ML20084Q280

Ao:On 731124,recirculation Pump 2B Started W/Recirculation Loop Temp Differential Greater than 50 F.Caused by Failure to Recognize That 50 F Requirement Was Limiting Condition for Operation.Procedure Will Be Revised

ML20084Q280
Person / Time
Site:	Quad Cities
Issue date:	12/04/1973
From:	Stephenson B COMMONWEALTH EDISON CO.
To:	Oleary J US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20084Q254	List: ML20084Q280 ML20084Q293 ML20084Q303
References
NUDOCS 8306130192
Download: ML20084Q280 (2)

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DE07 m e 1973u- Qj December 4, 1973 [ b

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_3 Mr. John F. 0' Leary, Director Directorate of Licensing Regulation UNITED STATES ATOMIC ENERGY COMMISSION Washington, D. C. 20545

REFERENCE:

Quad-Cities Nuclear Power Station, Unit 2 Docket #50-265. DPR-30 Appendix A, Section 1.0.A.2, 3.6.A.4; and 6.6.8.

Dear Mr. O' Leary:

The purpose of this letter is to inform you of the details concerning the abnormal occurrence which took place November 24, 1973, whereby 28 Recircu-lation Pump was started with a recire loop temperature differential greater than 500F. This abnormal occurrence was previously reported to you by tele-phone and telegraph on November 26, IS/3.

PROBLEM AND INVESTIGATION

1. At 0701 on November 24, 1973, Unit 2 was operating at 665 W e. Load was being reduced to conduct MStV surveillance when the 2B recirculation pump tripped. The trip was caused by a failure of an MG set oli pump which was subsequently repaired within a few hours.

During this period the "A" recirc Icop remained in operation with the cross-tie valves closed at an indicated temperature of 505 F. The "a" loop tempera-ture, however, decreased at a rate of about 180/ hour. The bypass around the pump discharge valve was opened in an attempt to maintain temperature. Fur-ther efforts to increase the idle loop temperature included opening the main discharge valve and increasing the 2A pump speed from 40 to 47%. The actions resulted in increasing the "B" loop temperature by about 15 degrees initially, but at'this point the temperature began to fall again. At 1320 after closing the discharge valve and reducing the 2A pump speed to 45%, the 28 pump was started. The temperature at this time was about 70 less than the "A" loop.

When the loop temperatures equalized, the 2B pump discharge valve was throttled open slowly. No reactivity transient of any significance was observed in the reactor.

EVALUAYl0N AND CORRECTIVE ACTION l SAFETY IMPLICATIONS ..

The start-up of a cold recirculation loop is analyzed in section 4 of, the FSAR.

'The assumed tempsrature was 110 0 compared to about 430 in this occurrence.

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U John F. O ' Leary, Di rector December 4, 1973 Table 4.2.1. of the FSAR Indicates that the vessel design includes ten im-proper cold loop start-ups over the design life. Thus considering either reactivity transients or vessel stress this occurrence did not have any safety implications.

The Limiting Condition for Operation involved, section 3.6.A.4, is not addressed in the bases of the Technical Specifications. We have been ad-vised by the General Electric Company that the 50 degree limit was set by the pump supplier, Byron-Jackson, af ter an analysis showed that case warpage and subsequent Icakage at the case mating surfaces might occur at higher differential temperatures. A related wear problem involving clearances be-tween the more rapidly heated pump rotor and the pump bearings was also a factor in setting the limit.

CAUSE AND CORRECTIVE ACTION The cause of this abnormal occurrance was a failure to recognize that the 50 F AT requirement was a Limiting Condition for Operatlon. Had the personnel involved remembered this fact, obviously, the idle pump would not have been started. The details of this report have been brought to the attention of all operators and their supervisors. Furthermore, the problems associated with depending on memory to prevent errors of this r.ature was reviewed by station management. it was premised that particular dif ficulties arise when the basis for a LCO is not apparent; for example, as compared to a degraded RPS or ECCS condition. It was concluded that this abnormal occurrence could have been avoided if the operating procedure specifically identified this limit as a Tech Spec LCO. Therefore, this procedure will be revised accord-ingly. Quad-Cities Station is currently revising and upgrading all of its procedures to meet the requirements of AEC Regulatory Guide 1.33. With the completion of this review, all operating procedures will include reference to Technical Specifications where appropriate.

A report concerning possible effects of this occurrence is expected in January from Byron-Jackson. We will inform you of the contents of this report.

EVALUATION OF CUMULATIVE EXPERIENCE FOR SAFETY IMPLICATIONS This is the first occurrence where a recirculation pump started in an idle loop condition with any appreciable temperature differential. Therefore, there is no safety implication in view of cumulative experience. .

Very truly ours,-

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[B.![h h B. Stephenson

, Station Superintendent

! BBS/dkp i BBS-73-265 cc: Regional Director Directorate of Regulatory Operations - Region lli

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