Document: NRC Regulatory Guide
Document ID: 96baa826-d3bb-478b-8f38-e74500f6d433
Document Type: regulatory_guide
Title: 06/2009 (Rev. 2)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML0911/ML091170109.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.21
CFR Part: 
CFR Title: 

Content:
e considered a hypothetical exposure pathway if the grass, the cow, or the milk did not actually exist at a specified location or if an infant did not actually consume the milk. impacted areas—Means the areas with some reasonable potential for residual radioactivity in excess of natural background or fallout levels. [Note: See 10 CFR 50.2, “Definitions”, and NUREG-1757 for a discussion of impacted areas. For example, impacted areas include locations where radiological leaks or spills have occurred within the onsite environs (i.e., outside of the facility’s systems, structures, and components). (See also the definition of “significant contamination.”)] ISFSI—Independent Spent Fuel Storage Installation leachate—Water containing contaminants that is percolating downward from a pond or lake into the subsurface. less-significant release point—Any location, from which radioactive material is released as a liquid or gaseous effluent, contributing less than or equal to 1 percent of the activity discharged from all the release points for a particular type of effluent considered. Regulatory Guide 1.109 lists the three types of effluent as (1) liquid effluents, (2) noble gases discharged to the atmosphere in gaseous radioactive waste, and (3) all other nuclides discharged to the atmosphere in gaseous radioactive waste. Example: If 1000 Ci of tritium are released in all liquid effluents in a given period of time (e.g., a typical calendar year or fuel cycle) and 0.01 Ci of tritium are released in steam generator blow down, then the steam generator blow down would be a less-significant release point. Similarly, for gaseous releases of radionuclides other than noble gases (i.e., iodine, particulates, and tritium) if the total effluents are 10 Ci (iodine, particulates, and tritium) and the Refueling Water Storage Tank released 0.009 Ci of iodine, particulates, and tritium, then the Refueling Water Storage Tank would be a less-significant release point. In both of