ML15183A159
| ML15183A159 | |
| Person / Time | |
|---|---|
| Site: | Vogtle  |
| Issue date: | 07/15/2015 |
| From: | Martin R Plant Licensing Branch II |
| To: | Pierce C Southern Nuclear Operating Co |
| Bob Martin, 415-1493 | |
| References | |
| TAC MF6323 | |
| Download: ML15183A159 (4) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 July 15, 2015 Mr. C. R. Pierce Regulatory Affairs Director Southern Nuclear Operating Company, Inc.
Post Office Box 1295, Bin - 038 Birmingham, AL 35201-1295
SUBJECT:
VOGTLE ELECTRIC GENERATING PLANT, UNIT 1 - REQUEST FOR ADDITIONAL INFORMATION ON LICENSE AMENDMENT REQUEST FOR RESIDUAL HEAT REMOVAL PUMP MOTOR (TAC NO. MF6323)
Dear Mr. Pierce:
By letter dated June 4, 2015 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML15155B593), Southern Nuclear Operating Company, Inc.,
submitted a license amendment request for the Vogtle Electric Generating Plant, Unit 1, to revise the completion time for one inoperable residual heat removal (RHR) train from 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to 7 days to allow for replacement of an RHR pump motor. In order to continue the review, the U.S. Nuclear Regulatory Commission staff requests additional information as discussed in the enclosure.
Docket No. 50-424 Sincerely, R;/l/a/f,;J
/Bob Martin, Senior Project Manager Plant Licensing Branch 11-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation
Enclosure:
Request for additional information cc: Distribution via Listserv
REQUEST FOR ADDITIONAL INFORMATION (RAI)
VOGTLE ELECTRIC GENERATING PLANT (VEGP), UNIT 1
- 1.
In response to an RAI on another license amendment request (LAR) (probabilistic risk assessment (PRA), No. 27 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML13184A267), dated July 2, 2013, Southern Nuclear Operating Company, Inc. (SNC), identified four fire PRA methods which may not be consistent with U.S. Nuclear Regulatory Commission (NRC)-accepted methods. SNC stated that those methods would be removed from the VEGP fire PRA and further stated that the resulting model would be refined, as necessary, using NRG-accepted methods. Confirm that the PRA model used to calculate risk results presented in the June 4, 2015, LAR, incorporated the necessary refinements using NRG-accepted methods.
- 2.
SNC's application states that defense-in-depth is maintained, in part, by efforts to ensure that the 1A residual heat removal (RHR) pump is not removed from service for the motor replacement during a period of time of impending inclement weather. Enclosure 2 of the LAR, under Tier 2: "Restrictions are established for Dominant Risk-Significant Configurations," states the compensatory actions to be taken by SNC for the proposed Completion Time of 7 days. The NRC staff requests that:
a)
SNC provide a clarification of the steps taken to ensure that the 1A RHR pump is not removed from service for the motor replacement during a period of time of impending inclement weather; and b)
SNC provide clarification of the steps taken to ensure that the 1 B RHR pump will remain OPERABLE if the 1A RHR pump is out of service.
- 3.
General Design Criterion (GDC) 5 - "Sharing of structures, systems, and components," of 1 O CFR Part 50, Appendix A, states the following:
Structures, systems, and components important to safety shall not be shared among nuclear power units unless it can be shown that such sharing will not significantly impair their ability to perform their safety functions, including, in the event of an accident in one unit, an orderly shutdown and cooldown of the remaining units.
With 1A RHR pump out of service and the 1 B RHR pump remaining OPERABLE, can a cross tie to VEGP, Unit 2, be made to have available inventory to cool the reactor core?
The NRC staff requests that SNC provide a clarification regarding whether a cross tie is available when the Unit 1 1A RHR pump is out of service and address if it meets GDC 5.
- 4.
On page E 1-3 (page 6 of 39) of the June 4, 2015, LAR, SNC states that, "The risk-informed analysis identified compensatory actions that will be put in place to both decrease the likelihood of failure of a second ECCS [emergency core cooling system] as well as decreasing the likelihood of an initiating event during the time the 1A RHR pump is Enclosure out of service.. " Although the submittal states that compensatory actions are described in, the NRC staff requests further detailed information, as follows:
Describe all compensatory actions being proposed in support of the LAR.
Describe how the compensatory actions will be implemented and by whom.
- email dated
- Memo dated OFFICE DORL/LPL2-1 /PM DORL/LPL2-1 /LA DSS/SRXB/BC DORL/APLNBC NAME BMartin SFigueroaSRohrer for CJackson SRosenberg DATE 07/ 16 /15 07/16/15 06/24/15 **
06/30/15 **
OFFICE DSS/AHPB/BC DORL/LPL2-1 /BC DORL/LPL2-1 /PM NAME SWeerakkody RPascarelli MKhanna for BMartin DATE 07/08/15
- 07/16/15 07/15/15