A safer route to a nuclear future?

Jun 13, 2012
"Nuclear." Credit: Andrea Kirby

By using thorium instead of uranium as fuel, nuclear power could be safer and more sustainable, according to new research.

Since the development of nuclear power, many different strategies for the minimisation and disposal of nuclear have been considered.

There are two types of nuclear waste: Fission product waste and actinide waste. Fission product waste is generally easier to manage, because it has relatively short half-lives. By contrast, actinide waste has much longer half-lives; disposal strategies usually envisage that it will have to be stored in purpose-built facilities for thousands of years.

As a result, many researchers have begun to consider the as a resource instead of a waste product, using the reactors themselves to recycle the actinide waste and then reuse it as .

“The idea of taking actinide waste and getting rid of it in nuclear reactors rather than disposing of it in the ground is well-established, but this hasn’t been thought possible using current commercial reactor technology,” Dr. Geoff Parks, of the Department of Engineering, said.

As well as the lack of suitable reactor technology, another issue with establishing an actinide recycling program is the which is used as fuel in nuclear power plants. The safety of nuclear reactors relies upon negative feedback coefficients, which stabilise the power level in the reactor if operating conditions change. What has been shown when recycling actinide waste in a uranium is that it can be recycled just once or twice before the recycled fuel develops a positive feedback coefficient, making it unsafe for use.

However, as one of Parks’ undergraduate students found, if uranium was replaced by thorium as a fuel source, current reactor technology could be used and the actinide waste could be safely recycled indefinitely.

The idea of using thorium as a fuel source is not new; prototype reactors using thorium were operated in the United States in the 1960s. “The reason why thorium was never seriously pursued as an alternative to uranium is believed to be because the uranium fuel cycle generates much more plutonium, which is the raw material used for nuclear weapons,” said Parks. In addition to its greater resistance to proliferation than uranium, thorium is also about four times more abundant.

Ben Lindley, at the time a fourth-year undergraduate student, discovered that when recycling actinide waste in a thorium-based fuel cycle, the feedback coefficients stay negative, meaning that it can be continuously recycled, leaving only the much shorter lived fission product waste to be disposed of.

Thorium could, in principle, be exploited immediately in existing nuclear reactors, but in order to maximize efficiency, Lindley is looking at ways of reconfiguring the design of such . Now in the first year of his PhD under the supervision of Dr Parks, Lindley is working with Cambridge Enterprise to commercialise his research.

There are issues with using thorium, however. There is currently no thorium industry, so a great deal of infrastructure needs to be put in place before existing power plants can make the switch. However, in order to address the dual concerns of electricity supply for an exponentially growing population and global warming, a major investment needs to be made in nuclear power. While Parks says nuclear is not the only part of the solution to those twin problems, it is a key component. With the advantages that thorium presents, and finite resources of uranium, thorium is now being seen as a viable alternative.

“The reasons for choosing are its abundance in comparison to uranium, its greater proliferation resistance and the possibility of a fuel cycle where the only waste is fission product waste,” said Parks. “I think our vision of how might work in the future addresses quite a lot of the concerns about it such as very long-lived radioactive waste which is a burden on future generations.”

With the 50% increase in global population which is expected over the next 50 years, in order just to maintain per capita electricity consumption, a major power station would need to go online every day somewhere in the world. “The electricity-generating infrastructure to meet global energy demands is staggering when you think about it in those terms,” said Parks. “And if it’s going to be low-carbon, then nuclear has to play a role in that.”

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User comments : 18

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CapitalismPrevails
1.9 / 5 (9) Jun 13, 2012
Yes, thorium is 4 times as abundant and can be used at 96% fuel efficiency in LFTRs as compared to 1% uranium fuel efficiency in PWRs. This is old news.
http://www.youtub...eBSoEnRk
Satene
1.5 / 5 (16) Jun 13, 2012
Thorium reactors will not make the nuclear reactors safer - on the contrary, they're running at higher temperature or pressures in general. The cold fusion is the only safe route for the nuclear future. I even presume, all fission reactors will be banned in future.
extremity
1 / 5 (1) Jun 13, 2012
I wonder if Thorium reactors and Uranium reactors even produce the same type of actinide waste?
Satene
2.7 / 5 (9) Jun 13, 2012
According to some studies,the thorium cycle can fully recycle actinide wastes and only emit fission product wastes, and after a few hundred years, the waste from a thorium reactor can be less toxic than the uranium ore that would have been used to produce low enriched uranium fuel for a light water reactor of the same power. But other studies assume some actinide losses and find that actinide wastes dominate thorium cycle waste radioactivity at some future periods.

In a reactor, when a neutron hits a fissile atom, it either splits the nucleus or is captured and transmutes the atom. In the case of 233 U, the transmutations tend to produce useful nuclear fuels rather than transuranic wastes. The result is shorter-lived transuranic waste than in a reactor using the uranium-plutonium fuel cycle than with using of thorium cycle.
antialias_physorg
2.6 / 5 (10) Jun 13, 2012
and after a few hundred years,...

That's really the problem. Which country has existed for a 'few hundred years' in its current political system? Which country's government feels responsible for securing waste disposal sites created a few hundred years ago (or cleaning them up if they should leak)?

We can't even be sure that what some government decided to do 4 years ago is still valid/binding today.
ShotmanMaslo
1 / 5 (3) Jun 13, 2012
Which country has existed for a 'few hundred years' in its current political system?


Political systems may change, but as long as the new system does not involve some crazy dictatorship with nuclear poisoning ambitions, it does not matter. This is certainly not enough of an issue to be taken as a serious disadvantage, IMHO.

Which country's government feels responsible for securing waste disposal sites created a few hundred years ago (or cleaning them up if they should leak)?


