ML25225A066
| ML25225A066 | |
| Person / Time | |
|---|---|
| Site: | Wolf Creek  |
| Issue date: | 08/12/2025 |
| From: | Samson Lee Plant Licensing Branch IV |
| To: | Lee N Wolf Creek |
| Lee S, 301-415-3168 | |
| References | |
| EPID L-2025-LLA-0017 | |
| Download: ML25225A066 (1) | |
Text
From:
Samson Lee To:
Nathan Lee Cc:
Jeffrey Suter
Subject:
Wolf Creek 10 CFR 50.69 audit questions (APLC) dated August 12, 2025 Date:
Tuesday, August 12, 2025 3:17:00 PM By letter dated January 30, 2025, (Agencywide Documents Access and Management System (ADAMS) Accession No. ML25030A384), Wolf Creek Nuclear Operating Corporation (WCNOC, the licensee) submitted a license amendment request (LAR) for the WolfCreek Generating Station (WCGS, Wolf Creek) to adopt Title 10 of the Code of Federal Regulations (10 CFR) Section 50.69, Risk-Informed Categorization and Treatment of Structures, Systems, and Components for Nuclear Power Reactors.
The U.S. Nuclear Regulatory Commission (NRC) staff has identified the need for a regulatory audit to examine the licensees non-docketed information with the intent to gain understanding, to verify information, or to identify information that will require docketing to support the basis of the licensing or regulatory decision. The NRC staff issued an audit plan dated April 2, 2025 (ML25090A217). The NRC staff has formulated initial audit discussion questions below for certain technical areas. If time allows, please prepare responses to these questions in advance. It would facilitate the audit discussions, especially if responses can be posted in the online portal as they become available. The NRC staff plans to issue additional audit discussion questions for other technical areas to support breakout audit meetings for efficiency.
Wolf Creek 50.69 Audit Questions (APLC, August 12, 2025)
PRA [Probabilistic Risk Assessment] Licensing Branch C (APLC)
APLC-01 In Section 3.2.3, Seismic Hazards, of the LAR, the licensee states:
WCNOC will follow the same alternative seismic approach in the 10 CFR 50.69 categorization process for WCGS as that which was approved by the NRC staff for LaSalle [ML21082A422], except for the site-specific LaSalle information (e.g., seismic capacity discussions, etc.). WCGS site-specific seismic capacity information is described above herein.
However, the seismic capacity discussions in the LAR appear to be generic in nature and not specific to the Wolf Creek site. Please identify and clarify the portions of the LAR that contain Wolf Creek-specific seismic capacity information referenced in the statement above.
APLC-02 In Section 3.3.3, High Winds PRA Model, of the LAR, the licensee describes its approach for determining high wind qualitative component-level active risk significance and includes the following remark in Step 1:
Remark: Components within Seismic Category 1 structures do not have failures due to high wind exposure. This is true for all components within Seismic Category 1 structures, with the exception of certain components in the BN system (RWST and Isolation Valve Room), which are in Seismic Category 1 structures but are not designated as high wind impact screened.
This is due to conservative modeling of Refueling Water Storage Tank (RWST) failure resulting from high wind-induced failure of the Radwaste Building wall.
In light of this statement, the licensee is requested to:
- a. Provide specific examples of components within the BN system (RWST and Isolation Valve Room) that are located in Seismic Category 1 structures but are not designated as high wind impact screened.
- b. Describe how failure of the RWST due to high wind-induced failure of the Radwaste Building wall is modeled and explain in what manner the modeling approach is considered conservative.
Docket No. 50-482