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:
ld 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 as filters, fans, and dampers. Maintaining air pressure gradients and airflows from areas of low potential airborne contamination to areas of higher potential contamination can limit the spread of airborne contamination within the facility. Maintenance programs should include periodic checks of ventilation systems to ensure that the design pressure differentials, direction of flow, and flow rates are being maintained and that the design continues to be adequate for controlling contamination. y. To prevent uncontrolled release through ventilation systems, condensation from all coolers handling potentially contaminated air should be collected and routed to a monitored liquid effluent discharge. z. Provisions should be made for containing and controlling potential tank overflow through the tank vent discharge piping. Such provisions may include the use of a receiving tank or indoor sump to catch any overflow, and high-level alarms on the source tank to indicate overflow occurrences. aa. Tank sampling stations should be designed to minimize the possibility of sample fluid leaking to the ground or to the underlying pad surface. A-2. Minimizing Contamination of the Environment To minimize contamination of the environment, 10 CFR 20.1406 applicants should consider the following specific measures (or a combination thereof): a. Applicants should evaluate the system design with respect to the hydrogeology of a site before construction to (1) gather information for inclusion in a conceptual site model, (2) identify potential migration and ground-water transport pathways for potential environmental contaminating events, and (3) assess the effect of construction on the hydrogeological characteristics of the site. The conceptual site model should address both the horizontal and