ML17300A297

Non-Acceptance of Relief Request RV-2 Related to Extension of Pressure Relief Valve Testing Intervals (Cac/Epid Nos. 000976/05000454/L-2017-LLR-0091 and 000976/05000455/L-2017-LLR-0091)

ML17300A297
Person / Time
Site:	Byron
Issue date:	11/01/2017
From:	Joel Wiebe Plant Licensing Branch III
To:	Bryan Hanson Exelon Generation Co
Wiebe J
References
05000454, 05000455, CAC 000976, EPID L-2017-LLR-0091
Download: ML17300A297 (3)

Text

Mr. Bryan C. Hanson Senior Vice President UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 November 1, 2017 Exelon Generation Company, LLC President and Chief Nuclear Officer (CNO)

Exelon Nuclear 4300 Winfield Road Warrenville, IL 60555

SUBJECT:

BYRON STATION, UNIT NOS. 1 AND 2, NONACCEPTANCE OF RELIEF REQUEST RV-2 RELATED TO EXTENSION OF PRESSURE RELIEF VALVE TESTING INTERVALS (CAC/EPID NOS. 000976/05000454/L-2017-LLR-0091 AND 000976/05000455/L-2017-LLR-0091)

Dear Mr. Hanson:

By letter to the U.S. Nuclear Regulatory Commission (NRC) dated September 25, 2017, Exelon Generation Company, LLC submitted a relief request to extend the test frequency for a limited number of pressure relief valves (PRVs) (i.e., 10 PRVs) from 48 months to 54 months to allow implementation of a "divisional outage strategy" during refueling outages, for the Byron Station, Unit Nos. 1 and 2.

The NRC staff has reviewed your application and concluded that your request is not necessary, because American Society of Mechanical Engineers (ASME) OM Code Case OMN-20 can be applied to extend the test intervals by up to 6 months. OMN-20 allows test intervals be extended 25 percent of the Code required frequencies up to but not to exceed 6 months.

OMN-20 was approved by the ASME OM Standard Subcommittee on February 15, 2012, and was later published in the 2012 Edition of the ASME OM Code. This Code Case was incorporated into 10 CFR 50.55a by reference and published in Federal Register (82 FR 32934) on July 18, 2017. The Code Case became effective on and after August 18, 2017, and can be implemented by licensees without NRC authorization.

ASME OM Code Case OMN-20 allows period extension to facilitate test scheduling in consideration of plant operating conditions that may not be suitable for performance of the required testing. In your September 25, 2017, letter you stated that the proposed relief would allow implementation of an outage strategy during refueling outages that maintains one division/train of equipment/components fully operational and protected while performing maintenance/testing on the opposite division/train. The NRC staff acknowledges that this approach reduces risk because one division/train of equipment/components would always be operational during the outage thereby avoiding a potential maintenance or equipment restoration error on the equipment/components for an entire division/train. To meet the current Mandatory Appendix I, paragraph 1-1350 requirement of testing 20 percent of the valves in each group every 48 months, a test on a "B" division valve during an "A" division outage would be

required. The alternative would be to perform a division valve test each refueling outage (alternate division/train each outage). Based on the above, the NRC staff does not consider this use of OMN-20 to be merely for operational convenience to extend the test intervals beyond those specified. The NRC staff determines that this use of OMN-20 is to facilitate test scheduling that considers plant operating conditions (maintaining one division/train of equipment/components fully operational and protected while performing maintenance/testing on the opposite division/train).

The NRC staff finds the request unnecessary and therefore terminated its acceptance review.

By teleconference on November 1, 2017, your staff agreed to withdraw the request.

Docket Nos. STN 50-454 and STN 50-455 cc w/encl: Distribution via Listserv Sincerely, Uoel S. Wiebe, Senior Project Manager Plant Licensing Branch Ill Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation

ML17300A297 LPL3 R/F OFFICE NRR/DORL/LPL3/PM NRR/DORL/LPL3/LA EMIB/BC NAME JWiebe SRohrer SBailey DATE 10/30/2017 10/30/2017 10/31/2017