ML19347C761
| ML19347C761 | |
| Person / Time | |
|---|---|
| Site: | Big Rock Point File:Consumers Energy icon.png |
| Issue date: | 11/24/1975 |
| From: | CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | |
| References | |
| AO-25-75, NUDOCS 8102130101 | |
| Download: ML19347C761 (1) | |
Text
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ABNORMAL OCCURRENCE REPORT Big Rock Point Plant 1.
Report No: A0-25-75, Docket 50-155 2a.
Report Date: November 24, 1975 2b.
Occurrence Date: November 13, 1975 l
3 Facility: Big Rock Point Plant 4.
Identification of Occurrence: Rod drive scram accumulator removed from service during low reactor pressure operation.
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5 Conditions Prior to Occurrence: Reactor power and pressure being reduced to work on main turbine condenser.
6.
Description of Occurrence: The accumulator for E-b drive was removed from service in preparation for maintenance at 1030 hours0.0119 days <br />0.286 hours <br />0.0017 weeks <br />3.91915e-4 months <br />, November 13, 1975, while the reactor pressure was approximately 300 psig. During a review meeting held to discuss E-4 drive withdraw inoperability, the condition above was identified and'the accumulator was returned to service at 1210 hours0.014 days <br />0.336 hours <br />0.002 weeks <br />4.60405e-4 months <br /> on November 13, 1975 7
Designation of Apparent Cause of Occurrence: Misunderstanding of the implications and intent of operations memo 12-75, "The reactor shall be
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shut down if any one control rod becomes incapable of scram during the remainder of this operating cycle."
8.
Analysis of Occurrence: The operations memo had been issued in September 1975 Since only a one-rod shutdown margin had been demonstrated for core Cycle 13, the accumulator stored energy is required for scram at reactor pressure below h50 psi. Reactor physics analysis of shutdown margin available indicates that the one-rod shutdown margin criteria was not violated during the incident.
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Corrective Action:
The accumulator was returned to service and the incident discussed with a.
the Shift Supervisor.
b.
Operations Memo 12-75 will be revised to clarify requirements for this operating cycle.
Operating Procedure Section B30 will be revised to include Technical c.
Specifications requirements that'are implied in Paragraph 5.1.3(b) of the Technical Specifications.
e d.
The administrative procedures are being revised to include a require-ment for Plant Review Committee review of operations memos after they
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have been issued.
The action described in "b," "c" and "d" will be completed by January 1, 1976.
10.
Failure Data: Not Applicable T/0 W 3blO) h ?-
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