The role of nuclear power in a low carbon future

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There have been a few different types of reactors that have claimed to be able to run on thorium, many of these the molten salt type, which have their own share of problems. Breeder reactors are able to utilize it as well, but currently breeders are primarily used to deal with used uranium fuel and the only few in operation are in Russia.

I don't think I'm missing any "finer points", it's that the only reactors currently in production that can run on thorium are HWR's like the CANDU and there's no real point in Canada, because of the amount of uranium we have.

I've not heard of a "candle" type reactor, but the reason you have to mix it with something else is the reason I outlined earlier, and that's because thorium isn't fissile, it's fertile, so it needs to be mixed with something that is fissile, like plutonium or uranium in order to undergo fission.

No, it means it needs to be mixed with a fissile isotope so that fission can commence. Yes, that can be spare weapons material, like plutonium from warheads, but it can also be dirtier plutonium from used fuel or even uranium.

No it isn't, not in the form of used fuel without reprocessing. It's a pain in the butt, because it has to be stored and the US has no DGR, so it just gets stored in cooling ponds until it can go into casks, which then sit around. That's the case at every plant in the US.

The US could also reprocess that waste (PUREX for example) and run it in their existing reactor fleet. Nobody has been willing to invest the money to build a reprocessing plant, that's the issue.

Yes, there are always waste products. The CANDU fuel cycle, which in most instances uses natural uranium, has a "lesser" waste stream than an LWR or BWR, but you can also run a MOX or a DUPIC cycle where you use spent LWR/BWR fuel in the CANDU. China is doing this at Qinshan with the two C6's located there.

The US already used surplus weapons material (warheads) in reactor fuel after the cold war. The burned tons of former Soviet weapons material this way, which is why US uranium production tanked during that time period.

The issue isn't government cooperation, it's somebody being willing to spend the money to build something. PUREX is a tried and true reprocessing technique for LWR and BWR fuel, used extensively by France, they even reprocess used fuel for the Japanese, but the US doesn't have a single PUREX facility.

Anybody handing SNF or anything radioactive needs to be approved by the appropriate regulatory body. So while the ability to factory assemble a given reactor type might sound wonderful, they still are required to be monitored by and compliant with the nuclear standards, which immediately torpedoes the simple and cheap part because then you are into permits, monitoring, regulation, approvals, oversight, site visits...etc.

This is why these things are typically operated by large utilities who have the money to jump through these hoops and regulatory hurdles.

So was the CANDU. It didn't require enrichment, which only countries pursuing atomic weapons (like the US and the Soviets) had. We had developed a number of different designs that were supposed to vary suitability for different sized markets. Ultimately, the anti-nuclear movement coupled with Chernobyl killed that.

There's actually a new twist on the "pre-fuelled" reactor design here in Canada. It's the USNC/GFP MMR, which is basically a reactor and power unit about the size of a shipping container designed to power remote communities. The fuel load is designed to last ~20 years at which point you swap out the reactor portion for a fresh one.

This is the first design slated to be built at Chalk River.

Bombs typically aren't made with reactors anyways. All you need is a gas centrifuge. That's why North Korea has nuclear weapons and no nuclear reactors.
The first fully automated (fluoride and hydrogen moderated) underground Thorium reactor was patented around 1950. I I thought all amateur nuclear power proponents with a knowledge of Atomic History knew about a thorium candle reactor. Put in place fully fueled, it would run 30-50 years before the fuel was used up. Quite simply it used fertile thorium fuel pellets mixed with neutron rich waste. What could be simpler? Although any Atomic physicist will tell you these candle reactors would work quite well, they were never put into production. However, a more advanced version is in use, and has been in use for decades. There has never been a nuclear accident from the propulsion system of a US nuclear powered naval vessel. Same principle, different fuel. In simplistic vernacular of today they are called TWR or traveling wave reactors.
 
