized.

In addition, each day of delay in resuming power operation, if the requested schedular exemption is not granted, represents a significant lo88 of power generation and increase in generating costs.

The incurrence of such costs and effects is not justified in light of the 8tudies which show that pipe whip restraints are not necessary for safe operation. Reference (D) is the NRR staff evaluation of the C-E report entitled, "Basis for Design of Plant Without Pipe Whip Restraints", which provided the technical basis for eliminating large ruptures of the RCP as a design

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basis for C-E System-80 plants. To re-emphasize, the NRR report state8:

lq "The staff concludes that the probability, or likelihood of large pipe breaks occurring in the primary coolant system loop of a CESSAR facility is sufficiently low such that protective devices associated with postulated pipe breaks in the CESSAR primary coolant system need not be installed."

The C-E analysis was performed using the PVNGS design, which assures that the as-built design for PVNGS Unit 1 agrees with the design described in the C-E analysis. This analysis is discussed in detail in Reference (C).

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Mr. Harold Denton Director of Reactor Regulation Update to Request for Partial Schedular Exemption to GDC 4 Page Three ANPP-34020 If you have any questions or require additional information, please contact Mr. W. F. Quinn of my staff.

Very truly yours, E. E. Van Brunt, Jr.

Executive Vice President Project Director EEVB/WFQ/PGN/dim cc: G. W. Knighton E. A. Lf.citra R. P. Zimmerman A. C. Gehr

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