ML070890297

RAI Regarding Alternative Source Term Application

ML070890297
Person / Time
Site:	Hatch
Issue date:	04/10/2007
From:	Martin R NRC/NRR/ADRO/DORL/LPLII-1
To:	Madison D Southern Nuclear Operating Co
Martin R, NRR/DORL, 415-1493
References
TAC MD2934, TAC MD2935
Download: ML070890297 (5)

Text

April 10, 2007 Mr. Dennis R. Madison Vice President - Hatch Edwin I. Hatch Nuclear Plant 11028 Hatch Parkway North Baxley, GA 31513

SUBJECT:

EDWIN I. HATCH NUCLEAR PLANT, UNIT NOS. 1 AND 2 (HNP) - REQUEST FOR ADDITIONAL INFORMATION (RAI) REGARDING ALTERNATE SOURCE TERM APPLICATION (TAC NOS. MD2934 AND MD2935)

Dear Mr. Madison:

By letter to the Nuclear Regulatory Commission dated August 29, 2006, Southern Nuclear Operating Company, Inc., proposed to revise the HNP, licensing and design basis with a full scope implementation of an alternative source term. We have reviewed your application and have identified a need for additional information as set forth in the Enclosure.

We discussed this issue with your staff on April 6, 2007. Your staff indicated that it plans to submit a response to this issue within sixty (60) days of receipt of this letter.

Sincerely,

/RA/

Robert E. Martin, Senior Project Manager Plant Licensing Branch II-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-321 and 50-366

Enclosure:

RAI cc w/encl: See next page

- ML070890297 *transmitted by memo dated OFFICE NRR/LPL2-1/PM NRR/LPL2-1/LA NRR/EEMA/BC NRR/LPL2-1/BC NAME RMartin MOBrien KManoly by LOlshan for memo EMarinos DATE 04/09/07 04/9/07 03/30/07* 04/10/07 REQUEST FOR ADDITIONAL INFORMATION CONCERNING IMPLEMENTATION OF AN ALTERNATIVE SOURCE TERM FOR EDWIN I. HATCH NUCLEAR PLANT, UNIT NO. 1

1. It is stated on page 10 of Enclosure 8 of the August 29, 2006, application, that While the Turbine Building was designed as a category II structure, to withstand the effects of the [Uniform Building Code] UBC earthquake, critical portions of the turbine building were also evaluated for [Operating Basis Earthquake] OBE and [Design Basis Earthquake] DBE seismic loads to ensure no collapse on category I structures or components. The Nuclear Regulatory Commission (NRC) staff requests the licensee to identify the critical portions of the turbine building, which were evaluated for OBE and DBE seismic loads, and describe how the OBE and DBE seismic loads were calculated and applied to these critical portions of the turbine building.

2. It is stated on page 10 of Enclosure 8 that the allowable stress for load combinations involving tornado loads can be found in Section 2.1.5b(5). Since the NRC staff could not find the specified information, please indicate the allowable stress values as a percentage of the yield stress for steel and the compressive strength for concrete.

3. Enclosure 8 indicates that the original design of the turbine building involved tornado loads, but did not involve a dynamic analysis of DBE loads. During the telephone conference on March 22, 2007, the licensee stated that it had performed a dynamic analysis for the turbine building. The NRC staff requests the licensee to list and confirm that for representative floors, the maximum story shear (lateral) forces resulting from tornado and DBE satisfy the acceptance criterion for structural adequacy of the turbine building.

4. Regarding the condenser anchorage, page 19 of Enclosure 8 states that two of the four sets of the cast-in-place anchor bolts (four 2-1/4 inch diameter bolts per set) for one load case exceeded their allowable capacity by 11 percent, but was judged to be acceptable because (1) the bolt material has probably higher yield strength than the specified minimum yield strength, and (2) the total load from all four piers for that load case is less than the total capacity of the anchor bolts at those four piers. With respect to the licensees argument concerning bolt material yield strength, the NRC staff cannot accept a statement of probable higher yield strength as a basis for acceptability of the anchor bolts. The NRC staff requests the licensee to verify that such higher yield strength does exist based on Certified Material Test Report (CMTR) data for the bolt material or other means acceptable to the NRC staff. With respect to the argument concerning applied loads vs. anchorage capacity comparison, the NRC staff requests the licensee to describe the type of loads, such as axial tension, axial compression, flexural, shear, and torsion, and their magnitudes of the total load from all four piers, identify the loading combinations (case) that caused the actual bolt stress to be greater than the allowable capacity by 11 percent, demonstrate that concrete failure strength of the anchorage is greater than that of the anchor bolts, and justify the logic that the capacity of the anchor bolts at all four piers can be summed up to compare with the total load for that load case.

5. It is stated on page 26 of Enclosure 8 that The minimum design margin for the pipe supports and pipe support anchorage is over three (3.0) times the 0.15g plant design basis. As stated on page 31 of Enclosure 8, the method used to obtain the above design margin appears to not be the anchorage verification method specified in the Generic Implementation Procedure (GIP). However, it is stated on page 24 of Enclosure 8 that Evaluation of bolted anchorage to concrete follows the procedures established in the Generic Implementation Procedure (GIP) for Seismic Verification of Nuclear Plant Equipment. The NRC staff requests the licensee to address the apparent discrepancy between the statements on pages 31 and 24. Furthermore, the NRC staff requests the licensee to specify and confirm that the anchorage with the minimum margin still satisfies the GIP criterion.

Edwin I. Hatch Nuclear Plant, Units 1 & 2 cc:

Laurence Bergen Mr. Jeffrey T. Gasser Oglethorpe Power Corporation Executive Vice President 2100 E. Exchange Place Southern Nuclear Operating Company, Inc.

P.O. Box 1349 P.O. Box 1295 Tucker, GA 30085-1349 Birmingham, AL 35201-1295 Mr. R. D. Baker General Manager Manager - Licensing Edwin I. Hatch Nuclear Plant Southern Nuclear Operating Company, Inc. Southern Nuclear Operating Company, Inc.

P.O. Box 1295 U.S. Highway 1 North Birmingham, AL 35201-1295 P.O. Box 2010 Baxley, GA 31515 Resident Inspector Plant Hatch Mr. K. Rosanski 11030 Hatch Parkway N. Resident Manager Baxley, GA 31531 Oglethorpe Power Corporation Edwin I. Hatch Nuclear Plant Harold Reheis, Director P.O. Box 2010 Department of Natural Resources Baxley, GA 31515 205 Butler Street, SE., Suite 1252 Atlanta, GA 30334 Steven M. Jackson Senior Engineer - Power Supply Municipal Electric Authority of Georgia 1470 Riveredge Parkway, NW Atlanta, GA 30328-4684 Mr. Reece McAlister Executive Secretary Georgia Public Service Commission 244 Washington St., SW Atlanta, GA 30334 Arthur H. Domby, Esq.

Troutman Sanders Nations Bank Plaza 600 Peachtree St, NE, Suite 5200 Atlanta, GA 30308-2216 Chairman Appling County Commissioners County Courthouse Baxley, GA 31513