ML20141D399

Summary of ACRS Subcommittees on C-E Plants & Palo Verde 851105 Meeting in Washington,Dc to Review Operating Experience at Palo Verde Unit 1 in Consideration of Unit 2 License & Discuss Depressurization of C-E Plants

ML20141D399
Person / Time
Site:	Palo Verde
Issue date:	11/06/1985
From:	Advisory Committee on Reactor Safeguards
To:	Advisory Committee on Reactor Safeguards
References
ACRS-2371, NUDOCS 8601070255
Download: ML20141D399 (6)

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11/6/85

!!lt/ts ACRS Meeting Minutes for the Combined Combustion Engineering Plants /

Palo Verde Subcommittees November 5, 1985 Washington, D.C.

Purpose:

The ACRS Subcommittees on Combustion Engineering Plants and Palo Verde met in a combined meeting on November 5,1985 at 1717 H Street, N.W.,

Washington, D.C.

The purpose of this meeting was to:

(1) review the operating experience on Palo Verde Unit 1, in consideration of the forthcoming license for Unit 2, and (2) discuss the issue of rapid depressurization for CE plants without PORVs, given the operating experience with the auxiliary pressurizer spray system at Palo Verde.

Unit 1.

The ACRS reported on December 15, 1981 and May 13, 1985 regard-ing Palo Verde Nuclear Generating Station, Units 1, 2 and 3.

Other than dn issue regarding rapid depressurization of the primary system which would continue to be reviewed under USI A-45, the Committee had re-quested a review of the startup experience on Palo Verde, Unit 1 prior to fuel load at Unit 2.

On November 5,1985, the combined Subcomittees heard presentations from the NRC Staff (NRR and Region V), the Applicant (Arizona Nuclear Power Project) and the NSSS Supplier (Combustion Engineering). The meeting began at 8:30 a.m. and was adjourned at approximately 5:30 r.m., and was held entirely in open session. The principal attendees were as follows:

8601070255 851106 ACRS LZlic. ' 10 C "'"i3 L c~uma n Ans

CE/Palo Verde Meeting Minutes November 5, 1985 ACRS ANPP J. Ebersole, Subcomittee Chairman J. Haynes

- C. Wylie, Subcommittee Chainnan G. Waldrep C. Michelson, Member T. Quan G. Reed, Member M. Radspinner D. Ward, Member G. Sowers P. Boehnert, Staff J. Barrow D. Houston, Staff A. Krainik R. Adney NRC

,C_E E

W. Houston, NRR R. Turk G. Knighton, NRR~

G. Davis E. Licitra, NRR A. Marchese, NRR J. Wermeil, NRR C. Liang, NRR J. Crews, Region V Highlights:

1.

The NRR Project Manager on Palo Verde sumarized the licensing position for continued operation of Unit 1 and consideration of the issuance of a low power license (fuel load) for Unit 2.

Three issues required resolution prior to licensing of Unit 2:

(1) Post Accident Sampling System - relocation of a containment sampling station to an accessible area, (2) ECCS Reanalysis - an analysis performedwiththecurrentCEmodel,and(3)AuxiliaryPressurizer Spray System - Component modifications and evaluation of the Steam Generator Tube Rupture analysis submitted on November 4,1985.

SSER No. 9 is-tentatively scheduled to be issued by mid-November to support licensing activities. The Staff also indicated that criticality for Unit 2 would be restricted until the completion of the power ascension test program for Unit 1.

The Subcomittee

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CE/Palo Verde Meeting Minutes November 5, 1985 questioned the basis for this restriction and were informed that per the current Schedule, the availability of Unit 2 would not be impacted. The Staff's i.ain concern wn' based on having two new units concurrently in startup and the dilution of technical support to any single unit. The Applicant indicated that power ascension testing on Unit I was expected to be completed by the end of December 1985, and initial criticality for Unit 2 was expected to be achieved by late February 1986.

2.

The Region V' Chief Engineer summarized their evaluation of the C

pe'rformance of operating shift crews, technical support groups and plant systems during the operation of Unit I since June 1985. He reported that the operating crews had been challenged substantially since some systems, tests and instrumentation had not functioned as planned. The region felt that the crews had performed rearkably well. The Technical Support Groups had demonstrated a tech. cal understanding of the plants operation and contributed to improve-ments in the procedures. The performance of this Group was evalu-ated as adequate. Plant systems with the exception of the Auxilia-ry Pressurizer Spray System, Charging Pumps and Multiplexer, to be discussed individually later in this report, were judged to be performing as designed. Some system problems were experienced with the plant or that system in a unique configuration, thus would not have been a problem under normal circumstances.

3.

The Applicant discussed the deficiencies that were identified in the Auxiliary Pressurizer Spray System (APSS) during the planned Loss of Load Test on September 12, 1985. During this event, the APSS was not actuated or needed but it was detennined later on that the APSS would have been unavailable had it been required. The deficiencies were associated with shed electrical power to certain valves, improperly functioning water level instrumentation and non-safety grade controls. The Applicant discussed the safety

e CE/Palo Verde Meeting Minutes November 5, 1985 grade design for the APSS, the details of the September 12 event, the planned modifications to the system to enhance its reliability and the results of the Steam Generator Tube Rupture (SGTR) analysis that currently takes credit for the APSS for depressurization of the primary system. The Staff agrees with the planned modifica-tions and has allowed Unit 1 to continue to operate on the basis of the modification or additional surveillances until the modification.

has been completed.

The currently approved SGTR analysis takes credit for APSS actua-tion within 17 minutes. Two additional analysis have been submit-ted by the Applicant and are under review by the Staff.

In one submitted on October 15, 1985, APSS actuation was assumed within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />.

In another submitted on November 4, 1985, no credit was taken for APSS actuation but it was assumed that the Pressurizer Gas Vent System would be opened within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />. Dose rates were calculated and showed a slight increase in dose for the exclusion area boundary from 200 to 208 REM and for the low population zone from 41 to 44 REM, all values within the 10 CFR 100 limit of 300 REM.

CE discussed the APSS design at Palo Verde versus other non-PORV plants, specifically Waterford and San Onofre 2 and 3.

The APSS on these plants had been designed with the enhanced features, thus the Palo Verde deficiencies would not be present on those plants.

4.

The NRR Task Manager discussed the status of bleed and feed effort in the USI A-45 program. Seven plants are to be examined in the review. Two, Point Beach and Turkey Point, have been examined to date. The bleed and feed capability at these plants reduced the core melt frequency by a factor of 2.30 and 5.88, respectively, each with a core melt frequency in the 10-4/R-Yr range. He also discussed the sensitivity study results which showed success with

CE/Palo Verde Meeting Minutes November 5, 1985 bleed and feed in regard to actuation time after scram. Success times varied from 8 minutes (B&W Plant) to 40 minutes (W Plant). A summary of the bleed and feed approach.in eight foreign countries was also presented.

5.

The Applicant discussed the Auxiliary Feedwater System Reliability and operating experience with the Main Feedwater System at Palo Verde, Unit 1.

A comparison of the PVAFWS to the Davis-Besse AFWS was presented. The AFWS has one safety grade electric driven pump, one non-safety grade electric pump and one steam driven pump. The Main Feedwater Pumps are steam driven. No problems have been experienced with these pumps when operating in the automatic mode during startup or continued power operation.

6.

Two Loss of Offsite Power events were experienced, one on October 3 and the other on October 7, 1985. Although not completely de-termined, the cause of.this problem seems to be a multiplexer that-controls certain breakers in the Startup Transformer Yard. This apparently is the initial application of a multiplexer in safety systems at a nuclear power faci.lity. To eliminate this problem, the Applicant has removed the multiplexer from the control circuits and hard wired the breaker control circuit to the control room.

i The Staff has visited the site, examined the modifications and l

agrees with resolution.

l 7.

The Committee will have a presentation by the Staff and Applicant l

during its next full Committee meeting on November 7, 1985.

Appropriate Committee action in regard to Unit 2 will be taken during the meeting.

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I CE/Palo Verde Meeting Minutes November 5, 1985 NOTE:

Additional meeting details can be obtained from a transcript of this meeting available in the NRC Public Document Room, 1717 H Street, N.W., Washington, D.C., or can be purchased from ACE-Federal Reporters, 444 North Capitol Street, Washington, D.C. 20001, (202) 374-3700.

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