A new interatomic potential for a uranium-molybdenum system with xenon is developed in the framework of an embedded atom model using a forcematching technique and a dataset of ab initio atomic forces. The verification of the potential proves that it is suitable for the investigation of various compounds existing in the system as well as for simulation of pure elements: U, Mo and Xe. Computed lattice constants, thermal expansion coefficients, elastic properties and melting temperatures of U, Mo and Xe are consistent with the experimentally measured values. The energies of the point defect formation in pure U and Mo are proved to be comparable to the density-functional theory calculations. We compare this new U-Mo-Xe potential with the previously developed U and Mo-Xe potentials. A comparative study between the different potential functions is provided. The key purpose of the new model is to study the atomistic processes of defect evolution taking place in the U-Mo nuclear fuel. Here we use the potential to simulate bcc alloys containing 10 wt% of intermetallic Mo and U 2 Mo.

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Argonne Nat~onal L a b o n z~o r~, Argonne, Ill~nors 60439 (Received 2 l)eii.niher 1973)In an exposure of the Fermi Xational Accelerator Laboratory 30-in. bubble chamber ta a beam of 20.;-GeV/c protons, we have determined total and differential cross sections for the inclusive reactions p + p -7 ' , Y, KO +X, +X, ' 1 -X. Invariant distributions in x indicate that for y, K O , .i production, scaling has set in somewhere before 69 GeY. The ; differential cross sections are consistent with the relation duIfdlD, (no) = $ [do/dP, (IT+) +du/dP, (n-)I for all P,, where P, -Pf o r P I . The differential cross sections for 11 and Ko production indicate a break in the distribution at ~t-t,,,,,,~ -1.5 ( G~v / c ) ' and 0.5 ( G~V / C )~, respectively. The A polarization is found to be -(0.25+ 0.26), consistent with zero throughout the x region.

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