2015.B.3.4. Small-Scale Radioisotope Thermoelectric Generator and Heater Units Based on Americium-241

Author(s)

Richard Ambrosi (1)
Hugo Williams (1)
Emily Jane Watkinson (1)

University of Leicester, United Kingdom

Session

B.3

Keywords

Radioisotope, Power, Americium

Abstract

Space nuclear power systems are under development in the UK in collaboration with European partners as part of a European Space Agency (ESA) programme. Radioisotope thermoelectric generators (RTGs) and heater units (RHUs) are important elements of this new European capability. A constant supply of electrical and thermal energy derived from radiogenic decay heat can benefit and enable a range of mission scenarios, providing more science return through increased longevity. The focus in Europe has been the cost effective production of americium-241 for the heat source. The high purity americium-241 is product of a chemical separation process from stored plutonium produced during the reprocessing of civil nuclear fuel. The development of small scale RTG systems (10 W to 50 W in electrical power output) and RHUs in the 1 W to 4 W thermal power range could enable a range of smaller or lower cost planetary missions to the colder, more inhospitable and distant regions of the Solar System. In addition, systems that harvest heat from RHUs to generate small amounts (<1 W) of electrical power have also been considered and could offer a range of small-scale electrical power and thermal power solutions for future low cost missions or small spacecraft. This paper describes the most recent updates in system design, provides further insight into recent laboratory prototype test campaigns and provides a summary of future development plans.