05000315/FIN-2014003-03
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Finding | |
|---|---|
| Title | Deficient Annunciator/PPC Design |
| Description | The inspectors identified a finding of very low safety significance associated with the licensees failure to design the annunciator and plant process computer (PPC) systems in accordance with design specifications. Specifically, the licensee failed to design the systems to preclude loss of the system on a single active failure. In part, this issue would result in loss of the annunciator and PPC systems following a loss of offsite power. The licensee recognized a weakness during a loss of power (LOP)/loss-of-coolant accident (LOCA) testing when the annunciator system failed about 15 minutes into the test. Although the licensee corrected the condition related to rack fans, the inspectors identified a similar issue associated with the server rooms. The annunciator and PPC systems do not have regulatory requirements; therefore this finding did not include a violation. The licensee has modified the ventilation system to provide cooling and assure operation following a loss of offsite power. The inspectors determined that failure to design and install the annunciator system in accordance with the design description of the applicable Engineering Calculation (EC) was a performance deficiency that warranted a significance evaluation. Using IMC 0612, Appendix B, issue screening, the inspectors determined the finding was more than minor because it is associated with mitigating system cornerstone objective of ensuring the availability and reliability of systems that respond to initiating events and is related to the human performance attribute, post event. Specifically, the annunciator and PPC systems aid human performance by alerting operators to degrading plant and equipment conditions. Using IMC 0609, Significance determination process for at power findings, the inspectors determined that the condition would result in loss of the annunciator and PPC function during some accident scenarios. Therefore the inspectors determined a detailed risk analysis was needed and forwarded the issue to the Region III Senior Reactor Analyst (SRA). The Region III SRA performed a detailed risk evaluation for the finding. To perform the risk evaluation, the SRA determined that the reliability of some operator actions modeled in the NRCs Standardized Plant Analysis Risk (SPAR) model for Donald C. Cook would be negatively impacted if annunciators were not available to cue operators to take action. The delta core damage frequency calculated was 5.5E-7/yr, which represents a finding of very low safety significance (Green). The SRA determined delta large early release frequency was minor as well. Because the licensee failed to identify the extent of condition, the inspectors concluded that the finding included cross-cutting aspect, PI.2 Evaluation, in the area of problem identification and resolution. |
| Site: | Cook  |
|---|---|
| Report | IR 05000315/2014003 Section 1R18 |
| Date counted | Jun 30, 2014 (2014Q2) |
| Type: | Finding: Green |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.18 |
| Inspectors (proximate) | A Schwab J Ellegood J Mancuso K Riemer M Mitchell R Jickling T Taylor |
| CCA | P.2, Evaluation |
| INPO aspect | PI.2 |
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Finding - Cook - IR 05000315/2014003 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Cook) @ 2014Q2
Self-Identified List (Cook)
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