ML20098C434
| ML20098C434 | |
| Person / Time | |
|---|---|
| Site: | Limerick  |
| Issue date: | 04/06/2020 |
| From: | Michael Wentzel NRC/NRR/DORL/LPL2-2 |
| To: | David Helker Exelon Generation Co, Exelon Nuclear |
| References | |
| EPID L-2020-LLA-0064 | |
| Download: ML20098C434 (2) | |
Text
From:
Wentzel, Michael To:
Helker, David P:(Exelon Nuclear)
Cc:
Stewart, Glenn H:(Exelon Nuclear)
Subject:
Draft Request for Additional Information - Limerick Generating Station, Unit 1 - Emergency LAR to Increase Allowable MSIV Leakage (EPID L-2020-LLA-0064)
Date:
Monday, April 06, 2020 6:04:00 PM Mr. Helker,
By letter dated April 1, 2020 (Agencywide Documents Access and Management System Accession No. ML20092P478), Exelon Generation Company, LLC (the licensee) submitted a license amendment request for the Limerick Generating Station, Unit 1. The proposed amendment would revise Technical Specification 3/4.6.1, Primary Containment, Limiting Condition for Operation 3.6.1.2, to allow for a one-time increase in the allowable leakage rate limit for one main steam isolation valve. The one-time increase would be valid during operating cycle 19.
The U.S. Nuclear Regulatory Commission (NRC) staff is reviewing your submittal and has identified areas where additional information is needed to complete its review. The draft request for additional information (RAI) is provided below. If no clarification is needed, please respond to the RAI by April 7, 2020.
In the LAR, the licensee stated the following:
The EQ program has been evaluated for both chemical-mechanical and radiological impacts from MSIV leakage. The High Energy Line Break (HELB) scenario evaluated significantly more moisture and heat deposition on the equipment than the MSIV leakage would impose. The zone radiation calculations already incorporate a lumped leakage rate of 200 scfh. Therefore, there is no impact to the EQ program from MSIV leakage as long as the total leak rate does not exceed 200 scfh.
However, the licensee did not provide an evaluation of the impact of the revised MSIV increased leakage rate on pressure that the environmentally qualified electrical equipment may be exposed to as a result of the proposed change. It is also unclear to the staff as to whether the licensee considered the impact of the proposed change on non-safety related equipment whose failure under postulated environmental conditions could prevent satisfactory accomplishments of safety functions by the safety-related equipment.
10 CFR 50.49, Environmental qualification of electric equipment important to safety for nuclear power plants, identifies requirements for establishing a program for qualifying electric equipment that is important to safety as defined in 10 CFR 50.49(b). Section 50.49(e)(1) of 10 CFR requires that the time-dependent temperature and pressure at the location of the electric equipment important to safety must be established for the most severe design basis accident during and following which this equipment is required to remain functional. Section 50.49(b)(2) of 10 CFR requires qualification of non-safety-related electric equipment whose failure under postulated environmental condition could prevent satisfactory accomplishment of safety-related equipment.
- a. Provide an evaluation of the impact of the revised MSIV increased leakage rate on pressure that the environmentally qualified electrical equipment may be
exposed to as a result of the proposed change.
- b. Provide a discussion on how you assessed the impact of the proposed change on non-safety related equipment whose failure under postulated environmental conditions could prevent satisfactory accomplishments of safety functions by the safety-related equipment as a result of the proposed change.
- c. Clarify whether any components are being added to the EQ equipment list to comply with 10 CFR 50.49 due to the proposed change.