Document: NRC Regulatory Guide
Document ID: a03860d0-46a2-4c53-b0e5-9398a146bf12
Document Type: regulatory_guide
Title: Safety-Related Steel Structures and Steel-Plate Composite
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML2033/ML20339A558.pdf
Revision Date: 2023-05
Chapter: 
Section ID: RG-1.243
CFR Part: 
CFR Title: 

Content:
g from pool dynamics for SC structures in pressure-suppression containments should be analyzed. Licensees and applicants should justify the methods of analysis used. 2.2.6. The design for loads due to accidental explosions, accidental vehicle impacts, or small aircraft impacts should use load combination (NB2-7) with those loads in lieu of Wt, as well as further guidance provided in Appendix N9 of N690-18. The Wt load in the load combination (NB2-16) should be evaluated for both tornado and hurricane loads applicable to the site for which related regulatory guidance is covered in RG 1.76 (Ref. 6) and RG 1.221 (Ref. 10), respectively. RG 1.217 (Ref. 9) covers the effects from beyond-design-basis large aircraft impacts, which are outside the scope of this RG. 2.2.7. In load combination (NB2-18), 0.7Es is to be combined absolutely with the accident loads. In lieu of this, 1.0Es may be combined with the accident loads by SRSS, if all the provisions of ANSI/AISC N690-18, Commentary Section NB2.5, Paragraph 4, are satisfied. 3. ANSI/AISC N690-18, Chapter NC—Design for Stability ANSI/AISC 360-16, “Specifications for Structural Steel Buildings” (Ref. 23), Chapter C, referenced in Chapter NC of ANSI/AISC N690-18, is acceptable for design for stability, subject to the following qualifications: 3.1. The provisions of Appendix 7 for the equivalent length method should only be implemented where all the requirements on its use are clearly satisfied and minimal judgment is required to determine K (effective length factor). 3.2. The first order analysis method, using B1 and B2 factors from Appendix 8 to simulate second-order effects, should only be implemented where all the requirements on its use are clearly satisfied. DG-1304. Page 10 3.3. When prediction of elastic stability using the direct second-order analysis method is implemented, the stress state at the onset of instability should be confirmed to be in the elastic range to ensure valid results, since it only