ML18235A317
| ML18235A317 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 08/17/2018 |
| From: | Mark D. Sartain Virginia Electric & Power Co (VEPCO) |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 18-159 | |
| Download: ML18235A317 (6) | |
Text
VIRGINIA ELECTRIC AND POWER COMPANY RICHMOND, VIRGINIA 23261 August 17, 2018 United States Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555 10 CFR 50.55a Serial No.18-159 NRA/DEA RO Docket Nos.
50-338 50-339 License Nos.
NPF-4 NPF-7 VIRGINIA ELECTRIC AND POWER COMPANY (DOMINION ENERGY VIRGINIA)
NORTH ANNA POWER STATION UNITS 1 AND 2 ASME SECTION XI INSERVICE INSPECTION PROGRAM RELIEF REQUESTSN1-15-SPT-001 AND N2-15-SPT-001 PROPOSED ALTERNATIVE - REACTOR VESSEL BOTTOM HEAD VISUAL EXAMINATION In accordance with 10 CFR 50.55a(z)(2), Dominion Energy Virginia hereby requests Nuclear Regulatory Commission (NRG) approval of proposed inservice inspection (ISi) relief requests N1-15-SPT-001 and N2-15-SPT-001 for North Anna Units 1 and 2. The request is for a proposed alternative to allow the Class 1 VT-2 examination of the bottom of the reactor vessel to be conducted when the containment is at atmospheric conditions.
The request for alternative is provided in Attachment 1.
Approval of the proposed alternative is requested by September 1, 2019 to support the Unit 1 2019 Fall outage. If you have any questions, please contact Ms. Diane E. Aitken at (804) 273-2694.
Sincerely, ~-
Mark Sartain Vice President - Nuclear Engineering and Fleet Support
Attachment:
- 1. Relief Requests N1-15-SPT-001 and N2-15-SPT-001 for Proposed Alternative -
Reactor Vessel Bottom Head Visual Examination This letter contains no NRG commitments.
cc:
U.S. Nuclear Regulatory Commission Region II Marquis One Tower 245 Peachtree Center Ave., NE, Suite 1200 Atlanta, Georgia 30303-1257 Mr. Marcus Harris Old Dominion Electric Cooperative Innsbrook Corporate Center 4201 Dominion Blvd.
Suite 300 Glen Allen, Virginia 23060 Mr. James R. Hall NRG Senior Project Manager U. S. Nuclear Regulatory Commission One White Flint North Mail Stop 08 B1-A 11555 Rockville Pike Rockville, Maryland 20852 Ms. K. R. Cotton NRG Project Manager U. S. Nuclear Regulatory Commission One White Flint North Mail Stop 08 G-9A 11555 Rockville Pike Rockville, Maryland 20852-2738 NRG Senior Resident Inspector North Anna Power Station Serial No.18-159 Docket Nos.: 50-338, 50-339 RR N1-15-SPT-001 and N2-15-SPT-001 Proposed Alternative Page 2 of 2
Serial No.18-159 NAPS Reactor Vessel Bottom Head Visual Examination Page 1 of 4 ATTACHMENT 1 RELIEF REQUESTS N1-15-SPT-001 and N2-15-SPT-001 PROPOSED ALTERNATIVE REACTOR VESSEL BOTTOM HEAD VISUAL EXAMINATION VIRGINIA ELECTRIC AND POWER COMPANY (DOMINION ENERGY VIRGINIA)
NORTH ANNA POWER STATION UNIT 1 AND UNIT 2
Serial No.18-159 Reactor Vessel Bottom Head Visual Examination - Page 2 of 4 RELIEF REQUESTS N1-15-SPT-001 and N2-15-SPT-001 Proposed Alternative in Accordance with 10 CFR 50. 55a(z)(2)
-Hardship without Compensating Increase in Quality and Safety-
- 1.
ASME CODE COMPONENT AFFECTED The component associated with this request is the Class 1 reactor vessel which is accessible for examination from the bottom in the reactor vessel sump area.
1.1 Category and System Details:
Code Class:
System:
Examination Category:
Item Number:
1.2 Component
Description:
Class 1 Reactor Coolant (RC) 8-P 815.10 Reactor Vessel, 1-RC-R-1 and 2-RC-R-1
- 2.
