Karel Katovsky

Superasymmetric fission of heavy nuclei induced by intermediate-energy protons

In this work we present the results for the investigation of intermediate-mass fragment (IMF) production with the proton-induced reaction at 660 MeV on 238U and 237Np target. The data were obtained with the LNR Phasotron U-400M Cyclotron at Joint Institute for Nuclear Research (JINR), Dubna, Russia. A total of 93 isotopes, in the mass range of 30 < A < 200, were unambiguously identified with high precision. The fragment production cross sections were obtained by means of the induced-activation method in an off-line analysis. Mass-yield distributions were derived from the data and compared with the results of the simulation code CRISP for multimodal fission. A discussion of the super-asymmetric fragment production mechanism is also given.

Determination of the neutron flux by the temperature differences at the massive spallation uranium target QUINTA

There are several possibilities of the neutron flux determination inside of the facility. The most using one method is the determination of the neutron flux by threshold foils (detectors). This method is complicated to analyze. Irradiated foils need to be measured by gamma spectrometry and it usually takes a few weeks to get results of the neutron flux determination. Other methods are also available. One of them is the determination of the neutron flux by measuring of released heat inside of the facility. This method allows online measuring and is greatly variable to measure an unlimited number of positions in the facility with a low accrual of the cost. The research project to the topic of this type of neutron flux determination is led by Dzhelepov Laboratory of Nuclear Problems (DLNP) at the group of J. Adam. The temperature differences are measured by high accuracy thermocouples. Two experiments took place during 2015 at the massive spallation uranium target QUINTA at the facility Phasotron at JINR. Another four experiments are planned during 2016.

The spectrum of neutrons and its importance for nuclear power engineering

Most of the electricity produced in nuclear power plants comes from pressurized water nuclear reactors. Currently, the main fuel of pressurized water nuclear reactors is enriched uranium. The thermal energy is produced by fission of uranium 235 using slow (thermal) neutrons. Generation IV reactors are already contemplate obtaining thermal energy from the fission of uranium 238 using fast neutron. Neutrons interact simultaneously with materials present in a nuclear reactor. Probability and mode of interaction depend on the neutron energy. Therefore, the paper focuses on the measurement of neutron spectra and neutron field distribution using the reaction rate a gas filled detector in experimental stand SVICKA.

Neutron Flux Determination By High Accuracy Temperature Measurement

This paper is focused on the description of developing a method to determine neutron flux by high-accuracy temperature measurement. The paper deals with the procedure of sophisticated measurement, its analyzation and brings part of reached results. The method is in development in the research group aimed at ADS in the DLNP, JINR. Since the first experiment in November 2015, another 5 experiments have been performed and due to progress, the future experiment seems to be closer to reach relatively cheap probe with the ability to determine the neutron flux online.

Current research on ADS at the Joint Institute for Nuclear Research

The research on Accelerator Driven Systems (ADS) has more than 20 years tradition at the Joint Institute for Nuclear Research. Since 2010, the most experiments have been performed with a~spallation target composed of 512 kg of natural uranium. This target called QUINTA was irradiated with proton and deuteron beams of high energies. Currently, final preparations of a new spallation target BURAN consisting of 21 tons of depleted uranium are under way. The main tasks of the project are experimental investigation of neutron production inside the spallation target, possibility of natural thorium utilization and transmutation of the minor actinides and long-lived fission products. The supplementary field of interest is a measurement of nuclear data and verification of nuclear codes and theoretical models related to the ADS technologies.

Nuclear data generation sensitivity analysis for VVER reactor dynamic benchmark

The homogenized cross-section library generation is a very computer resources consuming process. Therefore optimal and efficient parameters of the calculation should be defined. This study investigates the dependence of selected parameters on accuracy of the calculation. Main goal is to determinate optimal parameters with sufficient accuracy and reasonable time and computer resources utilization. The deterministic calculation that is utilized to perform homogenized cross-section generation is compared with stochastic calculation. Monte Carlo calculation by KENO-VI is chosen to the comparison.

Determination of the neutron flux inside spallation target with the use of threshold activation detectors

Neutron flux is an important parameter for Accelerated Driven Systems. Density of the neutron flux is different in various positions inside a spallation target. The neutron flux can be obtained with the use of threshold activation detectors. An experiment with the spallation target made of 512 kg natural uranium and deuteron beam with energy 8 GeV was performed at the Joint Institute for Nuclear Research. Ten samples of Co-59 were irradiated of the secondary neutrons inside the spallation target at different positions. The reaction rates were determined by the gamma-ray spectroscopy with threshold activation detectors. The neutron flux was calculated by reaction rates. The experimental results were compared with Monte Carlo simulations.

A review of nuclear waste transmutation using accelerator beams up to several GeV

A review of transmutation rates of the unspent fuel elements like 238U, 239Pu and 237Np by way of (n, y) and (n, f) reactions has been presented in the light of neutron economy using data of reaction rates measured in the neutron environments produced by a number of proton and deuteron beams at E+T experimental set up at JINR Dubna. Transmutation power of GAMMA-3 set up in case of 232Th and natU are measured at JINR is also reviewed. Results have also been compared with the data of similar experiments with different particle beams. A fast reactor is found to be better than a thermal reactor for transmutation by way of capture and fission reactions due to neutron economy, which can be even better in Accelerator driven subcritical systems particularly for incineration of 239Pu fissile fuel because of higher neutron flux and possibility to incinerate by way of (n, xn) type reactions.

Reaction rates of residual nuclei produced of 59 Co at the target QUINTA

In December 2013, an experiment with the natural uranium spallation target QUINTA was performed at the Joint Institute for Nuclear Research (JINR). The mass of the QUINTA setup is 512 kg. It consist of five hexagonal sections. The experimental samples of Co have been irradiated in the field of secondary neutrons generated by the deuteron beam at the Nuclotron accelerator at JINR. Energy of the deuteron beam was 4 AGeV. During the experiment, samples were situated in different positions inside the assembly and after irradiation they were measured at the high-purity germanium semiconductor detectors. Experimental reaction rates of residual nuclei were determined and compared with reaction rates calculated with the MCNPX code.

Cherenkov glow analysis by Luminance Distribution Processing

Nowadays there are great operational challenges placed on nuclear power plants. It is not only the physical security of the nuclear power plant but it must be guaranteed even against diversion of nuclear fuel and proliferation risk. The spent fuel inspections are the one way to ensuring nonproliferation risk. Inspections are carried out to check the physical presence of fuel assembly. But it also is useful to have tools to detecting fuel assembly or fuel pin manipulation. A typical example is partial defect detection. It was developed several devices for inspections of spent fuel using a Cherenkov glow analysis. These include Scientific Cherenkov viewing device or viewing device with CCD cameras. These devices evaluated Cherenkov glow in the UV spectrum. This article deals with the detection Cherenkov glow in the visible spectrum. This is a new way of using a top LumiDISP measuring system, which was developed for the analysis of the luminance. Spent fuel pool was analyzed by the LumiDISP measuring system and results were compared with fuel assemblys information.