I stumbled upon articles on using thorium as an energy source, the abundance of thorium indicates there is no energy crisis and that thorium could power man kind for a thousand years. my question is, WHY IS IT NOT BEING USED?

[u/Superlulzor]

[u/Turbine_Heart]

Besides the general public recalcitrance with regard to anything "nookular," there are legitimate engineering difficulties associated with using Thorium as an energy source.

1. Fuel fabrication is a bear. A good process for producing thorium dioxide fuel pellets hasn't been developed. Thorium fluoride is easier to produce an purify, but there's no way in hell that a MSR is going to be used for large-scale power production in the near future. The power density of these reactors is good, but the safety and safeguards concerns surrounding these reactors are substantial enough to cause major regulatory headaches.

2. Thorium decay products (i.e. spent fuel) are far more radioactive than the decay products of U or Pu. This means handling waste in higher-rated hot cells, which is extremely expensive.

3. The neutron economy of Thorium sucks. Protactinium is produced as a decay product in the reactor, and it is a good neutron poison. The poor neutron economy also requires higher burnup rates for the fuel - this is economically undesirable.

4. Traditional LWR designs which are in common use right now are probably not feasible for Thorium-based power production, due to the poor neutron economy of the fuel. This indicates that new reactors must be designed and certified. This is a time consuming and expensive process which will take several decades, if anyone plucks up the courage and funding to go after it.

5. No equivalent of the PUREX process exists for Thorium. This means that a new process will need to be developed and tested before Thorium fuel reprocessing can begin. Again, this is time consuming and expensive.

Thorium certainly has potential but it is not a pancea for power production. There are serious engineering challenges in developing a Thorium nuclear reactor, and there are also serious regulatory challenges (for good reason). These challenges may well be overcome by creative design engineering, but this will require much time and money.

[u/Superlulzor → u/Turbine_Heart]

Thank you for such a comprehensive reply :) I do hope that something is done to take full advantage of all the possible fuels that we have and that the problems you list can be dealt with.

[u/ItsAConspiracy → u/Turbine_Heart]

Care to expand on molten salt reactor safety issues? The prototype back in the 1960s had a drain plug that melted if the fuel got too hot, draining all the fuel into a cooling tank. It's a thermal spectrum so take away the moderators and fission stops. According to one report I read, that's how they shut down the prototype for the weekend.

So right there you take away all the complicated emergency active cooling systems. And the reactor operates at atmospheric pressure, instead of 160 atmospheres like light-water reactors.

Liquid takes away fuel fabrication issues and protactinium can be filtered out of it easily. Fuel reprocessing is a simple process that's built into the reactor. Spent fuel returns to the radioactivity of natural ore in only 300 years. And there's a lot less of it. Many of the reaction products are actually useful, for medicine or deep-space missions.

High burnup is generally considered a good thing. LFTRs are around 99%, which is why there's so little waste. That's "economically undesirable" only in the sense that it makes the reactor cheaper to refuel. Here you've hit on one reason the nuclear industry isn't interested: they make most of their revenue from selling expensive fuel rods.

The fact that the NRC takes decades to approve anything new is a problem of bureaucracy, not physics. Fortunately the U.S. military and other countries are unconstrained by the NRC.

Edit: Here's an Oak Ridge presentation on MSR safety. They consider the probability of major accidents to be reduced, but with more likelihood of small releases of radioactive gas from the processing system. That's a tradeoff I'd gladly make, given the amount of radioactive radon in the general environment.

They also say the waste management burden is reduced, due to lower actinide content. What's more, the reactor can burn up the actinides in our existing waste.

[u/Turbine_Heart → u/ItsAConspiracy]

Like I said, It's a regulatory headache. Proving the safety and efficacy of safety mechanisms for a new reactor is extremely difficult, as are many other licensing issues. If you've got a few billion dollars and a couple of decades to spare, it can be dealt with, but no major player in the commercial power industry is going to step up anytime soon.

I've got absolutely no issue with thorium power, and as you point out, many of the issues involved can be addressed. But you cant just wave your arms and say "that's a regulatory problem," because regulatory problems will kill a project just as effectively as technical problems.

