NUCLEAR-DEBRIS FORMATION 2: Conclusions Under certain conditions of nuclear-debris formation, the thermo. dynamic model is realistic, but under others a kinetic approach i: necessary to treat the formation processes in a reasonable manner The situation is too complex to say at this time what the gain will b in terms of accuracy in predicting fractionation effects. The kineti: approach involves the determination of mass-transfer coefficients fo: fission-product deposition on various substrate materials, and thes: in turn depend upon both equilibrium (distribution coefficients and heat: of adsorption) and kinetic parameters (interdiffusion coefficients lingering times) and the species of the fission products which exis under the formation conditions. However, a completely fundamenta approach for each nuclide would place exhorbitant requirements 01 both input data and computer time. The semiempirical approach offer: a reasonable compromise among the demands of economy, realism and fundamental understanding. Despite recent advances’?! questions of particle-size and type distribution and of agglomeration effects continue to be pressing PREDICTION OF RADIOLOGICAL PROPERTIES The capability of predicting radiological properties constitutes < module of our prediction system worthy of individual attention. Although the primary purpose of this module is the prediction of radiological properties from fractionated debris, it is presently being usec to harvest an important by-product: the radiological properties of unfractionated debris. This by-product is important primarily because it can be compared with laboratory and large-scale measurements of un- fractionated debris carried out under carefully controlled conditions and presently under accumulation. This comparison, particularly in the eases of gamma-ray spectra and fidence in the potential accuracy of portance as a basis of comparison of fractionation effects. The heart of this module is a dose rate, will establish our consuch calculations. It is also of imby which to evaluate the magnitude computer program for calculating the abundances of fission-product nuclides. This program solves the Bateman equation for each nuclide at the time point requested, yielding an output list (on magnetic tape) of all nuclides, and the number of atoms of each present at the time point. For fission-product predictions fission is assumed to take place instantaneously. An optional calculation, used for reactor-contamination predictions, assumesfission to occur at a finite number of intervals, each of constant rate.