ULNRC-05351, Response to Request for Additional Information Regarding 10 CFR 50.55a Request ISI-33 (Request for Relief from ASME Section XI Inservice Inspection Qualification Requirements)

Response to Request for Additional Information Regarding 10 CFR 50.55a Request ISI-33 (Request for Relief from ASME Section XI Inservice Inspection Qualification Requirements)

ML063530466
Person / Time
Site:	Callaway
Issue date:	12/12/2006
From:	Fitzgerald D AmerenUE, Union Electric Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
ISI-33, ULNRC-05351
Download: ML063530466 (7)

Text

AmerenUE PO Box 620 CallawayPlant Fulton, MO 65251 December 12, 2006 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Mail Stop P1-137 Washington, DC 20555-0001 Ladies and Gentlemen: ULNRC-05351 10 CFR 50.55a S'Ameren UFe DOCKET NUMBER 50-483 UNION ELECTRIC COMPANY CALLAWAY PLANT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING 10 CFR 50.55a REQUEST ISI-33 (REQUEST FOR RELIEF FROM ASME SECTION XI INSERVICE INSPECTION QUALIFICATION REQUIREMENTS)

By letter dated May 18, 2006, Union Electric Company (AmerenUE) submitted for NRC approval a relief request pertaining to ASME Section XI Code requirements.

The relief request, identified as 10 CFR 50.55a Request Number ISI-33, pertains to non-destructive examination requirements for the safe-end weld associated with the reactor pressure vessel Loop C inlet nozzle. An indication in this weld was identified during Refuel 13 (Spring 2004).

As noted in the relief request, the depth-sizing procedure used by Callaway's contractor for evaluation of the indication identified during Refuel 13 was found to be inconsistent with Callaway's program which is based on the industry's Performance Demonstration Initiative program and proposed Supplement 14 to Appendix VIII of ASME Section XI. Approval of Relief Request ISI-33 would permit application of an alternative that compensates for the program-procedure difference. Re-examination of the affected weld is scheduled to be performed during Refuel 15 (Spring 2007) in accordance with the schedule specified in Paragraph IWB-2420(b) of the Code. The intent is to perform the examination (and future examinations) for the subject weld using the same or similar equipment and the same procedure as used for the examination during Refuel 13.

At present, Relief Request ISI-33 is under review by the NRC staff. From that review, several questions / requests for additional information were identified and a subsidiary of Ameren Corporation

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ULNRC-05351 December 12, 2006 Page 2 transmitted to AmerenUE from the NRC staff in September (2006). This letter provides AmerenUE's responses to those questions/requests in order to support continued review and processing of the relief request. The responses are provided in the attachment to this letter.

It may be noted that no new regulatory commitments have been made or identified pursuant to this letter and its attachments. Please contact me at 573 676-8763 or Dave Shafer at either 314-554-3104 or 573-676-4722 for any questions you may have regarding the attached.

Sincerely, David T. Fitzgerald Manager - Regulatory Affairs TBE/jdg Attachment

ULNRC-05351 December 12, 2006 Page 3 cc: U.S. Nuclear Regulatory Commission (Original and 1 copy)

Attn: Document Control Desk Mail Stop P1-137 Washington, DC 20555-0001 Mr. Bruce S. Mallett Regional Administrator U.S. Nuclear Regulatory Commission Region IV 611 Ryan Plaza Drive, Suite 400 Arlington, TX 76011-4005 Senior Resident Inspector Callaway Resident Office U.S. Nuclear Regulatory Commission 8201 NRC Road Steedman, MO 65077 Mr. Jack N. Donohew (2 copies)

Licensing Project Manager, Callaway Plant Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Mail Stop 7El Washington, DC 20555-2738 Missouri Public Service Commission Governor Office Building 200 Madison Street PO Box 360 Jefferson City, MO 65102-0360

ULNRC-05351 December 12, 2006 Page 4 bcc: D. T. Fitzgerald (w/o)

G. A. Hughes (w/a)

D. E. Shafer (w/a) (470) (2 copies)

S. L. Gallagher (w/o) (100)

NSRB Secretary K. A. Mills (w/a)

D. J. Maxwell (w/a)

G. A. Forster (w/a)

J. A. Doughty (w/a)

S. L. McCracken (w/a)

T. B. Elwood (w/a)

A160.0761 Chrono file The following are each provided a copy without the attachment:

