Saturday, November 22, 2008

Thorium at Google's Tech Talk

Dr. Joe Bonometti, with the help of thorium expert Kirk Sorensen, gave about an hour long "tech talk" at Google discussing liquid fluoride thorium reactors. Here's the video:



Slowly but surely thorium is gaining greater and greater interest in the country. Atomic Insights has some thoughts on how to keep it going.

10 comments:

Kirk Sorensen said...

Thanks for posting this David!

Anonymous said...

Good talk on MSRs. Everything about them seems so right; but, then I start to think about how hot the primary/secondary loop heat exchanger will be as well as all primary loop piping. I know the fission products are removed constantly, but there will always be some and a lot more than any LWR. But as he said, this is a large chemical engineering project as well, a field in which I have little knowledge.

Ian said...

great vid, spent the morning watching the whole thing. :)

Carlos H. Juárez-Gosselin said...

This is a great video. It would just be nice if people would stop saying "nucular".

J Speaker said...

Well worth watching and, with a couple of exceptions, will hold the attention of non-engineers interested in energy. Dr. Bonometti discussed features of the Liquid Fluoride Thorium Reactor (LFTR) that make it extraordinarily safe (and here I'm writing to engineers) such as atmospheric-pressure primary coolant, chemically well-behaved primary coolant, very low excess reactivity, strong no-delay negative temperature coefficient of reactivity, continuous fission product removal and passive cooling, passive overheating shutdown and quick recovery therefrom, etc. In my opinion, although the passively-safe Light Water Reactors (LWRs) now being ordered by utilities are calculated to be about 1000 times safer than U.S. LWRs now in operation (which have a long and excellent safety record), they are not safe enough to be sited in cities--but the LFTR is.

One point that I wish Dr. Bonometti had discussed is an implication of the extraordinary level of safety of the LFTR: that it could be located close enough to large population centers to provide district heating and cooling (via the ammonia absorption cycle) from the ~50% of heat normally wasted by any type of plant sited in the hinterlands. Such a cogeneration, or combined heat and power plant fueled mainly by waste wood but partially by natural gas provides downtown St. Paul, MN with heated and chilled water via underground insulated pipes (it also sells electricity to the grid). Similar plants are common in Europe, especially so in Denmark where they have substantially reduced the use of oil and natural gas for heating/cooling.

High capital cost, low fuel cost power plants (nuclear and to some extent waste wood-fired biomass) need to be operated 24/7 at 100% power as much as possible to reduce the capital component of the cost of a unit of electricity to its minimum. Comparatively, high fuel cost, low capital cost power plants (oil, natural gas and coal in decreasing order of fuel cost) need to be operated as little as possible to reduce the fuel component of the cost of a unit of electricity to its minimum. In a rational world, nuclear plants supplemented by coal plants would provide the base load and some portion of daily cycling and natural gas-fired plants, rooftop photovoltaic (eventually) and wind turbines would handle the relatively small amount of remaining demand (peaking). Biomass is a niche player, but well-suited for base load. Therefore a city's relatively constant demand profile for heating/cooling/electricity is more closely matched by the economic operation profile of nuclear (&coal) plants than by that of the other plants. An advantage of the LFTR over other reactor types is that daily power cycling would be a snap as there is essentially no Xenon poisoning and the fuel is liquid so there would be no concern about power changes damaging fuel cladding. This LFTR advantage would reduce somewhat the need for higher fuel cost plants (e.g., coal) for daily cycling but would not diminish the need for peaking plants.

Anonymous said...

Can you explain me why molten salts reactors can be safer than a "traditional" solid fuel reactor, where there are different redundant barriers against radioactive pollution. How is this problem solved in liquid fuel reactors?

LarryD said...

There's more than one correct way to pronounce "nuclear".

Don't get uptight just because someone pronounces one of the other correct ways.

----
Back when atomic energy was the stuff of science fiction, the writers usually picked thorium as the fuel, it seemed the most logical choice.

Georgfelis said...

Question: One of the difficulties of using a LFTR to make Hydrogen is the tested and working reactor material is only safe up to about 800C, and H2 manufacture would require a temp of 950C or so.

What would prevent you from heating the material to 800C, then piping it into an electric furnace for that extra 150C of heating. The electric furnace can be powered from the waste heat of the reactor.

Seems a lot easier (and safer) than trying to get the whole reactor to work at 950C, although less efficient. It would also allow you to throttle the electrical output of the plant by controlling how much H2 was being generated at the moment, something that Nukes are normally quite bad at.

Paul Hager said...

Haven't watched the video yet but looking forward to it. This topic has been an interest of mine for close to 30 years. I wrote an article back in 1981 dealing with molten salt fusion-fission hybrid technology (see http://www.paulhager.org/libertarian/FFhybrid.html)

Expect that the anti-nuke Luddites will be unimpressed with MSR technology. It will still produce waste and, worse from their perspective, it reprocesses its fuel. The production of nuclear fuel (by breeding or otherwise) is evil unless it is being done by the Islamic Republic of Iran.

Anonymous said...

"Can you explain me why molten salts reactors can be safer than a "traditional" solid fuel reactor, where there are different redundant barriers against radioactive pollution. How is this problem solved in liquid fuel reactors?"

Nuclear reactions depend on nuclear fuel density. If the fuel density drops then the reaction stops. In the LFTR, the molten salt expands as it gets hot. If it gets too hot, it expands too much and the reaction stops.