ML19319B788
| ML19319B788 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 09/12/1977 |
| From: | Lingerfelter J, Vallade S TOLEDO EDISON CO. |
| To: | |
| Shared Package | |
| ML19319B691 | List: |
| References | |
| NUDOCS 8001270256 | |
| Download: ML19319B788 (2) | |
Text
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Si ha 59 6a 68 69 7e 75 60 (vtNT Of SCRsPf tom g: The Absolute Positi,on Indicator (API) for Control Rod 4 of Group 4 was l
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@l inoperable. The indicator light for Rod 4 showed that it was 100%
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s9 to in 12 17 43 44 47 48 CAUST DESCRIPiioN l Instru:nent and_Cggt.r_o_1 Technicians found that a relay in the Position I
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It was replaced by the vendor.
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i sa to Jacque Lingenfelter/ Sue Vallade (4197'259-5000, Ext. 251 DVR # 095-1,129-1 8001270
TOLEDO EDISON COMPANY
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DAVIS-BESSE UNIT ONE NUCLEAR POWER STATION
/
SUPPLEMENTAL INFORMATION FOR LER NP-33-77-63
_DATE OF EVENT: August 12, 1977 F_ACILITY: Davis-Besse Unit 1
_IDE!TIIFICATION OF OCCURRENCE:
Rod 4 of Group 4 was inoperable.The Absolute Position Indicator (API) for Control Conditions Prior to Occurrence:
The plant was in Mode 2, with Power (MWT) = 0 and Load (M Tr) = 0.
Description of Occurrence: At 1910 hours0.0221 days <br />0.531 hours <br />0.00316 weeks <br />7.26755e-4 months <br /> on August 12, 1977, the Absolute Position Indicator (API) for Control Rod 4 of Group 4 was inoperable. The Control Room operator could not determine Control Rod 4 position within + 6.5%
This placed the Station in Action State =ent 3.1.3.3.
(a) of Technical Specification The indicator light (relative position indicator) for Rod 4 showed that it was 100% withdrawn, but the API reading fluctuated frem 70-100% withdrawn.
the indicator lights and API readings for the other reds in Group 4 shewed 100%
Since thdrawal, it was suspected that the API for Rod 4 was defective Designation of Aeoarent Cause of Occurrence:
Upon investigation, Instrument and Control Technicians round that a relay in the Position Indicator Panel was defective.
Dianond Controls.The relay, along with connecting cable, was replaced by the vendor, Analysis of Occurrence:
public or Station personnel.There was no danger to the health and safety of the The cont nl red was m-+= Thy aligned with the group, and relative indication was still operable.
properly.
The cvuisol rod was operating t
Corrective Action: On August 13, 1977 operability to the API for Control Rod 4the relay was replaced, returning Statenent (a) of Technical Specification 3.1.3.3.This removed the Station from Action
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- i Failure Data:
There have been no previous similar occurrences.
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