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Does anyone here work in the nuclear field?
Just curious. Wondering if I’m the only one on Tildes right now or if there are others.
I’d also be happy to answer questions about nuclear issues, if all y’all would like.
It’s hard to give an actual percentage. I will say that many criticisms have an ounce of truth, but there are often many caveats. For example, waste is certainly an issue, but mostly a political question rather than a technical one. Fuel can be reprocessed, actinides removed for fast reactor fuel, and fission products partitioned, either for transmutation, reuse in industrial applications, or vitrification and disposal in a deep geological repository. At that point, the radiation levels of the fission products will decay to less than that of uranium ore in approximately 500 years. Additionally, research from Oklo shows that these products will move very little over a long time span.
The criticism with the most validity would be cost and construction times, but even that isn’t unique to nuclear power; applying similarly to any large infrastructure projects.
It's worth noting that the next generation reactors hold out the promise of knocking the cost (and complexity and risk) for the plants down drastically as well. That doesn't do us a hell of a lot of good while we're still in need of billions for R&D to prove out the designs, though.
Every reactor (AP1000, EPR, etc) has promised to hold down the costs and the schedule while reducing complexity and risk. I’ve learned to be skeptical of claims made. I’m certainly optimistic for at least one of the Gen IV designs doing well, however. My personal bet is on Ultra-Safe Nuclear’s MMR.
I feel like I'm finding new projects and designs every month now. It's heartening to see the research and the interest level taking off like this.
Edit: Oh, that fuel process is clever business. This is a good one. Modular, simple, safe.
The fuel requires the most work of the overall project from what I’ve seen, but I don’t think it requires that much more than some reactors. The TRISO concept is relatively well-developed, this just encases it in Silicon carbide, which other companies are working on for accident-tolerant fuel. I think it’s most promising for three reasons:
Helium-cooled reactors occupy a sweet spot: more developed than MSRs (there are examples from the US, UK, Germany, China, and Japan) but without any of the safety hazards of using sodium metal of sodium fast reactors. Critically, there are existing ones in Japan and China, and another one is under construction in China (the HTR-PM). They can use those operating reactors to help build out their designs.
The company seems to have identified a market niche: remote locations like mines and Arctic towns. These places (of which there are dozens to hundreds) demand reliable power, often need direct heat, currently rely on vulnerable diesel supply chains, and are willing to tolerate higher prices than grid electricity. You can build a reactor that cuts electricity prices for towns in Nunavut but still costs more than would be bearable in Ontario. This enables scale-up of production, while preventing them from having to immediately scale down prices for their earliest units. Think of it like Tesla, their first cars targeted those who were rich, then those who were upper-middle class (high end), and now those who are middle to upper-middle class (low end).
They are moving along at a steady pace in terms of licensing with the Canadian regulator, and want a demonstration unit at Chalk River Labs by 2026, and even with delays I see it being built by 2030.
Edit to add: one more advantage is that this takes the good parts of TRISO (the barriers) and eliminates the operational complexity of having moving balls of fuel throughout the reactor and all of those issues.
Okay I'd love to ask a question! A few years ago I watched some Youtube documentary about thorium-salt reactors and it seemed so obvious and totally viable. They went into the research that was done at Oak Ridge in like the 60s but it never caught on. If you're familiar with this sort of reactor, why not? What's the catch? Also, does it drive you crazy that nuclear is never considered in the conversation about renewables? On an on about solar farms and wind panels but nuclear seems like the most obvious answer! Drives me crazy.
How did I know thorium/molten salt reactors would be the first question? ;)
Molten salt reactors (MSRs) originated at Oak Ridge National Lab in the 1950s as a potential reactor design for nuclear aircraft. ORNL operated one or two small experimental reactors during the 1950s. In the 1960s, the lab constructed the most well known, the Molten Salt Reactor Experiment. This design operated with different fuel loadings, including uranium-233, the fissile isotope derived from irradiating thorium (one common misconception is that thorium itself is the fuel; in reality it is the starting material). It operated for four years, and shut down in 1969 due to funding cuts.
Thorium as a fuel never took off because 1) you needed uranium to build the first reactors, 2) it isn’t fissile, 3) we aren’t actually running out of uranium, and 4) most of the infrastructure is already set up for uranium.
The major catches for MSRs are 1) there’s only ever been two or three MSRs ever operated (all at one site) and none capable of power production. Sodium fast reactors, on the other hand, have been built and operated far more frequently. MSRs therefore lag in terms of engineering knowledge. 2) Molten salts are generally very corrosive, especially when you throw radiation into the mix. In most cases you have to use specialized alloys, which add to your capital cost.
These are some good articles. The author was recently on Science Friday.
https://whatisnuclear.com/msr.html
https://whatisnuclear.com/thorium-myths.html
And yes, it does drive me crazy that new nuclear (or even maintaining existing nuclear until all coal and gas plants are closed) is left out of the discussion, although I’ve seen that changing, and apparently support for nuclear among Democrats has shot up 20 points in the last 2 years.
Any journalism I've read on MSRs says they're ready to go, basically, which got me on the bandwagon. Your reasons actually make sense, and I feel I've been slightly duped by bad science reporting.
