The latest breakthrough in isotope heat sources ha

2022-08-21
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New breakthrough! The isotope heat source has become the "warm baby" of instruments on the moon, and it has been predicted that more than 80% of cars will use plastic products in the future The shape of the cup is obviously asymmetric, with a temperature difference of 10 ℃ between day and night. Without air, it is very difficult for human beings to survive on the moon. The instrument that can automatically observe for a long time has become the clairvoyant of human understanding of the moon. Undoubtedly, the energy supply of instruments is a major event

according to media reports, the isotope energy supply of chang'e-4 launched at the end of last year has achieved a new breakthrough: the combination of isotope thermoelectric power generation and thermoelectric utilization

what kind of energy technology is this? What is unique? Science and technology made an exclusive interview with caishanyu, a Chinese isotope energy expert and researcher of the Institute of isotopes of the Chinese Academy of atomic energy

decay energy provides self-sustaining energy for space exploration

isotope heat source and isotope power supply are collectively referred to as isotope energy. This kind of energy comes from the decay energy generated during the decay of radioisotopes. Caishanyu told that decay energy, fission energy and fusion energy constitute three major ways of nuclear energy utilization

compared with fission energy and fusion energy, decay energy is much smaller, but it is unique for lunar exploration and deep space exploration: it does not need to rely on external energy, can provide long-term, self-sustaining and reliable power, and has good adaptability to the environment

so far, human beings have found 118 elements, each of which has a different number of isotopes, including 276 stable isotopes and more than 3000 radioisotopes

however, Cai Shanyu said that if the screening is carried out according to the principles of static physical and mechanical property testing, analysis and research with long half-life, high power density, which is more suitable for stretching, tightening, bending, peeling, tearing, puncturing, bursting, shearing and other experiments of automotive parts and automotive interior materials, such as light shielding mass, small biological toxicity and low production cost, there are only more than a dozen radioisotopes that can be used as energy fuels. According to the decay characteristics, isotope heat sources can be roughly divided into, and heat sources

the biggest feature of the heat source is that the required shielding material is of low quality, which can greatly reduce the rocket launch cost, and is most suitable for space applications. Most of the isotopic energy launched into space in the 20th century is polonium-210 and plutonium-238, the latter accounting for the vast majority

polonium-210 has high specific power but short half-life, which is suitable for demonstration devices or short-term space missions; Plutonium-238 has low specific power but long half-life, and can be used in long-term space missions. Caishanyu explained

isotope heat source becomes the warm baby of instruments on the moon

the decay energy of radioisotopes can be converted into light energy, heat energy and electric energy

caishanyu told that the high-speed charged particles emitted during the decay of radioisotopes interact with matter. When the kinetic energy is blocked or absorbed, the temperature of surrounding materials such as containers wrapped with radioisotopes will rise, and the decay energy will be converted into heat energy

the isotope heat source has a source core made of isotope fuel inside and a fuel box with sealed source core outside, which can be directly applied. For example, the Soviet Union has successively launched lunar rover-1 and lunar rover-2, which are equipped with 800 watts of polonium-210 heat source, specifically to establish a constant temperature environment for lunar observation instruments; The lunar scientific test station launched by the United States in the early stage used two 15 Watt plutonium-238 heat sources for the insulation of the lunar seismograph

the chang'e-3 lunar probe, launched in 2013 by China in two pairs of strict experiments, is equipped with plutonium-238 in both the lander and the lunar rover, so as to ensure that the instrument warehouse is as warm as spring, and the instruments carried on it can survive the moon night safely. Once the sun shines, the instrument becomes active again with the help of solar cells

caishanyu told that compared with isotope heat sources, isotope power sources also need to further convert the heat energy generated by isotope decay into electric energy directly or indirectly through thermoelectric converters (transducers). For this reason, the isotope battery includes not only the isotope heat source, but also the transducer. At present, the most mature and practical transducer used in space is the isotope thermoelectric generator, which has the advantages of no moving parts and safe and reliable power generation, but the thermoelectric conversion efficiency is only 4% 8%. As a kind of transducer, dynamic conversion can improve the efficiency of thermoelectric conversion, but because there are moving parts, it is difficult to manufacture

it can be predicted that China's increasingly abundant space activities will put forward more demands for space nuclear power, and the research results of space nuclear power will also provide a broader space for the development of China's space industry. Cai Shanyu said when looking forward to the prospect of isotope energy. (Chen Yu)

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