The experimental demonstration of fission product release from over heated reactor fuel is necessarily subject in many respects to the arbitrary conditions imposed by the experimenter. Since an almost infinite latitude exists in the choice of materials, atmospheres, gas, velocities, temperatures etc., some allowance for an extrapolation to alternate conditions is definitely in order. The conditions imposed in this study are best described as those most likely to maximize fission product release. Two of the most important variables not investigated in the present report are the influence of metal cladding and the difference in internal nuclear heating as opposed to external radiant heating. In addition a significant uncertainty exists in the understanding of diffusion through large masses such as might result from a scaled-up melt down in a reactor.

The objectives of this study have been to examine the problems of the pebble-bed reactor concept and to conceive a design of a facility for investigating the feasibility of this type of reactor. The design must provide for adequate leaktightness of the contaminated-gas system and adequate maintenance of contaminated components, the most vital feasibility questions of the concept.

"The previously found maximum in the cosmic radiation energy spectrum is discussed, and the possibility that it arises in part from a misinterpretation of the data due to oversimplifying assumptions about the composition of the beam is examined. The importance that lack of recognition of isotopic composition may have is pointed out, and it is clear that this importance is strongly dependent on the measurements made and on the cut-off rigidity."

"Graft polymers were made by Co60 mutual irradiation of mixtures of styrene and methyl acrylate in contact Teflon. These graft copolymers were analyzed by infra-red absorption and their composition determined. The composition of the graft copolymer formed from styrene and methyl acrylate was different from that which is predicted by the copolymer composition equation."

Abstract: This technical report describes the as-constructed SM-1 penetrated gasket designed for SM-1 Core and Flow Instrumentation (Task XIV). This report supplements APAE No. 79, The Summary Hazards Report for Task XIV, and evaluates the effects of a postulated failure of this gasket. The effects of failure on the Maximum Credible Accident are determined and conclusions and recommendations for the use of this gasket are made.

Abstract: Thermal characteristics of the SM-2 core were analyzed at steady state and loss of flow conditions. For steady state operation, the steady state code STDY-3 was used. For transients during a loss of flow accident, ART-02, a one-dimensional code, was used. This analysis indicates the SM-2 core is safe from burnout under steady state operation at design power level (28 tMW) because (1) no nucleate boiling exists, and (2) the minimum burnout ratio is above 2.0. The core is safe from burnout under loss of flow transient because the minimum burnout ratio in the hottest element channel of 1. 82 is above the minimum design criteria of 1. 5.