ML19319E214
| ML19319E214 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 11/05/1974 |
| From: | SACRAMENTO MUNICIPAL UTILITY DISTRICT |
| To: | |
| Shared Package | |
| ML19319E205 | List: |
| References | |
| NUDOCS 8003310723 | |
| Download: ML19319E214 (2) | |
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I ABNORMAL OCCURRENCE REPORT x,,/
DOCKET No. 50-312-74-7 Reporting Dste:
November 5, 1974 Occurrence Date:
October 6,:1974 Time: Unknown Freility:
Rancho Seco Nuclear Cencrating Station-Unit No. 1 Clay Station, California
' Identification of Occurrence:
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Nucicar Serv' ice.Co'oling Water "A" Flow below Technical Specification requirements.
Candition Prior to Cccurrence:
The reactor was at steady state power of 15% and initial power escalation testing was in progress.
Description of occurrence:
('~'N-The Technical Specifications require a quarterly performance
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lst on the Nuclear Service Cooling Water Systems. To accomplish the test, a Surveillance
'-frocedure (SP 203.07C) has the pump differential pressure measured and logged.
This test was conducted October 6, 1974 and all the information was forwarded to the Plant Mechanical
. Engineer for evaluation. The flow rate is obtained from the associated pump curve for the
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acasured differential pressure (AP) at the pump. The curve indicated the NSCW System A Loop to be 4,650 GPM, which is 1350 GPM less than the design flow rate as required in S:ction 4.5.1.2.0.3 of the Technical Specifications.
Carrective' Action Taken or Which Should Be Taken:
The flow rate through the NSCW "A" System was rotested on
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October 28, 1974~and the differential pressure was measured to be 55 psi.
The pump curve.
' indicated that the flow rate for this pump. differential is 6350 GPM, 350 GPM above the
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d; sign flow rate.
- Designation of Apparent Cause: Unknown.
Analysis of' Occurrence:
i There was.no transient associated with this occurrence-The-operator recorded the data as required on_the surveillance procedure and forwarded the r:sults to'the Plant Mechanical Engineer for review.
The_ procedure itself has no tangible
- ccecptance critoria but only a _ requirement that the Lpump dif ferential pressure measurements bi made. iDue ;to circumstances 1 regarding other testing commitments, the Plant-Engineer
.,lidid. not' ovaluate A he' recorded -pump _ hcad dif ferential ' pressure until October 23, at _ which lme it'was'dcterm1'ed'that the system hadinot met its' full design flow requirements.
f[s_,,3,0ctober'19,four'osyspriortotheLevaluation,.theplantwasshutdown1foramaintenan
- Autage. On October 18 when(the Nuclear Service' Cooling Water System "A" was rctested, the system met;itsl design flow ~ requirements. During the period of time from October 6 (through October 28 no.known.valvo changes were made to the NSCW System "A" which would' 8008314 M J
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have provided for a reduced flow. During the period from October 6 through October 28 tha NSCW System "A" was available on demand at all times.
Equipment I.D.:
The pump is manufactured by Babcock & Wilcox Company, Canada, and is Type D E, Size 12 x 14 x 16 - rated for 6500 GPM.
Action Required to Prevent a Reoccurrence:
1.
The surveillance procedure will be revised to put the-
" Acceptance Criteria" in a form that the operator who records the data will be able to evaluate the results.
2.
The surveillance procedure will have a " Limit and Prceaution" added which will require an Abnormal Occurrcace Report if the " Acceptance J
Criteria" is not met..
3.
The NSCW System "A" riow will be tested monthly for the nnxt three months.
If these tests are satisfactory, then the testing will revert to thm norcal quarterly interval.
lure Data:
None.
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