ML19263A768

Summary of 781211 Appeal Meeting Re Use of a Load Sequencer W/Offsite Power.Nrc Staff Concluded That Proposed Subj Facil Load Sequencer Was Acceptable

ML19263A768
Person / Time
Site:	Palo Verde
Issue date:	12/19/1978
From:	Stright R Office of Nuclear Reactor Regulation
To:	Office of Nuclear Reactor Regulation
References
NUDOCS 7901020296
Download: ML19263A768 (16)

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UNITED STATES

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NUCLEAR REGULATORY COMMISSION 3 ;*

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WASHINGTON, D. C. 20S55

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DEC 101978 Docket Nos. STN 50-592 and STN 50-593 APPLICANT: Arizona Public Service Company FACILITY:

Palo Verde Nuclear Generating Station, Units 4 and 5

SUMMARY

OF APPEAL MEETING HELD ON DECEMBER 11, 1978 REGARDING THE USE OF A LOAD SEQUENCER WITH 0FFSITE POWER A meeting was held between NRR staff members and representatives of the Arizona Public Service Company and their consultants in Bethesda, Maryland on December 11, 1978. The main purpose of the meeting was to conduct an appeal of the staff position concerning the use of a load sequencer with offsite power. Other matters concerning the safety review of Palo Verde 4 & 5 and the FSAR for Palo Verde were also discussed. A list of attendees is attached as Enclosure 1.

Summary of Meeting The applicant presented a description of the sequencer design and summarized the results of a reliability study that they had performed. The train-independent sequencers are made of solid-state components, have redundant power supplies, and have a continuous auto-test feature. The reliability study showed that the Palo Verde design has a higher predicted reliability then various design alternatives. A copy of the slides used by the dpplicant is included as Enclosure 2.

After considerable discussion, the staff concluded that the use of a load sequencer as proposed for Palo Verde was acceptable. The staff requested that the applicant submit the reliability study that had been used to support their position.

Other matters discussed during the meeting are listed below:

1.

The applicant plans to submit the Palo Verde FSAR in October 1979 and has a scheduled construction completion date for Unit #1 of November 1981. This time interval (submittal to construction completion) is less than that being used in planning other OL applications. The staff stated that it was their intent that the NRC review schedule be designed to coincide with completion of construction, and that further consideration of the Palo Verde schedule was warranted. To this end, a review of construction progress, for Unit #1, by the NRC's Caseload Forecast Panel is being planned.

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DEC 191978 2.

The applicant provided a comparison of the lumped parameter and finite element methods of seismic soil-structure interaction analysis.

3.

The applicant provided a preliminary design of the Unit 4 & 5 switchyard layout.

4.

The applicant provided an advance copy of a PSAR change that describes the shielding around the fuel transfer tube.

5.

The testing procedures and criteria for concrete stren)th tests were discussed. Also, the curing requirements for various types of concrete were discussed. The applicant will provide additional information on these subjects.

6.

The applicant provided a description of the instrumentation used to detect a loss of cooling flow to the reactor coolant pumps.

7.

The staff discussed their position on instrumentation used to detect long-term passive failures. These detector systems should be Class IE, seismic Category I, and alarm in the Control Room.

8.

The staff discussed their position on manual ECCS valves that, if mispositioned, would degrade ECCS performance. Control Room position indication is required for such valves.

9.

The applicants described alternative sources of water available for make-up to the auxiliary feedwater system. The staff stated that the description resolved their concern about long-tenn water sources.

10. The staff and the applicant reviewed calculations concerning the probable maximum flood at the East Wash diversion. The applicant will provide additional information on this review matter.

11. The applicants provided a copy of the results of the dust sampling program.

12. The criteria for the limitation of percentage fines in structural backfill was discussed.

Robert L. Stright, Pr ect Manager '

Light Water Reactors Branch No. 3 Division of Project Management

Enclosures:

1.

List of Attendees 2.

Load Sequencer Presentation

Mr. E. E. Van Bruz-:, Jr.

3-Vice President-Construction Projects Arizona Public Service Company P. O. Box 21666 Phoenix, Arizona 85036 cc: Arthur C. Gehr, Esq.

Snell & Wilmer 3100 Valley Center Phoenix, Arizona 85073 Charles S. Pierson, Assistant Attorney General 200 State Capitol 1700 West Washington Phoenix, Arizona 85007 Donald G. Gilbert, Executive Director Arizona Atomic Energy Commission 2929 Indian School Road Phoenix, Arizona 85017 George Campbell, Chairman Maricopa County Board of Supervisors 111 South Third Avenue Phoenix, Arizona 85003 Or. Stanley L. Dolins Assistant Director Energy Programs (0EPAD)

Office of the Governor 1700 West Washington Executive Tower - Rm. 507 Phoenix, Arizona 85007 e

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ENCLOSURE 1 LIST OF ATTENDEES NRC Staff APS F. Rosa D. Karner R. Stright J. Allen R. Boyd E. Van Brunt V. Benaroya M. Moreton - Bechtel - LA D. Ross D. Keith - Bechtel - LA

0. Chopra T. Killen - Bechtel - GPD J. Calvo R. Mattson D. Vassallo F. Ashe L. Engle

0. Parr

• R. Gonzales

• C.

