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:
JUNE 1973 U.S. ATOMIC ENERGY COMMISSION R EG U LATO RY 'Oft 0 8 HN' U.U10E DIRECTORATE OF REGULATORY STANDARDS REGULATORY GUIDE 1.55 CONCRETE PLACEMENT IN CATEGORY I STRUCTURES A. INTRODUCTION General Design Criterion 1, "Quality Standards and Records," of Appendix A to 10 CFR Part 50, "General Design Criteria for Nuclear Power Plants," requires that sturctures, systems, and components important to safety be designed, fabricated, erected, and tested to quality standards commensurate with the importance of the safety function to be performed. Appendix B to 10 CFR Part 50, "Quality Assurance Criteria for Nuclear Power Plants and Fuel Reprocessing Plants," requires that measures be established to assure design control, material control, special processes control, and inspection and test controls. Appendix B also requires that activities affecting quality be accomplished under suitably controlled conditions. This guide describes some acceptable bases for implementing the above requirements with regard to the placement of concrete in Category i structures.1 The Advisory Committee on Reactor Safeguards has been consulted concerning this guide and has concurred in the regulatory position. B. DISCUSSION Many standards, manuals, codes, and articles exist which address the proper designing, handling, and placing of concrete. Nevertheless, concrete continues to be improperly placed in nuclear power plants, resulting in Iengthly delays and much wasted effort. In particular, the presence of numerous concrete voids which have been detected at or near the surfaces of nuclear containment bulkdings raises concern about the density of portions of these and other concrete structures that cannot readily be inspected. For such unaccessible areas, 'Structures, systems, and components of 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