Nuclear power could become increasingly important as the world continues to combat climate change, but atmospheric carbon isn’t the only existential threat to the future of humanity. The waste produced by nuclear power is dangerous for millions of years, and no one can decide what to do with it. Nobel laureate Gérard Mourou is using his notoriety to call attention to an interesting solution. Mourou believes that it may be possible to transmute nuclear waste into a safer form. This isn’t medieval alchemy, though. It’s science and lasers.
Mourou shared half of the 2018 Nobel Prize in physics with Donna Strickland. The pair won for their work inventing a process called Chirped Pulse Amplification (CPA) at the Laboratory for Laser Energetics at the University of Rochester. CPA creates very short laser pulses with ultra-high intensity. The original research focused on applications like laser machining and eye surgery, but scientists could also use it to observe atomic processes that happen at almost unfathomable speeds. If we could speed it up a bit more, Mourou says CPA could have a use in processing nuclear waste, too.
Nuclear waste currently sits in drums in secure facilities across the world, and it’ll be dangerous for many years to come no matter where we store it. The most hazardous waste, uranium 235 and plutonium 239, have a radioactive half-life of about 24,000 years. So, these materials won’t be safe for millions of years. According to Mourou, it may be possible to turn that waste into something you can hold in your hand with a laser.
Close up illustration of atomic particle for nuclear energy imagery. Credit: Getty Images.
Currently, CPA can produce laser pulses as brief as one attosecond — that’s a billionth of a billionth of a second. To transmute nuclear waste into something safe, Mourou says you’d need to increase the pulse rate by roughly 10,000 times. That might sound like a tall order, but CPA itself was an order of magnitude increase over previous lasers. Another innovation like CPA, and we could be in the ballpark.
With an ultra-fast laser pulse, it may be possible to bombard nuclear waste and knock protons out of the nucleus. That turns a dangerous substance like uranium 235 into something comparatively harmless like lead. Other experts have chimed in to note that the physics makes sense on a theoretical level. However, the logistics of developing the right laser technology, separating out radioactive nuclei, and irradiating them is still beyond our reach.
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