ML19319B784

RO NP-33-77-54:on 770815,flowpath from Concentrated Boric Acid Storage Sys Via Makeup Pumps Found Inoperable.Caused by Two Rotors in Interlocking Valve MU11.Rotors Adjusted & Valve Declared Operable on 770815

ML19319B784
Person / Time
Site:	Davis Besse
Issue date:	09/09/1977
From:	Lingenfelter J, Vallade S TOLEDO EDISON CO.
To:
Shared Package
ML19319B685	List: ML19319B684 ML19319B784
References
NUDOCS 8001270252
Download: ML19319B784 (2)

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TOLEDO EDISON COMPANY j~)/ -

\ DAVIS-BESSE UNIT OSE NUCLEAR POWER STATION

SUPPL *24C!TAL INFORMATION FCR LER MP-33-77-54 DATE OF EVENT: August 15, 1977 FACILITY: Davis-Besse Unit 1 IDENTIFICATION OF OCCURRENCE: The flowpath from the concentrated boric acid storage system via the makeup pumps was inoperable.

Conditions Prior to Occurrence: The plant was in Mode 3, with Power (MWT) =0 and Load (MWE) = 0.

Description of Occurrence: At 0630 hours0.00729 days <br />0.175 hours <br />0.00104 weeks <br />2.39715e-4 months <br /> on August 15, 1977, the reactor operator attempted to add boric acid (3A) to the Makeup (MU) Tank, but valve MU40 (between the 3oric Acid Addition Tank and Makeup Pumps) would not open. The station entered Action Statement (a) of Technical Specification 3.1.2.2, since the concentrated boron injection flowpath was inoperable. This Action Statement required the res-toration of the flowpath to operable status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.

[m) Designation of Accarent Cause of Occurrence: Station Instrument and Control tech-

\., , / nicians found that an interlocking valve, Mull, contained two rotors that needed adjustment. One was in the interlock position, causing MU40 to remain closed. _

The rotors were adjusted,' and the valve declared operable at 1225 hours0.0142 days <br />0.34 hours <br />0.00203 weeks <br />4.661125e-4 months <br /> on August 15, 1977. This recoved the station from the Action Statement (a) of Technical Specification 3.1. 2.2.

Analysis of Occurrence: There was no danger to the health and safety of the public or to station personnel. The flowpath from the Borated Water Storage Tank was still operable. This borated water (at 1800 ppm boron) would have been able to increase boron concentration in the Reactor Coolant System (at 1475 ppm) if necessary.

Correcti've Action: Af ter the valve retor was adjusted and the valve declared operable, boric acid was again available to the Makeup Tank.

Failure Data: A boron injection flowpath was inoperable on August 1, 1977 ,

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(NF-33-77-43) , but the cause was personnel error.

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