ML022540271

Third 10-Year Inservice Inspection Interval Request for Relief 15

ML022540271
Person / Time
Site:	Monticello
Issue date:	10/01/2002
From:	Miranda S NRC/NRR/DLPM/LPD3
To:	Forbes J Nuclear Management Co
References
TAC MB5481
Download: ML022540271 (8)

Text

October 1, 2002 Mr. Jeffrey S. Forbes Site Vice President Monticello Nuclear Generating Plant Nuclear Management Company, LLC 2807 West County Road 75 Monticello, MN 55362-9637

SUBJECT:

THIRD 10-YEAR INSERVICE INSPECTION INTERVAL REQUEST FOR RELIEF NO. 15 FOR MONTICELLO NUCLEAR GENERATING PLANT (TAC NO. MB5481)

Dear Mr. Forbes:

By letter dated May 30, 2002, the Nuclear Management Company, LLC (the licensee),

submitted Relief Request No. 15 for the third 10-year inservice inspection (ISI) interval for the Monticello Nuclear Generating Plant. In Relief Request No. 15, the licensee requested relief from requirements of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code,Section XI, 1986 edition, no addenda, Table IWC-2412-1, Inspection Program B, regarding the distribution requirement for weld inspection categories. During the licensees initial selection of welds for inspection, an error was made and an insufficient number of welds were inspected according to ASME Code,Section XI, 1986 edition, no addenda, Table IWC-2500-1. Subsequently, the licensee altered the remaining inspection schedule to compensate for the initial error. The licensees proposed alternative allows for 100-percent inspection of C-F-1 welds by the end of the third ISI interval, as required by Table IWC-2412-1.

The Nuclear Regulatory Commission (NRC) staff concludes that the licensees proposed alternative provides an acceptable level of quality and safety to ensure the integrity of C-F-1 welds. Therefore, the licensees proposed alternative is authorized pursuant to 10 CFR 50.55a(a)(3)(i) for the third 10-year ISI interval for Monticello. The NRC staffs evaluation is enclosed.

Relief Request No. 16, which was also included in the licensees letter of May 30, 2002, will be addressed later, under separate cover.

Sincerely,

/RA/

Samuel Miranda, Project Manager, Section 1 Project Directorate III Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket No. 50-263

Enclosure:

Safety Evaluation cc w/encl: See next page

October 1, 2002 Mr. Jeffrey S. Forbes Site Vice President Monticello Nuclear Generating Plant Nuclear Management Company, LLC 2807 West County Road 75 Monticello, MN 55362-9637

SUBJECT:

THIRD 10-YEAR INSERVICE INSPECTION INTERVAL REQUEST FOR RELIEF NO. 15 FOR MONTICELLO NUCLEAR GENERATING PLANT (TAC NO. MB5481)

Dear Mr. Forbes:

By letter dated May 30, 2002, the Nuclear Management Company, LLC (the licensee),

submitted Relief Request No. 15 for the third 10-year inservice inspection (ISI) interval for the Monticello Nuclear Generating Plant. In Relief Request No. 15, the licensee requested relief from requirements of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code,Section XI, 1986 edition, no addenda, Table IWC-2412-1, Inspection Program B, regarding the distribution requirement for weld inspection categories. During the licensees initial selection of welds for inspection, an error was made and an insufficient number of welds were inspected according to ASME Code,Section XI, 1986 edition, no addenda, Table IWC-2500-1. Subsequently, the licensee altered the remaining inspection schedule to compensate for the initial error. The licensees proposed alternative allows for 100-percent inspection of C-F-1 welds by the end of the third ISI interval, as required by Table IWC-2412-1.

The Nuclear Regulatory Commission (NRC) staff concludes that the licensees proposed alternative provides an acceptable level of quality and safety to ensure the integrity of C-F-1 welds. Therefore, the licensees proposed alternative is authorized pursuant to 10 CFR 50.55a(a)(3)(i) for the third 10-year ISI interval for Monticello. The NRC staffs evaluation is enclosed.

Relief Request No. 16, which was also included in the licensees letter of May 30, 2002, will be addressed later, under separate cover.

