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Vegetation studies in aged plutonium fallout areas at the Nevada Test Site and Tonopah Test Range showed variations in the $sup 239$-$sup 240$Pu and $sup 241$Am contamination levels attributable to differences in the amounts of resuspendable particulate material superficially entrapped upon plant foliage. There was reasonable agreement between the mean activity levels in vegetation and soil samples collected across different activity strata defined by Fidler survey instrument within each fallout area. The ratio of vegetation Pu to soil Pu tended to increase moving out from higher to lower activity strata, which might reflect the increasing proportion of finer particulate material initially deposited in fallout debris at greater distance from ground zero. The Pu/Am ratio was reasonably constant for vegetation samples collected from a given fallout area. This ratio, however, varied among separate test events primarily as the result of differences in the ingrowth of $sup 241$Am within the aged source materials. Inventory estimates indicate that standing vegetation contributes a rather insignificant portion of the total contaminant remaining in these aged fallout areas. (auth)

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In order to retain the fission products within the coated fuel particles, the coatings which act as fission product barrier have to remain mechanically intact during irradiation. As the mechanical stability of well designed pyrocarbon (PyC) coatings is mainly governed by their microstructure, this paper discusses the influence of PyC microstructure on the irradiation performance of the coatings.

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This paper is centered around the use of stratified random sampling for estimating the total amount (inventory) of $sup 239-240$Pu and uranium in surface soil at ten ''safety-shot'' sites on the Nevada Test Site (NTS) and Tonopah Test Range (TTR) that are currently being studied by the Nevada Applied Ecology Group (NAEG). The use of stratified random sampling has resulted in estimates of inventory at these desert study sites that have smaller standard errors than would have been the case had simple random sampling (no stratification) been used. Estimates of inventory are given for $sup 235$U, $sup 238$U, and $sup 239-240$Pu in soil at A Site of Area 11 on the NTS. Other results presented include average concentrations of one or more of these isotopes in soil and vegetation and in soil profile samples at depths to 25 cm. The regression relationship between soil and vegetation concentrations of $sup 235$U and $sup 238$U at adjacent sampling locations is also examined using three different models. The applicability of stratified random sampling to the estimation of concentration contours of $sup 239-240$Pu in surface soil using computer algorithms is also investigated. Estimates of such contours are obtained using several different methods. The planning …

Conceptual design studies of possible fusion reactor configurations have revealed a host of interesting and sometimes extremely difficult heat transfer problems. The general requirements imposed on the coolant system for heat removal of the thermonuclear power from the reactor are discussed. In particular, the constraints imposed by the fusion plasma, neutronics, structure and magnetic field environment are described with emphasis on those aspects which are unusual or unique to fusion reactors. Then the particular heat transfer characteristics of various possible coolants including lithium, flibe, boiling alkali metals, and helium are discussed in the context of these general fusion reactor requirements. Some specific areas where further experimental and/or theoretical work is necessary are listed for each coolant along with references to the pertinent research already accomplished. Specialized heat transfer problems of the plasma injection and removal systems are also described. Finally, the challenging heat transfer problems associated with the superconducting magnets are reviewed, and once again some of the key unsolved heat transfer problems are enumerated.

The conference contained 14 papers, four of which appeared previously in ERA. Separate abstracts were prepared for 10 papers. (JFP)

Complete texts of 123 communications to the Congress (in the original language; the majority in English, some in Russian, French), on the following topics; radiation perspective in the U.S., radiation and man, non-ionising radiation, radiation effects on animals, radiation quantities, radioecology, reactor experience, late radiation effects, dose calculations and radiation accidents.