ML15216A366
| ML15216A366 | |
| Person / Time | |
|---|---|
| Site: | Surry  |
| Issue date: | 07/30/2015 |
| From: | Mark D. Sartain Virginia Electric & Power Co (VEPCO) |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 15-023A | |
| Download: ML15216A366 (3) | |
Text
VIRGINIA ELECTRIC AND POWER COMPANY RICHMOND, VIRGINIA 23261 July 30, 2015 10 CFR 50.90 U. S. Nuclear Regulatory Commission Serial No.:
15-023A Attention: Document Control Desk SPS LIC/CGL: RI Washington, DC 20555-0001 Docket Nos.:
50-280/281 License Nos.:
DPR-32/37 VIRGINIA ELECTRIC AND POWER COMPANY SURRY POWER STATION UNITS I AND 2 UPDATE REGARDING FLUENCE ASSESSMENT TO ENCOMPASS REACTOR VESSEL NOZZLES RELATED TO LICENSE AMENDMENT REGARDING CLARIFICATION OF REACTOR COOLANT SYSTEM HEATUP AND COOLDOWN LIMITATIONS TECHNICAL SPECIFICATION FIGURES By letter dated June 3, 2014 (Serial No.14-262), Virginia Electric and Power Company (Dominion) submitted a license amendment request (LAR) to revise the Surry Power Station (Surry) Units 1 and 2 Technical Specifications (TS) Figures 3.1-1 and 3.1-2, Surry Units 1 and 2 Reactor Coolant System Heatup Limitations and Surry Units I and 2 Reactor Coolant System Coo/down Limitations, respectively.
The response to an NRC request for additional information (RAI) was provided to the NRC on February 4, 2015 (Serial No.15-023). The NRC approved the LAR and issued TS Amendments 285/285 on June 26, 2015.
The February 4, 2015 letter stated that, upon receipt of the NRC RAI, Dominion initiated discussions with Westinghouse to determine a schedule for amending the axial extent of the fluence model to encompass the reactor vessel (RV) inlet and outlet nozzles.
Westinghouse indicated they could complete the requested revision of the fluence model by June 30, 2015. This statement, which was provided in the RAI response, was also reflected in the NRC's Safety Evaluation (SE) for TS Amendments 285/285. The purpose of this letter is to provide an update to the NRC regarding the status of the fluence assessment for the RV inlet and outlet nozzles.
Westinghouse completed a revision of the existing fluence model to include the axial extent of the RV inlet and outlet nozzles. On June 30, 2015, Westinghouse transmitted a draft report to Dominion with conservative two-dimensional synthesis fluence results that correspond to a location where the vessel shell weld attaches to the inlet and outlet nozzle forgings (i.e.,
at the lowest intersection of the nozzle weld at the reactor vessel shell).
The draft report confirms that eight of the twelve inlet and outlet nozzles on the Surry Units I and 2 RVs will have maximum fast neutron fluence less than the lx1017 n/cm2 (E > 1 MeV) fluence threshold.
The calculation was performed for an
Serial No. 15-023A Docket Nos. 50-280/281 Page 2 of 3 effective full power years (EFPY) value beyond the Surry projected end-of-life (i.e., calculated for 54 EFPY). The current Surry end-of-life is defined as 48 EFPY in the existing TS pressure-temperature (P-T) limits curves.
There are four nozzles (two nozzles on each of the RVs) that will require additional detailed fluence calculations at a more precise location in the nozzle.
Based upon our current understanding of the information in the draft Westinghouse report, Dominion will request Westinghouse to perform additional detailed fluence calculations to project the maximum fast neutron fluence at end-of-life for the remaining two nozzles on each reactor vessel.
It is anticipated that the revised, more precise calculations for the remaining four nozzles will be completed by October 30, 2015. As previously committed in our February 4, 2015 letter, if the revision of the fluence model indicates the neutron fluence exposure of the inlet and outlet nozzles would be greater than lxi10 17n/cm2 (E > 1 MeV) at the end of the licensed operating period, Dominion will notify the NRC accordingly and provide a schedule for determining the impact on the Surry Units 1 and 2 TS P-T limits curves.
Should you have any questions or require additional information, please contact Mr. Gary D. Miller at (804) 273-2771.
Respectfully, Mark D. Sartain Vice President - Nuclear Engineering Commitment contained in this letter:
- 1. If the revision of the fluence model indicates the neutron fluence exposure of the inlet and outlet nozzles would be greater than lx1017 n/cma2 (E > 1 MeV) at the end of the licensed operating period, Dominion will notify the NRC accordingly and provide a schedule for determining the impact on the Surry Units 1 and 2 TS P-T limits curves.
Serial No. 15-023A Docket Nos. 50-280/281 Page 3 of 3 cc:
U.S. Nuclear Regulatory Commission - Region II Marquis One Tower 245 Peachtree Center Avenue, NE Suite 1200 Atlanta, GA 30303-1257 State Health Commissioner Virginia Department of Health James Madison Building -
7 th floor 109 Governor Street Suite 730 Richmond, VA 23219 Ms. Karen Cotton Gross NRC Project Manager-Surry U.S. Nuclear Regulatory Commission One White Flint North Mail Stop 08 G-9A 11555 Rockville Pike Rockville, MD 20852-2738 Dr. V. Sreenivas NRC Project Manager - North Anna U.S. Nuclear Regulatory Commission One White Flint North Mail Stop 08 G-9A 11555 Rockville Pike Rockville, MD 20852-2738 NRC Senior Resident Inspector Surry Power Station