Jan
13
Safer Nuclear Power That Would Move to Thorium Fuel
January 13, 2015 | 6 Comments
Since the resignation of the last Nuclear Regulatory Commission chairman, Gregory Jaczko there has been a general lift in the industry’s spirits. So far the current chairwoman, Allison McFarlane hasn’t made any moves to quell American enthusiasm.
This situation, now well over a year in, has raised a lot of hopes and stirred a lot of activity. That new activity has produced some very interesting ideas and the great “Jaczko Gap” pushed a lot of business out of the U.S. where new partnerships have formed. There is also a good chance that the U.S. has lost or will lose its “Gold Standard” reputation. Its a deep shame, as the U.S. standard could be, and would be the means for a worldwide improvement in both safety and non-proliferation.
The firm ThorCon is offering a straightforward scale-up of the successful Molten Salt Reactor Experiment (MSRE). This isn’t new, its proven technology from the 1960s. The firm’s MSRE is a simple molten salt reactor. Unlike today’s’ commercial; light water reactors with solid fuel rods, the MSRE fuel is in liquid form. If the reactor overheats for whatever reason, this MSRE design will automatically shut itself down, drain the fuel from the primary loop, and passively handle the decay heat. There is no need for any operator intervention. In fact there is nothing the operators can do to prevent the drain and cooling. That could potentially be an operator’s problem, but it would be primarily a power going offline surprise and added expense instead of a threat outside the plant.
Just for certainty a ThorCon MSR would be built 30 meters underground. A ThorCon design has four gas tight barriers between the fuelsalt and the atmosphere. Three of these barriers are more than 25 meters underground. Unlike a light water reactor this MSRE operates at near-ambient air pressure. In the event of a primary loop rupture, there is no dispersal energy and no phase change. The spilled fuel merely flows to a drain tank where it cools. The most troublesome fission products, including strontium-90 and cesium-137, are chemically bound to the salt. These too will end up harmlessly in the drain tank.
The financial goodness of the ThorCon design is requiring one-sixth as much steel and one-fourth as much concrete as an approximate coal plant. A ThorCon MSR “nuclear island” of multiple MSRs requires less than 400 tons of superalloys and other exotic materials.
For those with some construction experience note that very little of a ThorCon MSR’s concrete is reinforced with rebar. Rebar reinforced concrete is impossible to build in an automated way, drives the critical construction path, and its not amenable to block construction. A rebar reinforced concrete structure entombs the critical portion of the plant in a mausoleum making repair and replacement extremely difficult.
But the ThorCon MSR can be produced entirely in bargable blocks at shipyard with assembly line kind of productivity. A 1 GWe ThorCon nuclear island would require less than 200 blocks. The 150 to 500 ton, fully outfitted, pre-tested blocks would barged to the powerplant site. The ThorCon enthusiasm has it that a single large reactor yard could turn out one hundred 1 GWe nuclear islands (20,000 MSRs) per year.
Sounds a bit incredible. But the leadership at ThorCon shouldn’t be dismissed. There is a lot of skill and experience there. Plus the business model makes 21st century sense with the U.S. Nuclear Regulatory Commission killing the industry. One of the leaders is experienced in raising financing for the technology and is actively finding a host country for the prototype power plant. They state quite plainly they are going directly to “the commercial aircraft model, not the Nuclear Regulatory Commission model.”
It would be a huge loss to the U.S. economy.
So how does ThorCon get to a thorium fueled reactor? They’re starting with thorium in the base fuel. In the executive summary they explain, “ThorCon can run on a range of fuelsalts. The baseline ThorCon uses eutectic NaF-BeF2·ThF4·UF4for the fuelsalt. NaF·BeF2is called nabe. The baseline ThorCon fuelsalt is nabe spiked with a 82%/18% mixture of thorium and denatured uranium. Barren nabe is used in the secondary loop.”
“Nabe is not the best salt neutronically. It will absorb about 6% of our neutrons as opposed to 1.5% for salts based on highly enriched 7Li. But nabe is available, reasonably cheap, and, according to our neutronics calculations, plenty good enough for a thorium converter. Nabe increases our fuel costs but that increase is much less than the cost of a lithium based salt if it were available, which it is not.”
Its an excellent executive summary well worth the read (a pdf download).
This firm might well get their prototype built and prove the materials challenges can be met. Its a huge disappointment that the U.S. is out from the running right at the start from regulation having morphed into corporate stateism on to pointless corruption. We’ve been had out of billions of dollars of revenue and thousands of very high quality careers and jobs.
This humble writer wishes them well and God’s speed. The whole world needs more better and cheaper energy supplies.
The story behind the story is an ending to a national leadership program peaking as a world Gold Standard being degraded into national corruption scandal that no one is seeing.
Comments
6 Comments so far
To get Thorium reactors started in the USA – the Pentegon should order them for military reservations where the anti-nuke civilian authorities have no juridiction.
The Thorium nuclear cycle cannot be modified to produce fissionable weapons grade Uranium and Plutonium like the present reactors based on the military technology. But Thorium is much better for commerical use because you don’t use the Thorium cycle if you are really planning to make fissionable material for nuclear weapons. The Molten salt reactor is much more effcient than our current reactors which can only “burn” (fission transmutation) a few percent of the fissionable fuel, so the wastes and refueling problem are largely mitigated. This is the only type of commerical reactors we should have today, forget the light water reactors don’t build those dinosaurs. It is a shame we could have had these reactors 20 years ago if we really wanted to do so. This will be China’s next technology to master and lead in since they desperately need a superior commerical (civilian) nuclear power system to generate electricity.
Agree with Matt, if that is indeed a legally functional route. That would provide zero-carbon / grid-independent power for large installations. That sounds like the requirements are fulfilled for the mission(s).
Also, agree with the author. I think there is something much larger at work; similar to the bigotry that surround non-tokomak projects, which usually goes thusly… “Well, the empirical evidence is encouraging, but we have our entire career(s) and our ego(s) invested in this other technology… so we can’t be wrong and we don’t want to investigate the possibility… no matter how inexpensive the research.”
Where’s FLIBE & Kirk Sorenson?
JPS
Hi JP. http://flibe-energy.com/company/ You might also look at http://www.the-weinberg-foundation.org/blog/ Well worth the time for a whole world view. Thanks for asking. BW
I also feel that it sounds a bit incredible. But the leadership at ThorCon shouldn’t be dismissed. There is a lot of skill and experience there. Plus the business model makes 21st century sense with the U.S. Nuclear Regulatory Commission killing the industry. One of the leaders is experienced in raising financing for the technology and is actively finding a host country for the prototype power plant. They state quite plainly they are going directly to “the commercial aircraft model, not the Nuclear Regulatory Commission model.