ML16014A691
| ML16014A691 | |
| Person / Time | |
|---|---|
| Site: | Braidwood  |
| Issue date: | 02/22/2016 |
| From: | Joel Wiebe Plant Licensing Branch III |
| To: | Bryan Hanson Exelon Generation Co, Exelon Nuclear |
| Wiebe J, NRR/DORL 415-6606 | |
| References | |
| CAC MF4671, CAC MF4672 | |
| Download: ML16014A691 (3) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 Mr. Bryan C. Hanson Senior Vice President February 22, 2016 Exelon Generation Company, LLC President and Chief Nuclear Officer (CNO)
Exelon Nuclear 4300 Winfield Road Warrenville, IL 60555
SUBJECT:
BRAIDWOOD STATION, UNITS 1AND2-REQUEST FOR ADDITIONAL INFORMATION RELATED TO THE LICENSE AMENDMENT REQUEST TO INCREASE THE ULTIMATE HEAT SINK TEMPERATURE LIMIT (CAC NOS.
MF4671 AND MF4672)
Dear Mr. Hanson:
By letter to the U.S. Nuclear Regulatory Commission (NRC) dated August 19, 2014 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML14231A902), Exelon Generation Company, LLC submitted a request to increase the ultimate heat sink temperature for Braidwood Station, Units 1 and 2.
The NRC staff is reviewing your submittal and has determined that additional information is required to complete the review. The specific information requested is addressed in the enclosure. During a discussion with your staff on February 19, 2016, they agreed to respond by April 29, 2016.
The NRC staff considers that timely responses to requests for additional information help ensure sufficient time is available for staff review and contribute toward the NRC's goal of efficient and effective use of staff resources. If circumstances result in the need to revise the requested response date, please contact me at (301) 415-6606.
Sincerely,
'yJftJ~
//Joel S. Wiebe, Senior Project Manager 1
Plant Licensing Branch 111-2
/
Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. STN 50-456 and STN 50-457
Enclosure:
Request for Additional Information cc w/encl: Distribution via Listserv
REQUEST FOR ADDITIONAL INFORMATION BRAIDWOOD STATION, UNITS 1 AND 2 DOCKET NOS. STN 50-456 AND STN 50-457 In reviewing the Exelon Generation Company, LLC's (Exelon's) submittal dated August 19, 2014 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML14231A902), related to the request to increase the ultimate heat sink (UHS) temperature, for the Braidwood Station, Units 1 and 2, the U.S. Nuclear Regulatory Commission (NRC) staff has determined that the following information is needed in order to complete its review:
SCVB-RAl-15 Exelon's response to SCVB-RAl-11 in its November 9, 2015, letter (ADAMS Accession No. ML15313A254), did not provide Braidwood Station, Units 1 and 2, plant-specific information regarding the impact of the corrections resulting from Westinghouse lnfoGram (IG) 14-1 on the loss-of-coolant accident (LOCA) mass and energy release, containment pressure, and temperature response, sump net positive suction head (NPSH) analysis, and minimum containment pressure for emergency core cooling system analysis. The Exelon response refers to analysis performed for a generic large containment plant which only addresses the impact on the containment peak pressure and temperature. The response does not provide a comparison of the related parameters of the generic plant with Braidwood Station.
Without additional quantitative information, the NRC staff evaluation of Braidwood Station, Units 1 and 2, containment performance due to increase in UHS temperature cannot be completed. After correcting the RCS metal specific heat and density to ASME values reported in IG 14-1, the NRC staff requests the following:
(a) Revise the analyses of record for the above containment analyses and provide results.
As an alternative, by performing Braidwood Station, Units 1 and 2, plant-specific sensitivity analysis, provide increase in containment peak pressure, peak temperature, sump water temperature and decrease in the available NPSH for the pumps that draw suction flow from the sump during the LOCA recirculation phase.
(b) In its November 9, 2015, response, Exelon stated that the containment peak pressure would increase for the Braidwood Station units. Discuss how this impacts the current integrated leak test rate and local leak rate test results.
(c) Impact on the residual heat removal (RHR) heat exchanger heat load and on the discharge temperature of the closed cooling water (CC) from the RHR heat exchanger.
(d) Impact on the reactor containment fan cooler (RCFC) heat load and on the exit temperature of the essential service water (SX) from the RCFC.
(e) Overall impact on the temperature of SX exiting the CC heat exchanger.
(f) Overall impact on the temperature of SX returning to the UHS.
Enclosure
ML16014A691 OFFICE LPL3-2/PM LPL3-2/LA NAME JWiebe SRohrer DATE 2/22/16 1/19/16 Sincerely,
/RAJ Joel S. Wiebe, Senior Project Manager Plant Licensing Branch 111-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation RidsNrrDorllpl3-2 Resource RidsNrrLASRohrer Resource RidsRgn3MailCenter Resource SC VB/BC LPL3-2/BC RDennig JPoole 1/28/16 2/22/16 LPL3-2/PM JWiebe 2/22/16