Document: NRC Regulatory Guide
Document ID: 0ae1e098-eccd-43e7-b12e-43b05aa1fe48
Document Type: regulatory_guide
Title: Safety-Related Concrete Structures for Nuclear Power Plants (Rev. 3)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML1617/ML16172A240.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.142
CFR Part: 
CFR Title: 

Content:
ement requirement for a foundation base mat. 2.8 Section 11.9 of ACI 349-13 incorporates by reference Section 11.9.1 of ACI 318-08 for the design of shear forces perpendicular to the face of the wall. Section 11.9.1 of ACI 318-08 refers to Section 11.11 for the design of shear forces perpendicular to face of wall. Section 11.11.1.1 of ACI 318-08 states that for the beam action each critical section to be investigated extends in a plane across the entire width of the wall or slab, which is not a conservative approach. Thus, the staff does not endorse that approach. Instead, the effective width of the critical section should be determined according to the zone of influence induced by the concentrated loads. Regulatory Position 3 3.1 The NRC staff endorses the new set of load combinations contained in ACI 349-13, Section 9.2, with the adjustments described below. With those adjustments, the NRC staff position is to use load factors that follow, to a large extent, those in Section 9.2 of ACI 349-13, with added conservatism for the design of safety-related nuclear power plant concrete structures. Operational temperature. In the design of nuclear power plant concrete structures, the operational temperature loading, To, is considered as a live load. Though extremes of anticipated temperatures are considered for this purpose, the computational methods of cracked section analysis and the extent of cracking do not lend themselves to the same degree of confidence in assessing its effect as those for a dead load computation. The NRC staff position is to use a load factor of 1.6 for To in Regulatory Position 3.1. Pressure. To a certain degree, the structural systems required to withstand pressures are related to the release of radioactivity to the atmosphere. In this regard, the structural systems could function as a direct barrier or as a support for a direct barrier. Also, the characteristics of the pressure transients would depend, in most cases, on the appropriate