ML061350295
| ML061350295 | |
| Person / Time | |
|---|---|
| Site: | Surry  |
| Issue date: | 05/15/2006 |
| From: | Grecheck E Virginia Electric & Power Co (VEPCO) |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 06-335A | |
| Download: ML061350295 (10) | |
Text
VIRGINIA ELECTRIC AND POWER COMPANY RICHMOND, VIRGINIA 23261 May 15, 2006 U.S. Nuclear Regulatory Commission Serial No. 06-335A Attention: Document Control Desk NLOS/GDM RO Washington, D.C. 20555 Docket Nos. 50-280 50-28 1 License Nos. DPR-32 DPR-37 VIRGINIA ELECTRIC AND POWER COMPANY SURRY POWER STATION UNITS 1 AND 2 PROPOSED TECHNICAL SPECIFICATIONS CHANGE REQUEST FOR REACTOR COOLANT SYSTEM PRESSURErrEMPERATURE LIMITS, LTOPS SETPOINT. AND LTOPS ENABLE TEMPERATURE BASIS RESPONSE TO REQUESTFOR ADmTIONAnNFORM~ION By letter dated April 20, 2006 (Serial No.06-335), Virginia Electric and Power Company (Dominion) requested amendments, in the form of changes to the Technical Specifica1:ions (TS) to Facility Operating License Numbers DPR-32 and DPR-37 for Surry Povver Station Units 1 and 2, respectively. The proposed TS change restores the Reactor Coolant System (RCS) Pressureflemperature (P/T) operating limits, Low Temperature Overpressure Protection System (LTOPS) setpoint, and LTOPS enable temperature (Tenable)basis to those that were in place prior to the approval of License Ame ndments 245/244.
During a conference call between the NRC staff and Dominion held on May 1, 2006, the NRC indicated that additional information was necessary to facilitate the completion of their review. Specifically, the NRC requested information demonstrating that:
- 1) the most recently completed fluence analyses for Surry Units 1 and 2 were prepared in accordance with Regulatory Guide 1.190, and 2) confirmation that the RCS P f l operating limit curves and LTOPS setpoint provided in the proposed TS change request remain conservative with respect to the more recently performed analyses. Dominions response is provided in the attachment and concludes that the requested Surry TS RCS P/T operating limits and LTOPS setpoint remain valid and conservative for their period of applicability, corresponding to 28.8 Effective Full Power Years (EFPY) and 29.4 EFPY for Surry Units I and 2, respectively.
The addi,tional information provided herein does not affect the significant hazards consideration determination or environmental assessment that were previously provided in support of the proposed TS change request.
Serial No. 06-335A Docket Nos. 50-280,281 Page 2 of 2 If you have any further questions or require additional information, please contact Mr. Gary D. Miller at (804) 273-2771.
Very truly yours, E. S. Grecheck Vice President - Nuclear Support Services Attachment Commitmients made in this letter: None cc: U.S. Nuclear Regulatory Commission Region II Sam Nunn Atlanta Federal Center Suite 23T85 61 Forsyth Street, SW Atlanta, Georgia 30303 Mr. S. R. Monarque U. S. Nuclear Regulatory Commission One White Flint North 11!555 Rockville Pike Mad Stop 8H12 Rockville, MD 20852 Mr. N. P. Garrett NFIC Senior Resident Inspector Surry Power Station Commissioner Bureau of Radiological Health 1500 East Main Street Suite 240 Richmond, VA 23218
Serial No. 06-335A Docket Nos. 280,281 TS Change Request- Reinstatement of P/T Limits COMMONWEALTH OF VIRGINIA )
)
COUNTY OF HENRICO 1 The foregoing document was acknowledged before me, in and for the County and Commonwealth aforesaid, today by Eugene S. Grecheck, who is the Vice President -
Nuclear Support Services of Virginia Electric and Power Company. He has affirmed before me that he is duly authorized to execute and file the forgoing document in behalf of that Company, and that the statements in the document are true and correct to the best of his knowledge, information, and belief.
Acknowledged before me this /sv day of ,2006.
My Commission Expires: 3,. 200~.
