05000327/FIN-2011005-03
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Finding | |
|---|---|
| Title | Nuclear Instrumentation System Channel Calibration Error |
| Description | A self-revealing non-cited violation of Unit 2 TS 3.0.3 was identified for the licensees failure to place the unit in Mode 3 within seven hours when a Limiting Condition for Operation (LCO) was not met in Modes 1 and 2. The requirements of LCO 3.3.1, Reactor Trip System Instrumentation, associated with the power range neutron flux function in Modes 1 and 2 were not met for a period of approximately 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. This was the result of an error made during the performance of a channel calibration activity, which caused one channel to be left in an inoperable condition. This issue was entered into the licensees corrective action program as PER 397142. The finding was determined to be greater than minor because it was associated with the human performance attribute of the mitigating systems cornerstone and affected the cornerstone objective to ensure the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences. Specifically, the inoperability of the N44 power range Nuclear Instrucment System (NIS) channel low range neutron flux trip function resulted in the failure to meet TS operability requirements associated with reactor trip system instrumentation. Using Inspection IMC 0609, Significance Determination Process, (SDP) Attachment 4, Phase 1 - Initial Screening and Characterization of Findings, the finding was determined to be applicable to Phase 2 SDP screening since it represented the loss of a channel of a TS required function for greater than its TS allowed outage time. A Phase 2 analysis using Saphire 8 software with the Sequoyah SPAR model in the SDP mode was performed by a regional SRA. Using an exposure period of 1 day with a truncation value of 1E-13, a result of CDF << 1E-6, or very low safety significance (Green), was obtained. The cause of this finding was determined to have a cross-cutting aspect in the area of Human Performance associated with the Work Practices component. The licensee failed to adequately implement human error prevention techniques, such as self and peer checking, to ensure that the work activity was being performed on the correct component. |
| Site: | Sequoyah  |
|---|---|
| Report | IR 05000327/2011005 Section 4OA3 |
| Date counted | Dec 31, 2011 (2011Q4) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | Self-revealing |
| Inspection Procedure: | IP 71153 |
| Inspectors (proximate) | S Shaeffer C Young M Speck R Baldwin J Hamman W Deschaine |
| CCA | H.12, Avoid Complacency |
| INPO aspect | QA.4 |
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Finding - Sequoyah - IR 05000327/2011005 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Sequoyah) @ 2011Q4
Self-Identified List (Sequoyah)
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