A Role for Fusion? (to eliminate nuclear waste)

[John d Marano]

I know fusion power is not economical but can a fusion reactor be used to eliminate nuclear waste (from old fission reactors)?Regards,
JDM

 

[mathman]

The problem with fusion power today is not economics, but rather finding a system that works.

 

[Hercuflea]

Fusion is not waste free, but a decommissioned fusion reactor would generally be much less radioactive than a nuclear waste repository.

 

[the_wolfman]

I know fusion power is not economical but can a fusion reactor be used to eliminate nuclear waste (from old fission reactors)?Regards,
JDM

Yes. There are a few people who advocate a fusion-fission hybrid. One of the advantages of the hybrid reactor is that you could use it to destroy high level waste. The hybrid concept also reduces some of the demands of fusion power plant by using a fusion blanket to produce some power. (Making it easier to build and cheeper). The downside is that you now have to deal with all the issues associated with both fission and fusion.

The hybrid makes some since if you're coming form the fusion side. The argument is a hybrid reactor could be a stepping stone towards a "pure" fusion power plant. On the other hand if you're a fission guy, then I think it makes a lot more since to build a fast reactor to burn the waste.

 

[John d Marano]

Yes. There are a few people who advocate a fusion-fission hybrid. One of the advantages of the hybrid reactor is that you could use it to destroy high level waste. The hybrid concept also reduces some of the demands of fusion power plant by using a fusion blanket to produce some power. (Making it easier to build and cheeper). The downside is that you now have to deal with all the issues associated with both fission and fusion.

The hybrid makes some since if you're coming form the fusion side. The argument is a hybrid reactor could be a stepping stone towards a "pure" fusion power plant. On the other hand if you're a fission guy, then I think it makes a lot more since to build a fast reactor to burn the waste.

Could a hybrid reactor be built from upgrading an old fission reactor? Would it make economical sense? I ask because I keep hearing that so many countries are getting ride of old fission reactors so I was wondering what these countries are going to do with all these old billion dollar sites . . .

 

[the_wolfman]

Could a hybrid reactor be built from upgrading an old fission reactor? Would it make economical sense? I ask because I keep hearing that so many countries are getting ride of old fission reactors so I was wondering what these countries are going to do with all these old billion dollar sites . . .

A fusion-fission hybrid reactor is very different than a commercial fission power reactor. So no you can't really upgrade a fission reactor into a fusion-fission hybrid.

 

[John d Marano]

A fusion-fission hybrid reactor is very different than a commercial fission power reactor. So no you can't really upgrade a fission reactor into a fusion-fission hybrid.

I was thinking mainly that since a hybrid reactor would be in the foot of an old reactor it would diffuse community opposition. Specifically since a hybrid could eliminate waste from the old fission reactor communities will welcome hybrids.

The alternative being that a shut down reactor sits in a community for fifty years with the waste no where to go. Instead you can reuse the concrete shell, the land, fresh water source and open a hybrid fission/fusion reactor . . .

 

[the_wolfman]

I was thinking mainly that since a hybrid reactor would be in the foot of an old reactor it would diffuse community opposition. Specifically since a hybrid could eliminate waste from the old fission reactor communities will welcome hybrids.

The alternative being that a shut down reactor sits in a community for fifty years with the waste no where to go. Instead you can reuse the concrete shell, the land, fresh water source and open a hybrid fission/fusion reactor . . .

There may be political/economic reasons to build a new fusion-fission hybrid power plant at the site of an old fission power plant. For example it may be easier to get a license to build the plant, you may be able to reuse existing high voltage transmission lines, etc. I think it's unlikely that you'd be able to reuse the containment building. For starters the fusion-fission hybrid reactor probably won't fit inside the containment building. But you may be able to reuse some of the other existing infrastructure.

