Design and performance analysis of a 500-W heat source for radioisotope thermophotovoltaic converters

Abstract

Summary A radioisotope thermophotovoltaic (RTPV) system effectively converts the decay heat of radioisotopes into electricity via thermally radiated photons. In this work, a 500‐W thermal heat source unit including 238PuO2 radioisotope fuel, shielding material, and selective emitter is designed from the viewpoint of radiation safety, thermal performance, and overall conversion efficiency by considering various shielding materials, fuel configurations, and packing factor (PF), defined as the ratio of fuel region volume to total heat source enclosure volume including fuel cladding and shield. The design study starts with a reference cubic configuration and extends to the more complicated configurations having separate cylindrical fuels. The results of the study showed that the heat source unit design suggested here can reduce the total radiation dose, peak neutron fluence, and maximum temperature using separate cylindrical fuel rods. For example, a design having a separated 3 × 3 cylindrical fuel rod array of 30% PF increases the overall efficiency by ~39% with similar maximum temperature and radiation doses in comparison with the reference heat source unit with a single cubic module and a 10% PF. This demonstrates the importance of the proper design of the RTPV heat source unit.

Thermal Emission‐Enhanced and Optically Modulated Radioisotope Thermophotovoltaic Generators

“…Alternative radioisotope heat source nuclei are mainly Sr/Y‐90, Am‐241, and Pu‐238. Table shows the main characteristics of them . Sr/Y‐90 has a high specific activity and initial specific power.…”

“…They only designed the prototype and were less concerned with the heat transfer optimization inside the RTPV. The numerical simulation analysis of the heat source distribution inside the RTPV by Cheon and coworkers is an improvement, but it has not been discussed experimentally …”

A Novel Optimization Method for TEG System Performance Based on Temperature and Heat Flux

“…In the model of the u‐RTG, 90 SrTiO 3 particles are used as the radioisotope material of heat source, and the specific properties are shown in the Table 1 . [ 31 ] The expected thermal power is 200 W. Considering the 90 SrTiO 3 volumetric power density (Table 1), the 200 W thermal power and 8 mm thick aluminum β ‐ray shield, the RHS is designed as a cylinder with a radius of 30 mm and a height of 47 mm. A uniform heat source is used to represent the energy distribution of heat source.…”

An Efficient Photon Utilization Radioisotope Thermophotovoltaic Based on Curled Reflectors

“…[4][5][6] RTPV has the inherent advantages of high output power density and high theoretical efficiency, which is regarded as one of the power sources with great development potential. [7] RTPV is mainly composed of radioisotope heat source, [8][9][10][11] thermooptical conversion emitter/coating, [12][13][14] and TPV cell. [15][16][17][18] For RTPV systems, since the infrared light generated by the heat source and regulated by the emitter/coating is isotropic and diverges during propagation, each TPV cell receives different irradiance and has different electrical properties resulting from the photovoltaic effect.…”