ML22306A023
| ML22306A023 | |
| Person / Time | |
|---|---|
| Site: | 99902049 |
| Issue date: | 02/07/2023 |
| From: | Carolyn Lauron NRC/NRR/DNRL |
| To: | Hawkins J Holtec International SMR |
| References | |
| Download: ML22306A023 (1) | |
Text
From:
Carolyn Lauron To:
Justin Hawkins Cc:
Greg Cranston; Jordan Glisan; Michael Dudek
Subject:
NRC staff questions and SMR (Holtec) responses dated 10/25/2022 re: Revised White Paper on I&C Architecture (Project 99902049)
Date:
Tuesday, February 7, 2023 9:18:00 AM Hi Justin -
The purpose of this email is to document the NRC staff questions and SMR (Holtec) responses regarding the Revised White Paper on I&C Architecture for the SMR-160 design.
The questions were sent on October 25, 2022, and the SMR (Holtec) responses were received on the same date.
Thank you, Carolyn Lauron US NRC
NRC Staff Question 1: Are there other white papers that will cover the SMR-160 architecture for further clarification including Revision 2 or other revisions of present white paper?
SMR (Holtec) response: Other white papers are planned to cover specific parts of the Architecture including Diversity and Defense In Depth Bi-Directional Communication and Independence Hazard Analysis Methodology
NRC Staff Question 2: Are the Class 1E sources for PSS application specific with applicant to decide how to supply PSS?
SMR (Holtec) response: The Class 1E power design of the SMR -160 is standard and would be described in detail in a Chapter 8 submittal. There are two divisions of Class 1E power, established at the battery chargers. Each division has a 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> battery, with redundant battery chargers. Each division has two redundant UPS that feed instrument bus loads. The two redundant UPS within a division share the same 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> battery. The Two UPS in Division-A provide redundant power to Division A of the PSS and the same applies for Division-B.