Scientists from the University of Warwick believe they may have discovered a way to shrink the thickness of a nuclear waste bubble that has long been found inside cores and fuel pools of spent nuclear fuel rods.
It could potentially be the final stop on the fuel cycle for nuclear waste as used reprocessing technology is being gradually abandoned for easier transportation, making the waste waste less likely to melt down or leak, according to Daniel Ballew, a professor of physics at the University of Warwick and senior author of the study.
For a big enough liquid to be converted into beryllium, there are currently two methods: one using dry ice, and the other using mixed oxygen and hydrogen gas. In the unlikely event that a boiling source of liquid beryllium could be found, investigators now believe the latter method would be the most effective.
This process would involve heating, by injecting water at high temperatures into the most basic solid-state properties of beryllium — a white powder that reacts with hydrogen to emit light. The hydrogen gas would then be heated to about 3,000 degrees centigrade, but further heating would allow it to become a liquid, which can then be processed and cooled and then ultimately returned to a waste reservoir.
Typically, when released into the environment, depleted nuclear waste is broken up, frozen, or destroyed by radiation. But experts say the reuse of spent nuclear fuel rods is one of the most promising means of resolving the problem. Many reprocessing facilities have even been built to remove spent fuel from nuclear reactors in the United States.
But because the waste is being stored deep inside spent fuel pools and nuclear fuel is mostly held in uranium-238 iron, some experts believe that eventually the spent fuel will need to be reprocessed into plutonium-238. Farther removed, the plutonium will have little value as a fuel source — plutonium may be at best a clean energy solution that would otherwise burn once burned. For this reason, reprocessing at that level is very expensive.
“Taken together, our findings add to a growing body of evidence that reprocessing waste is a less expensive and simpler way to retrieve this waste,” Ballew said in a statement.
It’s therefore unlikely that nuclear waste will need to be kept in a low-sulfur fuels pool at the same depth as uranium-238, given that it would be much easier to melt down and re-purpose.