ULNRC-05822, CFR 50.55a Request: Proposed Alternative to ASME Section XI Requirements Regarding Performance of Second Successive Examination for Indication on C Cold Leg Safe-End to Elbow Weld

CFR 50.55a Request: Proposed Alternative to ASME Section XI Requirements Regarding Performance of Second Successive Examination for Indication on C Cold Leg Safe-End to Elbow Weld

ML113050122
Person / Time
Site:	Callaway
Issue date:	10/31/2011
From:	Maglio S Ameren Missouri, Union Electric Co
To:	Office of Nuclear Reactor Regulation, Document Control Desk
References
ULNRC-05822
Download: ML113050122 (12)

Text

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~Ameren Callaway Plant MISSOURI October 31, 20 11 ULNRC-05822 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001 10 CFR 50.55a Ladies and Gentlemen:

DOCKET NUMBER 50-483 CALLAWAY PLANT UNIT 1 UNION ELECTRIC CO.

FACILITY OPERATING LICENSE NPF-30 10 CFR 50.55a REQUEST: PROPOSED ALTERNATIVE TO ASME SECTION XI REQUIREMENTS REGARDING PERFORMANCE OF SECOND SUCCESSIVE EXAMINATION FOR INDICATION ON "C" COLD LEG SAFE-END TO ELBOW WELD Reference 1: AmerenUE letter ULNRC-051 00, "Transmittal of In service Inspection Summary Report for Refuel 13, and WCAP-16280-P, "Flaw Evaluation Handbook for Callaway Unit 1 Reactor Vessel Inlet Nozzle Safe-end Weld Region," May 2004 Pursuant to 10 CFR 50.55a(a)(3)(i), Union Electric Company (Ameren Missouri) hereby requests NRC approval of attached ReliefRequest BR-13 regarding paragraph IWB-2420(b) of the American Society ofMechanical Engineers (ASME) Boiler and Pressure Vessel Code, i.e.,Section XI. The Code Edition applicable to this request and to the current (third) 10-year Inservice Inspection interval for Callaway Plant is the 1998 Edition (up to and including the 2000 Addenda).

During Refuel 13 (Spring 2004), non-destructive (ultrasonic) examination of the reactor pressure vessel (RPV) nozzle safe-end welds at Callaway confirmed a small flaw in the safe-end to elbow weld ofthe RPV 'C' inlet (cold leg) nozzle. An evaluation to determine the acceptability ofthe flaw was promptly performed by Westinghouse Electric Company, LLC (Westinghouse) using the procedures and acceptance criteria for indications in austenitic piping pursuant to Paragraph IWB-3640 of ASME Section XI. That evaluation determined the flaw to be acceptable such that further service without repair was justified. This evaluation, including the methodology that was used, was provided as part of the RF-13 lSI Summary Report submitted to the NRC (per Reference 1).

PO Box 620 Fulton, MD 65251 AmerenMissouri.com

ULNRC-05822 October 3I, 20II Page2 Pursuant to IWB-2420(b), the area containing the identified flaw was scheduled to be examined during each of the three subsequent, successive inspection periods. The first successive examination was completed in 2007 during Refuel I5, and it confirmed no growth in flaw size. The attached I 0 CFR

50. 55(a) request (Attachment I) concerns performance of the second successive examination which was scheduled to be performed during the current, ongoing refueling outage (RF-I8). In lieu of performing the second successive examination during the current refueling outage, however, Ameren Missouri is requesting NRC approval of an alternative wherein the second successive examination will be performed during the next refueling outage (RF-I9).

Justification for the request is provided in Attachment I. Also attached, as Attachment 2, are the examination results obtained for the stainless steel "C" cold leg safe-end to elbow weld during Refuel I3 and Refueli5.

No new regulatory commitments have been made or identified in this letter or its attachment. Please contact me at 573-676-87I9 or Tom Elwood at 3I4-225-I905 for any questions you may have regarding this request.

Sincerely,

~.A. VV\f/

S.A.M~

Regulatory Affairs Manager BLM/TBE/nls Attachments I) 10 CFR 50.55(a) Request BR-13

2) Examination Results for RF-13 and RF-I5

ULNRC-05822 October 31, 2011 Page3 cc: Mr. Elmo E. Collins, Jr.

Regional Administrator U.S. Nuclear Regulatory Commission Region IV 612 E. Lamar Blvd., Suite 400 Arlington, TX 76011-4125 Senior Resident Inspector Callaway Resident Office U.S. Nuclear Regulatory Commission 820 I NRC Road Steedman, MO 65077 Mr. Mohan C. Thadani (2 copies)

Senior Project Manager, Callaway Plant Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Mail Stop 0-8G 14 Washington, DC 20555-2738

ULNRC-05822 October 31, 2011 Page4 Index and send hardcopy to QA File A160.0761 Hardcopy:

Certrec Corporation 4200 South Hulen, Suite 422 Fort Worth, TX 76109 (Certrec receives ALL attaclunents as long as they are non-safeguards and may be publicly disclosed.)

