Document: NRC Regulatory Guide
Document ID: c64ed18e-c0e6-4b9a-8f77-2dc65c76782d
Document Type: regulatory_guide
Title: Concrete Placement in Category I Structures
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML1306/ML13064A106.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.55
CFR Part: 
CFR Title: 

Content:
a nuclear power plant are designated as Category I if they are designed to withstand the effects of the Safe Shutdown Earthquake (SSE) and remain functional (see Regulatory Guide 1.29, "Seismic Design Classification"). the only method of assuring a quality concrete structure is through good planning and control of the placement of concrete and all items embedded in it. Proper planning and control require that the designer and the constructor be familiar with each other's requirements. The designer should be conscious of the practicality of the design from the constructor's point of view, while the constructor. should recognize the consequences of deviating from conditions specified by the designer. It is essential that the two parties meet at an early stage and discuss how these structures will be constructed. Methods that seem expedient or economical .aW later turn out to have serious adverse consequences. To date the standards applied to quality control of concrete in nuclear power plants have been based on standards for conventional- building structures. Mass concrete standards have generally been considered inapplicable for nuclear construction because the quality level needed for each cubic yard of concrete placed more nearly approximates the quality level required for relatively slender sections of conventional buildings. At the same time, it is necessary to recognize that in placing deep foundation mats and thick-walled structures or components in nuclear power plants, there are placement problems (e.g., shrinkage and control of heat of hydration during curing) also found in mass concrete pours. Consequently, consideration must be given to the problems and practices of mass concrete pours, that are applicable to nuclear power plant structures. A list of standards, codes, papers, and other references which are generally directed toward the quality placement of concrete is given in Appendix A of this guide. These documents, appropriately selected by the user