ML20216E880

Safety Evaluation Authorizing Licensee Request for Relief from ASME Code Requirements,Paragraph IWA-2400(c) (Summer Edition W/Summer 1983 Addenda),For Upcoming Naps,Unit 1 Outage,Per 10CFR50.55a(a)(3)(ii)

ML20216E880
Person / Time
Site:	North Anna
Issue date:	03/06/1998
From:	NRC (Affiliation Not Assigned)
To:
Shared Package
ML20216E870	List: ML20216E865 ML20216E880
References
NUDOCS 9803180192
Download: ML20216E880 (2)

Text

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NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20006-0001 n%...../

SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION REllEF OF REQUEST FROM ASME CODE REQUIREMENTS. PARAGRAPH IWA-2400(c)

VIRGINIA FL FCTRIC AND POWER COMPANY NORTH ANNA POWER STATION. UNIT 1 DOCKET NO. 50-338

1.0 INTRODUCTION

The Technical Specifications for North Anna Power Station, Unit 1, state that the inservice inspection of the American Society of Mechanical Engineers (ASME) Code Class 1,2 and 3 components shall be performed in accordance with Section XI of the ASME Boiler and Pressure Vessel Code and applicable addenda as required by 10 CFR 50.55a(g), except where specific written relief has been granted by the Commission pursuant to 10 CFR 50.55a(g)(6)(i).

10 CFR 50.55a(a)(3) states that attematives to the requirements of paragraph (g) may be used, when authorized by the NRC, if (i) the proposed attematives 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, " Rules for Inservice inspection of Nuclear Power Plant Components," 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) twelve months prior to the start of the 120-month interval, subject to the limitations and modifications listed therein. The applicable ASME Code,Section XI, for North Anna Power Staten, Unit 1, second 10-year inservice inspection (ISI) interval is the 1983 Edition including the Summer 1983 addendum. The components (including supports) may meet the requirements set forth in subsequot editions and addenda of the ASME Code incorporated by reference in 10 CFR 50.55a(b) subject to the limitations and modifications listed therein and subject to Commission approval.

Enclosure l

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2 Pursuant to 10 CFR 50.55a(g)(5), if the licensee determines that conformance with an examination requirement of Section XI of the ASME Code is not practical for its facility, information shall be submitted to the Commission in support of that determination and a request made for relief from the ASME Code requirement. After evaluation of the determination, pursuant to 10 CFR 50.55a(g)(6)(i), the Commission may grant relief and may impose alternative requirements that are determined to be authorized by law, will not endanger life, property, or the common defense and security, and are otherwise in the public interest, giving due consideration to the burden upon the licensee that could result if the requirements were imposed.

In a letter dated October 15,1997, Virginia Electric and Power Company submitted to the NRC its request for an extension of the current inservice inspection interval which was originally scheduled to end on December 24,1998, to complete the examinations during the refueling outage scheduled during March 2000. The Civil Engineering and Geosciences Branch, Division of Engineering, has reviewed and evaluated the licensee's request for extension of the inspection interval, pursuant to 10 CFR 50.55a(a)(3)(ii) for North Anna Unit 1.

2.0 DISCUSSION.

IDENTIFICATION OF COMPONENTS:

Class 1, Class 2, and Class 3 components.

CODE REQUIREMENTS:

The 1983 Edition and Summer 1983 Addenda of ASME Section XI, IWA-2400(c) requires that a power unit must be out of service continuously for 6 months or more in order to extend the inspection interval to a period equivalent to the outage.

CODE REQUIREMENT FROM WHICH RELIEF 18 REQUESTED: (As stated)

Relief is requested from meeting the 6 month (continuously) out-of-service requirement of the 1983 Edition and Summer 1983 Addenda of ASME Section XI , IWA-2400(c) in order to extend the interval.

