ML20141G670

Safety Evaluation Accepting Proposed Alternative Use of TS Requirement for Code Class Snubbers

ML20141G670
Person / Time
Site:	Catawba
Issue date:	05/20/1997
From:	NRC (Affiliation Not Assigned)
To:
Shared Package
ML20141G664	List: ML20141G659 ML20141G670
References
NUDOCS 9705220446
Download: ML20141G670 (3)

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p >1 UNITED STATE 8

[i g P; NUCLEAR REGULATORY COMMISSION' WASHINGTON, D.C. 30e064001

SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION )

0F THE SECOND 10-YEAR INTERVAL INSERVICE INSPECTION PROGRAM PLAN l AND ASSOCIATED REQUEST FOR RELIEF REGARDING SNUBBERS DUKE POWER COMPANY

i. CATAWBA NUCLEAR STATION. UNIT 2  ;

DOCKET NO. 50-414 i i l

1.0 INTRODUCTION

i

- Section 4.0.5 of the Technical Specifications (TS) for Catawba Nuclear ,

l Station, Unit 2, state that the inservice inspection of the American Society - l l- 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  !

i: Code (ASME Code) and applicable addenda as required by Title 10 of the Code of Federal Reaulations (10 CFR) Section 50.55a(g), except where specific written >

relief has been granted by the Commission pursuant to 10 CFR 50.55a(g)(6)(1). ,

4 Section 50.55a(a)(3) states that altern'atives to the requirements of paragraph  :

(g) may be used, when authorized by the NRC, if (i) the proposed alternatives r would provide an acceptable level of quality and safety or (ii) compliance  !

. with the specified requirements would result in hardship or unusual i i difficulties without a compensating increase in the level of quality and ~

j safety.

l Pursuant to 10 CFR 50.55a(g)(4), ASME Code Class 1, 2, and 3 components .

L (including supports) shall meet the requirements, except the design and access  !

provisions and the pre-service 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 i i 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 Catawba Nuclear Station, Unit 2, second 10-year inservice inspection (ISI) interval is the 1989 Edition. The second 10-year interval start date is ,

_ August 19, 1996.  ;

Pursuant to 10 CFR 50.55a(g)(5), if the licensee determines that confomance with an examination requirement of Section XI of the ASME Code is not i practical for its facility, infomation 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  ;

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alternative requirements that are determined to be authorized by law, will not

- endanger life, property, or the commen defense and. security, and are otherwise 3 in the public interest, giving due consideration to the burden upon the i licensee that could result if the requirements were imposed.

In its letter dated February 14, 1996, Duke Power Company (licensee),

submitted to the NRC its second 10-year inservice inspection interval program plan and associated requests for relief for Catawba Nuclear Station, Unit 2.

The licensee also provided additional information in its letters dated '

i August 19 and Octo>er 23, 1996. On February 27, 1997, the staff granted a number of the requested reliefs but stated that Request for Relief No. 96-01

, regarding snubbers was being addressed under a separate licensing action. The following evaluation details the results of the staff's review of Request for ,

Relief No. 96-01.

2.0 EVALUATION

' The staff has reviewed the licensee's submittal pertaining to the relief request for snubbers. The licensee requested relief from the requirements of j ASME Code Section XI, 1989 Edition, Subsection IWF-5000, with regard to visual l examination and functional testing of snubbers. Subsection IWF-5000 i references the first addenda to ASME/ ANSI OM-1987, Part 4 (OM-4) for such

snubber activities. The licensee requested to continue the use of the current

Technical Specification (TS) for snubber visual examination and functional

testing.

The licensee stated that the current Catawba Unit 2 TS specifies an adequate

! program for visual examination and functional testing for all safety-related

- snubbers. The snubber examinations and tests at Catawba Unit 2 are currently .

i performed under TS Section 3/4.7.8, as amended in accordance with NRC Generic Letter 90-09, " Alternative Requirements for Snubber Visual Inspection ,

Intervals and Corrective Actions," dated December 11, 1990. The licensee

stated that the current inspection program as defined by the TS provides for a level of quality and safety equal to or greater than that of the OM-4.

Furthermore, the TS snubber program scope encompasses all Code Class 1, 2, ,

and 3 snubbers, since the majority of the safety-related snubbers at Catawba Unit 2 are also Code Class.

The licensee further stated that, unlike the OH-4 that requires failure mode ,

grouping (FMG) of snubbers, which fail visual examination, the existing TS requires that once a snubber fails, all snubbers in the population, rather i than only those identified in the FMG, be placed in a shortened inspection  !

interval. The TS requirement is, thus, more conservative in regard to  !

corrective action than the OM-4 requirements.  !

The functional testing plan of the OM-4 also includes the requirement for FMG.  !

In some' cases, it even allows for snubbers categorized in the same FMG as the failed snubbers to be reclassified as acceptable without further testing.

This may not be conservative, especially for the large snubber population, r which exists at Catawba (over 1000 per unit), as compared to the existing TS

I program. The current program at Catawba Unit 2 requires additional testing for all failed snubbers until the desired confidence level is assured, with no i allowances to reclassify the unacceptable snubbers, thus, it is more conservative.

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3.0 CONCLUSION

Based on the information provided, the staff has determined that the licensee ,

has presented an adequate justification for its relief request from the  !

requirements of ASME Code,1989 Edition,Section XI, Article IWF-5000 (which references OM-4, with regard to visual examination and functional testing of Code Class 1, 2, and 3 snubbers. The staff has determined that the proposed  ;

alternative use of the TS requirement for the Code Class snubbers would ,

provide an acceptable level of quality and safety and, therefore, the i

. alternative can be authorized pursuant to 10 CFR 50.55a(a)(3)(1).  ;

Principal Contributor: Arnold J. Lee ,

Date

May 20, 1997 1

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