Sincerely,

/RA/

Samuel Miranda, Project Manager, Section 1 Project Directorate III Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket No. 50-263

Enclosure:

Safety Evaluation cc w/encl: See next page DISTRIBUTION PUBLIC OGC BBurgess, RGN-III PDIII-1 Reading ACRS LRaghavan TChan SMiranda NTSanfilippo RBouling GHill(2) *Provided SE input by memo OFFICE PDIII-1/PM PDIII-1/LA EMCB/SC* OGC PDIII-1/SC NAME SMiranda RBouling TChan RHoefling LRaghavan DATE 09/12/02 09/12/02 09/09/02 09/19/02 09/26/02 ADAMS Accession No. ML022540271

OFFICIAL RECORD COPY Monticello Nuclear Generating Plant cc:

J. E. Silberg, Esquire Commissioner Shaw, Pittman, Potts and Trowbridge Minnesota Department of Commerce 2300 N Street, N. W. 121 Seventh Place East Washington, DC 20037 Suite 200 St. Paul, MN 55101-2145 U.S. Nuclear Regulatory Commission Resident Inspectors Office Adonis A. Neblett 2807 W. County Road 75 Assistant Attorney General Monticello, MN 55362 Office of the Attorney General 445 Minnesota Street Site Licensing Manager Suite 900 Monticello Nuclear Generating Plant St. Paul, MN 55101-2127 Nuclear Management Company, LLC 2807 West County Road 75 Mr. Roy A. Anderson Monticello, MN 55362-9637 Executive Vice President and Chief Nuclear Officer Robert Nelson, President Nuclear Management Company, LLC Minnesota Environmental Control 700 First Street Citizens Association (MECCA) Hudson, WI 54016 1051 South McKnight Road St. Paul, MN 55119 Nuclear Asset Manager Xcel Energy, Inc.

Commissioner 414 Nicollet Mall Minnesota Pollution Control Agency Minneapolis, MN 55401 520 Lafayette Road St. Paul, MN 55155-4194 Regional Administrator, Region III U.S. Nuclear Regulatory Commission 801 Warrenville Road Lisle, IL 60532-4351 Commissioner Minnesota Department of Health 717 Delaware Street, S. E.

Minneapolis, MN 55440 Douglas M. Gruber, Auditor/Treasurer Wright County Government Center 10 NW Second Street Buffalo, MN 55313 March 2002

SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION THIRD 10-YEAR INSERVICE INSPECTION INTERVAL REQUEST FOR RELIEF NO. 15 MONTICELLO NUCLEAR GENERATING PLANT NUCLEAR MANAGEMENT COMPANY, LLC DOCKET NO. 50-263

1.0 INTRODUCTION

Inservice inspection (ISI) of the American Society of Mechanical Engineers (ASME) Code Class 1, 2, and 3 components is to be performed in accordance with the ASME Boiler and Pressure Vessel Code (the Code),Section XI, Rules for Inservice Inspection of Nuclear Power Plant Components, Article IWA-5242(a), and applicable addenda, as required by the Title 10 of the Code of Federal Regulations (10 CFR), Part 50, Section 50.55a(g), except where specific written relief has been granted by the Commission pursuant to 10 CFR 50.55a(6)(g)(i). The regulation at 10 CFR 50.55a(a)(3) states that alternatives to the requirements of paragraph (g) may be used, when authorized by the Nuclear Regulatory Commission (NRC), if the licensee demonstrates that (i) the proposed alternatives would provide an acceptable level of quality and safety or (ii) compliance with the specified requirements would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety.

Pursuant to 10 CFR 50.55a(g)(4), ASME Code Class 1, 2 and 3 components (including supports) shall meet the requirements, except the design and access provisions and the preservice examination requirements, set forth in the ASME Code,Section XI, to the extent practical within the limitations of design, geometry, and materials of construction of the components. The regulations require that inservice examination of components and system pressure tests conducted during the first 10-year interval and subsequent intervals comply with the requirements in the latest edition and addenda of Section XI of the ASME Code incorporated by reference in 10 CFR 50.55a(b) 12 months prior to the start of the 120-month interval, subject to the limitations and modifications listed therein. The applicable edition of Section XI of the ASME Code for the third 10-year interval for the Monticello Nuclear Generating Plant is the 1986 edition.

By letter dated May 30, 2002, the Nuclear Management Company, LLC (licensee), submitted Request for Relief No. 15 proposing alternatives to the ASME Code,Section XI, for the Monticello Nuclear Generating Plant. The NRC staff has reviewed and evaluated the licensees request for relief pursuant to 10 CFR 50.55a(a)(3)(i), as discussed below.

