Thorium nuclear reactors could be our bridge to renewable energy

Climate change dwarfs the coronavirus as a threat to humanity. Greenhouse gasses are worse than nuclear waste — we cannot isolate and dispose of greenhouse gasses. They will be with us even after we stop creating them. What should we do?

We need a National Climate Mitigation Plan.

Let’s consider just one controversial opportunity: nuclear power as a “bridge” to 100% renewable power. Can we safely use nuclear power for a few more centuries? Nuclear power plants and waste dumps are subject to disasters and technical failure. Is a nuclear waste dump worse than rising CO2 levels? Good question.

Nuclear power comes in two flavors — fusion and fission. Fusion makes the sun and H-bombs work. It’s not usable (yet) in power plants. Fission, on the other hand, has been used to make weapons and to generate electricity.

What’s the difference between radioactive decay and nuclear fission? Radioactive decay is predictable; you can’t change its intensity, risk, or duration. Think of your household smoke detector; it emits low-level radiation for years.

In nuclear fission, the atomic nucleus splits. A mixture of various radioactive fission (waste) products, radiation, and heat is produced. Fission can be gradual and controlled, as in a power plant, or instantaneous as in a bomb.

A nuclear power plant today splits uranium 235, and changes uranium 238 into plutonium. Plutonium is radioactive and useful as nuclear fuel, but like uranium 235 it produces nasty waste in “spent fuel rods.” These waste products are a huge problem. The spent fuel must be isolated and cooled to prevent a meltdown before recovery of plutonium is possible. Waste containing plutonium may be diverted into weapons. The residual waste remains highly radioactive for millennia, and storage is an issue.

Some people think smaller uranium reactors are suitable for use around the country. Maybe so, but the waste from uranium and plutonium reactors needs storage for tens of thousands of years. How can we keep all these reactors (and their waste) secure? We should look elsewhere.

Here is a possible solution. Instead of uranium, why not use its neighbor element, thorium? Using thorium instead of uranium and plutonium avoids some of the waste storage problem and all of the weapons problem.

So what is thorium?

Thorium-233 is a natural radioactive element that can be used in power reactors, but won’t make bombs. The thorium atom itself does not split. It is converted in a reactor into uranium-233, which does. In a thorium reactor, no plutonium is produced. Because we can’t use thorium to make bombs, we have ignored thorium since the 1940s. We got hooked on uranium and plutonium. With thorium, we have a shorter waste storage problem to deal with; we humans can deal with the necessary time frame (500-1,000 years).

Thorium is available in quantity for power production over 500 years or more. Thorium nuclear waste is less intensely radioactive than uranium waste. Thorium waste does not require storage for tens of thousands of years. There’s no bomb risk. Thorium based fission is being developed in other countries.

In June, the Democratic Party published a detailed plan — Solving the Climate Crisis — but it ignores thorium-based reactors. We need to consider thorium in our National Climate Mitigation Plan because greenhouse gasses are a greater threat than nuclear waste and weapons. Talk to the Democrats after the election.

Frank Turner is a member of The Olympian’s 2020 Board of Contributors, and a retired physician (not a physicist). He is active in a number of climate action groups. He can be reached at ft113203@gmail.com