(SEAL)
Serial No. 06-335A Docket Nos. 50-280,281 ATTACHMENT ResDonse to NRC Reauest for Additional Information ProDose(dTechnical SDecifications Chanae Reauest for Reinstatement of RCS P/T Limits. LTOPS SetDoint. and LTOPS Enable TemDerature Basis Surry Power Station Units 1 and 2 Virginia Electric and Power Company (Dominion)
Serial No. 06-335A Docket Nos. 50-280, 281 Attachment ResDonse to NRC Reauest for Additional Information ProDosed Technical SDecifications Chanae Reauest for Reinstatement of RCS P/T Limits, LTOPS SetDoint. and LTOPS Enable TemDerature Basis Surrv Power Station Units 1 and 2 During a teleconference on May 1, 2006, the NRC staff indicated that additional information was required regarding the reactor vessel neutron fluence analyses that support the Surry Technical Specifications (TS) change request submitted by Dominion letter dated April 20, 2006 (Reference 1). Specifically, the NRC noted that the reactor vessel neutron fluence analysis originally performed in support of Surry TS Amendments 207/207 (References 2 and 3) did not apply the latest neutron cross-section lilbrary of the Evaluated Nuclear Data file, currently ENDF/B-VI. As noted in Regulatory Guide 1.I 90, Calculational and Dosimetry Methods for Determining Pressure Vessel Neutron Fluence, the updated ENDF/B-VI cross-section data have been dernonstrated to provide a more accurate determination of the flux attenuation through iron and are strongly recommended for use by licensees when performing reactor vessel neutron fluence analysis. The reactor vessel fluence analyses cited in Referencle 2 were performed by Westinghouse circa 1987, and utilized the ENDF/B-IV cross section library; however, the data has been updated since that time. Neither Regulatory Guide 1.190, nor its predecessor Draft Regulatory Guide-I 053, had been issued when the previous fluence analyses were performed.
To address this issue, Dominion proposed to submit relevant information discussing new reactor vessel fluence analyses for Surry that were recently performed by AREVA NP (formerly Framatome ANP). As discussed in this letter, the new reactor vessel fluence analyses used the current ENDF/B-VI cross-section library. The fluence analyses results used in conjunction with the current reactor vessel material properties for Surry demonstrate that the applicable 1/4-T and 3/4-T RTNDTvalues, which form the basis for the TS Reactor Coolant System (RCS) Pressure/Temperature (P/T) limits originally approved in Amendments 207/207 and are requested for reinstatement in Reference 1, remain valid and conservative.
Reactor Vessel Neutron Fluence Analvsis Methodoloav In support of Surrys reactor vessel integrity program, Dominion has recently procured revised 610-yearreactor vessel neutron fluence analyses for Surry Units 1 and 2 from AREVA. These neutron fluence projections are valid for cumulative core exposures of 48 Effective Full Power Years (EFPY) for both Surry Units 1 and 2. Future operating cycles are assumed to be equilibrium fuel cycles with a capacity factor of 95%. The revised 610-year fluence analyses consider the effects of certain core design changes planned ifor future operating cycles for Surry Units 1 and 2. These core design changes, and the impacts on Surrys Pressurized Thermal Shock assessment per 10 CFR 50.61, will be the subject of a forthcoming Dominion letter to the NRC.
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Serial No. 06-335A Docket Nos. 50-280, 281 Attachment The revised 60-year fluence analyses for Surry Units 1 and 2 were performed in accordance with NRC-approved methodology as described in Framatome Topical Report BAW-2241 P, Revision 1 , Fluence and Uncertainty Methodologies (Reference 4). The NRCs safety evaluation for Topical Report BAW-2241P, Revision 1, concluded that the methodology is acceptable for referencing in licensing applications for determining the reactor vessel fluence of Westinghouse, CE, and B&W designed reactors (Reference 5). In the NRCs safety evaluation dated April 5, 2000, the NRC noted the following limitations for use of Topical Report BAW-2241P, Revision 1:
- 1. The FTI dosimetry C/M data-base includes an extensive set of PWR core/internals/vesseI configurations. However, the dosimetry set is not complete and there are certain designs that are not included in the data-base (e.g., cores including partial-length fuel assembly designs). FTI has indicated (Response-9 of Reference-17) that in the case where the BAW-224lP, Revision I, methodology is applied to a plant including a feature not included in the FTI data-base, an additional evaluation will be performed. This will include an evaluation of the effect on the dosimetry measurements, calculation-to-measurement ratios and the analytical uncertainties. FTI has stated that the fluence calculational uncertainty will be increased if this evaluation indicates that the uncertainties given in BA W-224 1P, Revision I, are not adequate.
