I am not a nuclear engineer. All I can do is to report a phrase told me by Emilio Segre'. Nobel prize winner, one of the fathers of nuclear energy (and bombs). While visiting in Como an exhibition of ENEL. the Italian public utility which sponsored and financed the Superphenix fast breeder in France, which was later shut down because of losses of its coolant, liquid sodium, he told me: "Breeders are a folly". The Enrico Fermi fast breeder in Detroit was shut down for a similar reason in 1966.
Tullio
I think the point of Thorium is that you can burn down quicker to Lead - so the reactor 'ash' is far less dangerous. The prior 'fast breeders' would yield weapons grade Plutonium - the design manipulated the situation to enhance that.
Also Thorium is about four times more abundant in nature than uranium dioxide. It is more evenly distributed over the planet, so that no region has a monopoly on the stuff.
There are some who can live without wild things and some who cannot. - Aldo Leopold
Here is a CANDU Generation 3+ Reactor Technical Data developed by our (Atomic Energy of Canada) ACEL. I don't know Its like reading car specs I find it enjoyable. ( I almost went for nuclear engineering rather than electrical engineering) It capable of burning mix fuels and including Thorium.
India has a previous design CANDU system being used for power and research in Thorium fuel. Canada broke off cooperation with India when they used product from the reactors to build their nuclear weapons. Cooperation has been re-established again at a small level.
Our PM 'Harper' does not like to travel much:-)
There are some who can live without wild things and some who cannot. - Aldo Leopold
CANDU reactors used to accept natural uranium as fuel elements since they are moderated by heavy water. I see that ACR-1000 needs enriched uranium, otherwise it could not accept thorium fuel elements. Thorium is a fertile nuclide, not a fissile one like U-235. Where does Canada get enriched uranium, since I don't think it has enrichment plants?
Tullio
CANDU reactors used to accept natural uranium as fuel elements since they are moderated by heavy water. I see that ACR-1000 needs enriched uranium, otherwise it could not accept thorium fuel elements. Thorium is a fertile nuclide, not a fissile one like U-235. Where does Canada get enriched uranium, since I don't think it has enrichment plants?
Tullio
Ge Canada is a supplier of fuel bundles for Candu. Here is a Notice for a Public Hearing to produce LEU. It think it from spent fuel rods but I don't know..
There are some who can live without wild things and some who cannot. - Aldo Leopold
CANDU reactors used to accept natural uranium as fuel elements since they are moderated by heavy water. I see that ACR-1000 needs enriched uranium, otherwise it could not accept thorium fuel elements. Thorium is a fertile nuclide, not a fissile one like U-235. Where does Canada get enriched uranium, since I don't think it has enrichment plants?
Tullio
Ge Canada is a supplier of fuel bundles for Candu. Here is a Notice for a Public Hearing to produce LEU. It think it from spent fuel rods but I don't know..
Update: The ACR-100 design won't be finalized until 2012. There is no enrichment facilities in Canada.
The earliest is probably 2015. It is still up in the air one would be built on canadian soil relying on enrichment off shore. Another proposal is to licence the technology from a foreign company and allow them to set up a black box operation on canadian soil. The technology is rather mature and would not be cost effective to develop our own design..
Sorry, I made an error - looked up the wrong line/column in my table of nuclides. U237 has a half-life of months. It is U235 I was after anyway, that being what is enriched in HEU. That has a half life of some 700 million years.
The liquid metal ( lithium/sodium ) coolant idea is a thermodynamic efficiency thing. A nuclear reactor is a heat engine that extracts work while energy flows from a hotter spot to a cooler spot. The efficiency, being the fraction of energy converted to useful/directed work instead of random motion ie. 'waste' heat, goes like ( with temperatures measured on absolute scale ):
1 - (T_cool/T_hot)
so you get closer to unity ( an ideal, unachievable 100% case ) if the gap between T_hot and T_cool is as wide as you can. Typically one uses the liquid metal to transfer the heat from the core to exchange energy with some secondary circuit, say superheated steam running turbines for electricity generation. So lithium is quite hot as a liquid and with decent specific heat capacity to cart the heat off the core.
But lithium is ever so chemically reactive - thus how clever is a heat exchanger between lithium and seawater circuits, eh? Not very.
As for obtaining Uranium fuels I guess Canada could buy it from the US? Or have I demonstrated some terrible gauche/gaffe by suggesting that? :-) :-)
As for 'spent' fuel rods that's also an economic point. They still will generate heat, but much less and much slower too, having climbed well down the nuclear energy ladder. So the efficiency is way down and that flows to the generatable power etc. You could use them for heating say - maybe via a secondary circuit to distribute hot water to keep house structures warm in otherwise freezing climates. But I can't see a Nordic community accepting what is otherwise labeled as nuclear waste though ..... and I don't blame them.
Mind you if it wasn't for nuclear weapons use then radioactive materials would likely be more socially accepted. Particularly given that standard fuels like oil and coal etc are perceived to be 'safe' when they certainly are not. Ditto for conventional vs nuclear weapons. It's these sort of warped risk perceptions that may have to await generational change ( new people born ) for a more objective non-Cold-War viewpoint.
