ML20052C045

LER 82-003/01T-1:on 820220,boron Concentration Fell Below Tech Spec Requirement.Caused by Apparent Boron Loss Coupled W/Small Sodium Pentaborate Concentration Margin

ML20052C045
Person / Time
Site:	Vermont Yankee File:NorthStar Vermont Yankee icon.png
Issue date:	04/23/1982
From:	Murphy W VERMONT YANKEE NUCLEAR POWER CORP.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML20052C041	List: ML20052C040 ML20052C045
References
LER-82-003-01T, LER-82-3-1T, NUDOCS 8205040297
Download: ML20052C045 (2)

Text

NRC FORM 366 U.6 NUCLGA1((DEULAli@fdY CCl3213R)

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> a 60 61 DOCKET NUVSER 68 69 EVENT DATE EVENT DESCRIPTION AND PROBABLE CONSEQUENCES h 10121 l A SLC storage tank sample revealed that boron concentration was below T. S. Section I 1013 I I 3.4.C requirements. There were no consequences of this event (See attached.) l I

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CAUSE DESCRIPTION AND CORRECTIVE ACTIONS l i l 0 l l An apparent boron loss, coupled with a small sodium nentaborato concentration marnin. 1

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VTVYS1 05000271 LER 82-3/lT, Rev. 1 EVENT DESCRIPTION AND PROBABLE CONSEQUENCES Following the addition of water to the SLC Tank as a result of the ISI pump test on 2/19/82, a sample of the solution was taken as required by T. S. Section 4.4.C on 2/20/82. The sample revealed that the boron concentration was below that required by T. S. Section 3.4.C. The Shif t Supervisor was notified on 2/21/82 and took actions to restore the concentration to the nurmal level within the required 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> period.

Although there were no consequences of this event, it does constitute a situation in which a system required corrective action to prevent oper-ation in a manner less conservative than assumed in the accident analysis.

Therefore, it is being reported in accordance with T. J. Section 6.7.B.l.i.

CAUSE DESCRIPTION AND CORRECTIVE ACTIONS VY Plant management formed a task force to investigate the reasons for the reduced boron concentration in the SLC storage tank. The task force completed its investigation and concluded the following:

1. There was an apparent loss of boron from the SLC System that occurred between September 1981, to March 1982.

2. The exact mechanism for this boron loss is not known.

3. During 1981, VY maintained a small, administrative sodium pentaborate margin from T. S. Section 3.4.C concentration limits.

4. The apparent boron loss, coupled with the small sodium pentaborate concentration margin, caused the boron concentration to fall below T. S. Section 3.4.C limits.

To correct this problem, VY will' implement the following SLC task force recommendations for controlling sodium pentaborate concentration.

.l. A program of increased surveillance will be continued until the boron loss i . stopped or better understood.

2. A larger (1.5%) sodium pentabor te concentration margin will be incorporat'e d into VY Operating Procedures.

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