Efficiency of the use of material resources in small modular reactors

In 2015, 195 countries adopted the first universal and legally binding global climate agreement, which aims to keep the rise in global average temperature well below 2°C, requiring a shift in global energy production and consumption. Due to rising capital costs, small and medium-sized nuclear power plants, known as SMR (small modular reactors), which offer greater flexibility than larger units, have come to the fore. We know of many types of SMR reactors that vary in size, design, type of reactor coolant or moderator. In this project, we will focus on pressurized water reactors, such as NuScale (USA), ACP100 (China), and similar reactors that are already under construction or meet all safety requirements for operation. Basically, SMR reactors have larger leakage of neutrons from the core due to the smaller reactor core, so from the neutron transport point of view, poorer efficiencies can be expected. For this reason, the design of such reactors is adapted to partially compensate for neutron losses from the core. For example, the NuScale core design uses a reflector where some of the escaping neutrons are returned to the core. In general, waste management (high, intermediate and low level waste) depends on the generation of radionuclides in the reactor, which in turn depends on the geometry and material composition of the fuel, m Based on simple physical principles, researchers at the University of Pennsylvania found that the amount of waste per standardized unit of energy is greater compared to existing reactors. They estimated that the volume of spent fuel is by a factor of 1.7 greater than in existing pressurized water reactors, which contradicts predictions made by the manufacturers of such reactors. Such superficial analyses can be refuted only by accurate calculations. The main goal of the project is to analyze all processes of waste generation, from high-level radioactive waste (spent fuel) to low and intermediate-level radioactive waste generated during operation, to perform an analysis of damage to the reactor pressure vessel, and to compare the results with those of conventional pressurized water reactors. As part of the project, we will perform calculations on the leakage of neutrons from the reactor core and calculate the material composition of the spent fuel, from which integral parameters such as activity and delayed heat can then be calculated in a simple manner. We will evaluate the impact of these parameters for various conceptual solution options following the cessation of reactors in question. We will analyze solutions related to the temporary disposal of the fuel in a dry storage facility, the final disposal site and the possibility of fuel re-processing and reuse. We will analyze the activation of the reactor pressure vessel, as this is an important factor after the end of the life of such reactors. In addition, we will analyze radiation damage to the reactor pressure vessel and other components and associate it with material ageing, and compare it to those of conventional pressurized water nuclear reactors. All results will be normalized per unit of produced electricity for comparison with existing pressurized water reactors, e.g. NEK. The proposed studies will be carried out for both steady state operation as well for the load follow operation modes of the reactor. All calculations will be performed using the ROM-ICM method and Monte Carlo particle transport method, which are appropriate for this type of small reactor. We will use different tools with which we already have extensive experience. With the given results, we will provide a detailed insight into the amount waste and it's radiotoxicity, which is a significant economic and more importantly social aspect, especially in light of wider public acceptance of nuclear energy.