Tag: Yucca Mountain

The case for Thorium. 6. Radioactive waste from an Liquid Fluoride Thorium Reactor decays down to background radiation in 300 years compared to a million years for U-235 based reactors. A Limerick.

The nuclear waste meant for Yucca

would destine Nevada the sucka

But with Thorium we rid

us of waste that is hid

No need for that waste to be trucka!

Radioactive waste from an LFTR (Liquid Fluoride Thorium Reactor)  decays down to background radiation in 300 years instead of a million years for U-235 based reactors. Initially LFTRs produce as much radioactivity as an U-235 based nuclear reactor, since fission converts mass to heat, but the decay products have a much shorter half-life. See the figure below.

Where is the storage for spent nuclear fuel and other nuclear waste now? Look at the map, it is scary.

 

 

 

 

 

 

 

And these are just the U.S. installations!

Many years ago I studied Engineering at Chalmers’ University in Sweden and I thought I would become a nuclear engineer. Sweden had at that time a peaceful heavy water based nuclear power program together with Canada and India. The advantage with heavy water as moderator is that it can use natural, un-enriched Uranium. One of the end products is of course Plutonium 239, the preferred material to make nuclear bombs, but it could also use Thorium, and the end product is then mostly Plutonium 238, used in space exploration, and we were dreaming big. One of the advantages of Thorium as fuel is that it produces about 0,01%  of trans-Uranium waste compared to Uranium as fuel. About that time the U.S. proposed we should abandon the heavy water program and switch to light water enriched Uranium based nuclear power. They would sell the enriched Uranium, and reprocess the spent fuel at cost. They also had the ideal final resting place for the radioactive waste products in Nevada. This was an offer the Swedish government could not refuse, at the height of the cold war. This was  in the 1960’s! India on the other hand did refuse, and they eventually got the nuclear bomb. Since that meant Sweden was never going to use Thorium as nuclear fuel, and I could not figure out how to get rid of all the radioactive waste products, I switched my attention back to control engineering.

 

 

 

 

 

 

 

 

What did President Trump mean with innovative approaches?

Is this where Thorium comes in!?

The need to develop Thorium based Nuclear Energy as the major electric energy supply. 3. One ten-thousandth of the TRansUranium waste compared to a U-235 based fast breeder reactor.

 A Thorium based fast breeder nucear reactor produces much less TRansUranium waste, 0.01% waste products compared to a Uranium-235 fast breeder. The Thorium process has a much higher efficiency of fission than  the Uranium process. See the figure below.

Pu = Plutonium, Am = Americum, Cm = Curium, all TRansUraniums, nasty stuff.

With Thorium based Nuclear power, there are no real problems, with traditional U235 power long tern storage is an immense and urgent problem, and has been since the 1960’s. At that time Sweden had a heavy water  U-238 nuclear power program going, but abandoned it in favor of traditional U-235 power. U.S. promised to provide the material and take care of the reprocessing and final storage of all nuclear waste at cost if Sweden joined the nuclear proliferation treaty. Reprocessing was to be done in Washington State, and one of the final storage sites mentioned was Yucca Mountain in Nevada, having the ideal Geological properties.

Time goes by and in 1982 – Congress passed the Nuclear Waste Policy Act, requiring the establishment of a deep geologic repository for nuclear waste storage and isolation. Yucca Mountain was high on the list out of of 9 possible sites.

Time goes by, and Congress is still not able to decide on a solution. Meanwhile, TRU’s from spent and reprocessed fuel is piling up in less than ideal locations. Thorium based nuclear power would go a long way to alleviate this problem.