Just before World War II scientists discovered nuclear fission. There is such a thing as nuclear chemistry. In the same way chemical reactions change the structure and composition of molecules, nuclear reactions change the structure and composition of the nucleus of atoms.
In the '30s physicists were just starting to figure all this out. In particular, they learned that when they bombarded the nucleus of a Uranium atom with a neutron, the nucleus changed. They initially thought that the result would be the creation of an atom with the next higher atomic number. Uranium has an atomic number of 92 because it has 92 protons. We now call the element with atomic number 93 Neptunium.
But they didn't get Neptunium. Instead they got Boron, an element with the atomic number 5. What also turned out to be true was that a tremendous amount of energy was released. The neutron had, in fact, blasted the Uranium atom into fragments, one of which was an atom of Boron. This process of breaking a nucleus up into smaller fragments ended up being called nuclear fission.
And we all know where this story goes next, to the creation of the Atomic bomb. Atomic bombs depend on the fission process. The two popular formulations are based on using either Uranium or Plutonium as the fuel. Other formulations are possible. But these turned out to be the easiest to pull off.
And, before moving on, I will note that there is another way to use nuclear chemistry to produce vast quantities of energy. That's fusion. Here two or more nucleuses are fused together in a way that releases vast amounts of energy. The most common fusion bomb recipe is to fuse two Hydrogen nucleuses (atomic number = 1) to create one Helium nucleus (atomic number = 2). Again, there are other recipes but this turns out to be the easiest to pull off.
And I will note one other thing before returning to my main topic. Nuclear fusion tends to release energy if the atomic number of each constituent is less than 26, the atomic number of Iron. Nuclear fission, in turn, tends to release energy if the atomic number of the nucleus being broken apart is higher than 26.
And, apparently, the further, the better. Hydrogen is as far away as you can get from Iron on the low side. Among the "naturally occurring" elements, Uranium is the furthest away you can get on the high side. Plutonium is further away but it is an "artificial" element. It does not exist in nature in significant amounts.
After the War ended an effort was made to "harness atoms for peace". The idea was to see if fission, and later fusion, could be used in a creative and useful way, rather than just as the fuel for highly destructive explosive devices. The obvious idea was to try to use "atomic power" to create electricity. And scientists thought they knew a way.
As part of the process of figuring out how to make an atomic bomb, scientists had created an "atomic pile". It was literally a pile of stuff, hence the name. But the pile was carefully constructed so that it released atomic energy slowly and in small amounts. That approach sounded ideal.
But not exactly as it had been done during the War, famously on a squash court at the University of Chicago. There, blocks containing Uranium had been mixed in with blocks made of materials that were neutron absorbers to literally create a pile of blocks. Both kinds of blocks were needed because an atomic bomb depends on a "chain reaction".
The thing that causes a Uranium atom to fragment into pieces is a neutron. But the fission process, besides throwing off Boron atoms, also throws off atoms of various other elements. And, importantly for out discussion, it can also throw off neutrons. (This description vastly oversimplifies the fission process but retains the parts important to our discussion.)
In actuality, the Uranium nucleus can break up in many ways. Some of them produce a Boron atom. Some of them don't. But, if we look at a large number of Uranium atoms fissioning, we can expect to see this many Boron atoms, that many of some other kind of atom, and so on. How many of this or that even a small amount of Uranium throws off, when it is subjected to the fission process, is completely predictable.
If we know how many Uranium atoms are going to be subject to fission, we can predict how many of whatever we are interested in will be produced. We do need more than a few atoms of Uranium. But anything over a thousand will do. And a thousand atoms of Uranium is too small to see with an ordinary microscope.
So the question becomes, "how many neutrons, on average, does the fissioning of a single Uranium atom produce"? The answer turns out to be "about 2". So, under ideal conditions, if we have a big lump of Uranium and we cause a single Uranium nucleus to fission, it will produce 2 new neutrons. If each of these now causes some other Uranium nucleus to fission, we will get 4 neutrons.
As long as this keeps going we double the number of neutrons with each "generation". That means that after ten generations we will have a thousand neutrons. After twenty generations we will have a million neutrons. And, if we have arranged things properly, each neutron causes the fissioning of a Uranium nucleus.
Cutting to the chase, after 80 or so generations, enough Uranium will have undergone fission to produce a "ten kiloton" explosion, one equivalent to blowing up ten thousand (kilo) tons of high explosive. (The Hiroshima and Nagasaki bombs were each rated at about ten kilotons.) And the time it takes to double through 80 or so generations is only a fraction of a second.
This chain of one fission causing more fissions, causing still more fissions, is why the process is called a chain reaction. And going through 80 or so generations in a fraction of a second is a good way to make an atomic bomb.
But an atomic bomb is far too much energy getting released far too quickly to be of practical use, We need to keep the amount of fission happening to be far less and we need to slow things way down. And that's exactly what they did in that first atomic pile.
