ML20086J516
| ML20086J516 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 08/21/1974 |
| From: | Ullrich W PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| Shared Package | |
| ML20086J513 | List: |
| References | |
| AO-74-3, NUDOCS 8401240049 | |
| Download: ML20086J516 (2) | |
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August 11, 1974 p
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Mr. James P. O'ReillfEDTrector A
United Stat es Atomic Energy Cocsaission Directome of Regulatory Operations T
631 Par 6
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.ussia, Pettnsylvania 19406
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~-se Abnortaal Occurrence 24-Hour Notification
Subject:
_j Confirming W. T. U11 rich's phone conversation with Mr. V. Baunack,
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~A.E.degW1%gulatcdfUp~eranons MIice en August 21, 1974.
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Reference:
License Number DPR-56 M
Technical Specification Table 3.1.1 Note 11 I
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Report No..
50-278-74-3 Report Date:
August 21, 1974 Occurrence Date:
August 20, 1974 i
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Facility:
Peach Botton Atomic Power Station f
R. D. 1, Delta, Pennsylvanj2i 17314 I gg Identification of Occurrence:
W Setpoint of APRM inop trip circuit less conservative than allowed by the Technical Specifications.
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Conditions. Privr to Occurrence:
A The reactor was shutdown in a cold condition.
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Description of Occurrence:
During a surveillance tcat of the APRM systen the inoperative trip sigul y
from the LPRM count circuit was found to have it s setpoint out of the allowable tolerance on one APRM channel.
The Technical Specification q
requires that cach AFRM produce an inop trip when less than 14 cperable g
LFRM inputs exist for that c hannel. The as found setpoint would have g
allowed operation of APRM Channel B vith 12 operable LPRM inputs, g
h Designation of Apparent Cause of Occurrence:
Slight setpoint drif t of bistable trip device, g
er a
Analysis of Occurrence:
The APRM inop signal satisf actorily produced a scran and a rod withdrawal g
block.
The setpoint shif t was slight and of minical saf ety significance because no LFRM's in the APRM system were bypassed or otherwise inoperable.
This trip is an electronic enforcement of an administrative limit that was g
being complied with.
Corrective Action:
The bistabic trip device was i::anediately recalibrated to produce an inop trip with less than 14 operable inputs. The survei lance test is being Y
revised to change the LPRM dropout trip setpoint in the conservative direction.
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8401240049 740830 c.g-PDR ADOCK 05000278 s
PDR In-Q
Failuro Deto:
h previous foi en of this type cinco initial ibration.
Very truly yours, W. T. Ullrich, Superintendent Peach Bottom Atomic Power Station UA%
J/S*3 3
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