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OVERKILL

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The first fully automated (fluoride and hydrogen moderated) underground Thorium reactor was patented around 1950. I I thought all amateur nuclear power proponents with a knowledge of Atomic History knew about a thorium candle reactor.
Nope, never heard of it, and it has never been mentioned in any of the groups I'm a member of, at least not under that name.
Put in place fully fueled, it would run 30-50 years before the fuel was used up. Quite simply it used fertile thorium fuel pellets mixed with neutron rich waste. What could be simpler? Although any Atomic physicist will tell you these candle reactors would work quite well, they were never put into production.
I'm sure there were reasons that they weren't pursued. I have plenty of nuclear physicists in my circles, again, none have ever mentioned it.
However, a more advanced version is in use, and has been in use for decades. There has never been a nuclear accident from the propulsion system of a US nuclear powered naval vessel. Same principle, different fuel.
Ummm, no, conventional PWR power plants, as the article you linked states, were scaled-up versions of propulsion designs:

The authors discuss new types of nuclear fission reactors optimized for the generation of high-temperature heat for exceedingly safe, economic, and long-duration electricity production in large, long-lived central power stations. These reactors are quite different in design, implementation and operation from conventional light-water-cooled and -moderated reactors (LWRs) currently in widespread use, which were scaled-up from submarine nuclear propulsion reactors.

Sub and carrier reactors are just PWR's, but they use highly enriched uranium so that they don't have to be refuelled.
In simplistic vernacular of today they are called TWR or traveling wave reactors.

The TWR, like the MSR and other novel designs are paper reactors, there are none in operation. The TWR is similar to a breeder because it uses transmutation, but we actually have breeders in use, while there are no functional TWR designs at this juncture. I'd never heard of it referred to as a "CANDLE" reactor, but I'm familiar with the TWR term. It looks like the "CANDLE" label was used in Japan and is in fact a very recent term (2004), which is likely why I've never heard it. It's an acronym, and so all the characters should be capitalized. It's not a "candle reactor", it's "CANDLE", which stands for: "Constant Axial shape of Neutron flux, nuclides densities and power shape During Life of Energy production".

Bill Gates, through TerraPower, has been working on a TWR design that they hope to construct a prototype of.

History is full of "super simple" reactor designs that their proponents claim all kinds of wonderful things about. I find it interesting that you'd feign "shock" that I'd never heard to this design as you've promoted it here under an unpopular label, mocking my knowledge, while simultaneously not responding to any of the points as to why it isn't as simple or straightforward to produce as you've repeatedly claimed.

I feel like you read a symposium synopsis where this design was mentioned under the "CANDLE" moniker and either didn't know, or didn't read deep enough to understand that it was an acronym and are now here trolling me on a subject that is clearly my hobby. This is the same reason you misread the text in the link you provided and came to the (false) conclusion that naval PWR's were TWR derivatives.
 
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OVERKILL

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While I suspect your heart is in the right place, you simply do not understand the basics of atomic energy, or commonly used terms.
That's rich coming from a guy who hasn't addressed any of my points and hasn't even got the basis for his own argument for a specific tech right. Maybe some more work on reading comprehension and less work on trolling me might help?
You do seem to know a lot of factoids about the CANDU reactors. For instance, when you say atomic powered submarines and aircraft carrier reactors get refueled,
Please, point to where I said they get refuelled.

I specifically stated:
OVERKILL said:
Sub and carrier reactors are just PWR's, but they use highly enriched uranium so that they don't have to be refuelled.
that is entirely wrong. The reactors are not refueled, they are entirely replaced. Then good to go for another 20-35 years. These vessels use a uranium candle reactor.
No, they don't. I literally gave you the quote that you are confused on from the article you linked.

Marine propulsion systems use PWR's, the design for which was scaled up for commercial units, which use far lower enrichment levels because they can readily be refuelled (unlike a carrier or sub).

This is the reason so many former navy nukes end up working at civilian nuke plants, they are already qualified on the PWR's from their time in service.

Here's a whole article on marine propulsion to get you up to speed:

A quote:
Nautilus led to the parallel development of further (Skate-class) submarines, powered by single pressurised water reactors, and an aircraft carrier, USS Enterprise, powered by eight Westinghouse reactor units in 1960. A cruiser, USS Long Beach, followed in 1961 and was powered by two of these early units. Remarkably, the Enterprise remained in service to the end of 2012.

