How Much Heat is Produced by Radioactive Waste?

[Ilya Furman]

To begin, I am not sure whether or not this is the correct location for this post since I am a complete greenhorn to this forum (just joined today!).

I ask how much heat is produced by radioactive waste because I was wondering if it was viable to reuse all the tons of stored radioactive waste from nuclear power plants to produce electricity via TEGs (Thermoelectric Generators).

I appreciate any and all thoughts, opinions, and ideas.
Thank you

 

[anorlunda]

This is the correct forum for that question.

Yes, spent fuel generates heat. See this for more details https://www.nrc.gov/docs/ML0037/ML003761667.pdf

Yes that heat warms things up and it needs to be cooled. Yes, you can use warm water to generate electricity by the thermo-electric effect. But the amount of electric energy you would recover that way is tiny, and probably not worth the trouble. There are far better ways to make electric energy.

 

[Ilya Furman]

Thank you so much for the reply, that document is very interesting and it will be useful in my research.

According to the U.S. Government, the United States has about 80,000 metric tons of spent fuel and it is projected to rise to 140,000 metric tons (https://www.gao.gov/key_issues/disposal_of_highlevel_nuclear_waste/issue_summary).

The same site continues to mention that there is no disposal site. Are you certain that if we designed a TEG optimized for this many tons, we would not create a worthy amount of energy?

 

[anorlunda]

Are you certain that if we designed a TEG optimized for this many tons, we would not create a worthy amount of energy?

The only way to be certain is to try it. Have you tried researching the cost per watt of a TEG? Solar PV panels are down to $0.25 or less per watt.

 

[Ilya Furman]

The only way to be certain is to try it. Have you tried researching the cost per watt of a TEG? Solar PV panels are down to $0.25 or less per watt.

No, I have not researched that. I guess I could research a rough estimate of how much energy could be produced. Then consider that result with the necessary costs of the operation to see if it is a good idea. I know TEGs are not really the best energy source but I have worked with one on a extracurricular project. My professor encouraged me to try to brainstorm some ways to apply this technology in a new way.

I doubt I could try to build a working model of my idea since it is dealing with radioactive material.

Thanks for your insight! I will put some more research into the topic and return with findings at a later date.

 

[Rive]

No, I have not researched that.

Some pointers: the heat output of spent nuclear fuel declines over time. Freshly unloaded spent fuel is so 'hot' (in every sense) that it is stored underwater for some years before it can be moved to dry storage. Before that, it is too dangerous. So, you can try to google up the average heat production of a loaded storage cask.
Some years later the heat output falls so low that it's no longer useful for even TEGs.
So what you need is not the accumulated amount of spent fuel, but the spent fuel available in one to ten year, and the heat production.

Then, with the efficiency of TEGs you can get an estimate something about the energy to be harvested.

 

[anorlunda]

No, I have not researched that. I guess I could research a rough estimate of how much energy could be produced. Then consider that result with the necessary costs of the operation to see if it is a good idea. I know TEGs are not really the best energy source but I have worked with one on a extracurricular project. My professor encouraged me to try to brainstorm some ways to apply this technology in a new way.

Your first step in innovating should be to do your TEG research to learn rough numbers for the quantity of power produces, and the quantity of money needed.

Here is a recent and innovative use of TEG https://inhabitat.com/15-year-old-develops-hollow-flashlight-powered-by-body-heat/

I suggest that you'll find much more opportunity to innovate if you focus on milliwatts rather than megawatts. Perhaps a TEG that might permit a remote sensor to operate without a battery or external wires. In that case, it is the remoteness that makes a tiny amount of power very valuable.

I am particularly fond of this anecdote about our #1 innovator, Thomas Edison.

In Edison's boyish days … telegraphic supplies were hard to obtain. But he and his "chum" had a line between their homes, built of common stove-pipe wire. The insulators were bottles set on nails driven into trees and short poles. The magnet wire was wound with rags for insulation, and pieces of spring brass were used for keys. With an idea of securing current cheaply, Edison applied the little that he knew about static electricity, and actually experimented with cats, which he treated vigorously as frictional machines until the animals fled in dismay, and Edison had learned his first great lesson in the relative value of sources of electrical energy.

 

[Bigjoemonger]

Short answer, yes it can be used for TEG's.

Long answer, TEG's are very inefficient. Employeeing them at a commercial power plant would be like using a cigarette lighter to roast a marshmallow when you're standing next to a forest fire.