ET 14-0029, Response to Request for Additional Information Regarding 10CFR50.55a Requests 13R-08 and 13R-09

Response to Request for Additional Information Regarding 10CFR50.55a Requests 13R-08 and 13R-09

ML14251A030
Person / Time
Site:	Wolf Creek
Issue date:	08/28/2014
From:	Reasoner C Wolf Creek
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
ET 14-0029
Download: ML14251A030 (3)

Text

WOLF CREEK NUCLEAR OPERATING CORPORATION Cleveland Reasoner Vice President Engineering August 28, 2014 ET 14-0029 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555

Reference:

1) Letter WO 14-0002, dated January 8, 2014, from R. A. Smith, WCNOC, to USNRC

2) Letter dated August 1, 2014, from C. F. Lyon, USNRC, to A.C. Heflin, WCNOC

Subject:

Docket No. 50-482: Response to Request for Additional Information Regarding 10 CFR 50.55a Requests 13R-08 and 13R-09 Gentlemen:

Reference 1 provided Wolf Creek Nuclear Operating Corporation's (WCNOC) 10 CFR 50.55a Requests 13R-08 and 13R-09 for the Third Ten-Year Interval of WCNOC's Inservice Inspection (ISI) Program. Request 13R-08 requests relief from the schedule requirements of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code,Section XI, Category B-N-2 and B-N-3 examinations. Request 13R-09 requests an extension of the ASME Code,Section XI required interval between examinations of the reactor vessel Category B-A and B-D welds from 10 years to 20 years.

Reference 2 provided a Nuclear Regulatory Commission (NRC) request for additional information (RAI) regarding 10 CFR 50.55a Requests 13R-08 and 13R-09. The attachment provides WCNOC's response to the question in the RAI.

This letter contains no commitments. If you have any questions concerning this matter, please contact me at (620) 364-4171, or Mr. Steven R. Koenig at (620) 364-4041.

Sincerely, Cleveland Reasoner COR/rlt Attachment cc: M. L. Dapas (NRC), w/a C. F. Lyon (NRC), w/a N. F. O'Keefe (NRC), w/a Senior Resident Inspector (NRC), w/a P.O. Box 411 / Burlington, KS 66839 / Phone: (620) 364-8831 An Equal Opportunity Employer MIFIHCNET

Attachment to ET 14-0029 Page 1 of 2 Response to Request for Additional Information Regarding 10 CFR 50.55a Requests 13R-08 and 13R-09 Reference 1 provided Wolf Creek Nuclear Operating Corporation's (WCNOC) 10 CFR 50.55a Request Numbers 13R-08 and 13R09 for the Third Ten-Year Interval of WCNOC's Inservice Inspection (ISI) Program. Request 13R-08 requests relief from the schedule requirements of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code, Section Xl, Category B-N-2 and B-N-3 examinations. Request 13R-09 requests an extension of the ASME Code, Section Xl required interval between examinations of the reactor vessel Category B-A and B-D welds from 10 years to 20 years. Reference 2 provided a Nuclear Regulatory Commission (NRC) request for additional information (RAI) regarding 10 CFR 50.55a Request Numbers 13R-08 and 13R-09. The specific NRC questions are provided below in italics followed by the WCNOC response.

EVIB-RAI-1:

Table 2 of Attachment /I (13R-09) lists the following information regardingpast inspections:

Examinations for two 10-year inservice inspection intervals have been performed on the reactor vessel, closure head, inlet nozzle welds, and outlet nozzle welds, as summarized below.

- Category B-A welds (reactorvessel): RF8 - Spring 1996 and RF14 - Spring 2005 with the exception of weld RV-101-121 (reactorvessel flange to shell weld) which was also examined in RF2 - Spring 1987 and RFI0 - Spring 1999.

- Category B-A welds (closure head): Interval I examinations in RF1 - Fall 1986, RF4 - Spring 1990, and RF6 - Spring 1993. Interval 2 examinations were performed in RF9 - Fall 1997, RF1 I - Fall 2000, and RF13 - Fagl 2003.

- Category B-D welds (outlet nozzles): RF3 - Fall 1988, RF8 - Spring 1996, RF14 - Spring 2005

- Category B-D welds (inlet nozzles): RF8 - Spring 1996, RF14 - Spring 2005 It appears that more than two inspections were done on some of the welds. Please clarify if any weld has been given more than the two required inspections. Explain why additionalinspections, if any, were done.

Response

There were no additional inspections on the subject welds beyond code and regulatory requirements. The appearance that more inspections were performed is a result of ASME Section XI Code requirements, which do not allow deferral of some weld examinations to the end of the interval.

Attachment to ET 14-0029 Page 2 of 2 For the first interval examination of Category B-A flange-to-vessel welds and flange-to-head welds, the ASME Section Xl Code, 1980 Edition through the Winter 1981 Addenda, Table IWB 2500-1, allowed partial examinations to be conducted in multiple periods of the interval based on accessibility, with early interval examinations conducted only from flange face, and the remaining examinations at or near the end of the inspection interval conducted from the vessel wall or head wall. Therefore, multiple examinations spread over the interval combined to provide one complete inspection of these flange welds. For the second interval examination, the ASME Section Xl 1989 Edition Category B-A flange weld requirements are similar to those of the first 10-year ISI Interval.

Similarly, for Category B-D nozzle-to-shell welds, the ASME Section Xl Code, Table IWB 2500-1, allowed partial examinations to be conducted in multiple periods of the interval with early interval examinations conducted by straight beam ultrasonic method from the nozzle bore and the remaining examinations at or near the end of each inspection interval conducted from the shell. Therefore, multiple examinations spread over the interval combined to provide one complete inspection of these nozzle-to-shell welds.

References:

1. WCNOC Letter WO 14-0002, "10 CFR 50.55a Requests 13R-08 and 13R-09 for the Third Inservice Inspection Program Interval," January 8, 2014. ADAMS Accession No. ML14014A099

2. Letter from C. F. Lyon, USNRC, to A. C. Heflin, WCNOC, "Wolf Creek Generating Station

- Request for Additional Information Re: Request for Alternative 13R-08 and 13R-09 (TAC Nos. MF3321 and MF3322)," August 1, 2014. ADAMS Accession No. ML14206A012