[Nuclear Chemistry] - Nuclear Waste

Nuclear waste is the material that nuclear fuel becomes after it is used in a reactor. A reactor is a system that holds and controls sustained nuclear chain reactions. These reactors are used for generating electricity and for organizing research. Nuclear waste is very radioactive and stays that way for thousands of years. When waste first comes out of the reactor, it’s so toxic that if someone stood a few meters of it while it was unshielded, they would obtain a deadly radioactive dose and would die in a few seconds from acute radiation sickness. The used fuel is never unshielded. Instead, it'a kept underwater (water acts as the shield) until the radiation decays to levels that can be shielded by concrete.

In 2016, researchers from Indiana University had found the first actual evidence for a new molecular structure that has the potential to safely store nuclear waste and to reduce the

Bisulfate dimer 

chemical that can contaminate the water and kill large amounts of fish. They found experimental proof of a chemical bond between two negatively charged molecules of bisulfate. This structure is called a supramolecule, meaning there’s a bond between two negatively charged ions. A supramolecule was thought to not exist because it goes against Coulomb’s law. Coulomb's law states that two molecules with the same charge create a repellent force that prevents chemical bonding. This ability to produce a negatively charged bisulfate could advance the search for chemical solutions to solve some environmental problems. These molecules could be used to remove sulfate ions in order to transform nuclear waste into storable solids, this is called vitrification. This process can extract harmful phosphate ions from the environment. Removing phosphate from the environment is beneficial because excess phosphates from fertilizers can leak into lakes and the ocean. When the chemicals get into the water they can cause huge algae blooms that can poison the water supply and kill many fish.

Plutonium

Plutonium has been used in many countries in terms of nuclear energy, but scientists are trying to find heavier nuclear elements to clean up nuclear waste. Recently, Professor Thomas Albrecht-Schmitt explained that plutonium doesn’t really work the way many scientists thought it did. Albrecht-Schmitt and his team created a plutonium-organic hybrid compound that behaves similar to elements lighter than plutonium. His team found that electrons were moving back and forth between two plutonium ions. This was quite strange to them because the movement of electrons between two positive ions usually happens between ions in lighter elements like iron. Albrecht-Schmitt realized there was something different about the compound they engineered mainly because of its color. “Plutonium makes wild, vibrant colors,” said Albrecht-Schmitt. “It can be purple, it can be these beautiful pinks. It can be this super dark black- blue. This compound was brown, like a beautiful brown chocolate bar. When we saw that color, we knew something was electronically unusual about it.” The whole point of Albert-Schmitt's research is to focus on advancing scientific efforts to clean up nuclear waste. “In order to develop materials that trap plutonium, you first have to understand at the most basic level, the electronic properties of plutonium. That means making very simple compounds, characterizing them in exquisite detail and understanding both experimentally and theoretically all of the properties you’re observing,” says Albrecht-Schmitt.

Sources: https://www.sciencedaily.com/releases/2016/12/161221090126.htm
https://whatisnuclear.com/articles/nucreactor.html