ML082900027

Callaway Plant Unit 1, Follow-up Information Regarding 10CFR50.55a Request: Proposed Alternative to ASME Section Xi Requirements for Replacement of Class 3 Buried Piping (TAC No. MD67920)

ML082900027
Person / Time
Site:	Callaway
Issue date:	10/09/2008
From:	Graessle L H AmerenUE, Union Electric Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
TAC MD6792, ULNRC-05553
Download: ML082900027 (4)

Text

AmerenUE P0 Box 620 Callaway Plant Fulton, MO 65251 October 9, 2008 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Mail Stop P1-137 Washington, DC 20555-0001 ULNRC-05553 Ladies and Gentlemen:

DOCKET NUMBER 50-483 WAmeren CALLAWAY PLANT UNIT 1 UE UNION ELECTRIC COMPANY FACILITY OPERATING LICENSE NPF-30 FOLLOW-UP INFORMATION REGARDING 10CFR50.55a REQUEST: PROPOSED ALTERNATIVE TO ASME SECTION XI REQUIREMENTS FOR REPLACEMENT OF CLASS 3 BURIED PIPING (TAC NO. MD6792)

References:

1. AmerenUE letter ULNRC-05434 dated August 30, 2007 2. AmerenUE letter ULNRC-05490 dated April 17, 2008 3. AmerenUE letter ULNRC-05517 dated July 10, 2008 4. AmerenUE letter ULNRC-05529 dated July 24, 2008 5. AmerenUE letter ULNRC-05542 dated September 15, 2008 By letter dated August 30, 2007 (Reference 1 above), Union Electric Company (AmerenUE) submitted Relief Request 13R-10 regarding paragraph IWA-422 1(b) of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code,Section XI. The relief request, which is still under review by the NRC staff, was submitted to enable planned replacement of buried steel piping in the essential service water (ESW) system at Callaway Plant with high-density polyethylene (HDPE) piping.Following AmerenUE's initial submittal, additional letters (identified as References 2 through 4 above) were submitted to provide additional or clarifying information requested by the NRC staff. The additional information provided by AmerenUE included two calculations.

One of the calculations, provided with the letter of reference 2 above, was a preliminary stress analysis for the new ESW piping configuration, i.e., Calculation 2007-16760, "Analysis of Buried HDPE Piping." The other calculation was provided via the letter of Reference 3 above, and was performed for determining the minimum design wall thickness for the HDPE piping, i.e., Calculation 2007-13241, "Minimum Wall Thickness for ESW Buried HLDPE Piping," Revision 0.a i o o o a subsidiary of Ameren Corporation ULNRC-05553 October 9, 2008 Page 2 In early September (2008), a telephone discussion was conducted with the NRC staff, wherein AmerenUE was asked to provide updated versions of the subject calculations.

Accordingly, Revision 1 of Calculation 2007-13241 and Revision 0 of Calculation 2007-16760 were provided via the letter of Reference 5 above.After receipt of the updated calculations by the NRC, another telephone discussion was conducted on September 19, 2008, in which the NRC staff identified two notable differences between the versions of the calculations provided via the letter of Reference 5 and the versions provided earlier (via the letters of References 2 and 3). Specifically, it was noted that Revision 1 of Calculation 2007-13241 (the minimum wall thickness calculation) provided results obtained by use of 0.56 design factor, along with results obtained by the expected use of a 0.5 design factor. It was confirmed during the telephone discussion that the results obtained from use of the 0.56 design factor were provided for information only, as indicated in the calculation.

The NRC emphasized that their review would be based solely on the use of 0.5 as the value for the design factor.With regard to the second difference discussed, it was noted that in Revision 0 of Calculation 2007-16760, the thermal gradient stress evaluation that had been provided in the preliminary version was not included.

AmerenUE explained that there was a misunderstanding of whether this analysis needed to be included in the calculation.

Having provided it once, AmerenUE agreed to include the thermal gradient stress eviluation in a follow-up revision of the calculation to be provided via a follow-up letter to the NRC. In accordance with that agreement, Revision 1 of Calculation 2007-16760 is hereby provided as an enclosure to this letter.In Revision 1 of Calculation 2007-16760, the thermal gradient stress evaluation is included in a second thermal load case for the HDPE piping. As discussed with the NRC subsequent to the September 19, 2008 telephone discussion, the peak normal operating ESW water temperature was assumed (in lieu of a peak post-LOCA temperature) as appropriate for this case.This letter serves to document the issues raised in the September 19, 2008 telephone conference, as well as to provide the updated calculation discussed in that telephone conference.

No additional commitments are made per this letter. For questions concerning this letter, please contact Mr. Scott Maglio at (573) 676-8719.Very truly yours, Luke H. Graessle Manager -Regulatory Affairs TBE/nls Enclosure ULNRC-05553 October 9, 2008 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. 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 8201 NRC Road Steedman, MO 65077 Mr. Mohan C. Thadani (2 copies)Licensing Project Manager, Callaway Plant Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Mail Stop O-8G14 Washington, DC 20555-2738 ULNRC-05553 October 9, 2008 Page 4 Index and send hardcopy to QA File A160.0761 Hardeopy: Certrec Corporation 4200 South Hulen, Suite 630 Fort Worth, TX 76109 (Certrec receives ALL attachments as long as they are non-safeguards and may be publicly disclosed.)

Electronic distribution for the following can be made via Responses and Reports ULNRC Distribution (all w/o attachments):

A. C. Heflin F. M. Diya T. E. Herrmann D. W. Neterer L. H. Graessle M. A. McLachlan S. M. Maglio T. B. Elwood S. L. Abel J. L. Fortman M. D. Brandes S. L. Gallagher L. M. Belsky (NSRB)Mr. Ron Reynolds, Director (SEMA)Mr. Edward Gray, Senior REP Planner (SEMA)Mr. John Campbell, REP Planner (SEMA)Ms. Diane M. Hooper (WCNOC)Mr. Dennis Buschbaum (TXU)Mr. Scott Bauer (Palo Verde)Mr. Stan Ketelsen (PG&E)Mr. Wayne Harrison (STPNOC)Mr. John O'Neill (Pillsbury Winthrop Shaw Pittman LLP)Mr. Floyd Gilzow (DNR)