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Which reactor design will brighten our future? SNACR, LFTR, pebble bed, travelling wave, or sub-critical energy amplifier?
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Aug 8, 2020 via Slashdot
Latice Confinement Fusion. Researchers at NASA's Glenn Research Center have now demonstrated a method of inducing nuclear fusion without building a massive stellarator or tokamak. In fact, all they needed was a bit of metal, some hydrogen, and an electron accelerator.
Nov 5, 2019 via John Sokol
Website of Mark Schneider, Nuclear Futurist
Raising public awareness of Gen IV Nuclear technology. Lots of good current articles.
July 26, 2017 via Hacker News
Google enters race for nuclear fusion technology
After defeating the game of Go using neural networks, Google has made breakthroughs in algorithms that are solving the issues with stability and heat loss in fusion reactions. Nuclear fusion is very complex; it is very exciting that the problems are finally being solved through application of the most massive artificial intelligence software the world has ever seen.
Google is doing this work in partnership with Tri Alpha, the company of Microsoft founder Paul Allen.
April 28, 2016 via Digg
BBC - The secretive, billionaire-backed plans to harness fusion
In the city of Burnaby, British Columbia, General Fusion is busy developing nuclear fusion, funded by Jeff Bezos of Amazon, the Malaysian government, and a Canadian oil company.
In Orange County, California, Tri Alpha,
is also developing nuclear fusion using a different technique.
It is backed by Paul Allen of Microsoft, Peter Thiel of Paypal, the Rockefellers, and the Russian government.
I wish Michel Laberge all the best.
April 13, 2016 via John Sokol:
Did Norwegian scientists finally crack the riddle of Low Energy Nuclear Reactions? The key is deuterium fractured in a certain way that let's the Coulomb barrier be breached with a low investment of energy to start the reaction.
May 12, 2014 Comment from Scottingham:
After doing a lot of research into the current state of Thorium technology I was able to find the following non-FUD conclusions as to why Thorium and LFTRs in particular aren't working out so well.
- The liquid medium that is actually containing the fission events is incredibly caustic. This means that the reactor vessel, in addition to dealing with a very high neutron flux, has to handle severe corrosion issues at the surface. The fact that it is done at STP does not provide any help.
- The salt 'plug' that is often cited as a major safety asset for the LFTR has some major engineering obstacles that have been be able to be addressed yet.
- The liquid medium has to undergo re-processing on a fairly frequent basis. This is non-trivial as the medium is highly caustic and radioactive. The products pulled out are also highly problematic. This is probably one of the biggest hurtles for LFTR. It is a costly and messy chemical process.
There are other smaller problems, but these are the 'big three' I can recall.
For next-gen reactor tech my money is on traveling wave type reactors (which never need to be refueled for its entire lifespan..30-100 years). Look up the Toshiba 4s for the furthest along reactor.
There are also sub-critical 'energy amplifier' reactors that use a particle accelerator to drive a proton beam into a spallation target (lead) which causes a neutron flux suitable for fission events to occur, though not enough to cause a self-sustaining reaction. Only 10% of the energy is required to be redirected back to the accelerator (fission rules like that). This one has the advantage of being able to use pretty much any fuel, and waste we have as well as reducing the daughter products to benign isotopes. Belgium is currently in the process of building one.
Links: (original comment), (original article)
November 19, 2013 Watch this video by Gordon McDowell Thorium: An energy solution - THORIUM REMIX 2011 (YouTube) Video is 2 hours long, and every second of it is interesting. Liquid Fluoride Thorium Reactors (LFTRs) are being built in China right now. They can clean up the waste created by current nuclear reactors, and thorium mining would open up a lot of rare earth deposits, breaking China's monopoly on the electronics industry. Also very safe, cheap, etc. Also adding Kirk Sorenson to the blog-roll today.
September 26
The Forgotten Promise of Thorium, by Karl Denninger. Via
We experimented with Thorium as a nuclear fuel in the 1950s and 1960s. Carried in a molten salt there are a number of significant advantages to this fuel cycle. Chief among them is that the reactors operate at atmospheric pressure, have a strongly-negative temperature coefficient (that is, reactivity drops as temperature increases) and because they operate with their fuel dispersed in the coolant and rely on a fixed moderator in the reaction vessel shutting them down is simply a matter of draining the working fuel into a tank with sufficient surface area to dissipate decay heat. This can be accomplished passively; active cooling of a freeze plug in the bottom of the reactor vessel can be employed during normal operation and if for any reason that cooling is lost the plug melts, the coolant and working fluid drains to tanks and the reactor shuts down. In addition thorium is about as abundant in the environment as is lead, making its supply effectively infinite.
Finally, these reactors operate at a much higher temperature; the units we have run (yes, we've built them experimentally in the 1950s - 1970s!) run in the neighborhood of 650C. This allows closed-cycle turbine systems that are more efficient than the conventional turbines in existing designs, making practical the location of reactors in places that don't have large amounts of water available. That in turn means that the risk of geological and other similar accidents (e.g. tsunamis!) is greatly reduced or eliminated. Finally, the fuel cycle is mostly-closed internally; that is, rather than requiring both fast-breeder reactors and external large-scale reprocessing plants to be practical, along with a way to store a lot of high-level waste these units burn up most of their high-level waste internally and produce their own fuel internally as well as an inherent part of their operation.
So why didn't we pursue this path for nuclear power?
That's simple: It is entirely-unsuitable for production of nuclear bombs as it produces negligible amounts of plutonium.
I've seen similar information on the Internet before. But I haven't posted it here before, because of counter-arguments like this, found in the comments section of Karl's article:
The reason the US (and other countries) has a large stockpile of U-233 is the same reason (one of several) as to why enriched U-235 was used for nuclear power instead of the Thorium cycle.