But such suggestions/discussions these days I expect are a bit like Giordano Bruno before The Inquisition - expect flames in return for speaking up. The rabidness of many environmental groups ( they want mainstream respect but can't behave to earn it ) probably precludes that at present.
Cheers, Mike.
( edit ) 'I should pay more attention internally on what is going on..:-)' - don't worry Rod, DownUnda we rarely know what our mob in Canberra is up to - or we find out too late! Which is why the Internet is so valuable, as we can ignore the trash from 'news' organisations. Their bulletins should be re-badged as Factoids For Dummies .... :-)
( edit ) Whoops, ought be Factoids From Dummies!
I have made this letter longer than usual because I lack the time to make it shorter ...
... and my other CPU is a Ryzen 5950X :-) Blaise Pascal
Well I am putting the ACR-100 on the back burner.. You won't see one of them built for next fifteen years if ever.. and like windows .. I would wait for service pack 3..
Edit: The problem with nuclear plant construction is cost overruns that have been as high as 100%. How the hell do you budget that. But when you have a cold war mentality no problem.
There are some who can live without wild things and some who cannot. - Aldo Leopold
The cost of the concept demonstration fusion reactor ITER is even a worse example. It should have cost 5 billion dollars, it is now over 10 billion dollars.
Tullio
Wikipedia says 10 billion euros.
The cost of the concept demonstration fusion reactor ITER is even a worse example. It should have cost 5 billion dollars, it is now over 10 billion dollars.
Tullio
Wikipedia says 10 billion euros.
Last year the province of Ontario utility put out an Request for Proposal (RFP) for 3 Nuclear plants to replace ones that are decommissioning and have been plagued with expensive problems during their lifecyle (Nuclear Energy is reasonably inexpensive on a certain scale and over a good lifecyle). Westinghouse, AREVA, and ACEL responded but Ontario Hydro stated the cost must be fixed. Westinghouse AREVA backed away. ACEL says sure with a big smile on there face.
ACEL is crown corporation. Our government is trying to divest crown corporations like somebody trying to rid of a bad case of the fleas. I agree with this for this reason. Sure ACEL will agree to this. Once they get into trouble, they are at the federal Government with their handout look for a bailout. Of course the country will have to pick up the tab.
Ontario with drew the RFP. They are rethinking their entire power model. Back in the sixties the former PM proposed to create an National Electrical Grid (That is what I call foresight). It never bore fruit because there was too much bickering between the utilities. You have to understand Canada is a very big country in land mass and very few people. Here is Ontario with future potential power capacity problems and Quebec right next door with a tremendous excess capacity of Hydro and no way of carrying it to Ontario because the Grid does not exist. (Of course it can find it way to New England)
In closing.. I would gladly open my check book to create a national electrical grid but not to proof an ACEL design..
There are some who can live without wild things and some who cannot. - Aldo Leopold
I am not a nuclear engineer.
)
I am not a nuclear engineer. All I can do is to report a phrase told me by Emilio Segre'. Nobel prize winner, one of the fathers of nuclear energy (and bombs). While visiting in Como an exhibition of ENEL. the Italian public utility which sponsored and financed the Superphenix fast breeder in France, which was later shut down because of losses of its coolant, liquid sodium, he told me: "Breeders are a folly". The Enrico Fermi fast breeder in Detroit was shut down for a similar reason in 1966.
Tullio
RE: I think the point of
)
Also Thorium is about four times more abundant in nature than uranium dioxide. It is more evenly distributed over the planet, so that no region has a monopoly on the stuff.
There are some who can live without wild things and some who cannot. - Aldo Leopold
Here is a CANDU Generation 3+
)
Here is a CANDU Generation 3+ Reactor Technical Data developed by our (Atomic Energy of Canada) ACEL. I don't know Its like reading car specs I find it enjoyable. ( I almost went for nuclear engineering rather than electrical engineering) It capable of burning mix fuels and including Thorium.
India has a previous design CANDU system being used for power and research in Thorium fuel. Canada broke off cooperation with India when they used product from the reactors to build their nuclear weapons. Cooperation has been re-established again at a small level.
Our PM 'Harper' does not like to travel much:-)
There are some who can live without wild things and some who cannot. - Aldo Leopold
CANDU reactors used to accept
)
CANDU reactors used to accept natural uranium as fuel elements since they are moderated by heavy water. I see that ACR-1000 needs enriched uranium, otherwise it could not accept thorium fuel elements. Thorium is a fertile nuclide, not a fissile one like U-235. Where does Canada get enriched uranium, since I don't think it has enrichment plants?
Tullio
RE: CANDU reactors used to
)
Good Question.. It uses Low Enriched Uranium Fuel
Ge Canada is a supplier of fuel bundles for Candu. Here is a Notice for a Public Hearing to produce LEU. It think it from spent fuel rods but I don't know..
There are some who can live without wild things and some who cannot. - Aldo Leopold
RE: RE: CANDU reactors
)
Update: The ACR-100 design won't be finalized until 2012. There is no enrichment facilities in Canada.