ENCLOSURE

2.0 DISCUSSION (RELIEF REQUEST NO. 15) 2.1 Components Affected All ASME Class 2 pressure-retaining welds in austenitic stainless steel, Examination Category C-F-1.

2.2 Code Requirement Section XI of the ASME Code, 1986 edition, Table IWC-2412-1, Inspection Program B, requires a distribution of welds in an examination category per interval to be 16 percent - 34 percent for the first period, 50 percent - 67 percent for the second period, and 100 percent by the end of the third period.

ASME Code,Section XI, 1986 edition, no addenda, Table IWC-2500-1, for Category C-F-1, pressure retaining welds in austenitic stainless steel, Note (2), requires the welds selected for examination shall include 7.5 percent, but not less than 28 welds, of all austenitic stainless steel of high alloy welds not exempted by IWC-1220.

2.3 Licensees Proposed Alternative Pursuant to 10 CFR 50.55a(a)(3)(i), relief is requested to allow a weld inspection distribution during the third 10-Year ISI program interval for Category C-F-1 welds of 10 percent (1st period), 14 percent (2nd period), and 100 percent (3rd period). These examinations were performed during the third 10-year ISI inspection interval.

2.4 Licensees Basis for Relief During the development of the third ISI interval inspection plan, a total of 5 C-F-1 welds were selected for examination out of a total count of 31 C-F-1 welds on the control rod drive discharge system A and B. This initial selection satisfied the required 7.5-percent selection criteria of Table IWC-2500-1 C-F-1, but did not satisfy the second selection criteria of a minimum of 28 welds that needed to be inspected during the 10-year interval. During development of the Monticello Risk Informed Program and prior to the last scheduled refueling outage of the third ISI interval, it was identified that the Category C-F-1 weld selection for the third ISI interval plan was required to be 28 welds and not just the 5 welds previously selected.

The third ISI interval plan was immediately corrected and the additional C-F-1 welds were selected and examined during the last third interval refueling outage in December of 2001 to ensure that 28 C-F-1 welds were examined during the 10-year interval. The late discovery of the initial selection error made it impossible to readjust the weld distribution per period to conform to the requirements of Table IWC-2412-1, Inspection Program B.

3.0 EVALUATION Due to an initial selection error which satisfied the required 7.5-percent selection criteria of Table IWC 2500-1 C-F-1, but did not satisfy the second selection criteria of a minimum of 28 welds, the licensee was forced to deviate from the inspection requirements of Table IWC-2412-1, Inspection Program B. During the licensees development of the Monticello Risk Informed ISI Program, and prior to the last scheduled refueling outage of the

third 10-year ISI interval, the error was identified. During the last refueling outage, all necessary inspections were completed to bring Monticello into conformance with the ASME Code; however, the previous weld inspection distributions for the past two periods were outside of ASME Code requirements.

The licensee states in its justification for Relief Request No. 15 that it has recently submitted to the NRC a Risk Informed ISI Program Plan for Class 1 and Class 2 piping welds for the fourth 10-year ISI interval Plan. The risk ranking and degradation analysis of the risk-informed program has identified the C-F-1 subject welds to be risk category 6 and 7 in accordance with the Electric Research Power Institutes Topical Report TR-112657, Revision B-A. Due to this categorization, none of these welds have been selected for inspection during the fourth interval.

Additionally, no detectable flaws or degradation was detected during the third 10-year interval.

This supports the licensees proposed alternative by showing that the C-F-1 welds are of low risk.

Considering the low risk nature determined from the risk-informed ISI program and the timely manner in which the remaining inspections were conducted after the deficiencies were discovered, the adjusted weld inspection distribution provides an acceptable level of quality and safety.

4.0 CONCLUSION

The NRC staff concludes that the licensees proposed alternative to the requirements of Table IWC-2412-1, Inspection Program B, will provide an acceptable level of quality and safety to ensure the integrity of the subject C-F-1 welds. The NRC staff has authorized the licensees proposed alternative pursuant to 10 CFR 50.55a(a)(3)(i) for the third 10-year ISI interval for Monticello.

Principal Contributor: N. T. Sanfilippo Date: October 1, 2002