to produce 1.0 rad. “Btep 1. Determine the dose rate an the day of intake of 13 to produce 1.0 red to the thyroid. D=.R Where: D = dose (1.0 rad) Ae R © dose rate on initial day Ae 5 effective decay constant (radiological and biological) 1.00 =R 0.09 R ® 0.09 rads/day ‘ Step 2. Determine the number of microcuries of y131 to produce 0.09 rad/day X(uc)(2.2 x 10°)(60 x 24)(2.6 x 1075) (0.22) = | (3.00) (20) . X = 0.16 Heto thyroid (0.16) (5) == 0.80 po 1232 ingested Step 3. Determine relative doses from 7131 ang yehort according to Graph Three." At 48th hour, the relative contribution te total dose from I> and T°T* 46 spout1 . Therefore, ingestion of 0.4 pe 3+ (equivalent) at 48th hour will produce 1.0 rads to thyroid. Step 4. Determine the number of microcuriesaf fission producte required to yield the required I’>+ activity. At 48th hour, r3 constitutes about 2.35% of total activity. Therefore, 0.4 O,0a3 © 17 ne of fissicn products. e 777 DOE ARCHIVES 54