- 2. Shlould there be changes in the input cross section of this methodology, the licensee will evaluate the changes for their impact and, if necessary, will modify the methodology accordingly.
- 3. The licensee will provide the staff with a record of future modifications of the methodology.
The revised 60-year reactor vessel neutron fluence analyses performed by AREVA for Surry Units 1 and 2 meet these conditions as described below:
- 1. Surry Units 1 and 2 are included in the Framatome dosimetry database, as shown on Table E-6 of Topical Report BAW-2241P, Revision 1. Therefore, Condition No. 1 is met.
- 2. The cross section library utilized in Topical Report BAW-2241P, Revision 1, is shown1 below:
BUGLE-93: Coupled 47 Neutron, 20 Gamma-Ray Group Cross Section Library Derived from ENDF/B-VI for LWR Shielding and Pressure Vessel Dosimetry Applications, Radiation Shielding Information Center (RSIC), Oak Ridge National Laboratory (ORNL), DLC-175, April 1994.
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Serial No. 06-335A Docket Nos. 50-280,281 Attachment This is the same cross section library that was used in the revised 60-year reactor vessel neutron fluence analyses for Surry Units 1 and 2. Therefore, Condition No. 2 is met.
- 3. Any rriodifications to the methodology of Topical Report BAW-2241 P, Revision 1, will be, oir have been, submitted to the NRC by AREVA NP (previously Framatome ANP). Therefore, Condition No. 3 is met.
Revised IReactor Vessel Neutron Fluence Analvses Results The revised 60-year fluence analyses performed by AREVA also provide peak reactor vessel fluence results at a cumulative core exposure of 32 EFPY for each Surry unit.
The fluence values at 32 EFPY can be considered bounding with respect to the original 40-year operating period for Surry Units 1 and 2. A cumulative core exposure of 32 EFPY exceeds the cumulative core exposure for the TS RCS P/T limits curves, Low Temperature Overpressure Protection System (LTOPS) setpoint, and LTOPS enable temperature (Tenable)discussed in Amendments 207/207, which indicate cumulative exposure applicability limits of 28.8 EFPY for Surry Unit 1 and 29.4 EFPY for Surry Unit
- 2. Therefore, the 32 EFPY fluences represent a conservative point of comparison relative to cumulative core exposure applicability limits of the RCS P/T limits requested in Reference 1.
Results from the revised 60-year fluence analyses are shown below.
Table 1 - Revised RPV Fluence Proiections for Surrv Unit 1 Neutron Fluence (E > 1.0 MeV)
Location Material Fluence at 32 Fluence at 48 EFPY (n/cm2) EFPY (n/cm2) lntermedia Vessel Walll Inner Surface (0') I S H - l 4 Y 4 / U I 1334 6./ U t + l U 1. U U t + l Y Intermediate to Lower Shell Ci rcumferential Weld 5.61 E+19 Nozzle to Intermediate Shell Circumferential Weld J726/25017 7.75E+18 Page 3 of 6
Serial No. 06-335A Docket Nos. 50-280,281 Attachment Table 2 - Revised RPV Fluence Proiections for Surrv Unit 2 Surry Unit 2 Neutron Fluence (E > 1.0 MeV)
Location Material Fluence at 32 I Fluence at 48 I I EFPY (n/cm2) EFPY (n/cm2)
Intermediate Vessel Wall Inner Surface (0') and Lower 3.64E+19 5.38E+19 Plates-
-..~
Lower Shell Longitudinal WF-418T1762 7.62E+1 1.14E+19 Weld W F-8/8T1762 Intermediate Shell SA-1585/72445 7.63E+1 1.14E+19 Longitudinal Weld W F-4/8T1762 Intermediate to Lower Shell R3008/0227 3.62E+l9 5.37E+19 Circumferential Weld Nozzle to Intermediate Shell J737/4275 4.00E+18 6.32E+18 Circumferential Weld TS RCS P/T Limits The Surry Units 1 and 2 TS RCS P/T limits and LTOPS setpoints originally approved in Amendments 207/207 were based on a limiting 1/4-thickness (1/4-T) RTNDTof 228.4 O F ,
and a limiting 3/4-thickness (3/4-T) RTNDTof 189.5 O F . When the RCS P/T limits and LTOPS setpoints were developed, these values of RTNDTwere determined to bound all Surry Units 1 and 2 reactor vessel beltline materials at end-of-original 40-year license fluences corresponding to 28.8 EFPY and 29.4 EFPY for Surry Units 1 and 2, respectively.
