New technique paves the way for improved nuclear waste treatment facilities

Nuclear power is considered one of the ways to reduce dependence on fossil fuels, but one of the issues surrounding how to deal with nuclear waste products remains. Radioactive waste products can be converted into more stable elements, but this process is not yet feasible at scale.

New research led by physicists at the University of Tokyo reveals an important part of the process of making measurements, predictions and models more precisely. Nuclear waste more stable. This could lead to improvements in nuclear waste treatment facilities and new ideas about how some of the heavier elements in the universe came to be.

The very word “nuclear” can be a bit of a trigger for some, understandably so in Japan, where the atomic bomb and the Fukushima disaster are some of the defining moments in its modern history. Still, given Japan’s relative lack of suitable space for renewable energy forms such as solar or wind, Nuclear power The energy sector is considered an important part of decarbonisation efforts.

Because of this, researchers are working hard to improve safety, efficiency and other issues related to nuclear power. Associate Professor Nobuki Ami of the University of Tokyo’s Center for Nuclear Studies and his colleagues believe they can contribute to improving waste processing, a key aspect of nuclear power.

“Broadly speaking, nuclear power works by boiling water using a self-sustaining nuclear decay reaction. The unstable elements break down and decay, releasing heat, which boils the water. are, run turbines. But the process eventually leaves unusable waste that is still radioactive,” said. Mom

“This waste can remain radioactive for hundreds of thousands of years, so it’s usually buried deep underground. But there’s a growing desire to find another way, a way to dispose of unstable radioactive waste. can be made more stable, avoid Radioactive decay And making it far safer to deal with. This is called transmutation.”

Transmutation is the opposite of nuclear decay. Instead of breaking up an element and releasing radiation, a neutron can be added to an unstable element that turns it into a slightly heavier version of itself. Depending on the starting material, this new form may be stable enough to be considered safe.

The problem is that although the process has been generally known for some time, it has been impossible to quantify it accurately enough to take the idea to the next stage and ideally develop a new generation of waste management facilities. Is.

“The idea actually came from a surprising source: colliding stars in particular. Neutron starsAmy said. “Following recent observations of gravitational waves generated by merging neutron stars, researchers are better able to understand the interaction modes of neutrons and their ability to transform other elements.”

“Based on this, we used a number of tools to narrow our focus on how the element selenium, a common nuclear waste product, behaves when bombarded by neutrons. Our The technique allows us to predict how materials absorb neutrons and undergo transformation. This knowledge contributes to the design of nuclear waste transfer facilities.”

It is difficult for researchers to make these kinds of observations. In fact, they are not able to directly observe the conversion processes. Rather, the team can observe how much of the sample is not transmuted, and by taking readings to determine whether transmutation actually occurred, they can estimate, albeit very precisely, how much of the sample has transmuted. .

“We believe our measurements show the true rate of transition of unstable selenium to a more stable form,” said Amy. “We are now planning to measure this for other nuclear waste products. Hopefully, this knowledge will be combined with other areas needed to realize nuclear waste treatment facilities, and we will We can see in the coming decades.”

“However, our goal is to improve. Nuclear safetyI find it interesting that there is a bidirectional relationship between this research and astrophysics. We were fascinated by neutron star collisions, and our research could influence how astrophysicists look at nuclear fusion, the signatures of the creation of elements in stars, to better understand how iron How the heavier elements were formed, including those essential to life.”

Is published In the journal Physics Letters B.