ML19290E125

Submits Supplemental Response to IE Bulletin 80-01, Operability of Automatic Depressurization Sys Valve Pneumatic Supply. Leak Rate Test Will Be Performed on Check Valves in Safety/Relief Valve Air Accumulator Supply Lines

ML19290E125
Person / Time
Site:	Vermont Yankee File:NorthStar Vermont Yankee icon.png
Issue date:	01/25/1980
From:	Moody D VERMONT YANKEE NUCLEAR POWER CORP.
To:	Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
IEB-80-01, IEB-80-1, NUDOCS 8003040313
Download: ML19290E125 (2)

Text

, se, , &

• ( V ER310NT Y AN KEE NUCLEAR POWER CORPORATION L ,^ 4 J SEVENTY SEVEN GROVE STREET RUTI.AND VERSIONT 05701

=aruv re; WVY 80-19 January 25, 1980 ENGINEERING OFFICE TURNPIKE RO AD WESTDORO, M ASS ACHUSETTS 01581 TELEPHONE 617-364-9011 United States Nuclear Regulatory Commission Region I 631 Park Avenue King of Prussia, PA 19406 Attention: Office of Inspection and Enforcement Mr. Boyce H. Grier, Director

References:

(1) License No. DPR-28 (Docket No. '0-271)

(2) USNRC Letter to VYNPC dated January 11, 1980; IE Bulletin 80-01, Operability of ADS Pneumatic Supply (3) VYNPC Letter (WVY 80-14) to USNRC dated January 18, 1980; Response to IE Bulletin 80-01

Subject:

Supplementary Information in Response to IE Bulletin 80-01 Reference (3) supplied information in response to the concerns expressed in IE Bulletin 80-01. Subsequent to the response, discussions were held between Mr. William Raymond of your staff and Vermont Yankee personnel.

This letter will serve to supplement the information in Reference (3) with the conclusions reached as a result of those discussions.

We will perform a leak rate test on each of the four check valves in the safety / relief valve air accumulator supply lines during the next scheduled plant outage which will commence on February 16. 1980.

Acceptance criteria for the leak rate test will be established prior to that date. For the interim period, we will modify the Containment Air System in such a way that it will continue to supply control air to the ADS valves even in the unlikely event of a Group 3 isolation coincident with a loss of normal power (LNP).

As described in the Verront Yankee FSAR, the Class I seismic Containment Instrument Air System is a separate instrument air subsystem capable of providing compressed air required for pneumatic instruments and controls located within the primary containment. This subsystem makes use of a nonlubricated compressor, taking suction from within the primary containment, and compressing these gases to approximately 105 psig. The gases are stored in a receiver and pass through a prefilter, nonvented dryers and af ter-filter, before reentering the containment for use in actuating the valves. The compressor usec for this system is powered from 480 Volt MCC 9B which is powered by one of the two station emergency diesel generators during a loss of normal pcwer.

8 0 0304?g \3 Y

,.4 United States Nuclear Regulatory Commission January 25, 1980 Mr. Boyce H. Grier, Director Page 2 The modifications necessary to assure the continuous operability of this system during the interim period are as follows:

a. Provide a suction path from the Reactor Building atmosphere by removing a section of suction piping downstream of the containment isolation valves. A blank flange will be attached to the out-of-service suction line and the primary containment isolation valves will remain closed. This modification is necessary to ensure that the system will remain operable under primary containment isolation conditions.

b. Disable the compressor suction line valve closed interlock and the primary containment isolation interlock to allow the compressor motor to remain energized at all times.

This system will be placed in service following the comp.'ation of these modifications no later than January 25, 1980. In addition, we are presently verifying the seismic qualification of the Containment Air System and anticipate completion of that effort in the same time frame.

We trust that this information adequately supplements the material previously submitted; however, should you desire any additional information, do not hesitate to call.

Very truly yours, VERMONT YANKEE NUCLEAR POWER CORPORATION D.

RA@

Moody cr ManagercfOpe[ rations sec