Numerical modelling of modular high-temperature gas-cooled reactors with thorium fuel

The volumetric homogenization method for the simplified modelling of modular high-temperature gas-cooled reactor core with thorium-uranium fuel is presented in the paper. The method significantly reduces the complexity of the 3D numerical model. Hence, the computation time associated with the time-consuming Monte Carlo modelling of neutron transport is considerably reduced. Example results comprise the time evolutions of the effective neutron multiplication factor and fissionable isotopes (233U, 235U, 239Pu, 241Pu) for a few configurations of the initial reactor core.

The calculation of uranium metallic Fuel (U-10%wtZr) cell with helium coolant using SRAC 2K6

In this study, pin-shaped natural metallic uranium fuel cells with a diameter of 1.4 cm were designed with and without enrichment of 2-10% by using helium as a coolant. The calculations were conducted by using SRAC software and the results show that the greater the enrichment level, the more significant the value of the infinite-multiplication-factor (kinf), meanwhile the conversion ratio is smaller. Basically, uranium exists in two isotopic forms namely, U-235 and U-238 which are transformed into other element such as Pu-239 when they both go through fission and transmutation reactions in the reactor core. Therefore, to obtain the optimum reactor core design, the performance information of nuclear fuel cells from the variations of burn-up time needs to be taken into consideration.

Uranium Exploration, Deposit and Resources: The Key of Nuclear Power Plant Development Program in Indonesia

Uranium deposit in Indonesia was found in almost all Indonesian Archipelago, mainly in Kalimantan, Sulawesi, Sumatera, Papua, Bangka Belitung and Riau islands. Uranium exploration activities started in the 1960s to recent, conducted in many exploration stages. The exploration in prospects area are completed with drilling activities to delineate the mineralization zone and continued to resources estimation. In Kalan Area, the research had been completed with underground/tunneling mining. The uranium resources are classified into discovered or undiscovered based on exploration stages, and conventional or unconventional based on sources of primary/secondary/by-product mineral production. The resources are calculated from Kalan Area and its surroundings (Kalimantan) with addition of Mamuju Area (West Sulawesi) and Sibolga Area (North Sumatera). Uranium identified resource in Indonesia is 13,503 tU while the undiscovered is 62,330 tU. Meanwhile, categorized by uranium source, the conventional and unconventional resources are 48,388 tU and 27,445 tU respectively. The uranium resources categories should be increased and completed with feasibility study to increase the resources to reserve classification. The exploration, deposit, and resources are the key to ensure the readiness of developing nuclear power plants in Indonesia, where one of them is Experimental Power Reactor (EPR) or Reaktor Daya Eksperimental (RDE) with domestic uranium fuel.

Investigation of Critical Heat Flux for Plutonium-Based Mixed Oxide Advanced Fuel Bundle Design

The critical heat flux performance of an advanced plutonium-based mixed oxide fuel for potential use in a pressure tube heavy water reactor has been studied experimentally at Canadian Nuclear Laboratories with an electrically-heated string simulator of 43-element fuel bundles. The fuel simulator has a uniform axial power profile and a radial power profile representative of the plutonium-based MOX fuel. The CHF measurements were made in the MR-3 heat transfer loop facility using R-134a refrigerant as the working fluid. The test matrix included system pressures from 1.47 to 2.11 MPa, mass flow rates from 12.7 to 14.7 kg/s and inlet temperatures from 31 to 59°C, which are representative of the water-equivalent reactor operating conditions of 9 to 12.5 MPa pressure, 13.5 to 21.3 kg/s mass flow rate and the desired inlet subcoolings. Compared to conventional natural uranium fuel, the radial power profile of a MOX fuel exhibits a steeper and uneven distribution across the fuel element rings, with a higher value in the outer ring. It was found that CHF values of the MOX fuel are significantly lower than those of the natural uranium fuel. Based on the experimental data, a correlation has been derived to account for the effect of radial power profile on CHF. This correlation can be used to evaluate the relative CHF values of advanced/non-conventional fuel designs with radial power profiles deviating from that of natural uranium fuel.

Conceptual design of critical assembly using Low enriched uranium fuel and moderated light wate

Critical assembly is a very important facility to serve for fundamental reactor physics research, application of neutron source, training and education. In nuclear engineering, critical assembly is a facility for carrying out measurement of reactor physics parameters, creating benchmark problem, validation of neutron physics calculation tool in computer codes and nuclear data. Basing on concept using commercial Nuclear Power Plant (NPP) fuels such as PWR (AP-1000) and VVER-1000 fuel rods with limited 2 meter in length and fully controlled by water level, the conceptual design of the critical assembly has been carried out in neutronic, thermal hydraulics and safety analysis. Ten benchmark critical core configurations of critical assembly are established and investigated to show safety during normal opeartion and accident conditions. Design calculation results show that NPP fuels are fully adequate for critical assembly operating under nominal power 100W and having average neutron flux about 3×109 neutron/cm2.s.

Study on transmutation efficiency of the VVER-1000 fuel assembly with different minor actinide compositions

The feasibility of transmutation of minor actinides recycled from the spent nuclear fuel in the VVER-1000 LEU (low enriched uranium) fuel assembly as burnable poison was examined in our previous study. However, only the minor actinide vector of the VVER-440 spent fuel was considered. In this paper, various vectors of minor actinides recycled from the spent fuel of VVER-440, PWR-1000, and VVER-1000 reactors were therefore employed in the analysis in order to investigate the minor actinide transmutation efficiency of the VVER-1000 fuel assembly with different minor actinide compositions. The comparative analysis was conducted for the two models of minor actinide loading in the LEU fuel assembly: homogeneous mixing in the UGD (Uranium-Gadolinium) pins and coating a thin layer to the UGD pins. The parameters to be analysed and compared include the reactivity of the LEU fuel assembly versus burnup and the transmutation of minor actinide nuclides when loading different minor actinide vectors into the LEU fuel assembly.