China, Russia and the United States run to put nuclear power plants on the Moon. China and Russia in May agreed to work together to complete a lunar nuclear reactor by 2036. In response, the acting chief of NASA, Sean Duffy, announced in August that the United States would follow his lunar nuclear energy program to have one by 2030.
But this sudden frenzy raises a few questions – as why do we want nuclear reactors on the moon in the first place? And how would they work? To find out, Spectrum ieee spoken with Katy Huff, nuclear engineer and director of the Advanced Reactor Fuel Cycles laboratory from the University of Illinois in Urbana-Champaign. Huff was previously the assistant nuclear energy secretary at the US Department of Energy (DOE).
Why do the world’s largest spatial organizations in the world want nuclear reactors on the moon, and what would they divide?
Katy Huff: There is an increasing interest in having a more sustained presence of humans on the moon for scientific discovery. Resources like Helium-3, which can serve as fuel fuel, can be part of the call. NASA plans to build this type of lunar exploration basis thanks to its Artemis program, and China and Russia work together to build a called international lunar research station. Such a lunar base would absolutely need nuclear energy. Renewable energies are too intermittent to meet the energy needs of life on the moon. In addition, the cost of setting up things in mass space, therefore the unrivaled energy density of uranium fission is our greatest opportunity.
Why is it suddenly a race? What is the emergency?
Blow: The momentum began with the Fission Surface Power project at NASA, which a few years ago asked for conceptions for lunar microororeactors of 40 kilowatt. Three models were selected and allocated to $ 5 million each. Since then, China and Russia have at least announced a joint effort to design their own lunar micro -rector with a launch target in the mid -2030s. In response, NASA accelerates its calendar for the American reactor to 2030 and increases the target power capacity to 100 kW. Sean Duffy publicly said that if China and Russia were the first to submit a lunar power plant request, they could declare a de facto keep-out area, limiting the United States options to place its base. The United States is therefore aiming to get there before China and Russia to claim a region with access to water ice, which helps support for astronauts.
Design lunar nuclear reactors
What are the considerations to design a nuclear reactor for the moon?
Blow: In a very low severity, fluids will not behave exactly as they do on earth. Thus, the circulation models for the liquids of liquid of the reactor must be recalculated. And the large temperature oscillations of the moon, which vary hundreds of day -to -day degrees, will require the reactor for Use more isolated systems of these swings. On Earth, we easily eject the heat of waste because there are thermally stable heat dissipators such as available water bodies.
What type of reactor do you wait for NASA to choose?
Katy Huff was previously assistant to nuclear energy secretary in the American Department of Energy (DOE).Katy Huff
Blow: It would be logical for NASA to choose one of the three conceptions previously selected for the Fission Surface Power program, rather than starting from zero. But with the overhanging of the target capacity, from 40 kW to 100 kW, there will be a little overhaul, because you are not content to mount the button. The three prizes were awarded to Lockheed Martin / Bwxt, Westinghouse / Aerojet Rocketdyne and X-Energy / Boeing. Some of them develop micro -reacchers based on tristructive [TRISO] The fuel, which is a very robust uranium fuel type, so I expect the lunar reactor to be designed using this. For cooling fluid, I do not expect them to choose water, because the thermal properties of water limit the temperature range that it can cool effectively, which limits the effectiveness of the reactor. And I do not expect it to be a liquid salt either, because it can be corrosive, and this lunar reactor must operate for 10 years without intervention. So I suspect that they will choose a gas like helium. And then for power conversion, the NASA directive explicitly said that a closed brayton cycle would be a requirement.
What would transport and startups look like?
Blow: The reactor would be fully built on earth and ready to leave, with the fuel in place. I expect it to be transported with the control elements entirely inserted in the reactor to prevent a chain reaction from starting during the transit. Once on the moon, a startup sequence would be initiated at a distance or by astronauts there. The control stems would then withdraw from the reactor, and a small source of neutron like Californium-252 would launch the reaction.
A 2030 deadline feels fairly precipitated since the United States has no final design for the reactor, nor the firm plans for a lunar base.
Blow: RIGHT. This calendar seems ambitious. We will have enough trouble obtaining a reactor from this ladder deployed as a land prototype in the next four and a half years. Obtaining a ready launch for launch and on the moon is a recipe to finally explain why we did not meet this chronology. And this could be a problem, in a reinforcement, for nuclear energy more than spatial exploration because people love NASA. Little children and adults wear NASA t-shirts. No one has doe t-shirts.
Risks of the launch of the lunar reactor
What are the risks if something is wrong with the launch?
Blow: It is quite magnificent, the fresh uranium fuel does not have a radiological risk as the uranium spent would. It is only after it becomes the fission products that it is significantly radioactive. As long as the reactor does not work before launch, the danger is quite low. Even if the fuel was dispersed on earth, it would not present an important danger for the people around it. I literally have a sample of uranium seated near my office. In addition to that, there is a robust launching safety protocol already established for any radiological object. NASA has a lot of experience in this of sending thermoelectric generators of plutonium, which more like a nuclear battery, for previous missions.
Things went wrong with some of the fission reactors previously launched in space; What happened to these?
Blow: The largest fission reactors that anyone who launched in space were the 5 kW Topaz-i electric reactors which were part of the Soviet program. One of them had a serious incident and separated. It is now in high orbit in pieces, including a part of its sodium coolant, which is sort of floating up there as liquid metal spheres. But that does not have an impact on the earth because it is a small amount of radiological source material at an incredible distance from the earth. The most unhappy incident occurred with the Soviet reactor Kosmos 954, which, after having operated in orbit, experienced an uncontrolled return and disintegrated on a gang of 600 kilometers of Canadian territory.
What happens if an asteroid hits the moon or strikes the lunar nuclear reactor directly?
Blow: A direct strike could damage the reactor and cause a localized dispersion of the fuel. This could be a motivation to use Triso Fuel. It is so robust because fuel and fission products are housed in thousands of spheric particles of chia seeds that are coated with silicon carbide. It can withstand incredible impacts and heat – far beyond the lava temperature. The tests have shown that even when subjected to 1,700 ° C of heat for 300 hours, Triso retains its uncomfortable fission products. Thus, in the unlikely case that there is a dead collision with a large asteroid on the reactor site, the reactor debris can be distributed in the dust of the moon, but all these small Toriso particles will remain, hope, will remain intact.
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