Subjects: Nuclear Science and Technology >> Engineering of Nuclear Power submitted time 2024-06-23
Abstract: Background Pebble Bed High Temperature Gas-cooled Reactor (PB-HTGR) is very different from other type of reactor in terms of its geometric structure, neutron characteristics, and mode of operation. Thus, it is imperative to develop a specialized analysis and calculation code for the PB-HTGR. Purpose In order to further improve the precision of core physics calculation of the PB-HTGR, the Nuclear Engineering Computational Physics (NECP) Laboratory of Xi ’an Jiaotong University has independently developed the neutronics calculation module of the neutronics and thermal hydraulic calculation program called NECP-Panda, which is suitable for PB-HTGR. Method In the neutronics calculation, NECP-Panda adopted the two-step method. The first step is to calculate the component homogenized group constants based on Monte Carlo method. In the second step, the homogenization of the pebble bed was performed using collision probability equations, and the whole-core diffusion calculation was subsequently completed using the three-dimensional cylindrical geometric Nodal Expansion Method (NEM). In order to accurately account for the influence of neutron leakage effect on the group constants of the model region, the diffusion calculation and neutron leakage correction were iterated until the group constants of the region converged. In addition, the neutron streaming effect of the porous structures had been corrected in the iteration, and the cavity at the top of pebble bed had been treated specially in the diffusion calculation. Results NECP-Panda had been verified by two models, one is the simplified mixed pebble bed reactor, while the other is the High Temperature Reactor Pebble-bed Module (HTR-PM). The numerical results show that the eigenvalue calculation of the simplified mixed pebble bed reactor, calculated by NECP-Panda, is close to the Monte Carlo continuous energy result. The calculated HTR-PM critical loading height of the HTR-PM is highly consistent with the results of Monte Carlo continuous energy calculation, and the absorber value is also in good agreement. Conclusion Both of these results demonstrate that NECP-Panda possesses exceptional computational power and accuracy for the neutronics calculation of the PB-HTGR, establishing a solid foundation for the development of subsequent modules.
Subjects: Nuclear Science and Technology >> Engineering of Nuclear Power submitted time 2024-02-01
Abstract: Betavoltaic nuclear batteries offer a promising alternative energy source that harnesses the power of beta particles emitted by radioisotopes. To satisfy the power demands of microelectromechanical systems (MEMS), 3D structures have been proposed as a potential solution. Accordingly, this paper introduces a novel 3D 63Ni-SiC-based P+PNN+ structure with a multi-groove design, avoiding the need for PN junctions on the inner surface, and thus reducing leakage current and power losses. Monte Carlo simulations were performed considering the fully coupled physical model to extend the electron–hole pair generation rate to a 3D structure, enabling the efficient design and development of betavoltaic batteries with complex 3D structures. As a result, the proposed model produces the significantly higher maximum output power density of 19.74 µW/cm2 and corresponding short-circuit current, open-circuit voltage, and conversion efficiency of 8.57 µA/cm2, 2.45 V, and 4.58%, respectively, compared with conventional planar batteries. From analysis of the carrier transport and collection characteristics using the COMSOL Multiphysics code, we provide deep insights regarding power increase, and elucidate the discrepancies between the ideal and simulated performances of betavoltaic batteries. Our work offers a promising approach for the design and optimization of high-output betavoltaic nuclear batteries with a unique 3D design, and serves as a valuable reference for future device fabrication.
Subjects: Nuclear Science and Technology >> Engineering of Nuclear Power submitted time 2023-07-04
Abstract: It provides a necessary reference for the study of MPWR serious accident integration analysis program development standard and the development of serious accident integration analysis procedure. Based on the current domestic regulatory requirements and regulations, software development regulations, software development, nuclear safety analysis and design software evaluation requirements, studied in this paper, suggested the standard system, quality assurance, verification and confirmation, and preliminarily established the standard system of serious accident program development. Based on the practice of existing procedure evaluation, the evaluation requirements of serious accident procedure and its focus are discussed. On the basis of the existing and ongoing soft development and component evaluation of safety analysis of nuclear power plant, the standard system of the development of serious accident procedures has been preliminarily established, and preliminary suggestions have been made for the development specification of integrated analysis procedures for serious accidents of pressurized water reactor.
Peer Review Status:Awaiting Review
Subjects: Nuclear Science and Technology >> Engineering Technology of Fission Reactor Subjects: Nuclear Science and Technology >> Engineering of Nuclear Power submitted time 2023-05-30
Abstract: