By Mark Halper
Posting in Design
A nuclear future built on thorium instead of uranium would be safe and efficient, says Kirk Sorensen. It's an old idea, but he has started a new reactor company in Alabama to pursue it.
Kirk Sorensen believes firmly that safe nuclear power can contribute significantly to the world’s energy future – provided that reactors run on liquid thorium fuel rather than on solid uranium as they do today.
Showing the courage of his convictions, Sorensen has quietly launched his own thorium reactor company, called Flibe Energy, in Huntsville, Ala. He aims to have liquid thorium reactors operating within 5 to 8 years.
Sorensen says he wants to “redefine” nuclear, so that it deservedly takes on a clean and safe association, contrary to its long running negative place in popular opinion, as swaths of the public fear the hazards of nuclear waste and nuclear power accidents. The industry is fighting harder than ever to improve nuclear’s image after the meltdown earlier this year at Japan’s Fukushima Daiichi plant.
“After Fukushima, everybody is asking whether nuclear power can be safe,” Sorensen (pictured, below) said in an interview. His resounding answer is “yes.”
But it will take nothing less than for the industry to shift from its conventional reactor designs and from the uranium 235 fuel process on which it began to settle in the 1960s, according to Sorensen.
Instead, he says, it has to adopt a liquid thorium technology similar to what nuclear developers built in the 1960s at Oak Ridge National Laboratory in Tennessee, but that lost out (pictured above).
“In the 40s and 50s they had an expansive definition of what nuclear power was – it wasn’t just solid fuel uranium reactors,” said Sorensen, who is Flibe’s president. “But that’s what it has come to mean now.”
Thorium lost in part because it did not create lethal waste - plutonium - that could be used to make bombs the way uranium did. In the heat of the Cold War, the U.S. government and military demanded such deadly material. (Oak Ridge originated in the 1940s to support the Manhattan Project, which developed the world’s first atomic bomb).
Today, other countries including China and India are pursuing thorium nuclear projects. Sorensen believes that thorium should be the pillar of an American nuclear future, because thorium “is so fundamentally different than every other nuclear story out there right now.”
Because his thorium reactor would not produce plutonium, it would mitigate the chance of nuclear weapons proliferation and eliminate the need for utilities to bury plutonium waste.
Although thorium in some designs does produce plutonium waste, that waste is less hazardous than other mixes of plutonium waste, there's less of it, and it decomposes much faster than conventional waste – hundreds of years rather than thousands or more, according to various thorium proponents.
And thorium-based fuel fissions much more efficiently than does uranium 235, meaning a thorium reactor requires less fuel.
That is in part because the fission cycle runs hotter than conventional uranium cycles, said Sorensen. In the Flibe design, thorium reaction temperatures rise to about 750 degrees Celsius to drive gas turbines, compared to conventional reactors, which tend to reach less than half that temperature and drive less efficient steam turbines, he said.
“The hotter you can get, the more efficiently you can turn heat into electricity,” said Sorensen. “Typical reactors today, they only get about one third conversion efficiency. We can get about half.” He also claims that in his design, thorium “isobreeds”, meaning it creates as much fissile fuel as it burns up.
For Sorensen, the key to making it happen is to deploy an unconventional reactor technology, called a Liquid Fluoride Thorium Reactor (LFTR, pronounced “lifter”). It is a type of molten salt reactor, which uses liquid salt rather than water as its coolant, akin to what Oak Ridge developed.
Flibe’s LFTR uses a liquid fluoride salt to serve both as fuel carrier and coolant. The fuel consists of thorium and uranium 233 – different from the uranium 235 used in conventional reactors. It fissions in the liquid, heats up, and passes through a heat exchanger that conveys the heat to fuel-free liquid fluoride salt that eventually drives the gas turbine.
In the event of a total power loss, a frozen plug melts, allowing the fuel to drain into a passively cooled tank where fission stops. Normally, the plug is kept frozen by an external cooling fan.
The company name, Flibe, comes from the scientific term FLiBe, an anagram and acronym for the molten salt that Sorensen uses, which consists of lithium fluoride (LiF) and beryllium fluoride (BeF2).
Another inherent safety feature of the LFTR is that it runs at normal atmospheric pressure, rather than at the 3000-psi that many conventionally cooled reactors require to keep cooling water in liquid state, Sorensen claimed.
Conventional cooling systems can also require external generators to help pump and recombine water, and those generators can fail such as at Fukushima.