At revised reactor vessel neutron fluence projections corresponding to 32 EFPY, the limiting 114-T RTNDTvalue is 225.6 OF for Surry Unit 1 Lower Shell Longitudinal Weld SA-l526/299L44, and the limiting 3/4-T RTNDTvalue is 188.9 OF for Surry Unit 1 Intermediate to Lower Shell Circumferential Welds SA-1585/72445 and SA-1650/72445.
Details of the adjusted RTNDTcalculations are provided in Tables 3 and 4 below for the limiting reactor vessel materials. Values of initial RTNDT,chemistry factors, and margin terms are consistent with those most recently submitted by Dominion as updates to the NRC's Reactor Vessel Integrity Database for Surry (Reference 6).
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Serial No. 06-335A Docket Nos. 50-280, 281 Attachment Table 3 - Current Reactor Vessel Material ProDerties for Surrv Units 1 and 2 Weld Material Location Initial RTNDT Chemistry Margin ( O F )
(OF) Factor ( O F )
Surry 1 Intermediate to -5.0 131.4 68.5 SA-1585/72445, SA- 1650/72445 Lower Shell Circ. I I I Weld Lower SheII -7.0 220.6 69.5 SA-1526/29!3L44 Longitudinal Weld Surry 2 Intermediate to 0.0 132.4 48.8 R3008/0227 Lower Shell Circ.
Weld "able 4 - Adjusted RTNwValues at 32 EFPY for Surry Units 1 and 2 Weld Material 1/4-T Location 3/4-T Location Inner Surface Fluence ARTNDT RTNDT Fluence ARTNDT RTNDT Fluence (xlE19) (OF) (OF) (xlE19) (OF) (OF)
(xl E l 9)
Surry 1 SA- 1585/72445 3.740 2.282 160.8 224.3 0.849 125.4 188.9 SA-1650/72445 SA-l526/299L44 0.640 0.390 163.1 225.6 0.145 109.4 171.9 Surry 2 R3008/0227 3.620 2.209 160.9 209.7 0.822 125.2 174.0 When revised fluence projections at 32 EFPY are considered, the limiting 1/4-T and 3/4-T RTNDTvalues remain less than those values specified in support of the RCS P/T limits and LTOPS setpoints approved in TS Amendments 207/207. Therefore, the requested Surry TS RCS P/T limits, LTOPS setpoint, and LTOPS enabling temperature remain valid and conservative for their period of applicability, corresponding to 28.8 EFPY and 29.4 EFPY for Surry Units 1 and 2, respectively.
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Serial No. 06-335A Docket Nos. 50-280, 281 Attachment References
- 1. Letter from E. S. Grecheck of Virginia Electric and Power Company to USNRC, Virginia Electric and Power Company, Surry Power Station Units 1 and 2, Proposed Technical Specifications Change Request for Reinstatement of Previous Reactor Coolant System Pressurerremperature Limits, LTOPS Setpoint, and LTOPS Enable Temperature Basis, Serial No.06-335, April 20, 2006.
- 2. Letter from R. F. Saunders of Virginia Electric and Power Company to USNRC, Virginia Electric and Power Company, Surry Power Station Units 1 and 2, Request for Exemption - ASME Code Case N-514, Proposed Technical Specifications Change, Revised Pressurenemperature Limits and LTOPS Setpoint, Serial No.95-197, June 8, 1995.
- 3. Letter from USNRC to J. P. OHanlon, Surry Units 1 and 2 - Issuance of Amendments Re: Surry, Units 1 and 2 Reactor Vessel Heatup and Cooldown Curves (TAC NOS. M92537 and M92538), dated December 28,1995.
- 4. Framatome ANP Report BAW-2241P, Revision 1, Fluence and Uncertainty Methodologies, December 1999.
- 5. NRC Letter from S. A. Richards to J. J. Kelly (BaWOG), Acceptance for Referencing of Licensing Topical Report BAW-2241P, Revision 1, Fluence and Unlcertainty Methodologies (TAC No. M98962), dated April 5, 2000.
- 6. Letter from L. N. Hartz of Virginia Electric and Power Company to USNRC, Virginia Electric and Power Company, Surry Power Station Unit 2, Evaluation of Surry 2 Capsule Y Data, dated March 27, 2003.
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