Preliminary work has indicated that destruction by a nuclear explosion is not promising. Work is now under way with scaling experiments to determine the shatterability of core materials by a chemical explosive. This exploratory work should indicate what chunk or particle size is to be expected from a chemical explosive detonated inside of the reactor core. materials prior to rocket re-entry. This information is needed to permit calculations on the burnup of Some sort of rather complete dispersal is probably essential when the rocket impact area is unknown, Studies are continuing on the normal rate of release of fission products from Kiwi reactor fuel elements. These will also be carried to abnormally high temperatures to test the maximum attainable release by such processes as after heat with or without chemical additives. If burnup on re-entry cannot be achieved by some combination of explosive, high temperature, and chemical means to satisfy the final re-entry safety criteria, core design changes may be required, 99-100