ML19319B763

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RO NP-33-77-46:on 770803,auxiliary Feedwater Pump 1-2 Failed to Start on Loss of Feedwater Trip on Steam Generator 1-1.Caused by Closed Governor Valve Shut by Worker in Area. Valve Manually Opened & Personnel Instructed
ML19319B763
Person / Time
Site: Davis Besse Cleveland Electric icon.png
Issue date: 08/29/1977
From: Cheska R, Lingenfelter J
TOLEDO EDISON CO.
To:
Shared Package
ML19319B656 List:
References
NUDOCS 8001270227
Download: ML19319B763 (2)


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, [5]Dl Auxiliary Feedwater Pamo 1-2 did not start on s Loss of Feeddater tri.p_on.J 7 89 g (Steam Generator 1-1. A governor valve was found completely c.losed, which'Ol s ae e3 ye a9 l prevent.ed the turbine from rolling to provide oil pressure to open the J

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DAVIS-BESSE UNIT ONE NUCLEAR POWER STATION SUPPLEMENTAL INFORMATION FOR LER NP-33-77-46 DATE OF EVENT: August 3, 1977 FACILITY: Davis-Besse Unit 1 IDENTIFICATION OF OCCURRENCE: Auxiliary Feedwater Pump 1-2 did not start on a loss of feedwater trip on Steam Generator 1-1.

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

Description of Occurrence: At 2338 hours0.0271 days <br />0.649 hours <br />0.00387 weeks <br />8.89609e-4 months <br /> on August 3,1977, while running TP 600.11, (Auxiliary Feedwater System and Once Thru Steam Generator Level Control Test), a trip signal from the Steam Generator 1 loss of feedwater circuitry was received which should have started the 1-2 Auxiliary Feed Pump (AFP). The 1-1 AFP was already run-ning but 1-2 AFP did not start. AFP l-2 was, therefore, inoperable which placed the unit in the Action Statement of Technical Specification 3.7.1.2.

The investigation found that the governor valve had been stepped on and was completely closed. The steam supply valve upstream from the gove'norr valve cpened allowing steam to come down against the closed governor valve, but the completely closed valve would

[ not allow the turbine to roll and provide its own oil pressure to apen the valve. At

\s_s)/ 0010 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> on August 4,1977, when Auxiliary Feed Pump Turbine 1-2 governor was manually opened, AFFT 1-2 was returned to operability.

Designation of Aooarent Cause of Occurrence: There were several groups working in the area of the AFPT l-2 governor valve and any one of the workers could have stepped on or leaned on the governor valve to close it. Other workers had preiiously been observed standing on the governor valve and were instructed at that time to use care when working in this area.

Analvsis of Occurrence: There was not a threat to the health and safety of the public or to station staff. Auxiliary Feed Pamp 1-1 was operable, initial criticality had not been reached, and no accident requiring the Auxiliary Feed Pumps occurred.

Corrective Action: The valve was manually opened and all personnel workirg in the room were instructed not to stand or lean on the AFPT governor valves. The Control Roo=

Operator has been instructed to monitor the high speed stop light once per hour. As work in this room has been greatly reduced, this occurrence is not expected to re-occur.

Failure Data: On July 27, 1977, both Auxiliary Feedwater Systems were inoperable (NP-32-77-11). On July 29, 1977, Auxiliary Feed Pump Turbine 1-1 was inoperable (NP-33-77-42). On August 2, 1977, both Auxiliary Feed Pumps were inoperable

g (NP-33-77-39). The cause of these occurrences, however, was not related to the j governor valve closure.

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