How to reduce nuclear waste and make clean electricity at the same time.
Nuclear waste is a tricky problem, just like anything that can make people sick, must be stored under guard away from groundwater and population centers for thousands of years, is incredibly difficult to safely transport, and could be targeted by terrorists.
Ok, so maybe nuclear waste isn’t very much like anything else. That's why it will take a creative solution to dispose of it safely. The United Kingdom has one of the largest stockpiles of nuclear waste in the world, with nearly 100 tons of radioactive plutonium costing the country more than $3 billion a year to store. In February, the U.K.’s nuclear agency put out a request for solutions.
One of the most promising answers came from General Electric Hitachi, which proposed building a nuclear reactor that can process plutonium, producing low-carbon electricity and producing safer, easier to store nuclear waste.
The technology behind the new reactor, called PRISM, was developed in the United States. By using liquid sodium to cool the reactor instead of water, engineers say, the reactor can accomplish nuclear fission with chemically heavier fuels, including modified nuclear waste. One ton of used nuclear fuel can produce enough electricity to power 600,000 U.S. homes for one year—as much as three million tons of coal.
The reactor’s engineers have also learned from the recent disaster in Fukushima, Japan. Should the reactor be approved, it will be built on seismic isolation bearings, which absorbs some of the shock that occurs during an earthquake. Unlike like the reactor at Fukushima, which malfunctioned when it overheated, the PRISM reactor relies on passive cooling that Eric Loewen, the chief engineer behind the project, says can remove heat indefinitely without human help.
The waste produced by PRISM is much less radioactive than the fuel that went in; it needs to be stored for hundreds of years, rather than tens of thousands, and is easier to store and transport. GE also hopes that, should the U.K. get behind the reactor, they will also be interested in upgrading to a more robust nuclear fuel recycling system that would reduce waste impact even further.
PRISM’s chief competitor is a disposal process that creates MOX—mixed oxide—fuel by blending waste plutonium with other nuclear materials in a way that can be used in nuclear reactors. But this approach would require additional processing that doesn’t produce electricity, and would also require the government to find someone to purchase the MOX fuel, which is not used in new nuclear reactors and isn’t in high demand.
The process of approving and constructing this reactor will, if successful, still take more than a decade, and require a multi-billion-dollar expense on the part of the U.K. government. While the controversy over nuclear power—whether the benefits of clean energy are worth the environmental, human and security risks—isn’t going away any time soon, the pressures of climate change will maintain nuclear power as a viable part of a clean energy strategy. If a nuclear reactor can help reduce the dangerous waste from previous nuclear experiments, so much the better.
Photo courtesy of GE