ML20084Q827
| ML20084Q827 | |
| Person / Time | |
|---|---|
| Site: | Quad Cities  |
| Issue date: | 09/20/1973 |
| From: | Stephenson B COMMONWEALTH EDISON CO. |
| To: | Oleary J US ATOMIC ENERGY COMMISSION (AEC) |
| References | |
| NUDOCS 8306140268 | |
| Download: ML20084Q827 (2) | |
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,fg.Commohlth Edison
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Cordova, Illinois 61242 I
Telephone 309/654 2241 O.
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'k5{sTGh' September 20, 1973 J. F. O ' Leary, Di rector Directorate of Licensing Regulation U. S. Atomic Energy Corxalssion Washington, D.C. 20545
Subject:
Quad-Cities Nuclear Power Station, Unit i Docket llo. 50-254 DP.3-29, Appendix A, Section 1.0.A.2 & 6.6.B
Dear Hr. O' Leary:
In conducting an ensite review of ope. rating logs a plant condition was discovered which was subsequently cicssified as an abnormal occurrence on September 12, 1973. The purpose of this letter is to inform you of the details of this occurrence.
PROBLEM AND INVESTICATION on August 2,1973 the Unit I reactor was shutdown with all rods in and less than 212 degrees. The mode switch had been left in refuel to conduct instrumentation surveillance on the rod block circuitry. At 1030 the I and 1/2 diesel generators were taken out of service for maintenance.
This is allowed by Specification 3.9.E.3 If no core cooling system is required to be operable. At 1156 that same. day the torus water level was lowered to less than -2".
This is also allowed by Specification 3 7.A.] provided that the conditions of Specitication 3.5 F.2 are niet.
The minimun core cooling system availability requirement, 3.5.F.2, pemits core cooling systems to be Inoperable when the reactor is in cold shut-down and no work is being done which has the potential for drain:ng the reactor vessel. While the latter condition was met, the reactor was not in the cold shutdown condition as defined by paragraph 1.0.Z because the mode switch was in the refuel position.
EVALUATION AND CORRECTIVE ACTION The conflict between the definition of the shutdown condition in the Technical Specifications and the actual position of the mode switch was
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Mr. J. F. O ' Leary September 20, 1973 not recognized at the time, in fact, it is known that similar conditions have existed during previous outages when the torus was pumped to the i
main condenser to inspect for tube leaks. The discrepancy was detected 4
at this time by a formal onsite review of plant operation logs as required by paragraph 6.l.G.2.a.(6).
The finding was reported to the Superintendents of Production Division "A" and Nuclear and Fossil Systems.
In subse-quent discussions with members of the of fsite review and Region til Directorate of Regulatory Operations on September 12, 1973 it was concluded that this event should be classified as an abnormal occurrence and reported as such.
There are no safety Impilcations associated with this event since the Refuel mode blocks the withdrawal of more than one rod and no rods were withdrawn during the period in question. To meet the intent of Specifi-cation 3.5.F.2 no apparent safety benefit results from having the mode switch in Shutdown. We intend to discuss this and other inconsistencies with the requirements for primary containment with members of your staff and propose appropriate Technical Specification changes.
In the interim corrective action has been taken to insure that all shift engineers are aware of the mode switch requirements under similar circumstances.
Very truly yours, Co m0NWEALTH EDISON COMPANY QUAD CITIES HUCLEAR POWER STATION
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B. B. Stephenson Station Superintendent
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BBS/lk cc: Regional Director Directorate of Regulatory Operations - Region til i
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