ML13345A953
| ML13345A953 | |
| Person / Time | |
|---|---|
| Site: | Ginna  |
| Issue date: | 12/11/2013 |
| From: | Thadani M Plant Licensing Branch 1 |
| To: | Harding T Constellation Energy Group |
| References | |
| MF0900 | |
| Download: ML13345A953 (3) | |
Text
1 NRR-PMDAPEm Resource From:
Thadani, Mohan Sent:
Wednesday, December 11, 2013 1:08 PM To:
Harding Jr, Thomas (Thomas.HardingJr@cengllc.com)
Subject:
Ginna LAR for Containment Air Temperature RAI (TAC MF0900)
Tom:
By letter dated February 28, 2013, R.E. Ginna Nuclear Power Plant, LLC submitted a request for amendment to the Technical Specification 3.6.5, Containment Air Temperature, for R.E. Ginna Nuclear Power Plant. The containment would revise the containment air temperature from 120ºF to 125ºF. A request for additional information (RAI) was submitted to the licensee September 24, 2013. The NRC staff received the licensees response on November 11, 2013. The NRC staff has reviewed the licensees response to the RAI, and needs additional information related to the RAI.
The NRC staff requests a response to the additional RAI below.
REQUEST FOR ADDITIONAL INFORMATION REGARDING R.E. GINNA NUCLEAR POWER PLANT TECHNICAL SPECIFICATION REVISION TO CONTAINMENT AIR TEMPERATURE DOCKET NO. 50-244 By letter dated February 28, 2013 (ADAMS Accession Number ML13067A328), R.E. Ginna Nuclear Power Plant, LLC, the licensee for R.E. Ginna Nuclear Power Plant submitted a License Amendment Request (LAR) to revise Technical Specifications 3.6.5, Containment Air Temperature. The revision would increase the allowable containment air temperature from 120ºF to 125ºF. A RAI was issued by the NRC staff Branch on September 24 27, 2013. The licensee Provided its response to RAI on November 11, 2013 (ADAMS Accession No. ML13323A080), which supplements the LAR.
Title 10 of the Code of Federal Regulation (10 CFR) Section 50.46(a)(1)(i) states Comparisons to applicable experimental data must be made and uncertainties in the analysis method and inputs must be identified and assessed so that the uncertainty in the calculated results can be estimated.
The licensee uses the NRC-approved Automated Statistical Treatment of Uncertainty Method (ASTRUM),
documented in WCAP-16009-NP-A (ADAMS Accession Nos. ML050910157, ML050910159, and ML050910161), to evaluate Emergency Core Cooling System (ECCS) performance. ASTRUM relies on an approach based on order statistics, in which a set number of cases with randomly varied initial conditions are analyzed using the WCOBRA/TRAC (WC/T) reactor system analysis code. (The initial conditions are also referred to as inputs.) The number of cases is chosen so that the highest predicted Peak Cladding Temperature (PCT) within the case set becomes a predictor of the 95/95 upper tolerance limit for the PCT associated with a hypothetical population of Loss of Coolant Accident (LOCA) scenarios. This result is used to show compliance with the 10 CFR 50.46(b)(1) acceptance criterion concerning PCT.
In the supplement dated November 11, 2013 it was shown that a subset of the original 124 ASTRUM cases was chosen to be re-executed as a result of an error in the evaluation model relating to thermal conductivity
2 degradation (TCD). For TCD, the subset of cases was chosen based on those original cases where TCD would have the greatest potential to affect initial stored energy in the fuel. To evaluate the proposed increase in containment air temperature, a smaller subset of cases from the TCD subset was chosen to be re-executed.
The smaller subset was chosen based on the highest peak cladding temperature (PCT) cases from the TCD subset. It is not clear to the NRC how the smaller subset accounted for those cases within the original run set, where an increase in containment air temperature could introduce additional uncertainty in the inputs, and compromise the requisite, per 10 CFR 50.46(a)(i), high level of probability that the acceptance criteria contained in 10 CFR 50.46(b) would not be exceeded.
Please review the randomly varied evaluation model inputs, for which an increase in containment air temperature could introduce additional uncertainty (i.e., inputs that are affected by an increase in containment air temperature). Please demonstrate that the evaluation model and the results continue to account for the potentially increased uncertainty, such that the ECCS evaluation results continue to demonstrate that there is a high level of probability that the acceptance criteria set forth in 10 CFR 50.46(b) would not be exceeded.
Please provide your response to the above RAI by January 10, 2014, to facilitate timely completion of the requested action.
Best Regards, Mohan C Thadani Senior Project Manager FitzPatrick, Ginna, and Constellation Fleet Plant Licensing Branch I-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation (301) 415-1476 Mohan.Thadani@nrc.gov
Hearing Identifier:
NRR_PMDA Email Number:
950 Mail Envelope Properties (Mohan.Thadani@nrc.gov20131211130700)
Subject:
Ginna LAR for Containment Air Temperature RAI (TAC MF0900)
Sent Date:
12/11/2013 1:07:51 PM Received Date:
12/11/2013 1:07:00 PM From:
Thadani, Mohan Created By:
Mohan.Thadani@nrc.gov Recipients:
"Harding Jr, Thomas (Thomas.HardingJr@cengllc.com)" <Thomas.HardingJr@cengllc.com>
Tracking Status: None Post Office:
Files Size Date & Time MESSAGE 4600 12/11/2013 1:07:00 PM Options Priority:
Standard Return Notification:
No Reply Requested:
No Sensitivity:
Normal Expiration Date:
Recipients Received: