جستجوی مقالات مرتبط با کلیدواژه « research reactor » در نشریات گروه « فیزیک »

The production of trans-uranium isotopes such as Am-241 and Cf-252 is done using irradiated reactor fuels or by irradiating targets in the core of research reactors. The main production of these two radionuclides is done in America and Russia. In this study, at first, the feasibility study of producing these nuclides using the irradiated fuels of a typical research reactor for two powers of 5 and 10 megawatts has been done using the ORIGEN code. In another part, calculations for the target of uranium with 99.7% by weight of uranium-238, which exists at the end of the enrichment cycle, has also been done. The results of the calculations show that the production efficiency of trans-uranium radionuclides in 10 MW power is many times higher than 5 MW. Also, the efficiency of trans-uranium radionuclides production using the target irradiation of depleted uranium is about 2 times higher than the radionuclides produced form the irradiated fuel of the typical 5 MWe research reactor.

According to the process of loading, unloading, and shuffling a fuel assembly in Tehran Research Reactor core, the possibility of a fuel assembly fall and consequent damage must be considered in order to ensure the integrity of the assembly and no damage to the fuel plates after a possible drop accident based on the safety requirements. In this simulation, ABAQUS software is used for collision analysis. Three modes are considered for the drop of the fuel assembly and its impact on the bottom of the pool, which includes a vertical impact, with an angle of 45 degrees, and a horizontal impact. Based on the stress analysis, it was determined that the vertical collision with the bottom of the pool was the worst type, which could damage the side plates of the assembly, but the fuel plates inside the assembly were not seriously damaged and kept their integrity

The main purpose of the present study is the evaluation of the candidate sites for proposed Fars research reactor. Because the proposed research reactor is being designed conceptually and is very similar to the Tehran Research Reactor, the specifications of the Tehran Research Reactor have been used in this study. In this research with the help of site selection criteria and geographic information system utilities in Arc-Gis 10.4.1 software for three regions of Shiraz, Marvdasht and Sarvestan. The results show that Bajgah site in Shiraz region is the preferred site for Fars research reactor. The process of present research can be used as a methodology for site selection of other similar nuclear facilities.

Monitoring the power distribution of reactor core is one of the most challenging issues in the safe operation of nuclear reactors. The Number and arrangement of detectors in a core monitoring system should be determined in a way that maximum amount of information about core states is extracted, while avoiding duplication of similar and correlated measurements. Information theory is the best method to deal with the problem of optimal number and placement of instruments. In this paper, the effects of reactor fuel burn-up on the optimal number and arragement of in-core fixed detectors of Tehran Research Reactor has been investigated using information theory. Comparison the results for the two modes, with and without consideration of the fuel burn-up, shows that by considering fuel burn-up in the placement problem, more information can be extracted from measurements of the detectors. Also, for an equal number of detectors, determined arrangement by considering fuel burn-up, mostly provide larger share of total available information in the data set. Using the optimal arrangement, maximum information can be obtained from minimum number of the detectors, which leads to considerable decrease in the cost of construction, implementation, operation, and maintenance of the in-core detectors for monitoring of neutron flux.

The management of waste produced in the reactor is an essential aspect of the nuclear fuel cycle. In this research, it has been tried to reduce the amount of reactor waste at the end of the cycle without substantial changes in the fuel dimension and the core structure of the research reactor. Minimized the heat generation. The MCNPX2.6 code is used to calculate the fuel consumption and neutronic parameters of the reactor core. The results show that without any significant change in the structure of the reference core, the amount of waste decreases only by increasing the fuel enrichment and reducing the reactor power. In this study, two core models are proposed and investigated. The waste activity at the end of the cycle in the converted reactor cores reaches 15% -19% of its original value in the reference core. Moreover, fuel burn- up has increased up to 32% -40% relative to the reference core.

In this study, the trajectory and the concentration of radioactive nuclei in the atmosphere resulting from the Fars proposed research reactor innormal operation condition have been investigated. Since the reactor is in the conceptual design stage, so we use the characteristics of the Tehran research reactor, which is very similar to this reactor. Simulations were carried out for a one-year period (2016) and we use data from fission products leakage that extract from the Tehran Research Reactor in normal operating conditions and using HYSPLIT environmental code for studies that related to the trajectory and Concentration distributioncalculation. In this study, Meteorological Data NOAA (GDAS) have been used and then the total effective dose equivalent (TEDE) is calculated. The results show that, while the research reactor operated for a year, the received dose rateis less than the 1mSvthat adoped by the International Commission on Radiation Protection (ICRP).