- ’ . a TOE —lle - microcuries per cubic meter averaged over 24 hours, The hailstones were collected and melted down to examine the water for radioactivity. The activity measured on tpe third day after detonation by the Naval Research Laboratory was 2 x 10°” microcuries per cubic centimeter, and by the Division of Biology and Medicine, 3.2 x 10-9 and 1.6 x 10°" microcuries per cubic centimeter. These values may be compared to the maximum permissible concentration of 5 x 107 -3 microcuriesper cubic centimeter for drinking water, which is based on the assumptions that all of the water intake will be from the same source and consumed at this — concentration continuously. Of course, the activity decays rapidly according to well-established principles. Data have also been obtained by the Naval Research Laboratory showing that activity in the center region of the hailstones was approxi- mately = times greater than in the peripheral region. (®né-ef VII - PRODUCTION Feed Materials Uranium production. The feed material operations continued without incident. Although the production of UO3 and UF, was less than scheduled, the production of machined slugs remained on schedule. UF, feed preparation. Uranium hexafluoride production decreased 2.4 percent from the previous month. Maintenance work requirements, prin- cipally in the fluorine generators, largely accounted for the decrease. Production of vranium tetrafluoride increased 22.2 percent above that in April. This substantial increase resulted from the use of a recently developed experimental vertical hydrofluorinator and the use of a quantity of vranium trioxide received directly from Hanford. This material proved to have a higher reactivity than material which is purified at Harshaw. Test quantities of UO3 having impurities in excess of current specifications are being shipped directly to Oak Ridge to determine the maxinum level of impurities which may be tolerated in the UF6 feed plant. The bulk of Hanford's UOz continues to be shipped to Harshaw for purification. _—_ tte eb to pee oremtee Port, 2S * The use of more reactive material results in increased output of tetrafluoride of high purity, which in turn requires less fiuorine for conversion to the hexafluoride. Since the fluorine supply is a controlling ° Eee OE ARCHIVES