However, communities that are upset about a shut nuclear down power plant are not going to build thrilled about a new nuclear power plant in it's place. Also spent fuel has to be reprocessed before it can be reused. Communities who are upset about spent fuel in dry cask storage probably don't want a nuclear fuel reprocessing plant in their back yard. It would be better to build a national reprocessing facility elsewhere, and ship the spent fuel there. In general the answer "more nuclear" is not the way to appease community opposition to nuclear. It is a different story if the community is really upset about the job loss associated with closing down a power plant.

There are communities that receive nuclear positively. I think it's better to work with these communities to find good sites for a national reprocessing facility or a new nuclear plant regardless of it's type (fission, fission-fusion hybrid, and hopefully someday fusion).

 

[John d Marano]

There may be political/economic reasons to build a new fusion-fission hybrid power plant at the site of an old fission power plant. For example it may be easier to get a license to build the plant, you may be able to reuse existing high voltage transmission lines, etc. I think it's unlikely that you'd be able to reuse the containment building. For starters the fusion-fission hybrid reactor probably won't fit inside the containment building. But you may be able to reuse some of the other existing infrastructure.

However, communities that are upset about a shut nuclear down power plant are not going to build thrilled about a new nuclear power plant in it's place. Also spent fuel has to be reprocessed before it can be reused. Communities who are upset about spent fuel in dry cask storage probably don't want a nuclear fuel reprocessing plant in their back yard. It would be better to build a national reprocessing facility elsewhere, and ship the spent fuel there. In general the answer "more nuclear" is not the way to appease community opposition to nuclear. It is a different story if the community is really upset about the job loss associated with closing down a power plant.

There are communities that receive nuclear positively. I think it's better to work with these communities to find good sites for a national reprocessing facility or a new nuclear plant regardless of it's type (fission, fission-fusion hybrid, and hopefully someday fusion).

Opposition to nuclear power is intense. The evidence being the average age of reactors in the US is 35 years old and the last on built was Tennessee's Watts Bar 1 in 1996 https://www.eia.gov/tools/faqs/faq.cfm?id=228&t=21 .

I'm not saying reusing an old reactor site (for a reactor that processes waste) is a perfect solution but it's the best option for eliminating waste and keeping at least some of the industry alive . . .

 

[mheslep]

Opposition to nuclear power is intense. The evidence being the average age of reactors in the US is 35 years old and the last on built was Tennessee's Watts Bar 1 in 1996 https://www.eia.gov/tools/faqs/faq.cfm?id=228&t=21 .

I'm not saying reusing an old reactor site (for a reactor that processes waste) is a perfect solution but it's the best option for eliminating waste and keeping at least some of the industry alive . . .

The latest reactor placed online in the US started last month, Watts Bar 2. Four more light water reactors are under construction in the US. The US has half a dozen next generation nuclear power start up companies. Globally, 60 reactors are under construction in 15 countries, 20 of these in China where a new reactor comes online at an average of one every two months.

 

[Rive]

I know fusion power is not economical but can a fusion reactor be used to eliminate nuclear waste (from old fission reactors)?

The more I read about this the more concerns I have.

First, the amount of nuclear waste what needs to be addressed like this.
For high activity waste, it's futile. Just by leaving that stuff alone the problem solves itself within a few years.
For low activity waste, it's only a perfect way to spice it up to the point where it goes from 'mostly harmless' to 'hard to handle'.
It seems to be an option only for mid level activity, where the half-life is inconveniently long, but it's yet not long enough so it won't fit back to nature.

But is there that much waste with mid-level activity, which cannot be considered as 'fuel'?
Actually, I don't know this for certain, but feels suspicious.

Second. The idea - in general - is, that extra neutrons from the fusion will split/transform the waste.
However, the neutrons are pretty hard to steer. They won't hit only the waste, they will hit everything on the way. It seems to be hard to imagine a configuration where the waste at the end will be less than the waste in the beginning, since the container will just join the party...

Dunno. I think some more advanced fuel cycle would be better than push the problem to fusion.