ML20086K479
| ML20086K479 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 07/07/1974 |
| From: | Cooney M PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | Anthony Giambusso US ATOMIC ENERGY COMMISSION (AEC) |
| References | |
| AO-74-34, NUDOCS 8401270136 | |
| Download: ML20086K479 (2) | |
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PHILADELPHIA ELECTRIC COMPANY ri
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July 7,1974 Mr. A. Giambusso Deputy Director of Reactor Projects United States Atomic Energy Commiss
~1 Directorate of Licensing Washington, DC 20545
Dear Mr. Giambusso:
Subject:
Abnormal Occurrence The following occurrence was reported to Mr. Tom Shedlowsky, A.E.C. Region 1 Regulatory Operations Office on June 28, 1974. Written notification was made to Mr. James P. O'Reilly, Region I Regulatory Operations Office on June 28, 1974. In accordance with Section 6 7 2.A o.~ ti e Teclin i o. i Aner.i f ic a r i nns, u,nna nce i v a ne sweuq*e em: 2 Pc _.-h Bottom Atomic Power Station, the following report is being submitted to the Directorate of Licensing as an Abnormal Occurrence.
Reference:
License Number DPR-44, Amendment Number 1 Technical Specification 3 2.C Report No.:
50-277-74-34 F eport Date:
July 7, 1974 Occurrence Date: June 27, 1974 Facility:
Peach Bottom Atomic Power Station R.D.1, Delta, Pennsylvania 17314 Identification of Occurrence:
Rod block setpoint of two average power range monitors exceeded technical specification limiting setting by less than 0.4%.
Conditions Prior to Occurrence:
The reactor was at 97% power.
Description of Occurrence:
During a routine functional and calibration surveillance test of the JPRM system, two channels were found to hwe their rod block tri setpoints in excess of the technical specification upper limit r
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Mr. A. Giambusso July 7, 1974 Page 2 Channel A exceeded the limit by 0.4%' power and Channel D exceeded the limit by 0.2% power.
Designation of Apparent Cause of Occurrence:
1 A review of the previous wcek's APRM surveillance tests in-dicated that the trip setpoints were left in the conservative direction by less than 1.0% power. The setpoint failure is, therefore, attributed to slight instrument channel drift.
Analysis of Occurrence:
Due to the minimum deviation from the technical specification limit and the redundancy of the APRM system in its ability to initiate a rod withdrawal block (any one of the six channels can initiate a rod block), this occurrence has minimal safety significance.
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Corrective Action
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The rod block setpoints of the two out of specification i
channels were immediately recalibrated to within the technical speci-4 fication limits. The scram and rod block setpoints of all six APRM channels were innediately checked and found to be satisfactory. The J
calibration procedure has been changed to provide a 1% conservative setpoint to prevent recurrence. These setpoints have been applied to
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each channel.
l Failure Data:.
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L No previous failures of this type.
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Very truly yours, I }' s[Lbl.lL i
M.f.Cooney Ass t Gen'1 Sup,erintendent t
l Generation Division l
cc:
Mr. J. P. O'Reilly Director, Region i United States Atomic Energy Commission 1
631 Park Avenue King of Prussia, PA 19406 i
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