NL-11-1716, Proposed Alternative HNP-ISI-ALT-11 in Accordance with 10 CFR 50.55a(a)(3)(i) Response to NRC Request for Additional Information

Proposed Alternative HNP-ISI-ALT-11 in Accordance with 10 CFR 50.55a(a)(3)(i) Response to NRC Request for Additional Information

ML112290732
Person / Time
Site:	Hatch
Issue date:	08/16/2011
From:	Ajluni M Southern Nuclear Operating Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
NL-11-1716
Download: ML112290732 (5)

Text

Mark J. Ajluni, P.E. Southern Nuclear Nuclear licensing Director Operating Company. Inc.

40 Inverness Cente r Parkway Post Office Box 1295 Birmingham, Alabama 35201 Tel 205.992.7673 Fax 205.992.7885 August 16, 2011 SOUIHERN'\

COMPANY Docket Nos.: 50-366 NL-11-1716

u. S, Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D. C. 20555-0001 Edwin I. Hatch Nuclear Plant - Unit 2 Proposed Alternative HNP-ISI-ALT-11 In Accordance With 10 CFR 50.55a{a)(3)(i)

Response to NRC Request for Additional Information Ladies and Gentlemen:

By letter dated May 17, 2011, (ADAMS Accession No. ML111380211) Southern Nuclear Operating Company (SNC) submitted a request for proposed alternative HNP-ISI-ALT-11, for the lSI Program, in accordance with 10 CFR 50.55a{a){3){i).

Subsequently, by letter dated July 28, 2011, (ADAMS Accession No. ML11206A001) the NRC submitted a Request for Additional Information (RAI) to enable completion of the review. The SNC response to the RAls are provided in the Enclosure, This letter contains no NRC commitments. If you have any questions, please contact Jack Stringfellow at (205) 992-7037.

Respectfully submitted,

~~T M. J. Ajluni Nuclear Licensing Director MJAlGALllac

Enclosure:

Edwin I. Hatch Nuclear Plant - Unit 2 Proposed Alternative HNP-ISI- AL T -11, Response to NRC Request for Additional Information

U. S. Nuclear Regulatory Commission NL-11-1716 Page 2 cc: Southern Nuclear Operating Company Mr. S. E. Kuczynski, Chairman, President & CEO Mr. J. T. Gasser, Executive Vice President Mr. D. R. Madison, Vice President - Hatch Ms. P. M. Marino, Vice President - Engineering RTYPE: CHA02.004 U. S. Nuclear Requlatorv Commission Mr. V. M. McCree, Regional Administrator Mr. P. G. Boyle, NRR Project Manager Mr. E. D. Morris, Senior Resident Inspector - Hatch

Edwin I. Hatch Nuclear Plant - Unit 2 Proposed Alternative HNP-ISI-ALT-11, in Accordance With 10 CFR SO.SSa(a)(3)(i) Response to NRC Request for Additional Information Enclosure Edwin I. Hatch Nuclear Plant - Unit 2 Proposed Alternative HNP-ISI-ALT-11, Response to NRC Request for Additional Information

Enclosure to NL-11-1716 Edwin I. Hatch Nuclear Plant - Unit 2 Proposed Alternative HNP-ISI-ALT-11, Response to NRC Request for Additional Information

1. NRC RAI Confirm that the neutron fluence calculations used in the application conform to the requirements set forth in the NRC safety evaluation pertaining to the Radiation Analysis Modeling Application (RAMA) code, dated May 13, 2005.

Specifically confirm that:

The best-estimate [reactor pressure vessel] neutron fluence prediction is determined using the RAMA transport code, detailed plant-speci'fic geometry, core operating history, and the BUGLE-96 nuclear data library with a minimum of a P3 Legendre polynomial approximation in the iron inelastic scattering.

If this is not the case, detail how the neutron fl!Jence calculations used in the application are acceptable.

SNC RESPONSE As documented in TransWare Enterprises report, SNC-FLU-002-R-001, Revision 0, the Hatch-2 fluence evaluation was completed using the RAMA transport code, detailed plant-specific geometry, core operating history, and the BUGLE-96 nuclear data library. The RAMA transport calculation uses information from the RAMA nuclear data library to determine the scope of the flux calculation. This information includes the Legendre expansion of the scattering cross sections that is used in the treatment of anisotropy of the problem. By default, the RAMA transport calculation uses the maximum order of expansion that is available for each nuclide in the RAMA nuclear data library (Le., through P5 scattering for actinide and zirconium nuclides and through P7 scattering for all other nuclides in the model).

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Enclosure to NL-11-1716 Edwin I. Hatch Nuclear Plant - Unit 2 Proposed Alternative HNP-ISI-ALT-11, Response to NRC Request for Additional Information

2. NRC RAI The mean nil-ductility transition reference temperature (RTNOT) values reported in Tables 1 and 2 of the submittal are based on delta RTNOT values from "SIA ART Calculation[s]." Explain in detail how these calculations are, or are not, consistent with the guidance provided in Regulatory Guide (RG) 1.99, Rev. 2, "Radiation Embrittlement of Reactor Vessel Materials." If they are not consistent with the guidance in RG 1.99, Rev. 2, please indicate whether these proposed values (Le., the delta RTNOT values used in the calculation of the mean RTNOT values in this submittal) have been previously reviewed and accepted by the staff.

SNC RESPONSE As documented in SIA report, HTCH-21 Q-302R1, the updated fluence values were used to determine the RTNOT shift and projected Adjusted Reference Temperature (ART) values for the Hatch-2 reactor pressure vessel materials.

The calculations performed by SIA were performed using the equations and values provided in Regulatory Guide 1.99, Revision 2. Adjusted reference temperatures were calculated for each of the Reactor Pressure Vessel (RPV) welds and plates in locations projected to reach or exceed a fluence of 1 x 1017 n/cm 2 (> 1.0 MeV). The results were then tabulated in a series of Excel spreadsheets with ART calculations performed for 19.5, 36, 40, 44, 48, and 50.1 EFPY. The TransWare report provided outputs of fluence values at 19.5 (end of Cycle 18) and 50.1 EFPY (Cycle 18 extrapolated to end of extended period of operation). Fluence values were determined for selected intermediate Effective Full Power Years (EFPY) by use of linear interpolation. Material properties used for these calculations including chemistry values, chemistry factors and initial reference temperatures, were compared and found to agree with the values provided for the Hatch-2 RPV from the U. S. Nuclear Regulatory Commission, "Reactor Vessel Integrity Database Version 2.0.1," dated September 7, 2000.

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