ML23158A025
| ML23158A025 | |
| Person / Time | |
|---|---|
| Site: | 99902049 |
| Issue date: | 03/31/2023 |
| From: | Carolyn Lauron NRC/NRR/DNRL/NLIB |
| To: | Hawkins J Holtec International SMR |
| References | |
| Download: ML23158A025 (1) | |
Text
From:
Carolyn Lauron To:
Justin Hawkins Cc:
Greg Cranston; Andrew Brenner
Subject:
NRC Staff response to Follow-up Question re: Polar Crane Analysis for the SMR-160 design (Project Number 99902049)
Date:
Friday, March 31, 2023 7:53:00 AM Attachments:
image001.png image002.png image003.png Hi Justin -
Please find the NRC staff response to the subject question below.
Please let me know if you have questions or need additional information.
- Thanks, Carolyn
Background:
3-8 Email to J. Hawkins, SMR (Holtec) - NRC staff response to SMR-160 question re:
Polar Crane Analysis (Project 99902049)(ML23067A011) in ADAMS:
https://adamswebsearch2.nrc.gov/webSearch2/main.jsp?
AccessionNumber=ML23067A011
Follow-up question:
Did the NRC staff mean to state the guidance for determination of mass to be included in a model for dynamic seismic analysis is provided in Paragraph II.3.D (not II.1.D, which does not seem to exist) in SRP 3.7.2, Revision 4?
To further clarify, our reading of SRP 3.7.2 Revision 4 Paragraph II.3.D and ASCE 4-16 Section 3.4 (see below) does not include explicit guidance for considering live loads of the crane, only floor design live loads. This leads SMR to believe the SSI analysis does not need to consider the scenario that the polar crane is performing a heavy lift load. The seismic load determined by the SSI analysis will be used in conjunction with crane live loads for the appropriate Service Condition analyses as described in SRP 3.8.2 Paragraph II.3.B.iii.
SRP 3.7.2 Revision 4 Paragraph II.3.D:
ASCE 4-16 Section 3.4:
NRC Staff Response:
Yes, the NRC staff meant paragraph II.3.D Representation of Floor Loads, Live Loads, and Major Equipment in Dynamic Model in SRP Section 3.7.2, Revision 4. As stated therein, the mass of major equipment (e.g., polar crane) should be appropriately included in the dynamic model for SSI analysis.
Explicit approach for consideration of applicable crane lift loads for design should be determined based on the number and purpose of each of one or more structural models used by the applicant for design analysis, and applicable service conditions in which the crane heavy lifts are performed. In general, the polar crane can be considered unloaded (i.e., not performing a heavy lift) for the SSI analysis of the containment structure, considering that crane lifts are not expected to be performed during power operation. The in-structure response spectra (ISRS) derived from the containment structure SSI analysis at the elevation of the polar crane can be used as input for detailed design analysis of the polar crane and its supporting structure including seismic effects of lifted loads, as applicable, for the service conditions under which heavy lifts are performed.