It’s Critical: Don’t Pile Up Your Fissionable Material

December 12, 2024 by Lewin Day 52 Comments

Nuclear fission is a powerful phenomenon. When the conditions are right, atomic nuclei split, releasing neutrons that then split other nuclei in an ongoing chain reaction that releases enormous amounts of energy. This is how nuclear weapons work. In a more stable and controlled fashion, it’s how our nuclear reactors work too.

However, these chain reactions can also happen accidentally—with terrifying results. Though rare, criticality incidents – events where an accidental self-sustaining nuclear chain reaction occurs – serve as sobering reminders of the immense and unwieldy forces we attempt to harness when playing with nuclear materials.

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Boss Byproducts: Corium Is Man-Made Lava

November 27, 2024 by Kristina Panos 19 Comments

So now we’ve talked about all kinds of byproducts, including man-made (Fordite), nature-made (fulgurites), and one that’s a little of both (calthemites). Each of these is beautiful in its own way, but I’m not sure about the beauty and merit of corium — that which is created in a nuclear reactor core during a meltdown.

A necklace made to look like corium. Image via OSS-OSS

Corium has the consistency of lava and is made up of many things, including nuclear fuel, the products of fission, control rods, any structural parts of the reactor that were affected, and products of those parts’ reaction with the surrounding air, water, and steam.

If the reactor vessel itself is breached, corium can include molten concrete from the floor underneath. That said, if corium is hot enough, it can melt any concrete it comes in contact with.

So, I had to ask, is there corium jewelry? Not quite. Corium is dangerous and hard to come by. But that doesn’t stop artisans from imitating the substance with other materials.

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The Diablo Canyon NPP in California. This thermal plant uses once-through cooling. (Credit: Doc Searls)

US DOE Sets New Nuclear Energy Targets

November 14, 2024 by Navarre Bartz 63 Comments

To tackle the growing electrification of devices, we’ll need to deploy more generation to the grid. The US Department of Energy (DOE) has unveiled a new target to triple nuclear generating capacity by 2050.

Using a combination of existing Generation III+ reactor designs, upcoming small modular and micro reactors, and “legislation like the ADVANCE Act that streamlines regulatory processes,” DOE plans to add 35 gigawatt (GW) of generating capacity by 2035 and an additional 15 GW installed per year by 2040 to hit a total capacity of 200 GW of clean, green atom power by 2050.

According to the DOE, 100 GW of nuclear power was deployed in the 1970s and 1980s, so this isn’t an entirely unprecedented scale up of nuclear, although it won’t happen overnight. One of the advantages of renewables over nuclear is the lower cost and better public perception — but a combination of technologies will create a more robust grid than an “all of your eggs in one basket” approach. Vehicle to grid storage, geothermal, solar, wind, and yes, nuclear will all have their place at the clean energy table.

If you want to know more about siting nuclear on old coal plants, we covered DOE’s report on the matter as well as some efforts to build a fusion reactor on a decommissioned coal site as well.

The Nuclear Powered Car From Ford

July 8, 2021 by Al Williams 42 Comments

We think of electric cars as a new invention, but even Thomas Edison had one. It isn’t so much that the idea is new, but the practical realization for normal consumer vehicles is pretty recent. Even in 1958, Ford wanted an electric car. But not just a regular electric car. The Ford Nucleon would carry a small nuclear reactor and get 5,000 miles without a fillup.

Of course, the car was never actually built. Making a reactor small and safe enough to power a passenger car is something we can’t do even today. The real problem, according to experts, is not building a reactor small enough but in dealing with all the heat produced.

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Nuclear Reactors Get Small

May 13, 2021 by Al Williams 92 Comments

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.

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The Oldest Nuclear Reactor? Nature’s 2 Billion Year Old Experiment

January 7, 2020 by Al Williams 34 Comments

When was the first nuclear reactor created? You probably think it was Enrico Fermi’s CP-1 pile built under the bleachers at the University of Chicago in 1942. However, you’d be off by — oh — about 2 billion years.

The first reactors formed naturally about 2 billion years ago in what is now Gabon in West Africa. This required several things coming together: natural uranium deposits, just the right geology in the area, and a certain time in the life of the uranium. This happened 17 different times, and the average output of these natural reactors is estimated at about 100 kilowatts — a far cry from a modern human-created reactor that can reach hundreds or thousands of megawatts.

The reactors operated for about a million years before they spent their fuel. Nuclear waste? Yep, but it is safely contained underground and has been for 2 billion years.

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Kilopower: NASA’s Offworld Nuclear Reactor

August 28, 2019 by Tom Nardi 107 Comments

Here on Earth, the ability to generate electricity is something we take for granted. We can count on the sun to illuminate solar panels, and the movement of air and water to spin turbines. Fossil fuels, for all their downsides, have provided cheap and reliable power for centuries. No matter where you may find yourself on this planet, there’s a way to convert its many natural resources into electrical power.

But what happens when humans first land on Mars, a world that doesn’t offer these incredible gifts? Solar panels will work for a time, but the sunlight that reaches the surface is only a fraction of what the Earth receives, and the constant accumulation of dust makes them a liability. In the wispy atmosphere, the only time the wind could potentially be harnessed would be during one of the planet’s intense storms. Put simply, Mars can’t provide the energy required for a human settlement of any appreciable size.

The situation on the Moon isn’t much better. Sunlight during the lunar day is just as plentiful as it is on Earth, but night on the Moon stretches for two dark and cold weeks. An outpost at the Moon’s South Pole would receive more light than if it were built in the equatorial areas explored during the Apollo missions, but some periods of darkness are unavoidable. With the lunar surface temperature plummeting to -173 °C (-280 °F) when the Sun goes down, a constant supply of energy is an absolute necessity for long-duration human missions to the Moon.

Since 2015, NASA and the United States Department of Energy have been working on the Kilopower project, which aims to develop a small, lightweight, and extremely reliable nuclear reactor that they believe will fulfill this critical role in future off-world exploration. Following a series of highly successful test runs on the prototype hardware in 2017 and 2018, the team believes the miniaturized power plant could be ready for a test flight as early as 2022. Once fully operational, this nearly complete re-imagining of the classic thermal reactor could usher in a whole new era of space exploration.

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