Beijing time on February 8, according to foreign media reports, a small bucket of uranium equivalent to the size of a coffee pot, but this micro-nuclear reactor with shielding devices and detectors, the entire equipment does not exceed a trash size.At present, this Prototypes of small nuclear reactors will be tested in the Nevada desert in the United States, which will be one step closer to realizing humanity's future space exploration dream.
The picture shows the 'Kilopower' generator set by the artist on the surface of Mars.
Space nuclear reactor only trash size
The project, called 'Kilopower', is a joint venture between NASA and the U.S. Department of Energy and will be the first space nuclear fission reactor since the 'SNAP 10A project' of the 1960s. Currently, the prototype is still being tested Among them, it is more than any space project that has been carried out in the past few decades.
The Kilopower reactor is designed from two dimensions, one with a 1-kilowatt model and the other with a 10-kilowatt model. "Pat McClure, head of reactor at Kilopower, said: 'People need about 1 kilowatt of toast , Which consumes an average of 5 kilowatts of electricity a day in an average home, but this consumes a lot of energy for NASA, with NASA detection equipment consuming only a few hundred to a few kilowatts in space, So in the space of 1 kilowatt or 10 kilowatts is a big unit of electricity.
NASA's HNN detector has a maximum power of 240 watts and the Curiosity rover powers 120 watts. Both of these detectors use a nuclear-powered battery that converts the heat of naturally decaying plutonium into electricity. However, the shortage of plutonium supplies, with a mounting power of 1000 or 10000 watts, is a big step forward, even though it is smaller than the equipment on Earth Unlike the nuclear power cells, the Kilopower system forms a fission reaction that converts uranium atoms rapidly The split releases energy, which is then converted into electrical energy by connecting the engine.
McClure said: 'The traditional light-water-cooled reactor can produce a gigawatts of electricity, which is 100 million times more energy than the Kilopower reactors, and its structure is very complex and at the same time designed to make full use of the fuel.' 'For small Mars Reactor, fuel efficiency will be significantly reduced, but we need a predictable reactor easy to predict, and easy to operate, in fact, this small Mars reactor has a self-control function.This will reduce the possibility of accidents may occur on a larger power source .
In other words, we do not risk adventurous nuclear events on the surface of Mars. McClure said: 'For the work we are currently doing, it is very difficult to melt the fuel, and our physical design is that the reactor releases a lot of heat So we did not cool down, just radiated a small amount of heat, and the reactors reduced their power to match. '
At the same time, this small nuclear reactor can also operate in a peculiar space environment, which we think is very cold, but it is not an easy task to keep a reactor cool down in a vacuum environment. There is no air or water in space, Instead, the system relies on eight heat pipes, each containing about a tablespoon of sodium, which has a very high boiling point.
Sodium boils at high temperatures, and when sodium boils close to the heat pipe section, it is at a temperature close to the fission uranium fuel. The steam passes through the heat pipe and is gradually condensed, and the temperature difference helps to create electrical energy. The cooled material then returns to the hot pipe temperature The high part, the entire system is cycled in. In theory, the system is capable of producing reliable and efficient energy over many years.
Space nuclear reactor safety how?
If launch problems, many people will worry about nuclear leaks and space crisis, airborne nuclear power source will be potentially threatening.McCool said: 'People always think you will bring Chernobyl to space or Somewhere, in fact, not so dangerous, before the fission reactor, there was a small amount of radioactive material in the space reactor, because it is uranium, but its number is very small, even if there are some accidents during the launch, it will not be public cause trouble. '
McClure explained that in the event of a launch problem, the reactor's standard, non-fissile uranium residue may explode, posing a very small risk to the general public. Its radiation peak dose is well below 1 milliliter, and reality In the case of lower radiation peak doses, which are at the level of the microremy, Americans receive, on average, 620 millimeters of radiation a year, meaning that space-borne nuclear reactors emit far less radiation than background radiation or Equivalent to flying.
But launching a space nuclear power source is only the first step, and it must also remain safe at far-airspace distances and become more radioactive as soon as it leaves the Earth's atmosphere for a long time and starts up. However, the research team conducted a special design Will automatically shut down if the nuclear power source fails, and they plan to test in Nevada next month to connect the nuclear power source to two engines, each capable of generating around 80 watts of power, Thus heating the fission reaction to a high temperature of about 800 degrees Celsius.
Dave Poston, director of space nuclear reactor design, said: "We will turn off all heat removal, indicating that the reactor will not only survive, but will also be in standby mode. If the power conversion system is able to recover and begin generating electricity, then it It will confirm that we can handle any short-term or abnormal operation of the reactor and that people do not have to worry about it. "
How will this be done?
McClure said: 'The 1-kilowatt nuclear reactor is used for deep-space missions such as arriving at Pluto or Jupiter, the 10-kilowatt nuclear reactor being used for deep-space or Mars surface missions and currently NASA plans to send 5 10-kilowatt nuclear reactors to Mars This will provide 40 kilowatts of electricity to a Mars base.
Steve Jurczyk, the deputy director of NASA's space technology task force, said at a news conference: 'It is very difficult to lay out a power system on the surface of Mars, and it shines on less sunlight than the Earth and the Moon, and at night The temperatures are very low and there is a very unique sandstorm that can take weeks, months, and even engulf the entire planet.
Although NASA has explored solar panels as a potential source of power, NASA is actively exploring options to continue providing essential life support systems, especially when the sun's rays are not sufficient to provide solar power.
The first nuclear reactors will land on Mars and begin to power an automated system that separates water ice to form liquid oxygen and liquid hydrogen that produce fuel for return to Earth. Once humans land on Mars, these systems can provide space for their habitat and other Support system to provide power.At present, NASA is negotiating with other commercial agencies, proposed 1 kilowatt nuclear reactors for extraterritorial space exploration mission.
Janet Kavandi, director of NASA's Glenn Research Center, said: "As a former astronaut, I can assure you that having reliable power in space missions away from low Earth orbit is crucial Importantly, this type of power system will become especially important as we move deeper into the solar system and eventually to the surface of other planets.
