75 fraction of the radioactivity produced (but a large fraction of the 20 tons equivalent) becomes uttached to large dust particles and is deposited on the surt'nce in the immediate area of the excavation or wlthin a few miles to tens of miles downwind as the wind moves the dust cloud away from the critter. A much smaller fraction of the radioactivity produced (and a small fraction of the 20 tons equivalent) remains airborne for longer periods during which time it undergoes radioactive decay and is diffused and dispersed throughout an increasingly large air mass as the wind moves it away from the site. After a few tens of hours, the radio- activity levels are within the normal variations of background or natural radiation. The area of deposition, the direction and rateof travel, and the diffusion rate can all be predicted as a function of meteorological condittons. | Part C Question 16 How many curies of fusion products can be expected from a megaton Plowshare explosion, such as the one probably due for detonation next year? What percentage would be released to the enviromment? nuclides be found? Tritium? Carbon-14? Where might the unreleased Which fusion products do Plowshare excavations create? Iron-557 Tungsten-187? Answer Part C Question 16 The fusion reaction of the proposed 1 MT Plowshare excavation explosion would probably release something less than 2 X 10! curies of tritium, to the atmosphere. Certain other radionuclides produced by neutron inter- actions with the medium surrounding the explosion and with the downhole hardware miy also be released. The induced activities are dependent upon the chemical composition of the specific underground medium in which the