ML20084T252
| ML20084T252 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 08/29/1973 |
| From: | Sewell R CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | Oleary J US ATOMIC ENERGY COMMISSION (AEC) |
| Shared Package | |
| ML20084T246 | List: |
| References | |
| AO-12-73, NUDOCS 8306230093 | |
| Download: ML20084T252 (2) | |
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@4 s.s $ s.g; pi p* General Omces: 212 West MicNgan Avenue. Jackson, Mict.igan 49201.
517 788 0550 W
c, August 29, 1973 i
f Mr. John F. O' Leary Re: Docket 50-255 Director of Licensing License DPR-20 US Atomic Energy Cc= mission A0-12-73 Washington, DC 20545
Dear Mr. O' Leary:
This letter is written to apprise you of a failure of the motor operator of the concentrated boric acid pump feed stop valve at the Palisades Plant which was discovered August 21, 1973 At the time the failure was discovered, the plant was in a cold shutdown condition (and had been since August 12,1973) to investigate the cause of the primary to secondary leakage in the "B" steam generator.
On August 19, 1973, the Safeguards Initial Signal (SIS) was actuated by taking preferred power bus Y20 out of service. Following i
this SIS, it was noted that the test sequence light remained on for MOV 2140. As the plant was in a cold shutdown condition, further investigation was not conducted until August 21.
At that time it was discovered that the motor was running continuously and the valve re-mained shut. An "open" signal.vas still being applied from the pre-t vious SIS as the signal is sealed in until the valve open limit is reached.
This valve motor operator has a lever to select manual opera-tion of the gear train.
If this lever is left in the " hand" position, motor operation vill automatically shift the " clutch" pavls to allov the motor to operate the valve.
In this case, the lever was found in the " hand" position with the motor running. The operator jarred the lever and the valve opened properly. Disassembly revealed the.t both clutch pavls were broken.
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This is the first failure of this type of the Limitorque motor-operated valves in the plant. The valve location is such that it is suspected that the valve (hence, the lever) may have been used as a convenient stepping point during construction and early operation of the plant.
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4 Docket 50-255 August 29, 1973 Two other similar motor-operated valves that provide convenient stepping points will be disassembled and the clutch pavls inspected.
All similar motor operator valves will be test-operated in the " hand" position, then remotely actuated to ensure they shift properly from the " hand" to the " automatic" mode of operation. These corrective actions vill be com-pleted prior to resuming plant operation. In addition, steps are being taken to ensure that the use of these valves as convenient stepping points is minimized.
.The failure of this valve does not eliminate the ability to Provide concentrated boric acid to the volume control system. A backup gravity feed line, with redundant valves which are actuated automatically on an SIS, was also provided by plant design.
Yours very truly,
' UN RBS/mel Ralph B. Seven Nuclear Licensing Administrator CC: BHGrier, USAEC s
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