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According to Chinese state media, a group of scientists recently managed to refuel a working thorium molten salt reactor without causing a shutdown — a feat never achieved before. The success was announced by the project's chief scientist Xu Hongjie during a closed-door meeting at the Chinese Academy of Sciences on April 8, Chinese news outlet Guangming Daily reported last week.
Such a breakthrough could be transformative to the global energy landscape, as thorium has long been hailed as a far safer and cheaper alternative to uranium in nuclear reactors. While also a radioactive element, thorium produces less waste, and the silver-colored metal, mostly found in monazite, is much more common in the Earth's crust.
According to the International Atomic Energy Agency (IAEA), thorium is three times more abundant in nature than uranium, but historically has found little use in power generation due to the significant economic and technical hurdles.
[...] Compared to uranium, thorium can generate a significantly higher amount of energy via nuclear fission. A Stanford University research estimates that thorium's power generation could be 35 times higher. Thorium molten-salt reactors (TMSRs) are also compact, do not require water cooling, cannot experience a meltdown and produce very little long-lived radioactive waste, according to the IAEA.
When announcing the breakthrough, Xu acknowledged that its project was based on previous research by US researchers who pioneered molten salt reactor technology in the 1950s, but abandoned shortly after to pursue uranium-fueled ones.
Xu — who was tasked with the thorium reactor project in 2009 — told Chinese media that his team spent years dissecting declassified American documents, replicating experiments and innovating beyond them.
China's TMSR-LF1 Molten Salt Thorium Reactor Begins Live Refueling Operations:
Although uranium-235 is the typical fuel for commercial fission reactors on account of it being fissile, it's relatively rare relative to the fertile U-238 and thorium (Th-232). Using either of these fertile isotopes to breed new fuel from is thus an attractive proposition. Despite this, only India and China have a strong focus on using Th-232 for reactors, the former using breeders (Th-232 to U-233) to create fertile uranium fuel. China has demonstrated its approach — including refueling a live reactor — using a fourth-generation molten salt reactor.
The original research comes from US scientists in the 1960s. While there were tests in the MSRE reactor, no follow-up studies were funded. The concept languished until recently, with Terrestrial Energy's Integral MSR and construction on China's 2 MW TMSR-LF1 experimental reactor commencing in 2018 before first criticality in 2023. One major advantage of an MSR with liquid fuel (the -LF part in the name) is that it can filter out contaminants and add fresh fuel while the reactor is running. With this successful demonstration, along with the breeding of uranium fuel from thorium last year, a larger, 10 MW design can now be tested.
Since TMSR doesn't need cooling water, it is perfect for use in arid areas. In addition, China is working on using a TMSR-derived design in nuclear-powered container vessels. With enough thorium around for tens of thousands of years, these low-maintenance MSR designs could soon power much of modern society, along with high-temperature pebble bed reactors, which is another concept that China has recently managed to make work with the HTR-PM design.
(Score: 2) by VLM on Monday May 05, @01:37PM (2 children)
I wonder why you'd want to do that. The safety risks are high and the rest of the plant wears out and needs inspection so IIRC from my research there's somewhere between rarely and never a situation where the refit was delayed because of refueling process problems. ALL the time they find unexpected (unexpected as in out of limits) corrosion that needs research or some plumbing failed during final closeup tests or there's some bearing/shaft/turbine thing with a painfully long lead time that unexpectedly needs replacement.
Refueling while powered up would NEVER be allowed on US soil. For generations ALARA has been pretty deeply ingrained. "Well we could shut it down and do a room temp zero pressure refuel, but we thought it would be fun to do it during full power operation" NRC would absolutely shit themselves. To voilate ALARA like that would take something like losing an invasion by space aliens, maybe not even that.
The knee-jerk military claim doesn't work, the rest of the ship needs extensive maint around refueling time anyway. Everything in the propulsion system is worn, as is the rest of the ship, and the whole thing needs a refit stem to stern.
An interesting to think about problem for the military would be whatever the Navy analogy is to "GI Proofing" the refueling equipment and material. It'll all be radioactive and as part of hazing or just general inexperience you know some poor sailor is going to shove the nuclear refueling hose in a F-18, not knowing any better, or pour used radioactive refueling salt on the deck to prevent icing ("uh, it said salt on the barrel label"). This just isn't going to turn out well.
One thing I can think of is some kind of "picking up nickels in front of the steamroller" strategy of trying to extend maint intervals. This will probably lead to an accident, not directly because of refueling but because a lot of stuff gets found during maintenance intervals that now will ... not. It'll get found during the subsequent accident investigation.
Another thing I can think of is CIA cloak and dagger stuff to get around non-proliferation treaties. "Oh that barrel thats glowing blue? Thats not illegal nuclear proliferation trafficing thats merely supplies for our sub thats refueling while underway, you know, as you do, totally not illegal nuclear proliferation in violation of the treaty".
(Score: 3, Touché) by Anonymous Coward on Monday May 05, @01:59PM
The current administration will probably defund the NRC anyway, so there wouldn't be any push back from that organization.
(Score: 3, Informative) by gnuman on Monday May 05, @04:19PM
https://en.wikipedia.org/wiki/CANDU_reactor [wikipedia.org]
So, many reasons... maybe not so important these days as uptime of regular reactors has been brought up. Reddit has some interesting comments here,
https://www.reddit.com/r/NuclearPower/comments/twmixy/candu_vs_us_lwrs/ [reddit.com]
You can also put stuff in the reactor that has nothing to do with fuel. Like making medical grade Colbalt 60 -- half world supply comes from CANDU reactors. Having a high flux neutron source is very beneficial here.
https://www.nuclearfaq.ca/malkoskie_cobalt_paper.pdf [nuclearfaq.ca]
and others,
https://www.world-nuclear-news.org/Articles/Canadian-Candu-produces-cancer-therapy-isotope [world-nuclear-news.org]