Part 2 of 2 Parts (Please read Part 1 first)
Depleted Uranium
Another major product of the nuclear power industry is depleted uranium. This is the uranium left over after the ratio of fissile U-235 to non-fissile U-238 is increased from low natural levels to three to five percent. This byproduct is mainly U-238 and is less radioactive than natural uranium ore because the U-235 has been removed.
Depleted uranium is a heavy, dense metal which makes it useful for military applications. One of these applications is anti-tank ammunition. Depleted uranium shells have excellent penetration ability and can blast through tank armor. When depleted uranium hits a target, it flakes off as it passes through the armor and the projectile stays sharp. The cloud of depleted uranium particles is ignited by the heat of the impact. One big concern about this use is the fact that depleted uranium dust is spread around the battlefield and can be a threat to public health.
Another application for depleted uranium is in chemical processing. Researchers at the University of Sussex in the U.K. have been able to create a catalyst from depleted uranium which can help convert ethylene into ethane. This is a common chemical process using other methods but it is a novel application for depleted uranium.
There are thousands of tons of depleted uranium in stockpiles around the world. This new use in chemical processing would be preferable to either storing it or using it in warfare. It does have to be handled carefully because although it is not very radioactive, it could still pose a health threat.
Remaining Roadblocks
There are still multiple issues of concern in the repurposing of nuclear waste. In many cases, the uses proposed here could result in nuclear waste materials being stolen or diverted adding to the risk of nuclear proliferation.
It only takes a few pounds of plutonium to make a nuclear warhead. If nuclear waste is reprocessed on industrial scales, the amount needed for a nuclear bomb could easily be stolen or diverted without being noticed. It is a serious problem that depends on the exact isotopes and processes in use. Currently, spent nuclear fuel from light water reactors is too hot to be easily handled which reduces the risk of theft or diversion. However, technologies such as the reprocessing of spent nuclear fuel could be adapted to producing weapons-grade nuclear materials which undesirable.
Another issue that has been raised is that recycling and/or reprocessing of nuclear fuel could divert interest and resources from the quest for permanent geological repositories for spent nuclear fuel. Many countries that use nuclear power and produce spent nuclear fuel have been slow to create viable long-term disposal methods for such waste. Considering the danger from long-lived isotopes in spent nuclear fuel, creating such long-terms storage should be a priority.
Final Thoughts
The powerful radioactivity and dangerous nature of nuclear waste raises many challenges for countries that use nuclear power. The way in which this waste is currently handled is to let the stockpiles build up while the debate about ultimate solutions goes on and on. It would be best if new technologies were developed to deal with nuclear waste in a safe and efficient manner. In the meantime, there are a host of difficult political decisions that must be made with respect to the use of nuclear power.