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:
or release points monitored by plant process radiation monitoring systems, the release point is associated with the piping immediately downstream of the radiation monitor. (See also the definition for “significant release point.”) Several release sources may contribute to a common release point. Rev. 2 of RG 1.21, Page 47 residual radioactivity—Residual radioactivity means radioactivity in structures, materials, soils, ground water, and other media at a site resulting from activities under the licensee’s control. This includes radioactivity from all licensed and unlicensed sources used by the licensee, but it excludes background radiation. It also includes radioactive materials remaining at the site as a result of routine or accidental releases of radioactive material at the site and previous burials at the site, even if those burials were made in accordance with the provisions of 10 CFR Part 20. restricted area—Restricted area means an area, access to which is limited by the licensee for the purpose of protecting individuals against undue risks from exposure to radiation and radioactive materials. Restricted area does not include areas used as residential quarters, but separate rooms in a residential building may be set apart as a restricted area. route of exposure—A specific path (or delivery mechanism) by which radioactive material, originally in the environment at a specified location, can eventually cause a radiation dose to an individual. The path typically includes a type of environmental medium (e.g., air, grass, meat, or water) as the starting point and a recipient’s organ or body as the end point. For example, the grass-cow-milk- infant-thyroid route of exposure may contribute to the ingestion exposure pathway. Additionally, several routes of exposure may contribute to a single exposure pathway. scaling factor—A factor used to estimate the unknown activity of a radionuclide based on its ratio to the activity of a readily measured