ML20207E451

Forwards Results of Listed Sims Items,Including BWR Recirculation Pump Trip & BWR Drywell Vacuum Breaker Mods, Per 880727-29 Insp.Both Items Verified

ML20207E451
Person / Time
Site:	Vermont Yankee
Issue date:	08/08/1988
From:	Rooney V Office of Nuclear Reactor Regulation
To:	Wessman R Office of Nuclear Reactor Regulation
References
GL-83-08, GL-83-8, NUDOCS 8808180050
Download: ML20207E451 (4)

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August 8, 1988 Docket No. 50-271 MEMORANDUM FOR: Richard H. Wessman, Director Project Directorate I-3 Division of Reactor Projects I/II FROM: Vernon L. Rooney, Project Manager Project Directorate I-3 Division of Reactor Projects I/II

SUBJECT:

VERMONT YANKEE NUCLEAR POWER STATION SIMS INSPECTION REPORT On July 27-29, 1988 I performed an inspection of the following SIMS items at the Vermont Yankee site:

BWR Recirculation Pump Trip - MPS C-02 (TI 2515/95)

BWR Drywell Vacuum Breaker Modifications - MPA D-20 (TI 2515/96)

The enclosed presents my observations and will be forwarded to the Resident Inspector for inclusion in the next inspection report.

Original signed by:

Vernon I.. Rooney, Project Manager Project Directorate I-3 Division of Reactor Projects, I/II

Enclosure:

As stated Distribution: BockEt i

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File, NRC & Local PDRs, PDI-3 r/f, RWessman, BBoger, MRushbrook, VRooney,~0GC-Rockville EJordan, BGrimes, ACRS (10), JWiggins Region I, DHaverkamp Region I, G. Grant Region I PDI-3 PDI-3 RWessma VRoone[:ck y ,

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August 8, 1988 Docket No. 50-271 MEMORANDUM FOR: Richard H. Wessman, Director Project Directorate I-3 Division of Reactor Projects I/II FROM: Vernon L. Rooney, Project Manager Project Directorate I-3 Division of Reactor Projects I/II

SUBJECT:

VERMONT YANKEE NUCLEAR POWER STATION SIMS INSPECTION REPORT On July 27-29, 1988 I perfonned an inspection of the following SIMS items at the Vermont Yankee site:

BWR Recirculation Pump Trip - MPS C-02 (T! 2515/95)

BWR Drywell Vacuum Breaker Modifications - MPA D-20 (TI 2515/96)

The enclosed presents my observations and will be forwarded to the Resident Inspector for inclusion in the next inspection report.

Original signed by:

Vernon L. Rooney, Project Manager Project Directorate I-3 Division of Reactor Projects, I/II

Enclosure:

As stated Distribution: Docket File, NRC & Local PDRs, PDI-3 r/f, RWessman, BBoger, MRushbrook, VRooney, OGC-Rockville, EJordan, BGrimes ACRS (10), JWiggins Region I, DHaverkamp Region I, G. Grant Region I PDI-3 6 PDI-3 RWessmah VRooney:ck

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ENCLOSURE Vermont Yankee Nuclear Power Station SIMS Inspection Report INTRODUCTION The following licensing actions were selected to verify implementation at Vermont Yankee Nuclear Power Station:

BWR Recirculation Pump Trip - MPA C-02 (TI 2515/95)

BWR Drywell Vacuum Breaker Modifications - MPA 3-20 (TI 2515/96)

The purpose of the inspection was to satisfy the verification requirements of SIMS.

BWR Recirculation Pump Trip (TI 2515/95)

By letters dated January 8,1979 to all boiling water reactor (BWR) licensees that currently did not have recirculation purrp trips (RPT's) installed, the NRC staff requested the installation of RPT's. The licensees were informed that either of two alternative designs, known as the Monticello P.PT design or the modified Hatch RPT design, were acceptable. In response to the NRC letter of January 8,1979, the Vennont Yankee Nuclear Power Corporation comitted in its letter of February 4, 1980 to install an RPT similar to the Monticello RPT design during the 1980 Fall refueling outage. This comitment was confirmed by NRC order dated February 21, 1980.

I cs ,1 firmed the installation of Vennont Yankee's RPT by reviewing Engineering Design Change Request (EDCR) 79-2 including comparison of specifications, criteria, and design with staff guidance. The high reactor vessel trip pressure, which was not specified by staff guidance, was set for 1150 psig.

The RPT installation, which was accomplished during the September 1980 outage, was combined with ARI (alternate rod insertion) trip installation, and conversion of certain channels to analog circuitry. Spare capacity for the additional loads for the RPT and ARI and planned future analog circuits was added, by adding two 24V DC battery banks and chargers.

At the time of the 1980 outage Vermont Yankee's recirculation pumps were capable of tripping due to low water level. The modification accomplished during the 1980 outage (EDCR 79-2) added a trip on high reactor vessel pressure. No inconsistencies with staff guidance were identified for the recirculation pump trip at Vermont Yankee installed during the 1980 refueling outage. I conclude that completion of MPA C-02 is verified for Vermont Yankee.

BWR Drywell Vacuum Breaker Modifications (TI 2515/96)

Generic Letter 83-08 related to modification of vacuum breakers on Mark I containments identified a potential failure mode of the wetwell/drywell vacuum breakers in chugging and condensation oscillation phases of blowdown to the torus during a loss of coolant accident. In that Generic Letter the NRC staff requested that the impacted licensees provide a consnitment to submit the results of the plant unique calculations which either formed the bases for modifications to vacuum breakers, or provide justification for their as-built acceptability.

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In VY's letter of May 11, 1983, Vermont Yankee provided a response to Generic Letter 83-08, providing justification for the as-built acceptability of the VY vacuum breakers, and on November 24, 1986 the staff found the Vermont Yankee response to be acceptable. In VY's letter of May 11, 1983, although analysis showed as-built vacuum breaker acceptability, VY informed the staff that they changed the disc material in 1980 from cast aluminum to wrought aluminum in order to provide improved resistance to cyclic loading.

I confirmed the installation of wrought aluminum discs in VY's wetvell/drywell vacuum breakers by reviewing EDCR 80-11. I have also confirmed that the staff has previously accepted analyses showing that no changes are required for the VY vacuum breakers. I conclude, therefore, that MPA D-20 is verified for Vermont Yankee.

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