Tan

• G. Kelly

• J. Greeves

• Not present for appeal portion of the meeting.

ENCLOSURE 2 PVNGS OFFSITE POWER SYSTEM I.

ESF LOADS APPROXIMATELY 5300 KW PER IRAIN II.

ESF TRANSFORMER SIZEB 10/12.5 MVA, OA/FA A.

TWICE THE SIZE REQUIRED FOR A SINGLE TRAIN LOADING B.

CAPABLE OF SUPPLYING BOTH ESF TRAINS WITH MANUAL INTERCONNECTION C.

IMPEDANCE 5Z AT OA RATING III.

STARTUP TRANSFORMER SIZED 42/56/70 MVA, 0A/F0A/F0A A.

SIZED FOR ACCIDENT LOADS OF ONE UNIT AND MORMAL SHUTDOWN LOADS OF ANOTHER UNIT PLUS MARGIN B.

IMPEDANCE 6.5% AT OA RATING

SEQUENCER DESIGN FEATURES Tile SEQUENCER IS DESIGNED TO RESPOND T0:

e LOCA WITH OFFSITE POWER AVAILABLE e

LOCA WITH SIMULTANEJUS LOSS OF 0FFSITE POWER e

LOCA FOLLOWED AT A LATER TIME BY LOSS OF 0FFSITE POWER e

LOSS OF 0FFSITE POWER FOLLOWED AT A LATER TIME BY A LOCA e

LOSS OF 0FFSITE POWER WITHOUT LOCA e

ACCIDENT OTilER THAN LOCA WITH OFFSITE POWER AVAILABLE e

ACCIDENT OTHER THAN LOCA WITHOUT OFFSITE POWER AVAILABLE LOAD SHEDDING IS PERFORMED ONLY ON BUS UNDERVOLTAGE ACCIDENT SIGNALS FOLLOWING INITIAL SEQUENCER OPERATION CAUSE SEQUENCER RESET AND SEQUENTIAL STARTING 0F ANY ADDITIONAL REQUIRED EQUIPMENT

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SEQUENCER RESPONDS TO SIAS CONTACT OPENING (FAIL SAFE) e SEQUENCER OUTPUT RELAYS ARE NORMALLY ENERGIZED, DE-ENERGIZE TO ACTUATE e

SEQUENCER HAS CONTINU0US AUT0-TEST WITH CONTROL ROOM ALARMS ON DETECTION e

OF FAILURE SEQUENCER COMPONENTS ARE MODULARIZED PROVIDING QUICK AND EASY MAINTENANCE e

OR REPLACEMENT SPURIOUS ESF SYSTEM ACTUATIONS ARE AVOIDED BY ALLOWING THE SEQUENCER TO e

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PROCUREMENT STATUS

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DELIVERED AT PVNGS LOAD CENTERS DELIVERED AT PVNGS LOAD CENTER TRANSFORMERS DELIVERED AT PVNGS SWITCHGEAR ALL EXCEPi TWO DELIVERED AT PVNGS MOTOR CONTROL CENTERS MANUFACTURED, DUE FOR DELIVERY 2/9/79 ESF TRANSFORMERS SEQUENCERS MANUFACTURED, DUE FOR DELIVERY 12/26/78

DESIGN REVIEW

SUMMARY

PVNGS DESIGN USING SINGLE SOLID-STATE ESF LOAD SEQUENCER PER SAFETY TRAIN VS.

ALTERNATE RELIABILITY IMPACT REASON o

U"C 0F INDIVIDUAL UN-RELIABILITY INCREASED BY ADDITIONAL COMPONENTS TIME DELAY RELAYS 7 X 103 0F REDUCED RELIABILITY o

USE OF SEPARATE UN-RELIABILITY INCREASED BY 2 ADDITIONAL COMPONENTS ON-SITE AND TO CAUSE INADVERTENT OFF-SITE SIMULTANE0US LOADING SEQUENCERS o

USE OF RELAY

.UN-RELIABILITY INCREASED BY ADDITIONAL COMPONENTS LOGIC TO START 6 X 102 0F REDUCED RELIABILITY EQUIPMENT ON (RELAYS)

ESFAS AND SEQUENCING ONLY UNDER LOSS OF 0FFSITE POWER CONDITION

.