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:
raphical resolution of 1-131 activity. In any case, it would be desirable to hold the sample for at least a year to permit possible identification of the long-lived component should the need arise. C. REGULATORY POSITION The procedure for the analysis of 1-131 in milk described in the appendix to this guide is acceptable to the Regulatory staff as a basis for meeting analytical performance standards which are compatible with established guidelines.' Other procedures selected for analyzing 1.131 in milk should provide levels of analytical sensitivity and specificity similar It) those for the method described in the appendix. ISee footnote on page 4.3-1 4.3-2 Ao UNITED STATES 0 • •,•NUCLEAR REGULATORY COMMISSION ) 0 WASHINGTON. D. C. 20555. 9ýl4 OP *December 1, 1976 REGULATORY GUIDE DISTRIBUTION LIST (DIVISION 4) The Nuclear Regulatory Commission staff has withdrawn Regulatory Guide 4.3, "Measurements of Radionuclides in the Environment, Analysis of 1-131 in Milk." This guide was issued in September 1973 to describe one acceptable method for the determination of iodine-131 in milk which would meet the guidelines for iodine-131 dose to the thyroid of infants as given in Regulatory Guide 1.42, "Interim Licensing Pol- icy on as Low as Practicable for Gaseous Radioiodine Releases from Light-Water-Cooled Nuclear Power Reactors." With the adoption of Appendix I to 10 CFR Part 50 as an effective rule and the adoption of a series of implementing guides, there was no longer a need for Regulatory Guide 1.42, and it was withdrawn. Since Regulatory Guide 4.3 .was issued, a number of acceptable alternative methods and tech- niques for the determination of low levels of iodine-131 in milk have been demonstrated, including the analysis of milk containing preserva- tives and the use of beta-gamma coincidence counting techniques. Also since Regulatory Guide 4.3 was issued, there has been a recognition of the need to consider the effects of relatively high and variable con-