Ms. Diane Hooper Mr. Carl Corbin Supervisor, Licensing STARS Regulatory Affairs Manager WCNOC Comanche Peak SES P.O. Box 411 P.O. Box 1002 Burlington, KS 66839 Glen Rose, TX 76043 Mr. Scott Bauer Mr. Dennis Buschbaum Regulatory Affairs Comanche Peak SES Palo Verde NGS P.O. Box 1002 P.O. Box 52034, Glen Rose, TX 76043 Mail Station 7636 Phoenix, AZ 85072-2034 Mr. Scott Head Mr. Stan Ketelsen Supervisor, Licensing Manager, Regulatory Services South Texas Project NOC Pacific Gas & Electric Mail Code N5014 Mail Stop 104/5/536 P.O. Box 289 P.O. Box 56 Wadsworth, TX 77483 Avila Beach, CA 93424 Mr. John ONeill Certrec Corporation Shaw, Pittman 4200 South Hulen, Suite 630 2300 N. Street N.W. Fort Worth, TX 76109 Washington, DC 20037

Attachment to ULNRC-05351 Page 1 of3 Responses to NRC Questions / Requests for Information Regarding 10 CFR 50.55a Request ISI-33 Question 1:

For the second and third JO-year ISI interval, to use a depth sizing RMS that exceeds the ASME Code requirements, identify the specific paragraphand sentence of the ISI ASME Code of recordfor each interval thatpertainsto this request.

Response

The code of record for the second interval for austenitic piping welds, after 5/23/2000, is ASME Section XI 1995 edition with the 1996 Addenda. The code of record for the third interval is ASME Section XI 1998 edition with the 2000 Addenda.

Depth-sizing acceptance criteria for austenitic piping welds for both Code editions can be found in Appendix VIII, Article 2 paragraph 3.2(b). The 0.125" RMS criterion specified therein is applicable to both of the above-noted Code editions.

Question 2:

In the proposedalternative,a request was made to apply this proposedalternativefor the examinationsrequiredby IWA-2420(b) which requiresreexamination of the area containinga flaw during the next three inspectionperiods listed in the inspection program. IWA-2420(b) is not discussed in any other section in the May 18, 2006 (ISI-33) submittal. If the request includes IWA-2420(b), provide the necessary supporting informationfor review.

Response

The alternative sizing criteria are to be applied to each of the successive inspections required in response to the indication detected during Refuel 13, in accordance with the schedule specified in paragraph IWB-2420(b). (Note the correction to the applicable Code paragraph, as confirmed with the NRC staff.) The indications were accepted using analytical evaluation in accordance with IWB-3600. The proposed approach involves no changes to the requirements of IWB-2420(b) themselves.

Attachment to ULNRC-05351 Page 2 of 3 Question 3:

The May 18, 2006 (ISI-33) submittal discussedthe affected components in generic terms while specifically referencingweld 2-BB-01-F302. Provide clarificationas to the components affected by this request.

Response

The relief request is specific to 2-BB-01-F302 due to the indications detected during Refuel 13 (as noted in the response to Question 2).

Question 4:

The basisjustifying the proposedalternative is aflaw evaluation that adds the difference between the ASME Code 0. 125" RMS performance demonstrationacceptance criterion and the 0. 245" RMS calculated valuefor the vendor'sprocedureperformance demonstration. The proposed alternative isfor using the same depth sizing 0. 245" RMS errorfor allfuture Ultrasonic Testing (UT) applications.

The NRC staff considers the licensee's approachto address the current inability to meet the ASME Code-requiredUT depth-sizing RMS requirementas a short-term solution.

Vendors continue to make improvements in their UT sizing capabilities. These improvements may reduce the difference between the depth sizing RMS Code-requirement and the currently achievable RMS values. Discuss options that have been consideredfor the examinations of the subject welds. Explain why the ASME Code RMS value is not achievablefor the selected vendor.

Response

The configuration for weld 2-BB-01-F302 is an austenitic safe end to a cast austenitic elbow. There is also an adjacent dissimilar metal weld that interferes with the inspection.

(See attached figure of the overall weld profile, i.e., Figure 1 on page 3.) This type of configuration proves to be very challenging for ultrasonic inspection. Currently, no vendor has been able to achieve the 0.125" RMS criterion for such a configuration. In addition, since additional/successive inspections must be performed on the existing indication, it is imperative that the same inspection technique be used in order to determine if the flaw is propagating.

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