ML20086J535
| ML20086J535 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 07/10/1974 |
| From: | Ullrich W PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| Shared Package | |
| ML20086J533 | List: |
| References | |
| AO-74-1, NUDOCS 8401240066 | |
| Download: ML20086J535 (2) | |
Text
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O July 10, 1974
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I Mr. James P. O'Reilly, Director N b, y 3 7,, ggg United States Atomic Energy Coc:miesion Directorate of Regulatory Operations g--2. h j
631 Park Avenue King of Prussia, Penncylvania 19406
Subject:
Abnorm 1 Occurrence 24-Rour Notification Confirming R. S. Fleischmann's phone conversation with Mr. R. A. Feil, A.E.C. Region 1 Regulatory Operations Office on July 10, 1974.
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Reference:
License Number DPR-56
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Technical Specifiention Table 3 2.C Report No.:
50-278-74-1 Report Date:
July 10, 1974 Occurrence Date:
July 9, 1974 Facility:
Peach Bottom Atomic Power Station R.D. 1, Delta, Pennsylvania 17314 Identification of Occurrence:
Failure of IRM Channel "H" to produce a Downscale Tiip.
Conditions Prior to Occurrence:
Initial fuel loading was in progrecs with 68 fuel assemblies loaded.
Description of Occurrence:
During a routine surveillance test of the IRM system, the Channel 'T' IRM would not respond below 5 on the 12% acale when a sic:ulated electrical cignal was applied to its input. This malfttnetion would render the IRM downscale rod block from Channel 'T' inoperable. The downecale trip is set at 3 2 5 on the 12% scale.
Designation of Apparent Cause of Occurrence:
An investigation by the instrument technician revealed that the amplifier and alternator circuit board was generating an oscillation whose magnitude prevented the channel electronics from responding to a low value signal such as % on the 12% scale.
Analysis of Occurrence:
Due to the redundnney of the IRM Channels (any one of the ei ht channels 6
can produce a rod withdrawal block) and the immediate verification of the operability of the other seven channels, 'this occurrence has minimal safety implications.
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Corrective Action:
The proble= of the undesirable oscillations is under investigation. As a te=porary measure, the downceale trip setpoint of Channel "H" was moved up to 6% on the 125% neale. This setting would allow operation of the down-scale trip when the instrument. does not respond below %.
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Very truly yours,
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e-W. T. Ullrich Superintendent Peach Bottom Atomic Power Station.
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