ML12283A256

Wolf Creek - Email Request for Additional Information, Round 2, Amendment Request to Revise Technical Specification 3.8.1, AC Sources - Operating, Surveillance Requirements Related to Diesel Generator Test Loads, Voltage, and Frequency (TAC

ML12283A256
Person / Time
Site:	Wolf Creek
Issue date:	10/09/2012
From:	Benney B J Plant Licensing Branch IV
To:	Wideman S G Wolf Creek
Benney B J
References
TAC ME7674
Download: ML12283A256 (2)

Text

From:Benney, BrianTo:Wideman Steve GCc:Burkhardt, Janet; Chen, Qiao-Lynn

Subject:

ME7674 RAIsDate:Tuesday, October 09, 2012 12:33:34 PM

Dear Mr. Wideman:

By letter dated November 30, 2011 (Agencywide Documents Access and Management System Accession No. ML11340A033), Wolf Creek Nuclear Operating Corporation (WCNOC) submitted a request for amendment to Technical Specifications (TS) 3.8.1, of the Facility Operating License No. NPF-42 for the Wolf Creek Generating Station. Thechanges would modify the TS Surveillance Requirements (SR) by providing surveillance enhancements that will improve operation and testing of the Emergency Diesel Generators (EDG) and will provide a more restrictive voltage and frequency band for operation when not connected in parallel with the offsite sources.

The U.S. Nuclear Regulatory Commission (NRC) staff has reviewed the information provided by the licensee and determined that the additional information identified in the attachment is needed in order for the NRC staff to complete its review. The staff isrequesting a written response to the RAls no later than November 9, 2012.

Please contact me if you would like to have a clarifying conference call.

Thank you, Brian Benney

REQUEST FOR ADDITIONAL INFORMATIONREGARDING WOLF CREEK GENERATING STATIONLICENSE AMENDMENT REQUEST TO CHANGE EMERGENCY DIESEL GENERATORSURVEILLANCE REQUIREMENTSTAC NO. ME7674

The Electrical Engineering Branch requested additional information (RAI) by letter dated June 14, 2012 (ADAMS # ML12166A404) and WCNOC provided responses by letter dated August 16, 2012 (ADAMS #ML12237A298). The staff has reviewed the responses andhas the following supplemental question:

RAI question 2a requested information about motor operated valve (MOV) performance (accident analyses) with EDG operation at the lower end of the steady state TS allowable frequency coupled with the frequency and voltage variations allowed in RG 1.9 Rev. 3 during load sequencing. The licensee has indicated that the voltage and frequencyvariations may (emphasis added) have been included in the accident analysis performed using computer codes.

The nuclear steam supply system (NSSS) at WCNOC was provided by Westinghouse. As part of a PWR Owners Group initiative, Westinghouse has submitted a report "Treatment of Diesel Generator (DG) Technical Specification Frequency and Voltage Tolerances" dated April 2012. This report is being reviewed by NRC staff. The report states thathistorically, the DG frequency and voltage tolerances are not considered in thedevelopment of NSSS component performance and MOV stroke times.

In response to Generic Letter (GL) 89-10 "Safety-Related Motor Operated Valve Testing and Surveillance" licensees evaluated MOV performance under degraded voltage conditions with worst case differential pressure across the critical valves. Most licenseesdid not evaluate MOV performance under varying frequency conditions. Based on theevaluations performed for critical MOVs identified in response to GL 89-10, provide details on the change in stroke time as a consequence of EDG operation at the lower end of the allowable frequency. Include the impact of frequency transients during EDG load sequencing.