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Stainless steel may not be the best choice for storing nuclear waste

Stainless steel may not be the...
Stainless steel may not be the best choice for the long-term storage of nuclear waste
Stainless steel may not be the best choice for the long-term storage of nuclear waste
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Stainless steel may not be the best choice for the long-term storage of nuclear waste
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Stainless steel may not be the best choice for the long-term storage of nuclear waste

A new study by researchers at Ohio State University suggests that stainless steel may not be the best choice for containing high-level nuclear waste. By simulating long-term storage conditions, the team found that the storage materials interact with each other more than previously thought, causing them to degrade faster.

The storage of nuclear waste is more than a perennial political football, it is an existential problem. Whatever one's opinions about nuclear power or weapons, there are thousands of tons of nuclear waste temporarily stored around the world, meaning that a way must be found to store it all safely in the long term.

The most important type of nuclear waste is the high-level waste left over from reprocessing nuclear fuel or from nuclear weapon production. Such waste is made up of a complex mixture of radioactive isotopes with half-lives ranging from years to millennia. Though reactors have been operating all over the world for over 75 years, only Finland has started to build a permanent storage facility for such very dangerous waste.

That may show a remarkable lack of political will or even courage, but perhaps this reluctance will turn out to be serendipitous. That's because the favored way of storing high-level waste is to vitrify it. That is, to mix the isotopes with molten glass or ceramics to form a chemically inert mass that can be sealed in stainless steel canisters before being sealed in an underground storage facility.

That plan may now have to change if the Ohio study is correct. Led by Xiaolei Guo, the team took glasses and ceramics and put them in close contact with stainless steel in various wet solutions for 30 days in conditions similar to those that would be found in the proposed US Yucca Mountain nuclear waste repository.

"In the real-life scenario, the glass or ceramic waste forms would be in close contact with stainless steel canisters," says Xiaolei. "Under specific conditions, the corrosion of stainless steel will go crazy. It creates a super-aggressive environment that can corrode surrounding materials."

They found that the steel interacted with the glass or ceramic to produce severe and localized corrosion that both damaged the steel and corroded and cracked the glass and ceramics. According to the team, this is because the iron in stainless steel has a chemical affinity with the silicon in glass, accelerating corrosion.

"This indicates that the current models may not be sufficient to keep this waste safely stored," says Xiaolei. "And it shows that we need to develop a new model for storing nuclear waste."

The research was published in Nature Materials.

Source: Ohio State University

7 comments
Joe Ondish Sr.
It would be more appropriate to have a photo of an actual spent fuel container that is encased by concrete, rather than mislead people into believing the waste is stored in 55 gallon carbon steel drums.
snowflake0446
I'm not sure to what extent...I'm only a novice, but couldn't Gen IV reactors (fast-reactor versions), "burn" these wastes? If I recall correctly, by finally implementing recycling of nuclear fuel, so that the low-medium radioactive products are removed from the rods and the rods are rebuilt (as in France), the end result is (as stated in the documentation I've read), only those low/medium radioactive products remain.

Another aspect in all this is that according to a former Congressman I used to work with who was for nuclear energy, is that the depleted uranium (fewer U-235 atoms) is either used for warheads or set aside by the EPA. The EPA won't allow the miner to put it back where it came from. With all that U-238 lying around and the supposed ability of fast-breeder reactors to "burn" U-238 as well, wouldn't that help decrease nuclear waste? We could (again supposedly) open the current high-level radioactive casts (the ones that are supposed to go into the Yucca mountain and recycle the waste there and then turn it into medium/low level waste.

I'd say Gen IV Fast-Breeder reactors are a win-win...again based on what I read.
Ernie
This is a "duh" report. People who actually pay attention to science started questing the reliability of the nuclear storage materials in the late 70's. Just as a generalized concept, the ongoing nuclear reactions in nuclear waste would have an effect on the non-nuclear materials surrounding it, changing the ability of the storage material over time. But in the rush to develop the absurdities referred to as nuclear power and nuclear bombs, no one looked at basic science when it came to storing nuclear wastes.
Douglas Rogers
The problem with high level waste is that it is hot and needs to be stored in refractory materials. This material still contains a lot of fuel value. Beryllium fuel elements don't get hot spots like the older zirconium elements and will result in smaller and cooler waste.
aksdad
Use Adamantium. That'll hold anything. Makes great claws, too.
christopher
Just chuck it in the Ocean, like they did at hundreds of locations all the way up to 1982, and that still happens every day (150 tons worth) at Fukushima...
Chris Cha
Encase the waste in lead, then encase it in concrete. Go to the middle of the Death Valley desert, far away from water tables, and use an oil rig to dig a 2 mile deep hole. Place the encased wasted in hole, and pour 50 yards of dirt on it. Repeat until you fill one mile of the hole, and fill the rest of the hole with dirt. Repeat the process. Seems to me you could store quite a bit of waste with minimal environmental impact.