The blocked accident of plate fuel assembly is one of the serious accidents in the reactor. It will worsen the heat transfer capacity of the coolant and even affect the safe operation of the reactor. Therefore, Particle Image Velocimetry (PIV) technology and the Laser Induced Fluorescence (LIF) technology are used in current paper to investigate the edge blockage accidents in a narrow rectangular channel with a continuous-wave laser and two high-speed cameras. During the experiments, the obstacle has great effect on the flow field and temperature field. It is found that large-scale vortex structure will be generated in the wake downstream of the obstacle. And where the vortices exist, the fluid temperature is also higher, which means that the vortices prevent the heat from escaping in time. Besides, the temperature distribution at different Re numbers is also analyzed. It can provide a validation for numerical simulations.

As human beings explore the outer space, the demand for the nuclear sources in space missions is increasing. Almost all the existing space nuclear reactors have adopted the design of gas-cooled fast reactor, and the temperature feedback effect of the fuel of the small fast neutron reactor is different from that of the traditional pressurized water reactor. For the space fast reactors, they are designed to be compact and with a long operating lifetime to accomplish the long-term space missions. Due to the high-level enrichment of U-235 in the fuel, the Doppler effect of U-238 has little impact on the reactor reactivity. In the present paper, based on the design of the megawatt-class space gas-cooled fast reactor, the overall temperature feedback adjustment capability of the core, and the overall temperature coefficient of the core including fuel, structural materials, and coolant are investigated. The calculation results show that the temperature of the coolant has little effect on the reactivity. The temperature coefficient of the fuel is positive, and the structural material with a large negative temperature feedback coefficient. At the same time, the deformation of the fuel pellets due to thermal stress at high temperatures and the reactivity changes caused by the deformation are analyzed.

The space nuclear reactor has been widely studied since 60s in the last century. However, upon the signing of the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) and the ending of the Cold War, the space nuclear technology gradually faded out the public and researchers view. In recent years, due to the proposal of the United States’ Moon and Mars Project and China’s Deep Space Scientific Project, space nuclear technology are welcoming new opportunities for research and development. In this paper, the Prometheus project design has been analyzed and thereafter been based for multi-kilowatt He-Xe cooled space nuclear system preliminary design. Parameters like system efficiency, compressor ratio, temperature are given and neutron calculations are conducted in order to evaluate its physical performance and provide guidelines for future optimization. A computer program, which can calculate performance of heat pipe radiator, is also coded and thereafter used. At last, some consideration guidelines are concluded for larger power space reactor design.

The goal of this study was to construct a design methodology for a prosthesis which causes less stress shielding and meets fatigue requirements. Stress shielding is the reduction in bone stresses due to the introduction of an implant. Implants may become loose when stress shielding is present because bone resorption occurs as the bone adapts to the reduced bone stresses. Topology and lattice optimization were performed using OptiStruct to design a hip prosthesis where stress shielding and prosthesis fatigue were considered. The optimized design reduced stress shielding by 50+% when compared to a conventional generic implant, and the fatigue life met the ISO standards. Additionally, manufacturability was considered in the design process and a Ti-6Al-4V prototype was printed with an EOS selective laser melting machine.