The earliest is probably 2015. It is still up in the air one would be built on canadian soil relying on enrichment off shore. Another proposal is to licence the technology from a foreign company and allow them to set up a black box operation on canadian soil. The technology is rather mature and would not be cost effective to develop our own design..
Uranium Enrichment in Canada
Thanks Tullio. It was interesting exploring.. I should pay more attention internally on what is going on..:-)
There are some who can live without wild things and some who cannot. - Aldo Leopold
Sorry, I made an error -
)
Sorry, I made an error - looked up the wrong line/column in my table of nuclides. U237 has a half-life of months. It is U235 I was after anyway, that being what is enriched in HEU. That has a half life of some 700 million years.
The liquid metal ( lithium/sodium ) coolant idea is a thermodynamic efficiency thing. A nuclear reactor is a heat engine that extracts work while energy flows from a hotter spot to a cooler spot. The efficiency, being the fraction of energy converted to useful/directed work instead of random motion ie. 'waste' heat, goes like ( with temperatures measured on absolute scale ):
1 - (T_cool/T_hot)
so you get closer to unity ( an ideal, unachievable 100% case ) if the gap between T_hot and T_cool is as wide as you can. Typically one uses the liquid metal to transfer the heat from the core to exchange energy with some secondary circuit, say superheated steam running turbines for electricity generation. So lithium is quite hot as a liquid and with decent specific heat capacity to cart the heat off the core.
But lithium is ever so chemically reactive - thus how clever is a heat exchanger between lithium and seawater circuits, eh? Not very.
As for obtaining Uranium fuels I guess Canada could buy it from the US? Or have I demonstrated some terrible gauche/gaffe by suggesting that? :-) :-)
As for 'spent' fuel rods that's also an economic point. They still will generate heat, but much less and much slower too, having climbed well down the nuclear energy ladder. So the efficiency is way down and that flows to the generatable power etc. You could use them for heating say - maybe via a secondary circuit to distribute hot water to keep house structures warm in otherwise freezing climates. But I can't see a Nordic community accepting what is otherwise labeled as nuclear waste though ..... and I don't blame them.
Mind you if it wasn't for nuclear weapons use then radioactive materials would likely be more socially accepted. Particularly given that standard fuels like oil and coal etc are perceived to be 'safe' when they certainly are not. Ditto for conventional vs nuclear weapons. It's these sort of warped risk perceptions that may have to await generational change ( new people born ) for a more objective non-Cold-War viewpoint.
But such suggestions/discussions these days I expect are a bit like Giordano Bruno before The Inquisition - expect flames in return for speaking up. The rabidness of many environmental groups ( they want mainstream respect but can't behave to earn it ) probably precludes that at present.
Cheers, Mike.
( edit ) 'I should pay more attention internally on what is going on..:-)' - don't worry Rod, DownUnda we rarely know what our mob in Canberra is up to - or we find out too late! Which is why the Internet is so valuable, as we can ignore the trash from 'news' organisations. Their bulletins should be re-badged as Factoids For Dummies .... :-)
( edit ) Whoops, ought be Factoids From Dummies!
I have made this letter longer than usual because I lack the time to make it shorter ...
... and my other CPU is a Ryzen 5950X :-) Blaise Pascal
Well I am putting the ACR-100
)
Well I am putting the ACR-100 on the back burner.. You won't see one of them built for next fifteen years if ever.. and like windows .. I would wait for service pack 3..
Edit: The problem with nuclear plant construction is cost overruns that have been as high as 100%. How the hell do you budget that. But when you have a cold war mentality no problem.
There are some who can live without wild things and some who cannot. - Aldo Leopold
The cost of the concept
)
The cost of the concept demonstration fusion reactor ITER is even a worse example. It should have cost 5 billion dollars, it is now over 10 billion dollars.
Tullio
Wikipedia says 10 billion euros.
RE: The cost of the concept
)
Last year the province of Ontario utility put out an Request for Proposal (RFP) for 3 Nuclear plants to replace ones that are decommissioning and have been plagued with expensive problems during their lifecyle (Nuclear Energy is reasonably inexpensive on a certain scale and over a good lifecyle). Westinghouse, AREVA, and ACEL responded but Ontario Hydro stated the cost must be fixed. Westinghouse AREVA backed away. ACEL says sure with a big smile on there face.
ACEL is crown corporation. Our government is trying to divest crown corporations like somebody trying to rid of a bad case of the fleas. I agree with this for this reason. Sure ACEL will agree to this. Once they get into trouble, they are at the federal Government with their handout look for a bailout. Of course the country will have to pick up the tab.
Ontario with drew the RFP. They are rethinking their entire power model. Back in the sixties the former PM proposed to create an National Electrical Grid (That is what I call foresight). It never bore fruit because there was too much bickering between the utilities. You have to understand Canada is a very big country in land mass and very few people. Here is Ontario with future potential power capacity problems and Quebec right next door with a tremendous excess capacity of Hydro and no way of carrying it to Ontario because the Grid does not exist. (Of course it can find it way to New England)
In closing.. I would gladly open my check book to create a national electrical grid but not to proof an ACEL design..
There are some who can live without wild things and some who cannot. - Aldo Leopold