Electronic distribution for the following can be made via Other Situations ULNRC Distribution:

A. C. Heflin F. M. Diya C. 0. Reasoner ill L. H. Graessle S. A. Maglio L. H. Kanuckel NSRB Secretary T. B. Elwood M.G. Hoehn Ms. Diane M. Hooper (WCNOC)

Mr. Tim Hope (Luminant Power)

Mr. Ron Barnes (APS)

Mr. Tom Baldwin (PG&E)

Mr. Wayne Harrison (STPNOC)

Ms. Linda Conklin (SCE)

Mr. John O'Neill (Pillsbury Winthrop Shaw Pittman LLP)

Missouri Public Service Commission to ULNRC-05822 Page 1 Attachment 1 10 CFR 50.55a Request IJR-13 Proposed Alternative In Accordance with 10 CFR 50.55a(a)(3)(i)

Alternative Provides Acceptable Level of Quality and Safety

1. ASME Code Components Affected ASME Code Class: Code Class 1

References:

Code Case N-578 Examination Category: R-A (was B-J)

Item Number: Rl.20 (was B5.10)

Description:

Loop C Cold Leg Stainless Steel Safe-End to Pipe Weld System: Reactor Coolant System Component(s): 2-BB-01-F302

2. Applicable Code Edition and Addenda

ASME Section XI, 1998 Edition with 2000 Addenda.

3. Applicable Code Reguirement IWB-2420(b) states, in part, "If a component is accepted for continued service in accordance with IWB-3132.3 or IWB-3142.4, the areas containing flaws or relevant conditions shall be reexamined during the next three inspection periods listed in the schedule ofthe inspection program ofiWB-2400."

4. Reason for Reguest This 10 CFR 50.55a request concerns an indication (flaw) in the stainless steel safe-end to pipe weld of the Loop C cold leg nozzle. The flaw in 2-BB-01-F302 was identified in conjunction with a reactor pressure vessel 10-year examination during Refuel 13 (2004). As reported in the lSI Summary Report for Refuel 13 (Reference 3), the indication that was identified exceeded IWB-3514 requirements. The flaw was evaluated in accordance with IWB-3600 by both Structural Integrity Associates and Westinghouse and determined to be acceptable. It is important to note that this indication is in the stainless steel safe-end to pipe weld (i.e., not in an Alloy 600 weld).

A root cause analysis was performed for the identified flaw, and as stated in the root cause analysis report, "The preponderance of evidence supports that this crack indication is from original plant construction." [This was documented in Callaway to ULNRC-05822 Page2 Action Request (CAR) 200403580 (Reference 2) under Callaway's Corrective Action Program]. The root cause analysis concluded that this indication was first identified in 2004 due to improved technology (performance demonstration initiative) which was not available during construction and earlier examinations.

Subsequent to Refuel13, 2-BB-01-F302 was re-examined in the next period (as required by IWB-2242(b)), in Refuel15, and the indication was determined to be unchanged in size, as expected.

5. Proposed Alternative and Basis for Use The second successive examination of2-BB-01-F302 was scheduled to be performed during Refuel 18 which is now ongoing at Callaway. Due to challenges experienced during the outage, but based on the stable nature and negligible impact of the noted flaw, Ameren Missouri proposes to not perform the required second successive examination during Refuel 18, but to instead perform the required examination during Refuel 19 (Spring 2013).

Basis for Use: The indication has been evaluated by Structural Integrities and Westinghouse and found to not pose a threat to the structural integrity of the reactor coolant system, nor is the flaw likely to grow to a size of concern within the lifetime of the plant. Additionally, the indication has been examined following one lSI period of operation and found to be unchanged in size. Based on these determinations, Callaway requests to defer the second successive examination from Refuel 18 (Interval 3, Period 2) to Refuel 19 (Interval 3, Period 3). (The third successive examination required by IWB-2242(b) would be rescheduled to Interval4, Period 1, thereby completing the three required successive examinations prior to returning to the inspection frequency required by Examination Category R-A, Item Number R1.20.) For the noted reasons, this alternative will still ensure an acceptable level of quality and safety.

6. Duration of Proposed Alternative This relief is requested for the duration of the operating cycle following Refuel 18.

Weld 2-BB-01-F302 will be examined in Refuel19 (Spring 2013).

7. References

1. ASME Section XI, 1998 Edition with 2000 Addenda

2. Callaway Corrective Action Report (CAR) 200403580

3. AmerenUE letter ULNRC-051 00, "Transmittal of Inservice Inspection Summary Report for Refuel13, and WCAP-16280-P, "Flaw Evaluation Handbook for Callaway Unit 1 Reactor Vessel Inlet Nozzle Safe-end Weld Region," May 2004.

to ULNRC-05822 Attachment 2 Examination Results for RF-13 and RF-15 (5 pages)

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