ML20084T436
| ML20084T436 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 08/13/1973 |
| From: | Sewell R CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | Oleary J US ATOMIC ENERGY COMMISSION (AEC) |
| References | |
| AO-5-73, AO-6-73, AO-7-73, NUDOCS 8306230193 | |
| Download: ML20084T436 (2) | |
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.c igen Avenue. Jackson, Machigan 49201. Area Code 517 788 0550 August 13, 1973 Mr. John F. O' Leary, Director Re: Docket 50-255 Directorate of Licensing License DPR-20 United States Atomic Energy Comission A0-5 Thru 7-73 Washington, DC 20545
Dear Mr. O' Leary:
This letter is written to report three abnomal occurrences at the Palisades Plant. Two of these three events, the failure of a coupling on a cmponent cooling water pump and low frequency operation of a diesel generator, occurred on July 27, 1973. The third, a varia-tion in the thermal margin / low-pressure trip set point (one of four channels) was discovered on August 3,1973. All three events were re-ported to Regulatory Operations, Region III, within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> as re-quired by Section 6.6.1 of the Technical Specifications. At the time each one of these events occurred, the reactor was operating at about 100% power.
Component Cooling Water Pump Coupling Failure On July 27, component cooling water pump P52C was observed to be noisy. During a test start conducted while attempting to locate the source of the noise, the motor-pump coupling failed. Further in-vestigations revealed sections of teeth on both the hub and outer piece of the motor half of the coupling were stripped away.
A new coupling was procured and installed. Reshimming was required in order te properly align the coupling.
The couplings on the remaining two component cooling water pumps have been nondestructively tested. Both couplings were deter-mined to be free from cracks. One coupling was found to have greater than normal wear. A new coupling is being procured and will be in-stalled and aligned as soon as it is received.
Diesel Generator Low Frequency Operation The 1-2 diesel generator was test started for routine monthly testing on July 27 The unit started properly. However, the speed stabilized at 57 hertz. The unit was then shifted to the " parallel"
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Mr. John F. O' ary, Director 2
Docket 50-255 License DPR-20 AO-5 Thru 7-73 August 13, 1973 mode of operation and the speed was increased to 60 hertz. The unit was then shift back to " unit" mode of operation and the speed dropped to 57 hertz. The 1-1 diesel generator was started and verified to be operable.
Investigation revealed that a cam was loose in the electric governor. The com was tightened and the monthly test run of the 1-2 diesel generator was successfully completed.
Since this incident,the electric governor cam on the 1-1 diesel generator has been inspected and found to be secure.
Although the loose can would have precluded automatic opera-tion of the 1-2 diesel generator as described in the FSAR, the Plant Review Ccennittee concluded that it might be feasible to utilize the diesel generator under similar circumstances by using the manual hand-wheel with the electric governor bypassed. This course of action vill be further investigated and, if feasible, procedures vill be developed to provide operator guidance.
Thermal Margin / Low-Pressure Trip Set Point Variation On August 3 during a monthly testing, the reactor protective system Channel B themal margin / low-pressure trip set point was found to be lower than that required by plant operations. Further investiga-tion revealed a defective set point potentiemeter. This potentiometer was replaced and Channel B thermal margin / low-pressure trip returned to service.
This failure of Channel B themal margin / low-pressure trip did not result in a loss of a reactor protection function. Three ad-ditional channels of themal margin / low-pressure trip protection were provided by plant design. These three channels were verified to be functioning properly.
Yours very truly, Ralph B. Sewell (Signed)
RBS/ce Ralph B. Sewell Nuclear Licensing Administrator CC: BHGrier, USAEC
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