Steve Martin was ahead of his time when he told us “Let’s get small!” While you usually think of a nuclear reactor as a big affair, there’s a new trend towards making small microreactors to produce power where needed instead of large centralized generation facilities. The U.S. Department of Energy has a video about the topic, you can watch below.
You probably learned in science class how a basic nuclear fission reactor works. Nuclear fuel produces heat from fission while a moderator like water prevents it from melting down both by cooling the reactor and slowing down neutrons. Control rods further slow down the reaction or — if you pull them out — speed it up. Heat creates steam (either directly or indirectly) and the steam turns a conventional electric generator that is no more high tech than it ever has been.
The US Nuclear Regulatory Commission (NRC) recently announced that it had approved certification of NuScale’s SMR (small modular reactor) design, completing its Phase 6 review of NuScale’s Design Certification Application (DCA). What this means is that SMRs using NuScale’s reactor design can legally be constructed within the US as soon as the rulemaking process completes. An NRC certification would also mean that certification of the design in other countries should pose no significant hurdles.
A question that remains unanswered at this point for most is how this certification process at the NRC actually works. Are there departments full of engineers at the NRC who have been twiddling their thumbs for the past decades while the US nuclear industry has been languishing? What was in the literally millions of documents that NuScale had to send to the NRC as part of the certification process, and what exactly are these six phases?
Stay tuned for a crash course in nuclear reactor certification, after a bit of SMR history.
Do you remember in 1989 when two chemists announced they’d created a setup that created nuclear fusion at room temperature? Everyone was excited, but it eventually turned out to be very suspect. It wasn’t clear how they detected that fusion occurred and only a few of the many people who tried to replicate the experiment claimed success and they later retracted their reports. Since then, mentioning cold fusion is right up there with perpetual motion. Work does continue though, and NASA recently published several papers on lattice confinement fusion which is definitely not called cold fusion, although it sounds like it to us.
The idea of trapping atoms inside a metallic crystal lattice isn’t new, dating back to the 1920s. It sounds as though the NASA method uses erbium packed with deuterium. Photons cause some of the deuterium to fuse. Unlike earlier attempts, this method produces detectable neutron emissions characteristic of fusion.
A nuclear power plant is large and complex, and one of the biggest reasons is safety. Splitting radioactive atoms is inherently dangerous, but the energy unleashed by the chain reaction that ensues is the entire point. It’s a delicate balance to stay in the sweet spot, and it requires constant attention to the core temperature, or else the reactor could go into meltdown.
Today, nuclear fission is largely produced with fuel rods, which are skinny zirconium tubes packed with uranium pellets. The fission rate is kept in check with control rods, which are made of various elements like boron and cadmium that can absorb a lot of excess neutrons. Control rods calm the furious fission boil down to a sensible simmer, and can be recycled until they either wear out mechanically or become saturated with neutrons.
Nuclear power plants tend to have large footprints because of all the safety measures that are designed to prevent meltdowns. If there was a fuel that could withstand enough heat to make meltdowns physically impossible, then there would be no need for reactors to be buffered by millions of dollars in containment equipment. Stripped of these redundant, space-hogging safety measures, the nuclear process could be shrunk down quite a bit. Continue reading “No-Melt Nuclear ‘Power Balls’ Might Win A Few Hearts And Minds”→
Over the past decades, additive manufacturing (AM, also known as 3D printing) has become increasingly common in manufacturing processes. While immensely helpful in the prototyping of new products by allowing for rapid turn-around times between design and testing, these days additive manufacturing is used more and more often in the production of everything from small production runs of custom enclosures to hard to machine components for rocket engines.
The obvious advantage of additive manufacturing is that they use generic equipment and common materials as input, without requiring expensive molds as in the case of injection molding, or extensive, wasteful machining of raw materials on a lathe, mill, and similar equipment. All of the manufacturing gets reduced to a 3D model as input, one or more input materials, and the actual device that converts the 3D model into a physical component with very limited waste.
In the nuclear power industry, these benefits haven’t gone unnoticed, which has led to 3D printed parts being developed for everything from keeping existing plants running to streamlining spent fuel reprocessing and even the printing of entire nuclear reactors.
Doing the rounds today is an interesting lot in an otherwise unexciting industrial dispersal auction in Lincolnshire, UK. On sale is an “Ex nuclear plant reactor control/monitoring system“, at the time of writing attracting the low low bid of £220 ($270), but we guess it will rise. Everyone who has watched Chernobyl (or maybe The Simpsons) is now gazing awestruck at a crescent of metal consoles covered in screens, buttons, and joysticks just waiting for a staff of white-coated technicians to pore over them.
Chernobyl Unit 3 control room (still active). [Source: IAEA Imagebank on Flickr CC-SA 2.0]It’s a very cool lot indeed, but it raises more questions than it answers. The auction house has very little information indeed, so we’re left guessing, where did it come from? From this image showing the unit 3 control room at Chernobyl it’s obvious didn’t come from there (/s). Since it is for sale in the UK, and the country has decommissioned the majority of its first-generation reactors by now, so there is no shortage of candidates. But that intriguing possibility raises another question. Is it even a reactor control panel in the first place?
British civilian nuclear plants have tight security but they are hardly a secret, so plenty of photos are online showing their interiors. And in studying those we hit a problem, this panel doesn’t resemble any of the control panel images we can find. The first generation of Magnox (Magnetic Oxide Magnesium Non Oxidising) plants had panels covered in analogue dials and chart recorders so it’s unlikely to be one of those. The second-generation AGR (Advanced Gas-cooled Reactor) stations had similarly complex panels, and it’s evidently not one of them.
Looking closely at the photos it becomes apparent that there are a lot of camera controls and monitors, and even what looks like a uMatic video recorder. It’s definitely nuclear-related and the 1980s look of it suggests maybe it could have come from an Advanced Gas-Cooled Reactor (AGR) station, but could it be a little closer to Sector 7G than the centre of the action? Is it a video monitoring console used to keep a physical eye on its operation?
Be careful if you bid, you could end up with a rather cool but absurdly large 1980s CCTV system. Can any of our readers shed any light on the matter?
When it comes to nuclear fusion, the most well-known reactor type today is no doubt the tokamak, due to its relatively straight-forward concept of plasma containment. That’s not to say that there aren’t other ways to accomplish nuclear fusion in a way that could conceivably be used in a commercial power plant in the near future.
As we covered previously, another fairly well-known type of fusion reactor is the stellarator, which much like the tokamak, has been around since the 1950s. There are other reactor types from that era, like the Z-pinch, but they seem to have all fallen into obscurity. That is not to say that research on Z-pinch reactors has ceased, or that other reactor concepts — some involving massive lasers — haven’t been investigated or even built since then.
In this article we’ll take a look at a range of nuclear fusion reactor types that definitely deserve a bit more time in the limelight.
