ML080070262

(Hnp), Request for Additional Information (RAI) Regarding Alternate Source Term Application Tac Nos. MD2934 and MD2935)

ML080070262
Person / Time
Site:	Hatch
Issue date:	01/09/2008
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: ML080070262 (4)

Text

January 9, 2008 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 on meteorology issues as set forth in the Enclosure.

We discussed this issue with your staff on December 5, 2007. Please provide a response within thirty (30) 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

ML080070262 OFFICE NRR/LPL2-1/PM NRR/LPL2-1/LA NRR/AADB/BC NRR/LPL2-1/BC(A)

NAME RMartin:nc MOBrien RTaylor JStang DATE 01/9/08 01/9/08 01/9/08 01/9/08 REQUEST FOR ADDITIONAL INFORMATION CONCERNING IMPLEMENTATION OF AN ALTERNATIVE SOURCE TERM APPLICATION FOR EDWIN I. HATCH NUCLEAR PLANT, UNIT NOS. 1 AND 2 (HNP)

1) The Southern Nuclear Operating Company, Inc. (SNC), used a single set of atmospheric dispersion factors (X/Q values) as input in the control room dose assessment for all releases assumed to be at ground level. SNCs letter dated November 6, 2007, provided tables of values to show that the reactor building vent X/Q values were limiting. However, when the Nuclear Regulatory Commission (NRC) staff did comparison calculations using the inputs shown in the ARCON96 input files provided as Enclosure 2, the staff found that reactor building release X/Q values appeared to be more limiting than the reactor vent X/Q values.

Therefore, please provide further quantitative information sufficient to enable the NRC staff to perform confirmatory calculations, if appropriate, to verify SNCs conclusion that the reactor building vent X/Q values are limiting.

2) NRC Regulatory Issue Summary (RIS) 2006-04, Experience with Implementation of Alternative Source Terms, states that when running the control room atmospheric dispersion model ARCON96, two or more files of meteorological data, representative of each potential release height, should be used if X/Q values are being calculated for both ground-level and elevated releases. SNC used the 60-meter wind and 60- and 10-meter delta-temperature measurements to generate control room X/Q values for postulated releases from the 120-meter main stack because the wind data recovery rate at the 100-meter level during 1996 was below the 90-percent goal cited in Regulatory Guide 1.23, Onsite Meteorological Programs. The licensee stated that use of the 60-meter data rather than the 100-meter data would result in conservative X/Q values since the average wind speeds are lower at the 60-meter level.

The NRC staff agrees that average wind speeds would typically be lower at the 60-meter level, but notes that when using ARCON96 the highest X/Q values are not usually associated with the lightest wind speeds, but are a function of the frequency of occurrence of moderate speed winds. Therefore, please provide further quantitative information sufficient to enable the NRC staff to perform confirmatory calculations to verify SNCs conclusion that use of the 60-meter data resulted in X/Q values that are similar to or more limiting than those that would be generated using the 100-meter data.

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