05000251/FIN-2015003-01
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Finding | |
|---|---|
| Title | Inadequate Work Instructions for Replacing Main Generator Current Transformers |
| Description | A self-revealing finding was identified for the licensees failure to provide adequate instructions for performing work on the Unit 4 main generator protection control circuitry. As a result, the lugged connections on an installed current transformer lacked the appropriate tightness causing increased electrical resistance and ultimately catastrophic failure of a lug connection. The lug failure produced an open circuit condition on the current transformer causing the generator protection circuit to actuate. This resulted in a turbine trip and reactor trip. Corrective actions included replacing the damaged lug and torqueing all the current transformer lug connections to the vendor recommended value. A root cause evaluation was performed and a revision made to maintenance procedure 0-PME-090.03, Maintenance of Isophase Neutral Bus and Grounding Transformer Connection Assemblies, to include additional instructions on torqueing the lug assemblies. The licensee entered this performance deficiency in their corrective action program (CAP) as action request 02047137. The performance deficiency was more than minor because it was associated with the procedure quality attribute of the initiating events cornerstone and adversely affected the cornerstone objective to limit the likelihood of events that upset plant stability and challenge critical safety functions during power operations. Specifically, the work package associated with engineering modification package EC 246904 and work order 40063905 directed the technician to connect the current transformer (CT) lugs hand tight and did not require torqueing per the vendor specified torque value. The inspectors screened the significance of the finding using Manual Chapter 0609, Appendix A, Exhibit 1, Transient Initiators. The inspectors determined the finding was of very low safety significance (Green) because the finding did not result in a reactor trip and a loss of mitigation equipment relied upon to transition the plant to a stable shutdown condition. The finding was associated with a cross-cutting aspect in the resources component of the human performance area because the licensee failed to ensure an adequate work instruction document was available to support nuclear safety (H.1) (Section 4OA3). |
| Site: | Turkey Point  |
|---|---|
| Report | IR 05000251/2015003 Section 4OA3 |
| Date counted | Sep 30, 2015 (2015Q3) |
| Type: | Finding: Green |
| cornerstone | Initiating Events |
| Identified by: | Self-revealing |
| Inspection Procedure: | IP 71153 |
| Inspectors (proximate) | D Bacon L Suggs M Bates M Endress T Hoeg |
| CCA | H.1, Resources |
| INPO aspect | LA.1 |
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Finding - Turkey Point - IR 05000251/2015003 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Turkey Point) @ 2015Q3
Self-Identified List (Turkey Point)
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