LICENSEE'S BASIS FOR RELIEF REQUEST: (As stated)

North Anna Unit 1 was out of service for 140 days from February 25,1989 through July 16, 1989. This refueling outage was extended for eddy current inspection of all tubes in all 3 steam generators.

l- North Anna Unit 1 was out of service for 72 days from December 23,1991 through March 5, 1992 to perform mid-cycle steam generator inspection.

North Anna Unit 1 was out of service for 96 days from January 4,1993 through April 10,1993 for refueling and steam generator replacement.

Based on the above, North Anna Unit 1 was out of service for 308 days for refueling and steam generator work. Conservatively assuming sixty days for a refueling outage where normal steam

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. generator activities took place, six months of additional time was spent on steam generator related inspection and replacement activities.

The North Anna Unit i second laservice inspection interval is scheduled to end on December 24,1998. It is desired to complete the examinations to satisfy the requirements of the ten-year end-of-interval examinations during the refueling outage that is scheduled to commence on March 12,2000 and end on April 15,2000. The Unit out of service time during the interval exceeds ten months. This additional outage time, which was caused by steam generator problems exceeds the 6 month requirement of the Code for qualifying for an interval extension. However, even though the time is not continuous it was accumulated overjust two fuel cycles. The extension period requested by this relief for the interval is less than the durations of the combined out-of-service time for steam generator inspections and replacement.

To perform the ten-year end of interval examinations during the currently scheduled September 1998 refueling outage or schedule an outage in 1999 would present a hardship without a compensating increase in quality and safety. The last ten year reactor vessel examination was I performed in May 1989.

LICENSEE'S PROPOSED ALTERNATE PROVISIONS:

It is proposed that the second 10-year inspection interval be extended 127 days to April 30, 1999. The new interval completion date, along with the 1-year period allowed by the Code "lWA-2400(c)," will enable the licensee to c'mplete the 10-year examinations during the j scheduled 2000 refueling outage.

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3.0 EVALUATION

I The staff has reviewed the licensee's request for extension of the second inspection interval by )

approximately 127 days beyond the scheduled end date to April 30,1999, to complete certain examinations during the second inservice inspection interval to satisfy the requirements of the j ASME Code,Section XI,1983 Edition with Summer 1983 Addenda. This extension, in concert with the 1-year allowance provided in IWA-2400(c) of the Code, would permit completion of the second 10-year inservice inspection interval with the scheduled refueling outage ending in April 2000.

The applicable Code has a provision for extension of an inspection interval for a period equivalent to continuous out-of-service time of 6 months or more. The staff noted that North Anna Unit 1 was out of service for approximately 10 months at different times during the inspection interval due to steam generator work and other activities. The licensee has requested, however, an extension of the interval by 127 days. The components examined during the extended interval will only be credited to the current interval and will not compromise the schedule for examination of the same components during the next interval.

Therefore, the extension of the second inspection interval is considered to be an administrative change only. The staff has further determined that this change is of low risk FignificanCe and will not affect the public health and safety. On the other hand, if the licensee were to comply with the requirements of the Code, the last outage of the second intMction interval scheduled in September 1998 will have to be extended considerably to perform . N9ed examinations,  ;

causing undue hardship to the licensee without a compensating increase in the level of quality and safety. ,

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4 4.0 CONOLUSION North Anna Unit 1 was out of service for 10 months during the second inspection interval at different times. The applicable Code allows interval extension if the out-of-service time for the unit is continuous for 6 months or more. The staff, however, has determined that the proposed extension of the second 10-year inspection interve! by approximately 127 days beyond the scheduled end date to April 30,1999, is an administrative change and poses no risk to public health and safety. If the Code requirements were to be imposed, the licensee will be subject to undue hardship of exterding the outage in the end of the interval, without a compensating increase in the level of quality and asfety. Therefore, the licensee's proposed request for relief -

from the applicable ASME Code,Section XI, as stated in Relief Request No. NDE-45, is authorized pursuant to 10 CFR 50.55a(a)(3)(ii) for North Anna Unit 1 during the second 10-year inspection interval.

Principal Contributor: P. Patnaik Date: March 6,1998 I

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