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:
's thyroid. These are given below: Nuclide 1-131 1-133 Annual Infant Thyroid Dose Via Cows Milk (mrem) (243) 131,1 )(1500) MPC a (17.8) 133 )(1500). aPC a Alternative representations of the above are: D1 3 1 (mrem/yr) = 1.15 x 10 8 (X/Q)JQ 1 3 1R (11) and D133(mrem/yr) = 2.12 x 10 6 (x/Q)JQ 1 3 3R (12) 1.42-C7 In Equations 11 and 12, (x/Q)j is given in seconds per cubic meter, Qi is given in curies per year, and R (from Equation 2) is dimensionless. As indicated, each of the relations provided for the calculation of dose to an infant's thyroid assumesthat the cattle from which milk is obtained are pastured throughout the year. For those areas without year-around grazing, doses calculated using these relations may be reduced by multiplying the calculated values by the fraction of the year that grazing commonly occurs in the area. Annual Infant Thyroid Dose Via Goats Milk Goats pastured on green fodder containing iodine secrete in their milk a substantially greater fraction of the iodine ingested than do cows. In general, a significant part of the diet of milk goats takes the form of whole oats23 or processed feeds containing from about 13 to 16 24-26 percent protein. It may be inferred, however, that milk goats consume approximately 1.2 kilograms dry weight of green fodder daily if fed only by pasture. Using the average dry weight per square meter of hay harvested in the United States,27 0.365 kilogram per square meter, the milk goat is estimated to graze about 3.3 square meters daIly. A 25 number of observations have indicated that daily milk production ranges from 0.8 to 3.4 liters. A milk output of 2.3 liters per day26 was chosen to represent typical output for this examination. Based upon the above information and observed transfer coefficients for iodine28 normalized 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