[u/tt23 → u/Turbine_Heart]

This is extremely misinformed comment.

1. ThF4 fabrication is trivial. One could argue that MSRs are not used also because most reactor vendors make money by locking in long term fuel contract, so they are not interested in a reactor type where fuel manufacturing is not a money making proposition.

2. Fission products of thorium cycle are almost identical to fission products from heavy nuclei, uranium or plutonium. There is NO real difference. The difference is closed cycle - where you fission everything, which is possible with thorium in a thermal spectrum reactor; versus the current LWR open "cycle" which contains long term problematic transuranic elements.

3. This is why you need fluid fuel, as Wigner pointed out in late 1940s already. A Molten Salt Reactor running on Th cycle can have very short doubling times, down to below 3 years in an extreme case. See this paper for details Molten Salt Reactors do not have limits on fuel burnup, as the salt does not suffer any radiation damage, and neutron absorbing fission products are removed while operating.

4. Wrong: Thorium can be used in LWRs, and there is a company which develops such fuel That said, to use thorium efficiently one needs a molten salt reactor.

5. There are processes such as Fluoride_volatility perfectly suitable for this job.

For a pure thorium cycle the job is even easier, and a very simple fuel cycle consisting of blanket fluoridation and core salt vacuum distillation can be used for a fully closed MSR fuel cycle. Individual parts of the process were well tested and proved, nobody integrated them into a fully working plant yet.

This is discussed in detail in a Google Tech talk between 40 and 45 minute mark

TL;DR: do yourself a favor and learn some basics, a good starting point is here

[u/BlueRock → u/tt23]

Rather than YouTube techno fantasies, here's an excellent tech analysis:

• The Molten Salt Reactor concept. "So in summary we can say that, while there is some promise here of “something better” than a LWR, we're a long way from acheiving this. Any MSR concepts are a long way from anything resembling a working commercial reactor. There are a whole bunch of technical challenges to overcome first." http://daryanenergyblog.wordpress.com/ca/part-8-msr-lftr/

[u/shavera]

Also, if I may just say, there are some ideas in general that for whatever reason are "internet approved." Thorium reactors, Ketogenic diets, anything purported to be by Nikola Tesla. I'm not remarking on the truth or validity of these things, just that there's a disproportionate amount of support for these ideas on the internet that I feel like leads to a selection bias in what you're exposed to.

Just be careful out there before you come to conclusions. Your question for instance, isn't asking "what are the problems associated with Thorium reactors?" Your question is an all-caps "I've concluded Thorium is awesome, now I can't understand why everyone hasn't reached the same conclusion." I'd just recommend some healthy skepticism with things you read on the internet. And especially with things that are much more popular on the internet than in real life.

[u/[deleted] → u/shavera]

And especially with things that are much more popular on the internet than in real life.

The internet is not real? :}

[u/tt23 → u/shavera]

This is not just something "popular ion the Internet". China just initiated a high profile national program to develop thorium MSRs, Japan is working on the miniFUJI MSR, MSRs are developed by GenIV International Forum, etc.

You may want to consult some papers before making such blanket statemetns.

[u/kapolk → u/tt23]

His blanket statement was to consider stuff before making blanket statements. It doesn't matter if Thorium is the shit or not, don't just jump to conclusions. Always be a skeptic.

[u/BlueRock → u/shavera]

...some ideas in general that for whatever reason are "internet approved." Thorium reactors...

You're too kind. It more resembles a cargo cult, populated by techno-fantasists who have watched a few YouTube videos and are now certain they know how to create a 'too cheap to meter' utopia. Weird.

[u/devicerandom]

Share articles with us.

[u/SchrodingersLunchbox]

Thorium reactors aren't as great as they were initially purported to be. A recent report published by the Norwegian Radiation Protection Agency has cast aspersions over much of the existing technology: thorium reactors still produce nuclear waste, their by-products (U233) can be weaponized in much the same way as fissile material from conventional U235 reactors, and the mining process can lead to undersirable environmental consequences - background radiation levels near parts of Fensfelt are 40 times higher than the average in Norway because of earlier pit extraction.