Hastelloy-N is serviceable in the reactors as ORNL demonstrated in the 60s. It's just parts replacement (business as usual for a nuclear reactor), it can take the punishment for years. It's enough to get started. I am amused by all of the creative salt mixes people keep coming up with, though.
I remember reading something about high end ceramics being an underexplored option, but I have a hard time imagining that ceramics can take that level of neutron punishment. The salt corrosion isn't the worst element in the mix for your materials. Those tiny invisible bullets can and will wreck anything. Metal may corrode faster but it seems like it would still weather the bombardment better.
It would be so very nice if we could start running a couple of hot (as in, radioactive) salt loop experiments at universities all over the world so we could work on this. A lot of the work doesn't have to happen inside a reactor. Trouble is, the instant you involve radioactive materials, the regulations get real. It's hard to make progress on a technology while the parking brake is still engaged.
The ORNL team did document their work very well, and even wrote up where to pick up again. But there are several more years of work ahead.
Here is the 1969 documentary about the MSR experiment at ORNL.
I hear the NRC has been coming around big time to the new paradigms in the last few years. Have you had any experience with them directly or heard anything similar?
I’m actually on the DOE side of the nuclear sector, so I’m not intimately familiar with what’s occurring with the NRC. I know they do have a licensing program for non-light water reactors; but of course, the SMR progressing through the process the quickest is... NuScale, which is just a smaller PWR. Canada is seen as being more flexible, and several companies are working with the Canadian Nuclear Safety Commission to get start licensing, among them Terrestrial Energy (with an MSR, in my opinion the most promising one) and Ultra-Safe Nuclear Corporation (with an HTGR, in my opinion most promising overall).
Do plants typically run with all reactors? I live near the San Onofre power station and was looking into its decommission, and in the history of the plant it seemed only one or two reactors were operating at a time. Is there a reason, aside from obviously shutting down a reactor for safety reasons?
Not in the industry, but have family and friends who are. Maintenance windows are huge. Inspection of the plant and maintenance of the components can take a given reactor down for months. If you regularly inapect them and rotate the maintenance, you're not ever going to have more than 80% uptime or so.
It would make sense to have a few reactors then, to keep everything operating consistently if you take one or two down.
And many plants do exactly that. Given all the infrastructure and logistics that surround a plant, adding additional reactors to an existing facility is better in many ways than spreading them out. It's mostly distribution and redundancy issues that keep them as spread out as they are.
Usually plants will have a refueling and maintenance outage every 12-18 months, which takes one to two months, and is staggered to ensure at least one reactor is online. A safety issue could cause the reactor to be offline for longer, of course.
I don't work in nuclear, but I happen to be working with the nuclear engineering department at the University of Michigan to recreate a VR replica of the Ford nuclear research reactor. It was decommissioned and renovated starting in 2003 and while the containing building is still there none if the original facilities are. So our project is to recreate it using archive photos and blueprints.
So far we have the ability to pseudo-simulate a basic experiment irradiating a length of iron wire and analyzing the isotope distribution along it's length. I don't have a degree in anything close to this field, but I do love science, so it's been fun!
Question for you, what was your favorite/most interesting experiment you've run, either in school or on the job?
When this is done, will it be available to the general public?
This specific one probably won't be publicly distributed. Mostly because it's designed to be used in conjunction with classroom lectures and material.
There has been discussion of sharing it with other higher-ed institutions though.
My background is actually in chemical engineering, and I didn’t expect to get into the nuclear sector at all. My job doesn’t really have me performing experiments, although I have worked to collect samples that are routinely used for monitoring. The most interesting aspect is that I’m responsible for maintaining an Excel spreadsheet that dates back to 1992. We use it for trending water quality.
Have you had the opportunity to stare at Cherenkov radiation yet? I've still never seen a single picture or video clip that can capture that phenomenon. I was at the Cornell reactor and they pulsed it for us, was quite something to see.
Does that video not capture it well? Because it seems like a pretty good shot, I've found that video before when searching for reference material.
All the videos show you what's going on, but when I look at that I feel like half the color and motion of the light is missing from what I remember. Cornell's TRIGA reactor was a pretty small one, too. They mainly used it to generate neutrons to siphon off and use in other research.
Can you describe the motion of it? From video it seems pretty static.
The real thing isn't static at all. It moves, it's much more vivid, the light source is the water itself around the core (hot and in motion) so it's hard to pin it down. It's a unique sort of light that our brains just don't process quite right because it does not behave like every other light source we've ever seen. I'm sure there's an element of illusion to it, something there is tricking our eyes or our brains into filling in the blanks. Most likely explanation of why the films and images look so static yet the real thing looks like eldritch magic.
If you could put it in your living room as a lamp without killing yourself, I think it'd easily outsell lava lamps and dark lights. It's much more enchanting to look at than they are. :)
I wish! Haven’t had much of a chance to travel yet for work, and I’m not at an operating reactor.
If you get the chance, make the time for it. Everyone should see that at least once just so you can spend the rest of your days wondering why film can't capture it. The real thing is... somehow more vivid and alive, an almost campfire-like quality.