Document: NRC Regulatory Guide
Document ID: 535957c7-1203-410d-b709-8e4d381f00de
Document Type: regulatory_guide
Title: Measurements of Radionuclides in the Environment, Analysis of I-131 in Milk
Source: NRC Regulatory Guide Division 4
Source URL: https://www.nrc.gov/docs/ML1335/ML13350A246.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-4.3
CFR Part: 
CFR Title: 

Content:
(c) of § 20.1 of 10 CFR Part 20 states that every reasonable effort should be made by AEC licensees to maintain radiation exposures, and releases of radioactive materials in effluents to unrestricted areas, as far below the limits specified in Part 20 as practicable, i.e., as low as is practicably achievable, taking into account the state of technology, and the economics of improvements in relation to benefils to lite public heallh and saflby and in relation to the utilization of atomic energy in the public interest. The procedure for the determination of 1-131 in milk described in this glide constitutes a method acceplable to the Regulatory staff for measuring 1.131 as may he required by the ahove regnilalions or orders or license conditions imposed pursuant thereto. B. DISCUSSION In accord wilh the Commission's policy (f keeping exposure of man to radioactive materials released from licensed activities, including the operation of production or utilization facilities, as low as practicable, licensees should make every reasonable effort to limit the release of radioactive materials in effluents to unrest. -led areas as far below the limits specified by the Comm. qion as practicable. Iodine-131 requires special at:*-ntion because it is one of 'he more significant radionuclides present in releases from nuclear power plants, and it can be concentrated through the air.vegetation.cow.milk pathway and potentially contribute to the thyroid dose. Although most milk data have indicated little or no 1.131, milk monitoring at the suggested improved level of sensitivity would provide direct evidence that the potential exposure due to 1-131 does not exceed predicted values. Current guidelines' for 1-131 dose it) the thyroid of infants require that the sensitivity for measuring 1.131 in milk be improved over conventional direct gamma counting of the raw milk sample. Low-level beta counting techniques with a detection sensitivity about an order of magnitude better than