RS-08-057, Supplemental Information Concerning Requests for Relief from ASME OM Code 5-year Test Interval for Main Steam Safety Valves

Supplemental Information Concerning Requests for Relief from ASME OM Code 5-year Test Interval for Main Steam Safety Valves

ML081090634
Person / Time
Site:	Dresden, Quad Cities
Issue date:	04/18/2008
From:	Simpson P Exelon Generation Co, Exelon Nuclear
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
RS-08-057
Download: ML081090634 (3)

Text

Exelon.

Nuclear Exelon Generation wwwexeloncorp .com 4300 Winfield Road Warrenville, IL 60555 10 CFR 50.55a RS-08-057 April 18, 2008 U. S. Nuclear Regulatory Commission ATTN : Document Control Desk Washington, DC 20555-0001 Dresden Nuclear Power Station, Units 2 and 3 Renewed Facility Operating License Nos. DPR-19 and DPR-25 NRC Docket No. 50-237 and 50-249 Quad Cities Nuclear Power Station, Units 1 and 2 Renewed Facility Operating License Nos. DPR-29 and DPR-30 NRC Docket No. 50-254 and 50-265

Subject:

Supplemental Information Concerning Requests for Relief from ASME OM Code 5-year Test Interval for Main Steam Safety Valves References : 1 . Letter from J. L. Hansen (Exelon Generation Company, LLC) to U .S. NRC, "Request for Relief from ASME OM Code 5-year Test Interval for Main Steam Safety Valves (Relief Request RV-02C, Revision 0)," dated February 8, 2008

2. Letter from D. M . Benyak (Exelon Generation Company, LLC) to U. S . NRC, "Request for Relief from ASME OM Code 5-year Test Interval for Main Steam Safety Valves (Relief Request RV-30F, Revision 0) and Partial Withdrawal of Relief Request RV-30E, Revision 0," dated March 6, 2008 In References 1 and 2, Exelon Generation Company, LLC (EGC) requested NRC approval of proposed relief requests to extend the 5-year Inservice Test (IST) interval to a 6.5-year IST interval for all Dresser Model 37770 Main Steam Safety Valves (MSSVs) at Dresden Nuclear Power Station (DNPS), Units 2 and 3, and at Quad Cities Nuclear Power Station (QCNPS), Units 1 and 2, respectively .

The purpose of this letter is to provide additional information to the NRC concerning these two relief requests, in response to a request for additional information (RAI) that was transmitted to EGC in an email dated March 26, 2008. This additional information is provided in the attachment to this letter .

April 18, 2008 U . S . Nuclear Regulatory Commission Page 2 There are no regulatory commitments contained within this letter .

If you have any questions concerning this letter, please contact Mr. John L. Schrage at (630) 657-2821 .

Patrick R . Simpson Manager - Licensing

Attachment:

Additional Information, Dresden Nuclear Power Station Relief Request RV-02C, Quad Cities Nuclear Power Station Relief Request RV-30F

Attachment Additional Information Dresden Nuclear Power Station Relief Request RV-02C Quad Cities Nuclear Power Station Relief Request RV-30F NRC Request The American Society of Mechanical Engineers (ASME) OM-1 Sub-Group on Safety and Relief Valves developed Code Case OMN-17, "Alternative Rules for Testing ASME Class 1 Pressure Relief/Safety Valves ." Plans are to publish OMN-17 in the next addenda of the ASME Code for Operation and Maintenance of Nuclear Power Plants . Code Case OMN-17 allows owners to extend the test interval for safety and relief valves from 60 months to 72 months plus a 6-month grace period . The code case imposes a special maintenance requirement to disassemble and inspect each safety and relief valve to verify that parts are free from defects resulting from the time related degradation or maintenance induced wear prior to the start of the extended test interval . The purpose of this maintenance clause is to reduce the potential for setpoint drift.

The relief request adequately describes the procedure used for refurbishing the main steam safety valves (MSSVs) but does not state the frequency that the MSSVs will be refurbished .

Provide the frequency for implementing the described refurbishing procedure.

EGC Response EGC utilizes an ASME OM Code-certified off-site vendor to perform as-found and as-left testing, inspection, and refurbishment of the Dresser Model 3777Q Main Steam Safety Valves (MSSVs),

for both Dresden Nuclear Power Station (DNPS) Units 2 and 3 and Quad Cities Nuclear Power Station (QCNPS) Units 1 and 2, as described in References 1 and 2. EGC has verified that the approved and qualified procedure that is used by the off-site vendor for disassembly, inspection, repair, and testing of the MSSVs satisfies the special maintenance requirement specified in Code Case OMN-17.

All currently installed MSSVs at DNPS and QCNPS were disassembled, inspected, repaired, and tested in accordance with the qualified procedure, prior to installation, to verify that parts were free from defects resulting from time-related degradation or maintenance-induced wear.

Therefore, currently installed MSSVs at DNPS and QCNPS comply with the subject Code Case .

Furthermore, each MSSV removed from service at DNPS and QCNPS will continue to be disassembled, inspected, repaired, and tested in accordance with the qualified procedure, prior to reinstallation . Upon approval of the proposed relief requests, the test interval (i.e., the frequency for disassembly, inspection, repair, and testing) for any MSSV shall not exceed 6.5 years (i.e., 72 months plus a six-month grace period) .

References 1 . Letter from J . L. Hansen (Exelon Generation Company, LLC) to U. S. NRC, "Request for Relief from ASME OM Code 5-year Test Interval for Main Steam Safety Valves (Relief Request RV-02C, Revision 0)," dated February 8, 2008

2. Letter from D. M. Benyak (Exelon Generation Company, LLC) to U. S. NRC, "Request for Relief from ASME OM Code 5-year Test Interval for Main Steam Safety Valves (Relief Request RV-30F, Revision 0) and Partial Withdrawal of Relief Request RV-30E, Revision 0,"

dated March 6, 2008