Transient processes in radiative transfer have recently become of interest in the modeling of astrophysical phenomena, particularly with regard to the brightness of novae, supernovae, and perhaps even galactic clouds adjacent to quasars. Analytic solutions to a particular class of Marshak wave problems are presented with and without the Marshak (Milne) boundary condition. The choice of boundary condition can have a decisive effect on the coupling of radiative energy to the material energy in the vicinity of a material boundary. The analytic solution obtained can be useful as a tool for calibrating numerical calculation techniques.

Some criteria for identifying dense plasmas are given. The theoretical analysis gives the following: general characteristics of dense plasmas, statistical model for compressed atoms, and ionization equilibrium in dense plasmas. (MOW)

Actinide cross section data at thermonuclear neutron energies are needed for the calculation of ICF pellet center burnup of fission reactor waste, viz. 14 MeV neutron fission of the very long-lived actinides that pose storage problems. A major advantage of pellet center burnup is safety: only milligrams of highly toxic and active material need to be present in the fusion chamber, whereas blanket burnup requires the continued presence of tons of actinides in a small volume. The actinide data tables required for Monte Carlo calculations of the burnup of /sup 241/Am and /sup 243/Am are discussed in connection with typical burnup reactor fusion and fission spectra. 2 figures.