Radioisotope power systems in space missions: Overview of the safety aspects and recommendations for the European safety case

Feasibility Evaluation on European Capabilities for 238Pu Based Radioisotope Power Systems

“…Deep space missions can currently only rely on nuclear power systems [1][2][3]. Radioisotope power systems (RPS) generate power up to 5 kWe for a longer time period.…”

“…Plutonium-238 is the sole isotope that has been used for RTGs of flown missions, although other isotopes were investigated as well, e.g. strontium-90 [6], polonium-210 [3] and more recently the European Space Agency (ESA) has been investigating americium-241 for RPS use [2,3,7]. The importance of 238 Pu in RPSs stems from its unique properties.…”

“…This isotope might be useful for some space mission applications, but, due to its lower specific power and higher shielding requirements might not be suitable for long deep space mission where the heat source isotope selection must be "cost per weight" driven. ESA's strategic decision in 2010 was based on the easy availability of 241 Am, since it is produced through decay from 241 Pu which can be extracted isotopically pure from existing stocks of civil plutonium in France or the United Kingdom via chemical extraction, and to take advantage of the existing nuclear infrastructure related to the civil reprocessing of spent nuclear fuel in Europe [2,3], apart from the economical factor [23]. In 2021, ESA assessed again the costs associated with 238 Pu production which previously were reported to be prohibitively high, and looked at the technical possibilities to produce this isotope in Europe without relying on non-European partners [23].…”

Early fever detection on COVID-19 infection using thermoelectric module generators

“…Between 100-525 W of heat is released from the skin to the environment [7], and that thermal power can be converted using thermoelectric generators (TEG) directly into an electric current [8]. TEG devices have been used in a different context as thermoelectric solar generation systems [9], thermal energy harvesting for IoT devices and wearables [10], hybrid photovoltaic-TEG systems [11], [12], waste heat recovery from exhaust gas applications [13], small scale geothermal sources [14], even in space exploration with radioisotope heat fuel application like the last rover send by NASA Mars Mission (Perseverance) among others [15]. The standard sensor technologies for skin temperature measure sometimes require electronics and outer power supply like batteries or AC power [16] using TEG modules, the system could produce the necessary amount of energy to sense and report an early fever state, with no outer energy supply.…”