ML20248C883

SER Accepting Alternatives Proposed by Licensee for Use of Code Case N-535,pursuant to 10CFRa(a)(3)(i) in ASME Section XI Inservice Insp Program

ML20248C883
Person / Time
Site:	North Anna
Issue date:	05/29/1998
From:	NRC (Affiliation Not Assigned)
To:
Shared Package
ML20248C874	List: ML20248C869 ML20248C883
References
NUDOCS 9806020262
Download: ML20248C883 (3)

Text

!

p reg y t UNITED STATES j- NUCLEAR REGULATORY COMMISSION g WASHINGTON, D.C. 30eeHo01

. . . . . ,o SAFETY EVALUATION tBY THE OFFICE OF NUCI FAR REACTOR REGULATION VIRGINIA ELFCTRIC AND POWER COMPANY NORTH ANNA POWER STATION. UNIT 1 AND UNIT 2 DOCKET NOS. 50-338 AND 50-339

1. INTRODUCTION The Technical Specifications for Nordi Anna Power Station, Units 1 and 2, state that the inservice inspection (ISI) 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 I 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 1C LFR 50.55a(g)(6)(i). Paragraph 10 CFR 50.55a(a)(3) states that altematives 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 sa'aty, 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 Section XI of editions of the ASME Boiler and Pressure \: ssel Code and Addenda that become effective subsequent to editions specified in paragraphs (g)(2) and (g)(3) and that are incorporated by reference in paragraph 10 CFR 50.55a(b) 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 initial 120-month inspection l interval must comply with the requirements in the latest edition and addenda of the Code {

incorporated by reference in paragraph 10 CFR 50.55a(b) on the date 12 months prior to the date of issuance of the operating license subject to the limitations and modifications listed in paragraph 10 CFR 50.55a(b). Inservice examination of components and system pressure tests conducted during the successive 120-month inspection interval must comply with the requirements of the latest edition and addenda of the Code incorporated by reference in paragraph 10 CFR 50.55a(b) on the date 12 months prior to the date of start of the 120-month inspection interval, subject to the limitations and modifications listed in paragraph 10 CFR 50.55a(b).

Pursuant to Footnote 6 of 10 CFR 50.55a, ASME Code cases that have been determined suitable for use by the Commission are listed in the NRC Regulatory Guides 1.84,1.85 and 1.147. The use of other Code cases may be authorized by the Director of the Office of Nuclear Reactor Regulation upon request pursuant to 10 CFR 50.55a(s)(3). After evaluation of the determination, pursuant to 10 CFR 50.55pfg)(6)(i), the Commission may grant relief and may impose attemative 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.

9806020262 PDR 980529 --

P ADOCK 05000338 PDR

2.0 BACKGROUND

By letter dated March 25,1996, as supplemented May 12,1998, Virginia Electric and Power Company, the licensee for North Anna Power Station, Units 1 and 2, requested permission to utilize Code Case N-535 in North Anna's ASME Section XI ISI Program.

The applicable editions of the ASME Code,Section XI, for North Anna Power Station, Units 1 and 2, during the second 10-year ISI interval, are the 1983 Edition, Summer 1983 Addenda and the 1986 Edition, respectively, and for the third 10-year ISI interval, it is the 1989 Edition of the ASME Code,Section XI, for both units. The components (including 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 approval.

Code Requirement: Paragraph IWA-2432 requires that successive inspection intervals be l comprised of 10 years following the previous interval except as modified by Paragraph IWA-2430(d). Paragraph IWA-2430(d) allows an interval to be extended or reduced by as much as 1 year to coincide with an outage, thus changing the length of an interval.

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

Licensee's Request:

The licensee requested authorization to use Code Case N-535, Altemative Requirements for Inservice Inspection Intervals,Section XI, Division 1.

Licensee's Basis for Request (as stated):  :

i Code Case N-535 interprets interval inspection scheduling requirements and allows both interval and period extensions of up to one year to enable an inspection to coincide with a plant outage. Application of this Code Case would provide additionalinspection scheduling flexibility in completing interval inspections. The Code Case allows examinations to be performed to satisfy the requirements of the extended interval in conjunction with examinations performed to satisfy requirements of the successive interval.

3.0 EVALUATION Paragraph IWA-2432 requires that successive inspection intervals be comprised of 10 years following the previous interval except as modifieKi by Paragraph iWA-2430(d). Paragraph IWA-2430(d) allows an interval to be extended or reduced by as much as 1 year to coincide with an outage, thus changing the length of an interval.  !

Code Case N-535 is broken into four parts; these  ;

I 1

. ,, a I a) allow a 1-year extension of inspectica interval. Also, a successive interval may start prior to the end of the previous interval that was extended; b) prohiteit examinations performed as part of the extended interval from being credited in the successive interval; c) allow an inspection period to be extended or reduced to coincide with an outage; and d) require examination records to identify in what interval the examination was performed.

The licensee proposes to apply the requirements of Code Case N-535 for the scheduling of l intervals and examinations of Code Class 1,2, and 3 piping and components. This is in lieu of the existing Code requirements of Paragraph IWA-2432 as modified by Paragraph 2420(d).

Part (a) of the case is the only change from current Section XI requirements. The 1-year

, extension is independent of the plant operating cycle and two intervals can be open I

concurrently during that year. Although slightly different from current Code requirements, this case does not change the number of examinations, acceptance criteria, or any other Code requirement. Therefore, the staff believes that Code Case N-535 provides an acceptable level of quality and safety.

The licensee's proposed attemative, to implement Code Case N-535 for the scheduling of intervals and examination of Class 1,2, and 3 piping and components, will provide an acceptable level of quality and safety because, as explained above, it only clarifies and adds flexibility to examination scheduling and does not change any other Code requirement.

Therefore, it is recommended that the proposed altemative be authorized, pursuant to 10 CFR 50.55a(a)(3)(i).

4.0 CONCLUSION

l l

The staff has reviewed the attematives proposed by the licensee for the use of Code Case N-535, and concludes that use of Code Case N-535 provides an acceptable level of quality and safety. Therefore, pursuant to 10 CFR 50.55a(a)(3)(i), the staff authorizes the proposed use of Code Case N-535.

PrincipalContributor. N. Kalyanam Date: May 29, 1998 l

l l