ML19309G734

Ro:On 800418,discovered That Level of RCS Had Dropped Significantly.Control Room Operator Tripped Running Decay Heat Pump Because of Concern for Possible Loss of Suction. Caused by Vent Valve in Decay Heat Sys

ML19309G734
Person / Time
Site:	Davis Besse
Issue date:	04/19/1980
From:	Murray T TOLEDO EDISON CO.
To:
References
NUDOCS 8005070468
Download: ML19309G734 (1)

Text

6 U U 5 0 7 0 g(,y S l TELECo?Y NO%ed Veriting gcceipt: yyjno Date_ _ y.p.3}.

April 19, 1980 Tine- 9: g ----

Initials S TO: U. S. Nuclear Regulatory Ccemission Office of Inspection and Enforcement Region III Attention: Tcm Tambling SU3 JECT: Violation of Technical Specification 3.4.1 - Loss of Reactor Coolant (RC)

Flow Davis-Besse Unit 1 '.:cdc 5, ?over (MNT) = 0 and Load (WI = 0

\

In pr:rparation for re fue'_in ' .perations (specifically the detensioning and removal of the head) the Reac:ar xiant System (RCS) has been partially drained to establish a level in the vesrei C -:1 below the flange. Core cooling is accomplished via the

• decay heat removal e ::' .

At 1915 hours0.0222 days <br />0.532 hours <br />0.00317 weeks <br />7.286575e-4 months <br /> on .ipril 10, 1980, an operator discovered that the level in the RCS 1ad d:cpped significc.n:1j (to app; ately 35-40 inches above centerline of the hot leg). .it 1920 hours0.0222 days <br />0.533 hours <br />0.00317 weeks <br />7.3056e-4 months <br />, the control operator tripped the running decay heat pump (1-2) because of concern for possibi; loss of suction. The loss of RC flow is a vio-latica ;f T echni:.C. ?vc if ication 3.4.1.

The cause n the drap in level was quickly determined and corrected and the proper RCS level was re-estaolished using water from the borated water storage tank. Decay Heat Pucp 1-2 was restarted at 1945 hours0.0225 days <br />0.54 hours <br />0.00322 weeks <br />7.400725e-4 months <br /> and 3000 gpm flow was established by 1949 hours0.0226 days <br />0.541 hours <br />0.00322 weeks <br />7.415945e-4 months <br />.

The loss of RC inventary was from a vent valve in the decay heat system. This valve is located in ECCS Room 1. Exactly how this flow path was established is still under investigation.

The loss of RC flow caused no significant change in reactor core temperature and the discharge of reactor coolant into the ECCS room caused no significant radiation / con-tamination problems.

Luis Reyes, T.C en-site inspector, was notified at 1215 hours0.0141 days <br />0.338 hours <br />0.00201 weeks <br />4.623075e-4 months <br /> on April 19, 1980.

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l l , g' Terry D. Murray

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Station Superintendent Davis-Besse Nucicar Power Station \

Toledo Edison Campany

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