[en] PRIZMA code is a Monte-Carlo code dedicated to radiation transport. The paper describes parallelization and load balance algorithms implemented in the PRIZMA code. The parallelization algorithm described aims to maximally separate batch calculation and calculated results collection at minimal wastage. The algorithm implements a two-level procedure to collect calculated results. As often as specified, calculation results accumulated by processes of the same node are summed using shared memory. Current random numbers are also saved. Then we do inter-node summation of results on the process of rank 0 with the MPI-Reduce function. Random numbers are collected with the MPI-Gather function. All this is done using a separate thread on each node and hence does not require main computations to stop. After calculated results and random numbers have been collected, the threads inactively sleep till next saving session. So, calculated data collection and saving does not interfere with main computations and consumes almost no CPU time. Routine calculations demonstrate a rather high parallelization efficiency which is no lower than 99.99 per cent

[en] We developed a full-scale 3D model of the initially fueled core of the VVER-1000 water-moderated power reactor for criticality calculations by the code PRIZMA. The core contains 163 hexagonal fuel assemblies of different types. The model includes blocks of in-core detectors which are arranged in the central pipes of 64 fuel assemblies in the entire core. Each block unites seven detectors equally spaced in the fuel assembly length. The sensing element of the detectors is rhodium emitter shaped as a slim cylinder. Conversion functions which relate the number of fission reactions in fuel elements closest to the central pipe and the number of neutron absorption reactions in the rhodium emitter were obtained through PRIZMA calculations where we estimated the rate of neutron adsorption reactions in the rhodium emitter and the rate of fission reactions in six fuel elements closest to the detector. The emitter's volume is negligible compared to the core volume and neutron flux in the detectors can hardly be estimated through analog Monte Carlo tracking. We used splitting and Russian roulette to make calculations more efficient. With these methods statistical uncertainties in the calculated rates of neutron absorption in rhodium were acceptable. In each of the 64 fuel assemblies with in-core detectors, we defined a set of cylindrical surfaces for splitting. Their axis coincided with that of the central pipe. When a particle crossed any of the surfaces to the cylinder axis, it was split into a number of identical particles. The Russian roulette was applied to particles which crossed the surfaces back. At collision points, particle weights were corrected in accord with a one-dimensional weight function defined in the entire volume of the fuel assemblies

[en] At RFNC-VNIITF, the PRIZMA code which has been developed for more than 30 years, is used to model radiation transport by the Monte Carlo method. The code implements individual and coupled tracking of neutrons, photons, electrons, positrons and ions in one dimensional (1D), 2D or 3D geometry. Attendance estimators are used for tallying, i.e., the estimators whose scores are only nonzero from particles which cross a region or surface of interest. Importance sampling is used to make deep penetration and detection calculations more effective. However, its application to reactor analysis appeared peculiar and required further development. The paper reviews methods used for deep penetration and detection calculations by PRIZMA. It describes in what these calculations differ when applied to reactor analysis and how we compute approximated importance functions and parameters for biased distributions. Methods to control the statistical weight of particles are also discussed. A number of test and applied calculations which were done for the purpose of verification are provided. They are shown to agree either with asymptotic solutions if exist, or with results of analog calculations or predictions by other codes. The applied calculations include the estimation of ex-core detector response from neutron sources arranged in the core, and the estimation of in-core detector response. (authors)

[en] Rhodium in-core detectors are used for the on-line measurement of energy released in the core of VVER-type reactors. The paper describes calculations which were done by the PRIZMA code to predict indications of in-core rhodium detectors for some core fragments with allowance for fuel and rhodium burnout. Our calculations are performed over time steps in burnout. Each time step is calculated in two stages. The first stage involves criticality calculation to get the effective multiplication factor, data for nuclear reaction kinetics, and the distribution of neutron absorption rates in the rhodium emitter. Variance reduction techniques are used to make statistical uncertainties smaller. At the second stage we simulate the cascade of electrons, positrons and photons, and estimate electric current in the detectors for a configuration which only includes the detectors. Prompt and delayed signals are estimated

[en] The results of theoretical works carried out at the RFNC-VNIITF on simulation of the wide range of physical phenomena proceeded at the interaction of powerful pico-second laser pulses with matter are presented. The calculations were made with using of new versions of computer codes: ERA, PM2D and TARAN. The estimation of positron yield which could been achieved in experiments on the irradiation of targets by powerful ultra-short laser pulses are discussed. (authors)

[en] The results of the ICF indirect-driven targets optimization performed by ZARYA/ERA code for a better insight into the requirements imposed on both target designs and hohlraum drive temperature to gain the ignition with laser of minimum power are presented. Two modification of cryogenic shell targets for hohlraum drive temperatures in the range of 0.25 endash 0.38 keV are proposed for the ignition. The 500 TW lasers are needed to perform such investigations. copyright 1996 American Institute of Physics

[en] Highlights: • PRIZMA is a Monte Carlo code for solving fixed source and criticality problems. • Particles: neutrons, gammas, electrons, positrons, ions. • Application fields: nuclear and radiation safety; pulsed, thermal and fast reactors. • PRIZMA is a part of package for precision core simulation through reactor campaign. • Special techniques for perturbation analysis. - Abstract: For more than thirty years the code PRIZMA has been used at RFNC-VNIITF for solving radiation transport problems with the Monte Carlo method. The code models the separate and coupled transport of neutrons, photons, electrons, positrons and ions in one-, two-, and three-dimensional geometry. For criticality calculations the code implements the method of generations with a constant number of fission sites in one generation. Now the code is extending its capabilities for nuclear reactor calculations. The paper describes the current status of the code and gives examples of its application to particle transport in nuclear reactors and other physical facilities

[en] For more than thirty years the code PRIZMA has been used at RFNC-VNIITF (Snezhinsk, Russia) for solving radiation transport problems with the Monte Carlo method. The code models the separate and coupled transport of neutrons, photons, electrons, positrons and ions in one-, two-, and three-dimensional geometry. For criticality calculations the code implements the method of generations with a constant number of fission sites in one generation. Now the code is extending its capabilities for nuclear reactor calculations. The paper describes the current status of the code and gives examples of its application to particle transport in nuclear reactors and other physical facilities. (authors)