ML20008E010

Updates 800815 Response to IE Bulletin 80-17,Suppl 1, Failure of 76 of 185 Control Rods to Fully Insert During Scram at Bwr. Continuous Scram Discharge Vol Monitor Will Be Installed Prior to Startup After 1980 Refueling

ML20008E010
Person / Time
Site:	Vermont Yankee File:NorthStar Vermont Yankee icon.png
Issue date:	09/19/1980
From:	Marsolais L VERMONT YANKEE NUCLEAR POWER CORP.
To:	Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
IEB-80-17, WVY-80-133, NUDOCS 8010240056
Download: ML20008E010 (3)

Text

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g i VERMONT YAN KEE NUCLEAR POWER CORPORATION SEVENTY SEVEN GROVE STREET RUTLAND VERMONT 057O1 B.4.1.1.

WVY 80-133 September 19, 1980 "

E EER:NG CFFICE United States Nuclear Regulatory Commission TURNPIKE RO AD WESTBORO, M ASS ACH JS S 01581 Office of Inspection and Enforcement Region I 631 Park Avenue King of Prussia, Pennsylvania 19406 Attention: Mr. Boyce H. Grier, Director

References:

(a) License No. DPR-28 (Docket No. 50-271)

(b) USNRC Letter to VYNPC dated July 18, 1980; IE Bulletin 80-17, Supplement 1.

(c) VYNPC Letter (WVY 80-116) to USNRC dated; August 15, 1980.

Subject:

Supplemental Response to IE Bulletin 80-17, Supplement 1.

Dear Sir:

In our initial response to Reference (b), we provided justification for deferring installation of a scram discharge volume monitoring system until the upcoming refueling outage. In addition to our commitment to install the monitoring system during the outage, we committed to submit to the NRC a written description of our proposed design; this description is provided as an attachment to this letter.

In response to the NRC's telephone request that we revise / clarify the information contained in Reference (c), the following is provided:

a) A continuous scram discharge volume monitor will be installed prior to startup after the 1980 refueling; this installation will include alarm and indicator capability in the Control Room.

b) During the interim period between September 12 and the onset of the refueling cutage, ultrasonic testing surveillance of the scram discharge volume will be accomplished once per shift with no less than six hours between checks.

We trust that this supplemental information is satisfactory; however, should you desire additional information, pleast contact us.

Very truly yours, VERMONT YANKEE NUCLEAR POWER CORPORATION

, anO cm L. D. Marsolais Project Manager RJW/ dis Enclosures 8 %ouooSG

Attachment Scram Discharge Volume Water Level Measurement Water level will be measured at two locations in the scram discharge volume.

At each location an admittance probe will be inserted into the pipe, which, with its associated electronics and meter, will provide '.iie control room operator with an indication of water leveil at that location in the scram discharge volume. The locations selected are the low points of the six inch headers to ensure monitoring the volume of interest. An alarm signal will be provided for the control room annunciator to alert the operator whenever a pre-determined water level is exceeded.

The scram discharge water level indicators and the alarm annunciator are located on the nuclear section of the main control board. Power for the water level indication channels will be provided from the plant instrument bus which is fed from an emergency power source.

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