05000387/FIN-2011002-07
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Finding | |
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| Title | None |
| Description | PPL\\\'s CR 1220346 (December 30, 2009) identified that the anti-pumping feature of the RHR breakers was not modeled correctly in the simulator. Specifically, the breakers would cycle continuously open and closed when an open and closed signal was present. In actuality, the breakers would attempt to cycle once if both signals were present but then would trip and remain open until the anti-pumping circuit is reset and the breaker would have the ability to be closed. This error had been present in the simulator since 2007, when the RHR and other 4kV system breakers were modified to a new style of breaker. This violation occurred due to incorrect evaluation of the modification that installed the breakers in 2007. During the evaluation of the modification, the impact to the simulator from the anti-pumping feature of the breaker circuitry was initially installed in the simulator but was removed due to incorrect print reading and evaluation of the simulator changes by the licensee. The inspectors determined that PPL took corrective action to correct the simulator prior to providing scheduled training in 2010. This error in the simulator is a violation of 10 CFR 55.46(c)(1), Plant Referenced Simulators, because negative training was provided to the licensed operators since the SSES simulator did not accurately model the performance of RHR and other system breakers during plant transients where the breakers had at least momentary simultaneous open and close signals. Additionally, the incorrect modeling in the simulator helped prevent presenting the appropriate mitigative actions required by the licensed operators to restore equipment to service after the equipment remained tripped due to the anti-pumping feature of the effected breakers. The inspectors determined that PP&L\\\'s inaccurate modeling of the effected 4kV breakers was within PPL\\\'s ability to foresee and correct since the initial impact to the simulator was evaluated correctly and later made incorrect due to errors by the licensee staff. The finding is more than minor because it is associated with the Human Performance attribute of Mitigating Systems and affects the cornerstone objective to ensure the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences. Specifically, the modeling of the Susquehanna simulator introduced negative operator training that could affect the ability of the operators to take the appropriate actions during an actual event. The inspectors evaluated the finding in accordance with IMC 0609, Appendix l, Licensed Operator Requalification SDP. The finding was determined to be of very low safety significance (Green) because it is not related to the failure rate of licensed operators on the overall annual examinations or during the operating portion of the annual examination. The finding was also not related to the licensee\\\'s grading of the annual operating examination, the quality of the biennial written examination nor was it related to an individual operating examination. The finding is related to simulator fidelity, and a deviation between the plant and the simulator that could have a negative impact on operator actions. |
| Site: | Susquehanna  |
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| Report | IR 05000387/2011002 Section 4OA7 |
| Date counted | Mar 31, 2011 (2011Q1) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | Licensee-identified |
| Inspection Procedure: | |
| Inspectors (proximate) | E Dipaolo J Furia A Rosebrook P Finney J Tomlinson J Greives D Molteni |
| INPO aspect | |
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Finding - Susquehanna - IR 05000387/2011002 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Susquehanna) @ 2011Q1
Self-Identified List (Susquehanna)
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