The Practicability of Nuclear Waste Disposal in Space
Zachary Tait. 21 November, 2016.
Major amounts of nuclear waste have been a problem since the first ever nuclear reactor, Chicago Pile-1, was created as part of the Manhattan Project in 1942. Since then, nuclear power has become a critical part of our modern lives. It accounts for nearly 11% of all energy created around the world at this present time, with experts predicting that this figure is very likely to increase in the future as fossil fuels run out and more of our lives become dependent on nuclear energy. The problem stems from the waste that this type of fuel produces. LLW and MLW (Low and Medium Level radioactive Waste e.g. gloves and equipment that have been used to handle the radioactive material) can be disposed of relatively easily: Bag it, tag it and send it off to be canned up and buried in a secure facility. However HLW (High Level radioactive Waste) cannot be disposed of this simply. HLW is the category under which spent fuel rods and things directly connected to the fuel source are categorised. This means that the isotopes contained in this type of waste may have half lives of millions of years and be extremely harmful to any sort of biological life that goes near it.
Thankfully, we do have systems in place that mean this waste can be carefully disposed of. The problem being that when it has cooled for 50 years in an underwater bunker, it has to be transported somewhere underground on Earth. This still presents the problems of ecological harm and leaves the door wide open for seismic activity to crack the container, thereby releasing radiation into Earth’s biosphere. What if we could stop that possibility? What if we could remove the waste entirely, into a stable environment in which it would no longer be of any concern to us? Space provides these reassurances, with the added guarantee that the material cannot be stolen and used for nefarious purposes. There were several reports done by NASA in the 1980s which detailed how a mission like this could be achieved, however all reports concluded that no further action could be taken due to the technology and public opinion of the project at the time. However, no reports have come into the public domain since then. The NASA Technical Paper 1225 (Nuclear Waste Disposal in Space) gives a highly detailed explanation of how such a mission could occur. It gives several options on various different elements of the mission, such as providing the details of different destinations of the craft, how safe each of these destinations would be for future generations of humanity and how viable they were to reach using the technology they had at the time.
The ideas they had for the destination of the craft ranged from a High Earth Orbit all the way to crashing the craft into the surface of the sun. The below diagram is taken directly from the source in question and outlines the basic advantages and disadvantages of a few destinations they thought of.
The only two options not discussed here are a solar impact and an orbit around Venus. A Solar impact was decided to be impractical as it required far too much energy for even modern day propulsion systems to provide, however the orbit around Venus proves to be slightly more practicable.
If a container was placed in an orbit around Venus it would have the same advantages as a lunar orbit would and would cancel the disadvantage of orbital stability because Venus is so far away in relation to Earth. Even the most prominent of orbital perturbations cannot provide enough energy for an interplanetary transfer to take place. Even though the energy required to put it there is higher than that required of a lunar orbit mission, it still beats the other options that would put it into a Solar orbit and could be easily provided using modern propulsion systems. However, the main advantage that Venus provides is that of us knowing exactly where we put the waste and it still being accessible to future humankind. In the future, mankind may find a way to filter out this waste and reprocess it into new fuels and materials. The ability to collect waste from the reserve around Venus could possibly provide humanity with energy that we would have otherwise have wasted by sending it into an inaccessible orbit.
Nuclear Waste Disposal in Space Report, 1978, NASA