For the multiple sources of error introduced into the standard computational regime for simulating reactor cores, rigorous uncertainty analysis methods are available primarily to quantify the effects of cross section uncertainties. Two methods for propagating cross section uncertainties through core simulators are the XSUSA statistical approach and the “two-step” method. The XSUSA approach, which is based on the SUSA code package, is fundamentally a stochastic sampling method. Alternatively, the two-step method utilizes generalized perturbation theory in the first step and stochastic sampling in the second step. The consistency of these two methods in quantifying uncertainties in the multiplication factor and in the core power distribution was examined in the framework of phase I-3 of the OECD Uncertainty Analysis in Modeling benchmark. With the Three Mile Island Unit 1 core as a base model for analysis, the XSUSA and two-step methods were applied with certain limitations, and the results were compared to those produced by other stochastic sampling-based codes. Based on the uncertainty analysis results, conclusions were drawn as to the method that is currently more viable for computing uncertainties in burnup and transient calculations.

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The article considers a model for evaluating the reliability of integrated circuits (IC) depending on the temperature of the crystal and the environment. The calculation and experimental prediction of the reliability of the 1921VK035 chips was carried out, the dependences of the minimum time to failure of the product on the temperature of the 1921VK035 IC crystal and the gamma-percent life of the IC on the ambient temperature were obtained. The obtained values of these chip parameters meet the requirements of ISO 11 0998-99.

The article presents the method of evaluation and results of research Schottky diodes resistance for use in electronic equipment. Studies were carried out to determine the structural and technological reserves for durability. Also in the article the schemes of inclusion of Schottky diodes for measurement of direct reverse current and direct excitation of the diode applied at researches are considered.

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