The molten salt / Thorium reactor (a.k.a. LFTR) wouldn't have this problem. If it started to "run away" the salt plugs would melt and the whole fuel load would drop into the unmoderated catchments. No moderator, no reaction, end of issue.
I particularly like this hybrid in that there would be NO need to re-process the fuel wrt the actinides but only to remove the fission products.
New Scientist mentions Fusion-Fission hybrids
You still have the residual heat problem. It may be more tractable. It doesn't go away as long as there are fission fragments in the mix. You don't want to remove them from an operating reactor (if you can help it) because they represent 10% of your fission power.KitemanSA wrote:The molten salt / Thorium reactor (a.k.a. LFTR) wouldn't have this problem. If it started to "run away" the salt plugs would melt and the whole fuel load would drop into the unmoderated catchments. No moderator, no reaction, end of issue.
I particularly like this hybrid in that there would be NO need to re-process the fuel wrt the actinides but only to remove the fission products.
If you do remove them you have to cool the remover for about 3 days after shut down.
Engineering is the art of making what you want from what you can get at a profit.
It is not going to freeze right away unless your conduction is really good. But I do agree that it could work even if it has not been tested.KitemanSA wrote:Simple conduction out of the catchment suffices. It has been done ... repeatedly IIRC. Indeed, it is how the experimental reactor was shut down. Turn off the refrigerator for the plugs, they melt, the fuel/salt dump and freeze. No prob, Bob!MSimon wrote: You still have the residual heat problem.
BTW you have to operate the reactor for 10 or 30 days (I forget which) at full power to get a full fission fragment load. But you can calculate the maximum by operating for just a few days and then dumping (the typical bathtub flow problem - filling the tub with an open drain).
Wait - if the half life of importance is 3 days or so 30 days of full power will give you a full load. But 10 days will get you 95%.
Engineering is the art of making what you want from what you can get at a profit.
The problem I have with Thorium reactors is that the U232 (?) is fissile bomb material. It can be separated chemically, ie relatively easily.
But, it only lasts a few weeks, which is a show stopper for someone sane who only holds these things for deterrence and would like to keep them ready for decades or centuries and never use them.
But, for someone who wants to make them and use them right away and has people to burn it is not such a problem. Their problem then becomes use-it-or-lose-it.
Unstable nuclear weapons in the hands of unstable people/political/religious groups: very dangerous.
But, it only lasts a few weeks, which is a show stopper for someone sane who only holds these things for deterrence and would like to keep them ready for decades or centuries and never use them.
But, for someone who wants to make them and use them right away and has people to burn it is not such a problem. Their problem then becomes use-it-or-lose-it.
Unstable nuclear weapons in the hands of unstable people/political/religious groups: very dangerous.
-Tom Boydston-
"If we knew what we were doing, it wouldn’t be called research, would it?" ~Albert Einstein
"If we knew what we were doing, it wouldn’t be called research, would it?" ~Albert Einstein
Actually it is the U233 that is fissile. The U232 is a hard gamma emitter that seems will just ruin the day of anyone wanting to make the bred U into a bomb. But left in the fuel it gets burned eventually. Thyat is why I like the neutron augmentation of the hybred reactor. There need be no removal of the actinides at all.tombo wrote:The problem I have with Thorium reactors is that the U232 (?) is fissile bomb material. It can be separated chemically, ie relatively easily.