ML21048A088
| ML21048A088 | |
| Person / Time | |
|---|---|
| Site: | 99902049 |
| Issue date: | 02/17/2021 |
| From: | Holtec, SMR |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| HI-2201064 | |
| Download: ML21048A088 (7) | |
Text
www.holtec.com www.smrllc.com Date: February 17, 2021 Presented By:
SMR, LLC, A Holtec International Company Krishna P. Singh Technology Campus One Holtec Boulevard Camden, NJ 08104, USA Topical Report (HI-2201064)
Supplemental Information
holtec.com l smrllc.com l Page 2 Agenda Est. Time (EST)
Topic 1:00 to 1:10 PM Opening Remarks (NRC/Holtec) 1:10 - 1:30 PM Holtec Presentation (Public) 1:30 - 1:40 PM Q&A (NRC/Public) 1:40 - 1:55 PM Holtec Presentation (Closed Meeting) 1:55 - 2:15 PM Q&A and Wrap-up
holtec.com l smrllc.com l Page 3 Objectives of the Topical Report NRC approval that by following ASME B&PV Code Section III Subsection NB a postulated break in the Combined Vessel is not required as a Design Basis Accident, thus eliminating a large break LOCA for the SMR-160 NRC approval of the SMR-160 LOCA acceptance criteria.
holtec.com l smrllc.com l Page 4 Rationale and Basis for First Objective PNNL concluded that the ASME BPVC would allow the cross-duct to be constructed as a vessel or pipe for a high temperature gas reactor of similar geometry (PNNL-20869) and that the ASME BPVC allows the owner to select the preferred designation, and that either designation can be acceptable Holtec approach is to design the RPV, SG, PZR, and RPV/SG Connection as one continuous vessel, referred to as the Combined Vessel, according to ASME B&PV Code Secon III Subsecon NB RPV/SG Connecon is a communicang chamber joining the RPV to the SG The connecting welds are in compliance with NB-3350 Geometry of the RPV/SG Connection
holtec.com l smrllc.com l Page 5 Rationale and Basis for First Objective (cont)
All SMR-160 Reactor Coolant Pressure Boundary piping is postulated to break, and the break is evaluated as a LOCA as part of the SMR-160 Design Basis Accidents See Table 3-1 of the Topical Report BTP 3-4 contains the NRC position on pipe rupture postulation for Class 1 piping Based on actual piping failures that have occurred Allows Leak Before Break to eliminate the postulation of a pipe break to meet GDC 4 BTP 3-4 does not require postulation of a Class 1 vessel rupture, nor is there other regulatory precedence for postulating a Class 1 vessel rupture as a Design Basis Accident Initiating event frequencies for pressure vessel ruptures are highly dependent on pressurized thermal shock (PTS) [NUREG-1829] and are well below the threshold for Design Basis Accidents; therefore, by design there is an extremely low probability of a Class 1 pressure vessel rupture occurring Ruptures in the Combined Vessel are considered a Beyond Design Basis Accidents and will be analyzed with PRA
holtec.com l smrllc.com l Page 6 Acceptance Criteria for Combined Vessel Design will fully comply with NB-3200 and NB-3300 Stress intensities shall not exceed limits in Section III Mandatory Appendix XIII Fatigue analysis shall be performed in accordance with XIII-3500 Cumulative usage factor shall not exceed 1.0
Questions?
Krishna P. Singh Technology Campus One Holtec Boulevard Camden, NJ 08104 Tel: (856) 797-0900 www.holtec.com holtec.com l smrllc.com l Page 7