ML15299A279
| ML15299A279 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 11/03/2015 |
| From: | Alexander Chereskin Plant Licensing Branch 1 |
| To: | Bryan Hanson Exelon Nuclear |
| Chereskin A | |
| References | |
| CAC MF5588 | |
| Download: ML15299A279 (3) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 November 3, 2015
SUBJECT:
CALVERT CLIFFS NUCLEAR POWER PLANT, UNIT NO. 1 - REQUEST FOR ADDITIONAL INFORMATION REGARDING: RELIEF REQUEST FOR DISIMILAR METAL BUTT WELD EXAMINATIONS (CAC NO. MF5588)
Dear Mr. Hanson:
By letter dated March 5, 2015 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML15075A018), Exelon Generation Company, LLC submitted an application for a request for relief from the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME BPV Code) for Calvert Cliffs Nuclear Power Plant, Unit No. 1. The proposed relief request would authorize an alternative to the requirements of the ASME BPV Code,Section XI, 2004 Edition with no Addenda, and Code Case N-770-1 subject to the conditions specified in Title 10 of the Code of Federal Regulations Section 50.55a(g)(6)(ii)(F) regarding examination of dissimilar metal butt welds.
The Nuclear Regulatory Commission staff is reviewing the submittal and has determined that additional information is needed to complete its review. The specific questions are found in the enclosed request for additional information (RAI). On October 26, 2015, the Calvert Cliffs staff indicated that a response to the RAI would be provided no later than December 4, 2015.
If you have any questions regarding this issue, please contact me at (301) 415-2549.
Docket Nos. 50-317
Enclosure:
Request for Additional Information cc w/encl: Distribution via Listserv Sincerely, Alexander N. Chereskin, Project Manager Plant Licensing Branch 1-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation
REQUEST FOR ADDITIONAL INFORMATION REGARDING PROPOSED RELIEF REQUEST NO. RR-ISl-04-10 ALTERNATIVE TO DISSIMILAR METAL BUTT WELD EXAMINATIONS CALVERT CLIFFS NUCLEAR POWER PLANT, UNIT NO. 1 CALVERT CLIFFS NUCLEAR POWER PLANT, LLC EXELON GENERATION COMPANY. LLC DOCKET NO. 50-317 By letter dated March 5, 2015 (Agencywide Documents Access and Management System Accession No. ML15075A018), Exelon Generation Company, LLC, submitted an application for Relief Request No. RR-ISl-04-10. This submittal requests authorization of an alternative to the requirements of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME BPV Code)Section XI, 2004 Edition with no Addenda, and Code Case N-770-1 subject to the conditions specified in 10 CFR 50.55a(g)(6)(ii)(F) regarding examination coverage of dissimilar metal butt welds for the Fourth 10-year lnservice Inspection (ISi) interval at Calvert Cliffs Nuclear Power Plant, Unit No. 1 (CCNPP1 ). The Nuclear Regulatory Commission staff is reviewing the submittal and has the following questions:
- 1. Recent operational experience (OE) with ISi of dissimilar metal butt welds (DMBW) in nuclear power plants include several instances of human errors in the application of qualified nondestructive examination (NOE) procedures. These errors have resulted in degraded examination performance such as incomplete examination coverage, identification of service-induced defects where none exist, or failure to identify service-induced defects. The industry formed the NOE Improvement Focus Group (NIFG) to address this OE and develop improved guidelines for the examination of DMBW. Verify that the NIFG guidance will be implemented during the DMBW examinations at CCNPP1 in 2016 or justify how the examinations will avoid the issues present in the OE.
- 2. As a defense-in-depth measure for indications which may exist in the areas that cannot be examined and may grow through-wall, leakage monitoring is useful in the early detection of through-wall cracks. Describe the leakage monitoring used for the reactor coolant pressure boundary, including leak rates or trends that would cause actions to be taken to determine the location of leaks.
- 3. The NRC staff requests confirmation that the licensee will continue to evaluate new technologies and approaches that offer NOE exam coverage improvements as they become available. The goal of each examination should be to obtain 100 percent examination coverage of the required exam volume.
Enclosure
- via dated memo OFFICE DORL/LPLl-1 /PM DORL/LPLl-1 /LA DE/EPN B/BC(A)*
DORL/LPLl-1/BC DORL/LPLl-1 /PM NAME AChereskin KGoldstein RWolfgang TT ate AChereskin DATE 10/27/2015 10/27/2015 10/20/2015 11/03/2015 11/03/2015