The process of creating U-233, when produced from Th-232, creates an impurity in a nasty isotope of Uranium, U-232. U-232 is a very nasty isotope, and is the cause why U-233 was not used for weapons or power plants in the first place.
Overcoming the problem of U-232 is going to be one of the more expensive scaling costs of LFTR technology. It is possible to get rid of the continuum of U-232 impurities, but I'm afraid it isn't going to be cheap or easy. LFTR enthusiasts keep overlooking this problem as a minor fuel production issue, but the day has come for someone to come up with a valid, scaled up and tested production answer or the LFTR cycle will not be a viable process.
Age sometimes is an advantage in understanding. Although it is journalistically interesting and certainly exciting for those who find joy in discovering a long held US secret, the fact is that the adoption of enriched uranium light water reactors was never about creating a source for nuclear weapons material. It was just a statement of the limitation of our knowledge and computation capabilities at the time combined with the primary intended use of nuclear power.
The fact is that in the course of the Manhattan project effort one of the technical by-products was the scientific and engineering detailed data of enriched U-235 plus the basics for a design of a light water reactor. In addition, the primary initial use of nuclear power plants was to be for US Navy submarine use, and in those days it was expected that dumping at sea the refuse of a light water enriched U-235 reactor would be just fine (which BTW the Russians did).
WW2 had just ended, we knew the costs of the Manhattan project, knowledge of radiation protection and its effects was in its infancy and materials science and computing were really still nascent when it came to nuclear science and engineering. Going for a new technology like the Thorium cycle would have been arguably a huge cost that the nation, just finishing up with the Manhattan project, couldn't afford, and we also didn't know the true cost radiation effects and disposal with the U-235 cycle.
After the Navy work at ORNL and Idaho Falls, we had a prototype. As far as the power industry was concerned, why pay for an investment in a new process like the Thorium cycle which still has problems like U-232 when you could just do an extrapolation of the current Navy light water propulsion reactors and just build that instead?
The answer was it was cheaper to extrapolate what you knew than invest in inventing something new, not something nefarious as some would propose. In any case, the Hydrogen bomb made the question of the need for uranium except for triggers a mute question. Uranium and Plutonium did come back into vogue in weapons design in the late 70's at the height of nuclear battlefield weapons, but even then the yields of those weapons were never that good and the neutronic bomb (more publicly known as the neutron bomb took us back full circle, so to speak.
In 1972, the American Nuclear Society has a long frank and private (secret) discussion on this very subject. I, as a student of Al Sesonske and Sam Glasstone, two of the premiere early power plant designers, attended the event. I can remember very clearly first hand that everyone was surprised when someone brought up the fact that light water enriched uranium power plants would be a source for nuclear weapons. Even Admiral Rickover stated in the meeting as I recall in his famed acidic way: "Nice by-product, but we already had too much weapons material. Why get additional commercial sources that could be unreliable? That's stupid. All I wanted was the Nautilus and we got it quickly after we proved the plant would work at Shippingport and all you guys in the power industry wanted was the cheapest already tested design!"....and I heard that personally, folks. End of story as far as I'm concerned.
I am in favor of the Thorium cycle, but I believe it is not yet technical ready for prime time because of scaling issues and issues like U-232.
I don't know which side is right. Only a few people in the world have enough specialized knowledge of nuclear technology to say one way or the other. It sure would be exciting if the Thorium people are right. A few months ago, a fellow named Jim Stone was saying that the Thorium cycle can combine with the regular nuclear reactor technology to completely eliminate nuclear waste. Who knows.
February 17
Feature: Small modular nuclear reactors - the future of
energy?, by David Szondy.
Via.
"This year is a historic one for nuclear power, with
the first reactors winning U.S. government approval for
construction since 1978. Some have seen the green
lighting of two Westinghouse AP1000 reactors to be built
in Georgia as the start of a revival of nuclear power in
the West, but this may be a false dawn because of the
problems besetting conventional reactors. It may be that
when a new boom in nuclear power comes, it won't be led
by giant gigawatt installations, but by batteries of
small modular reactors (SMRs) with very different
principles from those of previous generations. However,
while it's a technology of great diversity and potential,
many obstacles stand in its path. This article takes an
in-depth look at the many forms of SMRs, their
advantages, and the challenges they must overcome."
Interesting article. Did you know that Russian
light-houses are powered by RTFs? (Radio-thermal
generators) The radio thermal generator is a type of
nuclear reactor that uses natural radioactive decay to
power a simple thermoelectric generator. It can produce at
most, two kilowatts.
There are a lot of different Small Modular Reactors in
production, use, and development. The future is very bright
and exciting for safe and cheap nuclear power. My favorite,
the salt reactor, is discussed:
In this type of SMR, the coolant and the fuel are one
in the same. The coolant is a mixture of lithium and
beryllium fluoride salts. In this is dissolved a fuel,
which can be enriched uranium, thorium or U-233. This
molten salt solution passes at relatively low pressure
and a temperature of 1,300 degrees F (700 degrees C)
through a graphite moderator core. As the fuel burns, the
waste products are removed from the solution and fresh
fuel is added.
One of the commenters had this to say:
VoiceofReason - February 16, 2012 @ 08:21 am
PST
One thing you didn't mention about Flibe's molten salt
reactor is that it runs at atmospheric pressure
(basically). That is a huge improvement in safety. Also,
there is no hydrogen buildup possible or any other
combustibles so explosions leading to the dispersion of
radioactive particles is eliminated.
Since the fuel is in a molten salt, if the core did
rupture, the salt would leak out and solidify (possibly
even plugging the hole and stopping the leak).
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