A predictive model of the time-dependent evolution of radial Pu/U + Pu gradients in operating nonmolten mixed oxide fuels is being developed. This model is based on preferential evaporation-condensation and vapor transport of metal-bearing species either along cracks and porosity channels within the fuel or inside closed pores migrating up the temperature gradient; equilibrium thermodynamics are applied to calculate the continually changing vapor composition over the hot fuel. Predictions of the model are used in combination with recent in-pile experimental data (from nonmolten mixed oxide fuel pins irradiated in EBR-II from 0.2 to about 11 at. % burnup at varying powers) to delineate the key parameters in radial actinide redistribution. A correlation between fuel stoichiometry (O-to-Pu ratio) and the degree of redistribution (described by an enrichment factor ..gamma../sub Pu/) identified, however, the degree of restructuring of the fuel - as determined by the peak linear power rating, time at this power, and the initial fuel density - also has a strong influence on the final value of ..gamma../sub Pu/. Certain kinetic features of the process and intended modifications to the present model are discussed, and evidence for axial actinide vapor transport in an irradiated annular fuel is also presented.

Scrap status reports requested by P.A. Craig of the Nuclear Materials Management Branch on July 14, 1972 are presented. The additional detail required disclosed the enriched uranium covered by the scrap declaration HYA-15 was not reported as scrap on the June 30 COEI Reports.

Analyses for plutonium in air, water, and foodstuffs have long been part of the routine surveillance program at Hanford. In addition, the ground and other surfaces have been surveyed for plutonium where there was possible deposition from stack emissions, waste spills, etc., using direct instrument measurements. Detectable plutonium deposition from the few such incidents has been confined to restricted areas. The surface contamination level that can be detected with the portable instruments is approximately 0.007 mu g Pu per 100 cm/ sup 2/. The desire to obtain additional information regarding any spread of Pu beyond the restricted areas, as well as to distinguish between any Pu in soil resulting from plant activities and that resulting from fallout led to a screening survey for plutonium in surface soils both on and off-site in February 1970. The results to date and the procedures followed are discussed. The limited amount of subsequent data has given resuits within the same range of Pu concentrations. (auth)

The possibility of an antiproton-neutron bound state for explaining a narrow peak which was found recently in the experiment p + n yields 4 pi and 6 pi is discussed. It is pointed out that the state is likely to be a /sup 1/P/ sub 1/ state or a higher angular momentum state. (auth)

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This report discusses adoption in the U.S. and includes statistics, information on adoption related legislation, and articles on challenges and current topics of discussion related to adoption.

In this third paper in a series in which the characteristics of nuclear fragments produced in the interaction of 5 GeV protons with Ag and U targets were studied by means of dE/dx-E measurements with semiconductor detector telescopes new information was obtained on the energy spectra of light fragments. One set of measurements on fragments from a Ag target involved the use of a two-element telescope incorporating a {Delta}E detector as thin as 16 {micro}m. A new algorithm for processing the {Delta}E and E data to extract particle identification was developed and the resulting particle spectra showed superior resolution for the elements from Li(Z = 3) to S (Z = 16). Segments of the energy spectra of each of these elements were measured at 20{sup o} and, for many of them, also at 45{sup o}, 90{sup o}, 135{sup o} and 160{sup o} to the beam direction. By use of 3-element telescopes and absorbers the high energy part of the energy spectrum for isotopes of He, Li, Be, B, and C ejected from Ag and U targets was measured at 20{sup o}. The measurements extended beyond 300 MeV for {sup 6}Li and {sup 7}Li and to 400 MeV for {sup 7}Be. …

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