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The article presents the results of numerical simulation of the experiments conducted during the physical start-up of unit 1 of the Novovoronezh II NPP. The list of measured parameters includes the critical concentration of boric acid and the scram efficiency. The calculations were performed using both the RAINBOW-TPP code intended for the combined neutronics and thermal-hydraulic calculation of the reactor facility and precision neutronics Monte Carlo codes. The scram efficiency was defined from steady-state calculations and using the inverse kinetics equation solution method based on numerical simulation of the neutron flux at the location of the ionization chambers. The results of the numerical simulation of the scram efficiency were compared with the measured data defined in the course of the physical start-up.

Nanostructured powders of pseudoalloys of immiscible Cu and Mo metals are prepared by highenergy ball milling (HEBM). Mechanical alloying in an Activator-2S planetary ball mill for 60 min provides a uniform distribution of refractory Mo particles in a moldable Cu matrix on submicron and nanoscopic levels. Nanostructured Cu–Mo powders are consolidated by spark plasma sintering (SPS) in a temperature range of 700–950°C at a pressure of 50 MPa for 10 min. The effect of preparation conditions on the microstructure, crystal structure, and properties (density, hardness, electric resistivity) of the nanostructured Cu–Mo pseudoalloys is studied. It is shown that a combination of HEBM and SPS provides the formation of a high-density (97%) nanostructured consolidated Cu–Mo composite with a hardness of 3.68–3.88 GPa and an electric resistivity of 6.1–6.2 μΩ cm; these parameters made the composite promising for use as an electric-contact material.

A method for reconstructing the neutron field in a reactor with consideration of the spatial correlation of the cross-section value error was analyzed. It was shown that this method is more accurate than the classical approach to reconstruction. An efficient way of using this technique was proposed. The efficiency for the RBMK critical test facility was estimated.

Statistical errors in sampling neutron fields in physically large systems like an RBMK are analyzed both qualitatively and quantitatively. Recommendations concerning the choice of parameters for calculations are given. A new procedure for Monte Carlo RBMK calculations with model corrections on the basis of data from in-core detectors is proposed. Dedicated software based on the CUDA software and hardware platform is developed for computational research. Results of testing the procedure and software in question via calculations for real RBMK reactors are discussed.

The reactivity determination methods which are based on the neutron field reconstruction procedure and the spectral-projection method are analyzed. The approximate methods of reactivity determination which can be used in practice are offered. The efficiency of the proposed methods in comparison to that of the methods applied in operation of nuclear power plants is demonstrated using computational models.

K± → e±νπ0 decays have been studied using the KMN setup at the Institute for High Energy Physics (Protvino). The experiment has been performed in the 36-GeV/c hadron beams of the IHEP accelerator. The accumulated data allow us to select ∼1.08M candidates for Ke3 decays. Analyzing the Dalitz plot of these events, we estimate the linear slope of the charge form factor to be λ+ = [30.44 ± 0.83(stat.) ± 0.74(syst.)] × 10−3.

The results are presented for the charge asymmetry of the Dalitz plot parameters g, h, and k measured for K± → π±π0π0 decays. The experiment has been carried out in the 35-GeV/c kaon beams at the IHEP accelerator. The g, h, and k parameters appear to be identical for K+ and K− decays within the experimental uncertainty. In particular, a value of (0.2 ± 1.9) × 10−3 is obtained for the charge asymmetry Ag = (g+ − g−)/(g+ + g−) of the Dalitz plot slope.