ML19331E418

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Responds to IE Bulletin 80-17,Suppl 1, Failure of 76 of 185 Control Rods to Fully Insert During Scram at Bwr. Installation of Water Level Monitoring Sys by 800901 Is Not Possible for Listed Reasons
ML19331E418
Person / Time
Site: Vermont Yankee File:NorthStar Vermont Yankee icon.png
Issue date: 08/15/1980
From: Tribble J
VERMONT YANKEE NUCLEAR POWER CORP.
To: Grier B
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
IEB-80-17, WVY-80-116, NUDOCS 8009100127
Download: ML19331E418 (2)


Text

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. n VERMONT YAN KEE NUCLEAR POWER CORPORATION SEVENTY SEVEN GROVE STREET B.4.1.1.

RUTLAND, VERMONT 05701 WVY 80-116

,t E Pt.Y TO s ENGINEERING OFFICE TURNPIKE ROAD WESTBORO. M ASSACHUSETTS 01581 August 15, 1980 """*"'"*-""

i United States Nuclear Regulatory Commission Office of Inspection and Enforcement Region I 631 Park Avenue King of Prussia, Pennsylvania 19406 Attention: Mr. Boyce H. Grier, Director i

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

(b) USNRC Letter to WNPC dated July 18, 1980; IE Bulletin 80-17, Supplement 1 (c) WNPC Letter (WVY 80-108) to USNRC dated July 28, 1980; Response to Bulletin 80-14 (d) VYNPC Letter (WVY 80-109) to USNRC dated July 28, 1980

Subject:

Response to IE Bulletin 80-17, Supplement 1

Dear Sir:

Reference (b) requests that BWR licensees install water level monitoring systems on all the control rod drive scram discharge volumes. Reference (b)

further states that the design installed should represent the design with the highest level of reliability compatible with completion of installation by September 1, 1980. We have determined that installation of the water level monitoring system by September 1,1980 is not post.ible; our reasons are provided below.
We have investigated several design possibilities, specifically the use of ultrasonic and emittance probes sensors. Discussion with the respective vendors reveals equipment delivery times ranging from four to ten weeks.

t - Vermont Yankee is scheduled to begin a refueling / maintenance outage on September 26, 1980, We believe that the continuous monitoring system installation can be deferred until the outage with no undue hazards or safety implications because:

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1. The scram discharge system vents and drains installed at Vermont Yankee, unlike those installed at Brown's Ferry, are independent of each other and are not affected by other systems. We feel that these. differences make our system significantly less susceptible to the condition experienced at Brown's Ferry.

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.8009100127

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Unit:d Stctco Nu31c2r Regulntcry Commis:icn August 15, 1980 Mr. Boyco H. Grice, Director Paga 2

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2. Historically, the control rod drive scram system hss proven to be entirely dependable and rvliable. Information supporting this statement was previously transmitted to the NRC in Reference (c).

3 Modifications have been made to the existing vent lines such that the vent remains effective regardless of component operability other than the vent valve [see Reference (d) for additional information.]

4. Daily monitoring of water levels in all scram discharge volumes will be continued until a continuous monitoring system is installed and opera tional. The results of monitoring done since the issuance of Bulletin 80-17 has shown that the scram discharge volumes remain free of water.

A written description of the system design will be provided to the NRC Regional Office as requested. It is anticipated that this will be done by September 19, 1980.

The following information is submitted in response to your request for estimatec of manpower expended in the research and subsequent performance of actions associated with this Bulletin.

Manpower Requirements Hours Bulletin Response 15 Corrective Actions 2/ day (Daily Monitoring)

We trust that the above supplied information and our commitment to install the monitoring system during the 1980 refueling outage is satisfactory; however, should you desire additional information, please contact us.

Very truly yours, VERMONT YANKEE NUCLEAR POWER CORPORATION l Y(

J. E. Tribble

)ss COUNTY OF WORCESTER )

Then personally appeared before me, J. E. Tribble, who, being duly sworn, did state: that he is a Vice President of Vermont Yankee Nuclear Power Corporation, that he is duly authorized to execute and file the foregoing request in the name and on the behalf of Vermont Yankee Nuclear Power Corporation, and that the statements therein are true to the best of his knowledge and belief.

%^ -

Robert H. Groce ' '

Notary Public My Commission Expires September 14, 1984 l