Some of Sorensen’s thorium competitors advocate using thorium in conventional reactors like pressurized water reactors, using thorium in solid fuel form, not liquid. They say that would substantially lower the costs of moving to a new fuel, because it would not entail the high-priced development of new reactors.
Sorensen countered that you only get the full benefits of thorium by applying it in a LFTR type reactor.
Sorensen faces huge hurdles. His project won’t be cheap. Flibe co-founder and chief legal counsel Kirk Dorius estimates it will cost at least $1 billion to develop a modest utility-sized reactor (it’s not clear whether that would mean something around or above a gigawatt of capacity).
So Flibe is initially focusing on smaller, “modular”-sized reactors of around 20 to 30 megawatts. Dorius said even that size would cost “hundreds of millions” for “the first in kind demonstrator reactors” but that “mass production” could slash costs in half within 5 years.
He faces stiff resistance from the status quo, as the nuclear supply chain is heavily vested in solid uranium 235. Likewise, other carbon-free alternatives such as wind and solar are gaining traction. And regulators like the Nuclear Regulatory Commission in the U.S. would have to approve LFTR, which is not assured.
If anyone can pull this off, it’s Sorensen, an impassioned thorium zealot who worked as chief nuclear technologist at Huntsville-based Teledyne Brown until he left earlier this year, and who also runs a blog called EnergyFromThorium.
“It’s a challenge,” said Sorensen. “But what is the end product worth to the world? I’d say the benefit is more than compelling enough to take on the risk. If we don’t change the public’s definition of nuclear power pretty soon, it’s going to become more and more difficult to realize the great potential of nuclear energy.”
Top: Wikimedia Commons (from U.S Federal Government)
Lower: provided by Kirk Sorensen
Jul 20, 2011
There are thousands of people who can fact check articles about nuclear energy. You can find some of them here: https://www.facebook.com/EnergyFromThorium Most of them would would probably do it for free if you ask. I'm not going to point out any inconsistencies here, though I assure you there are several. None are earth-shattering, but I truly wish bloggers would have someone with the appropriate technical knowledge proofread their text before they post. I understand a technical writer makes difficult subjects accessible to laymen -- but that doesn't mean articles can't be technically accurate.
No, xenon isn't chemically poisonous, in fact it's inert, or as they say of gases, 'noble'. But the fission products of a reactor include isotopes of xenon, some of which are profound neutron absorbers. That upsets the chain reaction. Worse still, they're a secondary product that increases when the reactor is shut down. They're not very long lived, Xe-135 has a half life of just over 9 hours. In rods of solid fuel, the gas atoms distort them. Perhaps the neatest property of the Liquid Fluoride Thorium Reactor is that an arrangement can be made to suck off or bubble off the xenon at the highest point of the circuit, let it into a storage cavity, and let it decay to solid or dust there. This makes the reactor more stable, and also more responsive.
CANDU reactors can burn thorium, yellow cake (ie natural, unenriched uranium) spend fuel rods from light water reactors, (you know the ones that boiled off at Fukushima) and weapons grade uranium and plutonium from old weapons. They can replace the rods while the reactor is running, can cool down in a day, etc, etc.....the technology already exists. China is already burning Thorium in CANDU reactors. This has been around for over 50 years.....new? Just not well known.
The LFTR architecture is "right ON" Japan will not be scared from nuclear, only from solid Uranium. Whether they join with China or go it alone to build their LFTR., here is a second powerhouse. For a third, see Singapore: whose government has declared itself in favour of nuclear energy; and they too (pop. 90% expatriate Chinese, Literate & English speaking) will choose the LIFTR architecture. What else? And Korea? Like Singapore, they too see profits from all their high tech exports drained by high cost of fossil fuel imports. Watch for these four Asian Tigers to get it right this time! P. Daykin Ph.D. (UBC 1952/physics)
In Feb 2011, China announced that it plans to mass-produce and export thousands of transportable Thorium LFTR units which will gradually replace coal-fired boilers in existing electricity plants worldwide. These 'mass produced' power plants will provide 'carbon free' electricity at a fifth the price of coal-fired. This announcement will drastically change the whole 'Renewable Energy' debate. May 2011 - Quoting Lee Easton of the Canadian 'Alberta Party'.. "China is racing ahead of everyone in LFTR (thorium reactor) development, and have stated their intention to control the intellectual property. July 2011 - Article From 'Russia Today'. "It's impossible for China to give up nuclear energy... No-one in China is under any illusions that the country desperately needs to find alternative, clean ways to generate electricity. The current reliance on coal, which provides some 80 per cent of Chinese energy needs, costs the economy more than $200 billion a year through air pollution alone." - "they are pouring millions of dollars into Thorium research." Quoting the Vs20 Group.. "The world has been waiting 50 years for someone with enough money to perfect thorium reactors. Following this Chinese announcement, India, Japan, Russia & USA are now defensively stepping up their LFTR research!
