Document: NRC Regulatory Guide
Document ID: c0dbb594-6262-4b83-96b1-366758ad9676
Document Type: regulatory_guide
Title: Interim Licensing policy on as low as Practicable for Gaseous Radiodine Releases from Light-Water-Cooled Nuclear Power Reactors (Rev. 1)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML1229/ML12298A137.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.42
CFR Part: 
CFR Title: 

Content:
ed to milk output, the calculated iodine transfer coefficient, k for 1-131 is 1.44 curies/liter per curie/square meter. It is here assumed that this parameter is reduced for 1-133 in the same ratio as for the cow. Consequently, it is assumed that the iodine transfer coefficient for 1-133 is 0.65 curie/liter per curie/square meter. It is furthermore here assumed that over a large range of supplemental feeding, no sub- stantial reduction occurs in the green fodder intake of goats. As 1. 42-C8 a consequence, no allowance is made for supplemental feeding of goats. As with the cow, the transfer of radioiodine to the milk of the goat 29 is affected by the addition of stable iodine to its diet. At low supplemental levels of stable iodine feeding (4 mg I/day), radioiodine transfer to milk appears to be enhanced; while at high levels of sup- plemental feeding (0.9 g I/day), the transfer of radioiodine to milk is substantially reduced. It is here assumed that normal agri- cultural practices will not significantly affect iodine transfer. Consequently, no allowance is made for this effect. * The average equilibrium concentrations of radioiodine-131 and -133 may then be calculated using: 1.44 klV n131,j x131 + xw C131,j (13) 0. 65 klV n 133,J k C (14) 133 + xw 133,J Under the above considerations, the radioiodine equilibrium concentrations of 1-131 and 1-133 in goat milk relative to radioiodine equilibrium concentrations in air are given below: *31,J= 4.02 x 10 3C131,j (15) 2 = 2.95 x 102C133,J (16). n133,,j The goat milk ingestion rate for a child is assumed to be 700 milliliters S per day. The breathing rate used in defining the MPC values for radio- iodines in air is 3 cubic meters per day. Using the fractional thyroid 1.42-C9 * 0 deposition values from human ingestion and inhalation as 0.30 and 0.23, respectively, the daily depositions of radioiodine within the thyroid by goat milk ingestion and air inhalation are given by: Daily Thyroid Deposit (milk) = (0.30)(0.70) nij and