By 1962 the US Navy had 26 nuclear submarines operational and 30 under construction. Nuclear power had revolutionised the Navy.

The technology was shared with Britain, while French, Russian and Chinese developments proceeded separately.

After the Skate-class vessels, reactor development proceeded and in the USA a single series of standardised designs was built by both Westinghouse and GE, one reactor powering each vessel. Rolls Royce built similar units for the UK Royal Navy submarines and then developed the design further to the PWR-2.

*snip*

The US Navy has accumulated over 6200 reactor-years of accident-free experience involving 526 nuclear reactor cores over the course of 240 million kilometres, without a single radiological incident, over a period of more than 50 years. It operated 81 nuclear-powered ships (11 aircraft carriers, 70 submarines – 18 SSBN/SSGN, 52 SSN) with 92 reactors in 2017. There were 10 Nimitz-class carriers in service (CVN 68-77), each designed for 50-year service life with one mid-life refuelling and complex overhaul of their two A4W Westinghouse reactors*.

Heck, there's even a Wiki on it:

Wikipedia said:
Current U.S. naval reactors are all pressurized water reactors,[3] which are identical to PWR commercial reactors producing electricity, except that:

  • They have a high power density in a small volume and run either on low-enriched uranium (as do some French and Chinese submarines) or on highly enriched uranium (>20% U-235, current U.S. submarines use fuel enriched to at least 93%)[4]
  • They have long core lives, so that refueling is needed only after 10 or more years, and new cores are designed to last 25 years in carriers and 10–33 years in submarines,
  • The design enables a compact pressure vessel while maintaining safety.[clarification needed]
Long core life is enabled by high uranium enrichment and by incorporating a "burnable neutron poison", which is progressively depleted as non-burnable poisons like fission products and actinides accumulate. The loss of burnable poison counterbalances the creation of non-burnable poisons and result in stable long term fuel efficiency.

I'm sure those that are or have been recently in service such as @Astro14 can comment on the accuracy of this, in case you still somehow think you are right.

Bill Gates does talk about a TWR now. He used to refer to it as a candle reactor. Same thing.
Again, CANDLE is an acronym, you should be capitalizing it. As long as I've heard Gates talk about it, he has referred to it as a TWR and there are no functional examples in existence.
 
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My opinion of traveling wave reactor: it is way too complicated compare to a "standing wave" type of design and relies heavily on the robustness of a robot that shuffle fuel rods through the decades it would operates with, and sealed. Because of that, we would not see anyone pick this as a first choice vs using a standing wave design, and the development would be much harder (redundancy, all corner case fail over, all the training to make sure human operator won't screw up when the automation fails) than separating the breeding and the burning operation.
 
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I view nuclear power as a contributor to a power grid just like wind, solar , hydro and fossil fuel. Nothing special just another equally viable contributor with pros and cons.
 

OVERKILL

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I view nuclear power as a contributor to a power grid just like wind, solar , hydro and fossil fuel. Nothing special just another equally viable contributor with pros and cons.

I mean, it is quite special in the sense that it can provide reliable baseload power without any direct emissions. That sets it apart from fossil fuels and puts it in the same segment as hydro, which is geographically limited.
 
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I think that nuclear power should be a priority as it seems to be a better solution, but our waste problems when regarding to landfills need to be solved along with it.
 
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As an ex reactor operator on submarines, I am not able to confirm or deny any information regarding Naval Nuclear Propulsion.
 
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I think that nuclear power should be a priority as it seems to be a better solution, but our waste problems when regarding to landfills need to be solved along with it.
For commercial nuclear power to be successful at producing the large amounts we need, we must allow reprocessing of the fuel and we need to open up waste storage at Yucca mountain. Both of these require politics to be removed from the equation. Sadly politics will destroy civilization as we know it.
 

OVERKILL

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For commercial nuclear power to be successful at producing the large amounts we need, we must allow reprocessing of the fuel and we need to open up waste storage at Yucca mountain. Both of these require politics to be removed from the equation. Sadly politics will destroy civilization as we know it.
Yes, there needs to be capital put into PUREX reprocessing, which France has been doing for decades.
 
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