The country waste disposal site is located in?
ShotmanMaslo
2.7 / 5 (7) Jun 13, 2012

Thorium reactors will not make the nuclear reactors safer - on the contrary, they're running at higher temperature or pressures in general. The cold fusion is the only safe route for the nuclear future. I even presume, all fission reactors will be banned in future.


The IEER "factsheet" criticism of thorium reactors is full of misconceptions and outrights falsehoods. Debunked here:
http://energyfrom...ebuttal/
And here:
http://energyfrom...psrieer/

And cold fusion is bunk, and hot fusion is always 20 years in the future. IMHO thorium reactors (LFTRs) are the best shot we have at delivering the fusion power promises without fusion.

LFTR: What Fusion Wanted to Be:
http://www.youtub...2Ugxo7-8
Roland
5 / 5 (7) Jun 13, 2012
When you mine rare earths, you get thorium, and vice versa. Mining rare earths is expensive partly because of thorium disposal costs. If you could sell it instead of disposing of it, the economics of mining rare earths changes dramatically.
dnatwork
3 / 5 (2) Jun 13, 2012
Which country has existed for a 'few hundred years' in its current political system?


Political systems may change, but as long as the new system does not involve some crazy dictatorship with nuclear poisoning ambitions, it does not matter. This is certainly not enough of an issue to be taken as a serious disadvantage, IMHO.


Iran, Iraq, Syria, Afghanistan, Yemen, Pakistan, to name a few in the last decade that would have done (or did do) to us if they had the chance. There is always a dictator waiting to take over somewhere. The less stuff there is in the world that they can weaponize, the better.
antialias_physorg
4 / 5 (3) Jun 13, 2012
The country waste disposal site is located in?

And what happens when borders shift (as they are wont to do over the centuries)

Political systems may change, but as long as the new system does not involve some crazy dictatorship with nuclear poisoning ambitions, it does not matter.

For example: today there's are a lot rubble strewn around silver mines abandoned a scant hundred years ago. It's radioactive pitchblend (uranite). No one cares. A war, a bankruptcy, a change of leadership (or simply a redefinition of what constitutes 'safe' levels for a few years) - and all is forgotten.

Thadieus
5 / 5 (1) Jun 13, 2012
antialias_physorg, you sir are misinformed. There are countless capital investments that countries have made and have been around only for a fraction of the life cycle.
Ask any Caesar.
Deesky
5 / 5 (3) Jun 13, 2012
http://ieer.org/wp/wp-content/uploads/2012/04/thorium2009factsheet.pdf is the only safe route for the nuclear future. I even presume, all fission reactors will be banned in future.

Satene, or should I say Zephir, on what basis do you choose your new sockpuppet names? This one sounds French, no?
Jeddy_Mctedder
2.2 / 5 (6) Jun 13, 2012
there are a couple of well known cheerleaders for thorium out there, they've been touting thorium as the 'way to go'. china and india seem to be the only truly interested parties in thorium , and really, supposedly india's research is going super slow.

nuclear energy research requires massive talent and massive amounts of financial and political will. the entire industry is hostage both to the 'greens' who see everything as destructive and , moreso, the big nuclear companies, whose business model is about mining and disposing of uranium without using it efficiently. natural gas , coal, and everyone else competing with nuclear energy does not want thorium , nor any substantial 'progress' that would make electricity far cheaper and undermine their competitiveness. ------the problem is that mature society's with many lobbyists and large industries that OWN government, block the best decisions from being made. and this problem cannot easily be solved.
ShotmanMaslo
1 / 5 (3) Jun 14, 2012
And what happens when borders shift (as they are wont to do over the centuries)


Why should border shift be a problem? Do we need to rebuild everything when borders shift? Storage site would stay where it is.


For example: today there's are a lot rubble strewn around silver mines abandoned a scant hundred years ago. It's radioactive pitchblend (uranite). No one cares. A war, a bankruptcy, a change of leadership (or simply a redefinition of what constitutes 'safe' levels for a few years) - and all is forgotten.


A hundred years ago it was not known about the hazards of radiation. Noone would leave nuclear waste lying around now.
Eric_B
not rated yet Jun 16, 2012
"Political systems may change, but as long as the new system does not involve some crazy dictatorship with nuclear poisoning ambitions, it does not matter. This is certainly not enough of an issue to be taken as a serious disadvantage, IMHO.

Iran, Iraq, Syria, Afghanistan, Yemen, Pakistan, to name a few in the last decade that would have done (or did do) to us if they had the chance. There is always a dictator waiting to take over somewhere. The less stuff there is in the world that they can weaponize, the better."

there are idiots who don't seem to know that it was President Richard Nixon who founded the EPA, who are spewing about how we should eliminate the EPA.

America, you old whore, you are bought, spent and doomed.
Cornelius2008
5 / 5 (1) Jun 17, 2012
As always I enjoy reading the comments as much as the story itself. I am an advit supporter of nuclear power, especially thorium based nuclear power. I am an engineer and as other engineers know engineering is about taking a problem and building a full proof solution and of all the solutions to electrical power generation on the 1000MWe range or better nuclear is the best way to go, no CO2 in operation (not counting construction), safest when compared to any other proven technology (gas, coal, etc per Kwh) the only downfall is storing waste and proliferation, but as time goes by proliferation matters less and less and with thorium there is none, and as far as waste, there has never been an accident period and thats a great record.

Not to mention the space applications.
Husky
not rated yet Jun 17, 2012
how about throwing in a few thorium/actinide balls in a pebble reactor you can give them a slightly different size, so you can pick them out easily in the recycling and have different cycling times from the uranium balls and the actinides dont mix with the uranium.
XQZME
1.8 / 5 (5) Jun 18, 2012
A site dedicated to following thorium development:
http://www.energy...ium.com/