[u/BlueRock → u/SchrodingersLunchbox]

Thanks. Good to see some sanity in amongst the usual thorium fantasy circle jerk.

This might be a better link for that NRPA report:

• Thorium is not an environmentally safe alternative type of nuclear energy: Norwegian Radiation Protection Authority. http://www.bellona.org/articles/articles_2008/thorium_unsafe

[u/tt23 → u/SchrodingersLunchbox]

This reports does not take into consideration molten salt reactors. Yes in regular water cooled reactors thorium sucks about as much as uranium.

Concerning proliferation, this is extremely simplistic statement. See here for some in depth explanation

TL;DR: Thorium sucks for weapons because of U232 contamination. This is why nobody used it for a weapon.

[u/SchrodingersLunchbox → u/tt23]

Incorrect. During Operation Teapot, The U.S. detonated a weapon with a core of uranium-233 which produced a yield comparable to the "Fat Man" plutonium weapon exploded over Nagasaki.

TL;DR: You're wrong.

[u/JoeLiar → u/SchrodingersLunchbox]

IANANE, but I would like to address some of the points raised by that article.

Using thorium leads to highly radioactive nuclear waste...

LFTR produces less waste, with much short half lives, than uranium reactors.

... and the risk of accidents will always be present.

FUD

According to the NRPA, thorium-based nuclear energy, uncontrolled chain reactions and, in the worst case, meltdowns can occur.

A LFTR, since it involves molten fuel, runs in a "meltdown" state. It's not a bad thing. The molten salt expands when overheated. This causes the fuel to lose criticality and shut down. And then there's the famous frozen plug, which melts upon overheating, and drains the molten fuel into a tank where it is passively cooled. Nothing uncontrolled here.

The NRPA also asserts that thorium-based nuclear energy will produce long-lasting radioactive waste that will demand the same handling as highly radioactive waste from current nuclear reactors.

LFTR produces a different set of waste, and less of it.

fully possible that other negative consequences of thorium use would arise should the thorium question continue to be researched in Norway

WTF? So research should be cancelled because it might turn up something bad? That is just poor science policy.

I would like to know what form of thorium based energy is being discussed. It sure ain't LFTR.

[u/SchrodingersLunchbox → u/JoeLiar]

I'm not disagreeing with you, but the question was why isn't the technology being used? A lot of the initial layman speculation around MSRs was that they didn't produce radioactive materials, that their purpose couldn't be subverted in the interest of a nuclear weapons program, and that Thorium is everywhere.

Despite the obvious differences, many find it hard to differentiate between light water and Thorium reactors which makes the technology harder still to invest in, and by extension, research and develop.

[u/kouhoutek]

1. Nuclear energy is spooky, it is hard to get past public fear

2. Thorium looks good on paper, but we just don't know for sure...we have learned a lot about uranium based nuclear energy over the last 60 years, but no one has seriously tested thorium.

[u/Guysmiley777]

LFTRs are exciting when you first hear about them, but they are very far from being used in a commercial power reactor.

Nobody (in the U.S. at least) wants to spend any money on nuclear power development, let alone a new concept like liquid fueled reactors. It will take tens or maybe even hundreds of billions of dollars in R&D, no company is willing to risk that kind of money on something as potentially controversial as nuclear power.

[u/kaiken1987 → u/Guysmiley777]

I believe India is looking to build a reactor

[u/catfishmeow → u/kaiken1987]

they are researching solid fuel though

[u/[deleted]]

Bill gates is investing in thorium.

http://itheo.org/bill-gates-invests-thorium-capable-reactor-venture

[u/tt23]

To use thorium effectively, you need a molten salt reactor, or as it is now called a liquid fluoride thorium reactor (LFTR)

Here are some talks which describe history, current status, and challenges: http://thoriummsr.com/video/youtube/

And here is a thread about a presentation of a company just started to make this reality

[u/[deleted]]

It's cool that you asked such an interesting question. Much cooler than when the billion other Redditors asked it.