Document: NRC Regulatory Guide
Document ID: 05969442-49ea-4f4a-a9e2-de3a14628b5e
Document Type: regulatory_guide
Title: Minimization of Contamination and Radioactive Waste Generation:  Life-Cycle Planning - HISTORY 07/2013 – Periodic Review of Revision 0 – No issues identified
Source: NRC Regulatory Guide Division 4
Source URL: https://www.nrc.gov/docs/ML0805/ML080500187.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-4.21
CFR Part: 
CFR Title: 

Content:
sure that concrete block walls designed to enable the future removal of large components for maintenance or replacement are completely sealed to prevent the intrusion of radioactive materials into the block interiors. Tops of block walls that are not connected to the ceiling should be sealed to prevent contamination from entering the block interiors. Porous, unsealed blocks should not be used in areas subject to contamination. Appendix A to RG 4.21, Page A-3 v. A program should be developed for maintaining control over the storage and use of radioactive materials in the restricted area outside the physical facility structures. For example, areas in which waste is to be stored should be evaluated and approved for storage and have appropriate design and control features. Administrative controls (e.g., controls on packaging and transport of radioactive material in and around the facility) should be established to prevent the spread of contamination when radioactive material or contaminated equipment must be transported from one station location to another within the facility and when the route of transport through lower radiation zones cannot be avoided. w. Drains from locker rooms and cleanup showers in personnel decontamination areas should be routed to radwaste processing facilities to prevent the re-concentration of radioactive materials in onsite sewage plants. x. Ventilation system designs should confine airborne radioactive materials within the process areas and as close to the point of origin as practicable. Construction materials for the ventilation systems should be carefully selected and have smooth internal and external surface finishes to aid in decontamination. The length of ventilation stacks and duct work, and the number of abrupt changes in direction, should be minimized to reduce the potential plate-out of contamination. Designs should permit convenient inspection, maintenance and decontamination, and facilitate replacement of critical components such