...reads like a conspiracy novel, so much so that I've been trying to figure out whether it's real or not. Seems it is real! And as there's so much talk of it lately, perhaps in 50 years we'll have that clean air we all hope for. This could even help to make electrically powered transportation more feasible, because infrastructure to support it would no longer require air-polluting production of the power. Of course, the most rabid environmentalists will be disappointed that we don't get forced out of our cars, but they'll eventually refocus their efforts toward whatever important fight is next.
Over here in the UK, we have a Campaigning Website called '38 Degrees'. Anyone can suggest a campaign issue and a recent success was a high level of votes on stopping Murdoch's takeover of BSkyB, which bombards local MPs with campaigning emails. I've got one on the go for 'UK manufacture of Liquid Fluoride Thorium Reactors', so any UK readers following SmartPlanet, please have a look and see if you are inspired to vote. I'm intrigued to know if such a campaigning website is available in the USA. If it is, I hope a LFTR enthusiast will get a campaign going which will help Kirk in his Flibe Energy endeavours. If there isn't one in place, then 'Dear Mr. Halper' you would seem the ideal person to get something onto the launch-pad. What do you think?
This is the first I've heard of them and I live in Saskatchewan. A party that's never won a seat doesn't seem very relevent on a world issue.
Yes, Thorium as a fuel lost out because it doesn't produce Plutonium. That was a military decision made in the 1950's here in the US. Russia mad a simiar decision based on the same concerns. Thorium is often touted as a 'clean' technology. There are physics charts for isotopes that give the decay sequences involved. The short answer is that yes, Thorium doesn't produce any (or very little) fissile plutonium, but it does produce fissile Uranium. Both the Plutonium produced in Uranium reactors, and the Uranium produced in Thorium reactors can be used as fuel, if the reaction temperature is changed. The reactions are controlled by the neutron energy, which is in turn controlled by the moderator temperature. This typically requires higher temperatures. There was a reactor built during the 1970's in Colorado that used a uranium-plutonium fuel cycle, and produced no waste plutonium. The Government shut it down. I think it was designed and built by Brown and Root. HTGR (High Temperature Gas Reactor) if my memory is working right.
We (Vs20 Group) are starting a Political Party in USA that is actively promoting a phase-out of Coal-fired electricity and converting to Thorium LFTR. We are seeking 'peer review' on our Energy related articles (and our other 100+ policy articles) if you or any other readers can help with that? We are at Vs2020 dot com.. See article on 'Green Electricity' (Max Ward referred us to this site - thanks Max - see his comment below - This site does look promising!)
The bomb dropped on Hiroshima was an easy design, made of uranium so highly enriched with U-235 that they didn't even test it first. The only use of plutonium in actual warfare was dropped on Nagasaki. The "Trinity" test, which invoked Oppenheimer's quote "Now I am become Death, destroyer of worlds", was plutonium. Neutron bombardment of thorium produces uranium 233, whch is just as fisssile as U-235, but the trouble for bomb makers is that it contaminates quickly with U-232, and that spoils the bomb. The Nixon administration canceled the LFTR because it didn't help the production of weapons. Ironically, the Sierra Club persuaded the Clinton administration to cancel the IFR because they erroneously believed that it could easily be used for bomb production. Worse yet, and apparently invisible to my environmentalist and anti-weapon friends, there seems to be no outrage at the fact that the TVA's Watts Bar reactors are equipped to provide tritium for thermonuclear weapons, by bombarding lithium with neutrons. They use essentially ordinary PWRs, equipped with auxiliary rods that are removed after suitable irradiation. In the first place, why do we still need thermonuclear? Plain old plutonium is quite sufficient to attack Pyongyang or Teheran. Thermonuclear war against Russia or China would be suicidal madness, no matter who started it. In the second place, tritium is a more insidious radiotoxin than plutonium. Tritium hydrogen oxide is chemically indistinguishable from water, as is ditritium monoxide.
It had problems because the technology wasn't robust enough to stand up to the heat cycle. It also had to comply with a bunch of NRC rules written for PWRs and BWRs that had no basis in the reality of an HTGR. The economics of those superfluous regulations were prohibitive.