05000237/FIN-2010003-03
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Finding | |
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| Title | |
| Description | During the conduct of one of the dynamic simulator scenarios, the inspectors identified an unresolved item related to procedure implementation. 15 Enclosure During one of the dynamic simulator scenarios, conditions were simulated during an Anticipated Transient Without Scram (ATWS) that required the operating crew to lower reactor pressure vessel (RPV) water level in accordance with emergency operating procedure DEOP 400-5, Failure to SCRAM. The purpose of lowering RPV water level is to reduce core inlet sub-cooling and thus reduce the potential for power oscillations. DEOP 400-5, directs the operators to Terminate and Prevent all injection flow into the RPV except for flow from the CRD and Standby Liquid Control (Boron) systems. Contrary to the BWR Owners Group (BWROG) Emergency Procedure Guidelines (EPG) and Severe Accident Guidelines [Revision 2] which states that failure to completely stop RPV injection flow (with the exception of CRD, RCIC, and Standby Liquid Control) would delay the reduction in core inlet sub-cooling, thus increasing the potential for flux oscillations the crew was observed to implement this step in accordance with the licensees expectations, by decreasing the FWLC SETPOINT to -40 inches in incremental steps, such that the set point was always less than actual level. Using this method, feedwater flow was not actually stopped but level was dropped to -35 inches in approximately 1.5 minutes. When asked why the licensees procedural steps deviated from the BWROG EPG, the licensee stated that the deviation was necessary to prevent the loss of the Main Condenser heat sink (bypassing the Group 1 Isolation interlocks is performed in parallel and cannot be completed quick enough to prevent isolation of the Main Steam lines if flow is terminated completely). The BWROG EPG states that reducing reactor power and preventing power oscillations is of greater importance than preventing loss of the main condenser. Technical Specification 5.4.1 requires, in part, that written procedures/instructions be established, implemented, and maintained covering the emergency operating procedures required to implement the requirements of NUREG-0737, Clarification of TMI Action Plan Requirements, and NUREG-0737, Supplement 1, as stated in GenericLetter 82-33. NUREG-0737 and the associated Supplement 1 requires licensees to analyze transients and accidents, prepare emergency procedure technical guidelines, and develop symptom-based emergency operating procedures based on those technical guidelines. The BWROG EPG provides the technical basis for the development of the emergency operating procedures used by BWR licensees. Licensees are permitted to deviate from the BWROG guidelines provided they document the technical basis for the deviation. When asked to provide justification for the deviation from the BWROG EPG, the licensee was unable to do so. The licensee has initiated an engineering evaluation to provide the necessary basis for the deviation. This issue is an URI pending further NRC review and completion of the licensees actions to provide the necessary documentation to support the deviation: (URI 05000237/2010003-03; 05000249/2010003-03, Undocumented Technical Basis for Change to EOP ATWS Mitigation Strategy) |
| Site: | Dresden  |
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| Report | IR 05000237/2010003 Section 1R11 |
| Date counted | Jun 30, 2010 (2010Q2) |
| Type: | URI: |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.11 |
| Inspectors (proximate) | C Zoia D Melendez-Colon C Phillips D Reeser R Baker M Ring T Go J Drapera Dunlopd Melendez-Colon W Slawinski C Phillips D Reeser B Palagi J Neurauter M Ring J Draper M Learn D Sand R Edwards R Jickling R Schulz J Tapp R Russell |
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Finding List (Dresden) @ 2010Q2
Self-Identified List (Dresden)
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