05000289/FIN-2010005-01
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Finding | |
|---|---|
| Title | Inadequate Preventative Maintenance for Signal Converter Causes Turbine Trip and Plant Transient |
| Description | A self-revealing Green finding was identified, because station personnel did not establish a periodic task to calibrate and/or replace the integrated control system (ICS) to digital turbine control system (DTCS) signal convertor, a critical component, in accordance with procedure MA-AA-716-210, Performance Centered Maintenance (PCM) Process, Rev. 10. Consequently, the signal converter remained in operation past the vendor recommended service life and failed due to age related degradation, causing a turbine trip and a plant power transient from 100 to 14 percent reactor power. Station personnel replaced the failed signal convertor, entered the issue into the corrective action program (Issue Report 1115086), and performed extent-of-condition reviews regarding other critical station components. The finding is more than minor because it adversely affected the equipment performance attribute of the initiating events cornerstone and the associated cornerstone objective to limit the likelihood of those events that upset plant stability. The inspectors evaluated the finding in accordance with IMC 0609.04, Phase I - Initial Screening and Characterization of findings. The finding was of very low safety significance because although it contributed to increased likelihood of a plant trip, it did not affect the likelihood that accident mitigation equipment or functions would be available. The finding had a cross-cutting aspect in the area of Problem Identification & Resolution, Operating Experience (OE) component because station personnel did not properly collect and evaluate industry OE, including vendor recommendations, to establish appropriate preventive maintenance (PM) tasks (e.g., calibration, replacement) for the ICS to DTCS signal converter to minimize consequential failures P.2(a). |
| Site: | Three Mile Island  |
|---|---|
| Report | IR 05000289/2010005 Section 1R12 |
| Date counted | Dec 31, 2010 (2010Q4) |
| Type: | Finding: Green |
| cornerstone | Initiating Events |
| Identified by: | Self-revealing |
| Inspection Procedure: | IP 71111.12 |
| Inspectors (proximate) | F Arner R Nimitz D Kem J Brand R Bellamy J Heinly |
| CCA | P.5, Operating Experience |
| INPO aspect | CL.1 |
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Finding - Three Mile Island - IR 05000289/2010005 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Three Mile Island) @ 2010Q4
Self-Identified List (Three Mile Island)
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