APPLICABLE CODE EDITION AND ADDENDA ASME Section XI, 2013 Edition
- 3.
APPLICABLE CODE REQUIREMENT Category 8-P, Item No. 815.10 requires a visual (VT-2) examination of the bottom of the reactor vessel during the system leakage test of IW8-5220.
- 4.
REASON FOR REQUEST In order to meet the Section XI pressure and temperature requirements for the system leakage test of the reactor vessel, the reactor containment at North Anna Unit 1 is required to be at a sub-atmospheric pressure. Station administrative procedures require that self contained breathing apparatus be worn for containment entries under these conditions. This. requirement significantly complicates the visual (VT-2) examination of the bottom of the reactor vessel during testing. Access to the bottom of the reactor vessel requires that the examiner descend several levels by ladder and navigate a small entrance leading to the reactor vessel. In addition to these physical constraints, the examiner must contend with extreme environmental conditions: elevated air temperatures due to reactor coolant at temperatures above ~ 350 degrees F and limited air circulation in the vessel cubicle. In addition, the examiner is limited to the approximate 30 minute capacity of the breathing apparatus to accomplish containment entry, the VT-2 examination, and containment exit.
Serial No.18-159
- Reactor Vessel Bottom Head Visual Examination - Page 3 of 4 The hardship arises less from the time constraint created by the use of bottled air or the involved radiation levels, but rather more from the environmental conditions that exist during the test.
During the test, the reactor coolant system is at the operational temperature of ;::: 350 degrees F, and the containment is sub-atmospheric. Performing the examination in these conditions is complicated by the following factors:
The need to use a self-contained breathing apparatus (SCBA) with a full-face respirator. The weight of the air bottle is approximately 25 pounds.
Access to the bottom of the reactor vessel under sub-atmospheric conditions requires the examiner to descend several levels by ladders and to navigate a small, 2'-7.25" by 2'-0" hatch wearing the SCBA.
The physical environment that results due to the heat generated by a reactor vessel elevated to a temperature of 2: 350 degrees F coupled with a lack of ventilation.
These factors increase the safety hazard associated with the examination. To place the examiner under this increased risk and burden is not justified.
This combination of conditions does not exist during refueling outages when the proposed alternative examination would take place.
The proposed alternate examination would be performed under conditions that are safer and would allow for a more thorough examination.
- 5.
PROPOSED ALTERNATIVE AND BASIS FOR USE Dominion will continue to monitor leakage on the bottom of the reactor vessel with other surveillance requirements and alarms.
The Improved Technical Specifications (ITS) establishes limits on RCS leakage of one gallon per minute of unidentified leakage and no identified leakage in the pressure boundary.
To monitor for leakage, the ITS requires that; a) one containment sump (level or discharge flow) monitor, and; b) one containment atmosphere radioactivity monitor (gaseous or particulate) be operable during Modes 1, 2, 3, and 4. In addition, the plant must verify RCS operational leakage is within limits by performance of a RCS inventory balance at a frequency not exceeding 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. The ITS also requires a containment atmosphere radioactivity monitor channel check be performed at a frequency not exceeding 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. The incore sump room has a level alarm in the control room requiring operator action. Additionally, a VT-2 exar:nination will be conducted when containment is at atmospheric conditions during each refueling for evidence of boric acid leakage. The proposed alternative will ensure that the overall level of plant quality and safety will not be compromised and eliminates the burden and hardship in performing the Code requirements.
Therefore, Dominion requests approval of this alternative pursuant to the provisions of 10 CFR 50.55a(z)(2).
Serial No.18-159 Reactor Vessel Bottom Head Visual Examination - Page 4 of 4
- 6.
DURATION OF PROPOSED ALTERNATIVE The proposed alternative to the ASME Code is applicable for the Fifth 10-year Interval at NAPS Unit 1 (May 1, 2019 -
April 30, 2029) and NAPS Unit 2 (December 14, 2020 - December 13, 2030).
- 7.
PRECEDENTS Similar alternatives were approved for North Anna Unit 1 in the fourth inspection interval (SPT-001, ADAMS # ML090890171, dated April 14, 2009) and for North Anna Unit 2 in the fourth inspection interval (N2-14-SPT-001, ADAMS #
102510218, dated November 2, 2010).