ML24348A081
| ML24348A081 | |
| Person / Time | |
|---|---|
| Site: | 05200050 |
| Issue date: | 12/13/2024 |
| From: | NuScale |
| To: | Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML24348A006 | List:
|
| References | |
| LO-176318 | |
| Download: ML24348A081 (1) | |
Text
Response to NuScale Topical Report Audit Question Question Number: A-NonLOCA.LTR-59S2 Receipt Date: 09/12/2024 Question:
As a follow-up to audit question A-NonLOCA.LTR-59, NRC sent an advanced request for additional information (RAI) on the same topic on August 29, 2024. A clarification call to discuss the advanced RAI was held on September 12, 2024. During the clarification call, NuScale took an action to provide a revised topical report markup to address the NRC concerns from the original audit question A-NonLOCA.LTR-59 and the advanced RAI.
Response
As described above, NuScale took an action to provide a markup to TR-0516-49416-P, Revision 4, Non-Loss-of-Coolant Accident Analysis Methodology, to address the NRC concerns from the original audit question A-NonLOCA.LTR-59 and the advanced request for additional information (RAI). The markup is attached to this response. A summary of the changes is provided for convenience as follows: ((2(a),(c) Markups of the affected changes, as described in the response, are provided below: NuScale Nonproprietary NuScale Nonproprietary
Non-Loss-of-Coolant Accident Analysis Methodology TR-0516-49416-NP Draft Revision 5 © Copyright 2024 by NuScale Power, LLC 616 7.2.14.3 Biases, Conservatisms, and Sensitivity Studies The biases and conservatisms presented in Table 7-64 are considered in order to identify the bounding transient simulation for MCHFR and maximum fuel centerline temperature. Audit Question A-NonLOCA.LTR-59 Escalation of an AOO to an accident This criterion is satisfied by demonstrating stable RCS flow rates and constant or downward trending RCS and DHRS pressures and temperatures exist at the end of the transient, all acceptance criteria evaluated in the transient analysis are met, and shutdown margin is maintained at the end of the transient. RCS conditions during extended DHRS cooling are addressed in a separate analysis. Table 7-64 Initial conditions, biases, and conservatisms - uncontrolled control rod bank withdrawal at power Parameter Bias / Conservatism Basis (( Initial reactor power Varied. RTP biased upwards to account for measurement uncertainty. Initial RCS average temperature Varied. Biased to the high condition. Initial RCS flow rate Varied. Initial PZR pressure Varied. Initial PZR level Varied. Initial feedwater temperature Nominal. }}2(a),(c) Table 7-63 Acceptance criteria - uncontrolled control rod bank withdrawal at power Acceptance Criteria Discussion
Non-Loss-of-Coolant Accident Analysis Methodology TR-0516-49416-NP Draft Revision 5 © Copyright 2024 by NuScale Power, LLC 618 PZR Pressure Control PZR spray Varied. PZR heaters Nominal. PZR Level Control Charging Not credited. Letdown Varied.Disabled. Steam Pressure Control Turbine throttle valves Enabled. Turbine bypass valves Disabled. Feedwater and Turbine Load Control feedwater pump speed Enabled. CNV Pressure Control CNV evacuation system Enabled.
- 1. ((
}}2(a),(c) Table 7-64 Initial conditions, biases, and conservatisms - uncontrolled control rod bank withdrawal at power (Continued) Parameter Bias / Conservatism Basis (( }}2(a),(c)}}