ML20128N866

Safety Evaluation Approving Licensee Request to Use Code Case N-533 as Alternative to Code Requirements,Per 10CFR50.55a(a)(3)

ML20128N866
Person / Time
Site:	Callaway
Issue date:	10/11/1996
From:	NRC (Affiliation Not Assigned)
To:
Shared Package
ML20128N829	List: ML20128N825 ML20128N866
References
NUDOCS 9610170056
Download: ML20128N866 (3)

Text

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• j g UNITED STATES j g j t

NUCLEAR REGULATORY COMMISSION i

WASHINGTON. D.C. 20666-0001 o\ ..../

j SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION ASME CODE CASE N-53 s

UNION ELECTRIC COMPANY CALLAWAY PLANT. UNIT 1

} DOCKET NO. 50-483 3

1.0 INTRODUCTION

The Technical Specifications for Callaway Plant, Unit 1, state that the I inservice inspection and testing of the American Society of Mechanical

! Engineers (ASME) Code Class 1, 2, and 3 components shall be performed in j accordance with Section XI of the ASME Boiler and Pressure Vessel Code and ,

! applicable Addenda as required by 10 CFR 50.55a. Section 50.55a(a)(3) of  ;

l Title 10 of the Code of Federal Regulations states that alternatives to the i requirements of paragraph (g) may be used, when authorized by the NRC, if (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 I quality and safety.

I 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 i

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 tha first ten-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) on the date twelve months prior to ti.e start of the 120-month interval, subject to the

limitations and modifications listed therein. The components (including j supports) may meet the requirements set forth in subsequent 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 4 approval.

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 i practical for its facility, information shall be submitted to the Commission I in support of that determination and a reouest 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 j requirements that are determined to be authorized by law, will not endanger 9610170056 961011 PDR ADOCK 05000483

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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.

By letter dated September 18, 1996, as supplemented by letter dated September 30, 1996, Union Electric Company (the licensee) requested approval for the implementation of the alternative rules of ASME Section XI Code Case N-533, entitled " Alternative Requirements for VT-2 Visual Examination of Class 1 Insulated Pressure-Retaining Bolted Connections,Section XI, Division 1,"

pursuant to 10 CFR 50.55a(a)(3) to be applied to the Inservice Inspection (ISI) program for the Callaway Plant.

The NRC staff has reviewed and evaluated the licensee's request to use Code Case N-533 as a proposed alternative to the Cede requirements for the Callaway Plant.  !

2.0 EVALUAUM Reauest for Authorization to Use Code Case N-533. Alternative Reaufrements for VT-2 Visual Examination of Class 1 Insulated Pressure-Retainina Bolted Connections.Section XI. Division 1 Code Reauirement: IWA-5242(a) states that for systems borated for the purpose of controlling reactivity, insulation shall be removed from pressure-retaining bolted connections for a direct VT-2 visual examination.

Code cases are periodically published by ASME to either clarify the ir. tent of the Code rules or to provide alternatives to existing Code requirements. Use of these nonmandatory Code cases for inservice inspection is subject to general acceptance by the NRC staff and incorporation into Regulatory Guide 1.147. Pursuant to 10 CFR 50.55a, other Code cases may be used provided specific authorization is granted.

Licensee's Code Relief Reauest: The licensee has requested authorization to use Code Case N-533, Alternative Requirements for VT-2 Visual Examination of Class 1 Insulated Pressure-Retaining Bolted Connections,Section XI, Division 1.

If utilizing the provisions of Code Case N-533, the licensee will ensure that the component to be examined has been pressurized at normal operating pressure for a least 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> since the previous refueling outage.

Licensee's Basis for Reauestina Relief (as stated): .

" Insulation removal and inspection of components at a system operating temperature of 557*F is a parsonnel safety hazard."

Licensee's Proposed Alternative Examination:

In accordance with Code Case N-533, the following alternative requirements will be met in lieu of the requirement of IWA-5242(a) to remove insulation from Class 1 pressure retaining bolted connections to perform a VT-2 visual examination:

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! 1. A system pressure test and VT-2 visual examination shall be performed each refueling outage without insulation removal.

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2. Each refueling outage the insulation shall be removed from the bolted connection, and a VT-2 visual examination shall be performed. The

connection is not required to be pressurized. Any evidence of leakage l shall be evaluated in accordance with IWA-5250. .

l Evaluation:

} Paragraph IWA-5242(a) requires the removal of all insulation from pressure- l j retaining bolted cennections in systems borated for the purpose of controlling l i reactivity when performing VT-2 visual examinations during system pressure i tests. The licensee has proposed to use Code Case N-533, which requires (1)

performance of the Code-required pressure test without removing the i

! insulation, (2) examination of Class 1 bolted connections, each refueling  ;

I outage, at atmospheric or static pressure with the insulation rencved, and (3) '

evaluation of any evidence of leakage in accordance with IWA-5250. l 1

i Paragraph IWA-5242(a) provides requirements for detecting leakage or evidence j of leakage at bolted connections. After a 4-hour hold time, performing a l VT-2 visual examination during system pressure tests, as required by Code

! Case N-533, with the insulation in place will likely result in the detection l of any significant leakage. Furthermore, performing a VT-2 visual examination

! after removal of the insulation at atmospheric or static pressure during i outages, as specified by Code Case N-533, will allow examination for evidence i of borated water leakage. Evidence of leakage will be evaluated in accordance i with IWA-5250 of Section XI.

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3.0 CONCLUSION

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! The staff has reviesed the licensee's submittal and concluded that by using j

Code Case N-533 the ficensee will locate and evaluate leakage, or evidence of j leakage, in a manner comparable to following the requirements of the Code, and

! thus the licensee's proposed alternative provide

• an acceptable level of j quality and safety. Therefore, the licensee's pcoposed alternative, to

implement Code Case N-533 following a 4-hour hold time at normal operating j pressure, is authorized pursuant to 10 CFR 50.55a(a)(3)(i). The use of this 2

Code Case is authorized for the Callaway Plant for the Second 10-year ISI

Interval or until the Code Case is approved for general use by reference in i Regulatory Guide 1.147. After that time, the licensee may continue to use j Code Case N-533 with the limitations, if any, listed in Regulatory i Guide 1.147.

) Principal Contributor: T. McLellan K. Thomas l

Cate

October 11, 1996

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