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How Neutrons Changed Everything

Spacedog79 says...

Fair point. I barely consider reactors that need control rods as a legitimate design, there are much better ways to build a reactor that doesn't need to depend on such things for safety. Basic design using a molten salt core should be more than enough, and in any case none of them are anywhere near the chain reaction that would be in a nuclear bomb.

Jinx said:

So does inserting a control rod actually speed up the reaction?

How Neutrons Changed Everything

Jinx says...

So does inserting a control rod actually speed up the reaction?

Spacedog79 said:

Good video but a bit confused about how nuclear power works, extra neutrons are not absorbed they are slowed down through moderation so they can more easily interact with other nuclei. The core mass and configuration are what stops it becoming a a bomb and this is not a knife edge thing, it is a long way off.

Seconds From Disaster : Meltdown at Chernobyl

GeeSussFreeK says...

@radx No problem on the short comment, I do the exact same thing

I find your question hard to address directly because it is a series of things I find kind of complexly contradictory. IE, market forces causing undesirable things, and the lack of market forces because of centralization causing undesirable things. Not to say you are believing in contradictions, but rather it is a complex set of issues that have to be addressed, In that, I was thinking all day how to address these, and decided on an a round about way, talking about neither, but rather the history and evolution as to why it is viewed the way you see it, and if those things are necessarily bad. This might be a bit long in the tooth, and I apologize up front for that.

Firstly, reactors are the second invention of nuclear. While a reactor type creation were the first demonstration of fission by humans (turns out there are natural fission reactors: Oklo in Gabon, Africa ), the first objective was, of course, weapons. Most of the early tech that was researched was aimed at "how to make a bomb, and fast". As a result, after the war was all said and done, those pieces of technology could most quickly be transitioned to reactor tech, even if more qualified pieces of technology were better suited. As a result, nearly all of Americas 104 (or so) reactors are based on light water pressure vessels, the result of mostly Admiral Rickover's decision to use them in the nuclear navy. This technological lock in made the big players bigger in the nuclear field, as they didn't have to do any heavy lifting on R&D, just sell lucrative fuel contracts.

This had some very toxic effects on the overall development of reactor technology. As a result of this lock-in, the NRC is predisposed to only approving technology the resembles 50 year old reactor technology. Most of the fleet is very old, and all might as well be called Rickover Reactors. Reactors which use solid fuel rods, control rods, water under pressure, ect, are approved; even though there are some other very good candidates for reactor R&D and deployment, it simply is beyond the NRCs desire to make those kinds of changes. These barriers to entry can't be understated, only the very rich could ever afford to attempt to approve a new reactor technology, like mutli-billionaire, and still might not get approved it it smells funny (thorium, what the hell is thorium!)! The result is current reactors use mostly the same innards but have larger requirements. Those requirements also change without notice and they are required to comply with more hast than any industry. So if you built a reactor to code, and the wire mesh standards changed mid construction, you have to comply, so tear down the wall and start over unless you can figure out some way to comply. This has had a multiplication effect on costs and construction times. So many times, complications can arise not because it was "over engineered", but that they have had to go super ad-hawk to make it all work due to changes mid construction. Frankly, it is pretty amazing what they have done with reactor technology to stretch it out this long. Even with the setbacks you mention, these rube goldbergian devices still manage to compete with coal in terms of its cost per Kwh, and blow away things like solar and wind on the carbon free front.

As to reactor size LWRs had to be big in the day because of various reasons, mostly licencing. Currently, there are no real ways to do small reactors because all licencing and regulatory framework assumes it is a 1GW power station. All the huge fees and regulatory framework established by these well engineered at the time, but now ancient marvels. So you need an evacuation plan that is X miles wide ( I think it is 10), even if your reactor is fractionally as large. In other words, there is nothing technically keeping reactors large. I actually would like to see them go more modular, self regulating, and at the point of need. This would simplify transmission greatly and build in a redundancy into the system. It would also potentially open up a huge market to a variety of different small, modular reactors. Currently, though, this is a pipe dream...but a dream well worth having and pushing for.

Also, reactors in the west are pretty safe, if you look at deaths per KWH, even figuring in the worst estimates of Chernobyl, nuclear is one of the best (Chernobyl isn't a western reactor). Even so, safety ratcheting in nuclear safety happens all the time, driving costs and complexity on very old systems up and up with only nominal gains. For instance, there are no computer control systems in a reactor. Each and every gauge is a specific type that is mandated by NRC edict or similar ones abroad (usually very archaic) . This creates a potential for counterfeiter parts and other actions considered foul by many. These edicts do little for safety, most safety comes from proper reactor design, and skillful operation of the plant managers. With plants so expensive, and general costs of power still very competitive, Managers would never want to damage the money output of nuclear reactors. They would very much like to make plant operations a combination of safe, smooth, and affordable. When one of those edges out the other, it tends to find abuses in the real world. If something gets to needlessly costly, managers start looking around for alternatives. Like the DHS, much of nuclear safety is nuclear safety theater...so to a certain extent, some of the abuses don't account for any real significant increase in risk. This isn't always the case, but it has to be evaluated case by case, and for the layperson, this isn't usually something that will be done.

This combination of unwillingness to invest in new reactor technology, higher demands from reactors in general, and a single minded focus on safety, (several NRC chairmen have been decidedly anti-nuclear, that is like having the internet czar hate broadband) have stilted true growth in nuclear technology. For instance, cars are not 100% safe. It is likely you will know someone that will die in a car wreak in the course of your life. This, however, doesn't cause cars to escalate that drastically in safety features or costs to implement features to drop the death rate to 0. Even though in the US, 10s of thousands die each year in cars, you will not see well meaning people call for arresting foam injection or titanium platted unobtanium body frames, mainly because safety isn't the only point of a car. A car, or a plane, or anything really, has a complicated set of benefits and defects that we have to make hard choices on...choices that don't necessarily have a correct answer. There is a benefit curve where excessive costs don't actually improve safety that much more. If everyone in the USA had to spend 10K more on a car for form injection systems that saved 100 lives in the course of a year, is that worth it? I don't have an answer there as a matter of fact, only opinion. And as the same matter of opinion on reactors, most of their cost, complication, and centralization have to do with the special way in which we treat reactors, not the technology itself. If there was a better regulatory framework, you would see (as we kind of are slowly in the industry despite these things) cheaper, easier to fabricate reactors which are safer by default. Designs that start on a fresh sheet of paper, with the latest and greatest in computer modeling (most current reactors were designed before computer simulations on the internals or externals was even a thing) and materials science. I am routing for the molten salt, thorium reactors, but there are a bunch of other generation4 reactors that are just begging to be built.

Right now, getting the NRC to approve a new reactor design takes millions of dollars, ensuring the big boy will stay around for awhile longer yet. And the regularly framework also ensures whatever reactor gets built, it is big, and that it will use solid fuel, and water coolant, and specific dials and gauges...ect. It would be like the FCC saying the exact innards of what a cellphone should be, it would be kind of maddening to cellphone manufacturers..and you most likely wouldn't have an iPhone in the way we have it today. NRC needs to change for any of the problems you mentioned to be resolved. That is a big obstacle, I am not going to lie, it is unlikely to change anytime soon. But I think the promise of carbon free energy with reliable base-load abilities can't be ignored in this green minded future we want to create.

Any rate, thanks for your feedback, hopefully, that wasn't overkill

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