ML20084E354
| ML20084E354 | |
| Person / Time | |
|---|---|
| Site: | Ginna  |
| Issue date: | 05/31/1973 |
| From: | Amish K ROCHESTER GAS & ELECTRIC CORP. |
| To: | Oleary J US ATOMIC ENERGY COMMISSION (AEC) |
| Shared Package | |
| ML20084E338 | List: |
| References | |
| NUDOCS 8304150030 | |
| Download: ML20084E354 (1) | |
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May 31,1973
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N Mr. John F. O' Leary, Director e
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Subject:
R. E. Ginna Nuclear Power Plant, Unit No.1 4
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Rod Control System Malfunction Docket No. 50-244 m /@~.j'
Dear Mr. O' Leary:
In accordance with Ginna Station Technical Specifications Section 6.6.2b, we are reporting a rod control system malfunction.
On May 2,1973, a malfunction in the rod control system resulted in an un-planned Bank D rod withdrawal. Banks A, B and C control rods were all the way out of the core (230 steps) and Bank D control rods were controlling at 220 steps. The reactor was at 1266 MWt when the incident occurred.
At approximately 1500 hours0.0174 days <br />0.417 hours <br />0.00248 weeks <br />5.7075e-4 months <br />, the 1[ea Control Operator observed that the Bank D rods were stepping out of the core. He immediately switched from automatic rod control to manual rod control as required by Emergency Pro-cedure E-11, ' Continuous Rod Withdrawal. Bank D rods stopped at the 226 step position. There was no indication of any change in reactor power and the Head Control Operator then manually returned the Bank D rods to the 221 step position.
The Instrument and Control Section was immediately notified and their initial investigation indicated that the nuclear power averaging unit QM-401 appeared to be faulty.
A Plant Operations Review Committee meeting was held at 1630 hours0.0189 days <br />0.453 hours <br />0.0027 weeks <br />6.20215e-4 months <br /> to dis-cuss the occurrence. EM-69 " Replacement or Performance of Maintenance on Nuclear Channel Averaging Unit" procedure was reviewed and approved. The procedure was followed and the faulty nuclear channel averaging unit was repaired. It was checked out for proper operation and the control rods were returned to automatic control at 1955 hours0.0226 days <br />0.543 hours <br />0.00323 weeks <br />7.438775e-4 months <br /> on May 2,1972.
Tha malfunction was caused by a loose solder joint in QM-401. Adherence to the emergency procedure by the Head Control Operator stopped the malfunction before any change in power took place. There is no practical recommendation to prevent a recurrence of this incident since it was attributed to mechanical
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Very truly yours, A7) 8304150030 730621
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7 Keith W. Amish 3
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