ML120870362
| ML120870362 | |
| Person / Time | |
|---|---|
| Site: | Susquehanna  |
| Issue date: | 03/27/2012 |
| From: | Bhalchandra Vaidya Plant Licensing Branch 1 |
| To: | Petrilla J, Coddington C, Rochester M Susquehanna |
| vaidya B, NRR/Dorl/lpl1-1, 415-3308 | |
| References | |
| TAC ME8152 | |
| Download: ML120870362 (1) | |
Text
From:
Vaidya, Bhalchandra Sent:
Tuesday, March 27, 2012 1:27 PM To:
'Rochester, Margaret'; 'Petrilla III, John J'; 'Coddington, Cornelius T' Cc:
Casto, Greg; Purciarello, Gerard; Wilson, George; Matharu, Gurcharan; Scales, Kerby; Andersen, James; Waig, Gerald; Elliott, Robert
Subject:
Susquehanna Unit 2, ME8152, Additional Request for Additional Information (RAI) from Balance of Plant Branch John, Margie, and Neil, The NRC staff of Division of Safety Systems, Balance of Plant Branch has determined that additional information is required to complete its review of the license amendment request dated March 8, 2012, and your responses dated March 23, 2012, to its RAIs Re: Temporary Change to SSES Unit 2 TS 3.7.1 and TS 3.8.7, to Allow Implementation of Multiple Spurious Operations Modifications on SSES Unit 1 4160 B Buses.
The additional Request for Additional Information is provided below:
BALANCE OF PLANT BRANCH REQUEST FOR ADDITIONAL INFORMATION SUSQUEHANNA STEAM ELECTRIC STATION LICENSE AMENDMENT REQUEST REVISE UNIT 2 TECHNICAL SPECIFICATIONS 3.7.1 AND 3.8.7 DOCKET NOS. 50-388
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Background===
During the proposed extended Completion Time (CT) of TS 3.7.1, the licensee will establish a return flow path for the inoperable RHRSW train by manually opening the RHRSW Spray Pond Return Bypass Valve. The licensee has stated that with this return flow path established, the affected RHRSW loop on Unit 2 will be functional.
The licensee has stated that the potential heat loads during the proposed one time extended CT will be less than design basis heat loads because a) Unit 1 will already be in Mode 4 or 5, and b) the extended CT will expire on May 31, 2012 before initial spray pond temperature and ambient conditions may reach limiting design conditions.
Therefore, the licensee has justified extending the Completion Time (CT) for Conditions A.3 and B of TS 3.7.1 by stating Given this set of facts, it is expected that shutting down Unit 2 and continuing to cool Unit 1 through the open Spray Pond bypass valve, in the event that the operable loop of RHRSW were to fail in a configuration similar to that described above, would be acceptable for a period approaching 20 hours2.314815e-4 days <br />0.00556 hours <br />3.306878e-5 weeks <br />7.61e-6 months <br /> with no additional actions on the part of the operators. In this 20 hour2.314815e-4 days <br />0.00556 hours <br />3.306878e-5 weeks <br />7.61e-6 months <br /> period, however, actions could be taken by the operators to access the RHRSW Spray Pond Valve Vault and to manually close the bypass valve and to manually open the spray array valves. Re-aligning the bypass and spray array valves would return the UHS to its design condition with spray cooling. These actions could be accomplished well within the available 20 hour2.314815e-4 days <br />0.00556 hours <br />3.306878e-5 weeks <br />7.61e-6 months <br /> time frame. Therefore, the safety consequences of this condition are not considered to be high.
10CFR 50.36, Technical Specifications, paragraph (c) (2) (ii) (C) Criterion 3 requires a technical specification limiting condition for operation to be established for a structure, system, or component that is part of the primary success path and which functions or actuates to mitigate a design basis accident (emphasis added) or transient that either assumes the failure of or presents a challenge to the integrity of a fission product barrier. Therefore, the NRC staff concludes that TS 3.7.1 LCO established the limiting condition for operation for the RHRSW to mitigate a design basis accident including loss of coolant accident (LOCA).
Furthermore, FSAR Section 9.2.7.3.1 states, The maximum heat load to the spray pond will occur with a LOCA/Forced Shutdown combination, as opposed to a two unit forced shutdown.
Issue
As stated above in Background, the licensee has justified the proposed extended CT by stating that the configuration is adequate for Unit 2 shutdown, but did not address the heat loads for LOCA for which the TS was established as required by 10CFR50.36. The FSAR also provides justification for considering LOCA heat loads in this scenario.
Request a) Restate your technical analysis for justification of the proposed extended CT by considering LOCA heat loads on the RHRSW system and ultimate heat sink (UHS). The justification should include any new assumptions and new design inputs made compared to the design basis LOCA analysis. Clearly explain inputs and assumption and compensatory measures that add conservatism to your analysis.
b) Surveillance Requirements (SR) 3.7.1.3 through 3.7.1.7 are required every 31-92 days. If the last Surveillance Requirements have not been performed for times approaching the SR limits, what will the licensee do to ensure that when entering Condition A and B of TS 3.7.1 that the assumed operable loop/train of RHRSW system is actually operable?
This request was discussed during a teleconference between the NRC staff and the licensee staff on March 26, 2012.
The licensee has committed to provide the response to this request by Close-of-Business March 28, 2012.
Please contact me, if you have any questions.
- Thanks, Bhalchandra K. Vaidya Licensing Project Manager NRC/NRR/DORL/LPL1-1 (301)-415-3308 (O) bhalchandra.vaidya@nrc.gov