The trick they used was to cause a lot of the neutrons to be absorbed in things that were not Uranium. That meant that the average number of neutrons from a Uranium nucleus fissioning that ended up causing another Uranium nucleus to fission was one, plus or minus a bit.
We can have a chain reaction as long as the number of neutrons produced by a single Uranium nucleus's fission causes at least one other Uranium nucleus to fission. If the number is a tiny amount greater than one then the process will go very slowly.
By monitoring things carefully those scientists working on the first atomic pile arranged things so that at first less than one neutron chained. That told them that their design was sound. Then they carefully tweaked things so that the number was almost exactly one. That resulted in a steady amount of activity. Then they tweaked some more so that it was a tiny fraction above one. That caused activity to increase very slowly.
They had very carefully calculated which configurations would produce what behavior before they started. Their extremely careful tests proved that their theories were correct. They went on to use those theories to design the first atomic bombs. Needless to say, the designs they came up with worked.
When they went back to try to design a device that would produce far less energy than an atomic explosion but enough energy to be useful, they went back to the same ideas employed by that original atomic pile.
The general idea stayed the same but the materials and configuration changed completely. They could have come up with any of a number of different designs. But at this point it mattered who was paying for this very expensive research.
It turns out that the people who had a lot of money and were interested in spending it on this particular project were the U. S. Navy. Submarines of the time were very vulnerable to detection and attack when they were running on the surface.
The diesel powered submarine of the day had to spend a lot of time running on the surface so that its engines could get enough air to run. The diesel engines were used in part to drive the boat through the water at high speed and in part to charge the batteries. One way or another, a diesel sub had to spend a lot of its time on the surface. This is because the sub couldn't go very far or very fast while only using battery power.
A nuclear powered submarine, however, did not need to be on the surface to make full use of it's engines. They required no air. (The crew did, but that problem was easily solved.) And that meant that a sub powered by nuclear energy could travel long distances under water at high speed.
So the Navy was willing to provide lots of money to scientists to come up with a working design when no one else would. So it is not surprising that they came up with a design for what we now call a "nuclear reactor" that worked well on boats.
The Navy later adapted it for use on Aircraft Carriers, where it also worked fine. But it never saw wide use on other ship types. A nuclear powered merchant ship was built as a demonstration project. It was a technical success but a practical failure. The technology worked fine but it kept getting banned from ports out of fear of anything nuclear.
The navy design depended on water, a lot of water. A ship at sea, particularly a "blue water" type of ship, one that spends its time on the open ocean, has access to nearly unlimited amounts of water. This water can be used for cooling and as a "moderator", something that soaks up neutrons. Add in Boron rods, which are even better at soaking up neutrons, and you have the makings of a device that can produce a lot of energy in a controlled manner.
Nuclear fission produces a lot of radioactivity. Anything close to the Uranium (pretty much the only fuel used, although others would work) ends up getting very radioactive over the course of a year or so. So a "two stage" process was used. Pellets of Uranium are encased in Zirconium rods. Why? I am going to skip over that. If the right number of rods are put the right distance from each other then a slow chain reaction will take place.
The chain reaction can be quickly quenched by SCRAMing the reactor. (SCRAM is an acronym. I don't know what the letters stand for.) SCRAMing consists of quickly jamming Boron rods between the Uranium rods. This starves the process of neutrons and things quickly settle down.
Anyhow, water flows around the Uranium rods and carries away heat. But this water becomes radioactive over time. So this water is kept in a "primary loop". The hot water in the primary loop is used to heat more hot water in a "secondary loop". This exchange of heat is done far enough away from the Uranium rods that the water in the secondary loop does not get radioactive.
The hot water in the secondary loop is turned into steam that is used to turn a turbine that is connected to an electric generator. From there, the electricity can be used for whatever we want. On a ship it is used to run motors that turn the propellers. On land it is piped into the electrical grid.
This is a handy design for a boat. If something goes wrong, large quantities of ocean water can be used to cool things down. It is relatively compact. The components are heavy but this is not a problem on a boat. The U. S, Navy has been using nuclear powered submarines successfully for a long time now. Other navies have also been using them for almost as long.
When electric companies looked at nuclear power they saw a lot of possibility. They could have spent the money to come up with a new design that was well suited for use on land. But that would have been hugely expensive and the navy design was already right there.
The power industry figured that if they went with the Navy design they could save a lot of time, effort, and money Only relatively minor design changes would be necessary. The cost of doing only the minimum kept research and development kept costs down to an acceptable level.
The reactor design problem that the electric power industry needed to be solved when building a nuclear power plant was cooling. Nuclear plants throw off a lot of heat. There was no longer an ocean handy. But nuclear plants could be built on a coastline or a riverside. That amount of water was far less than the ocean could provide, but with a little engineering, it would be enough.
Several methods for keeping machinery cool were already in widespread use. They just needed to be scaled up. When most people see a nuclear power plant what they mostly see is these giant structures that are curved in a funny way. They think that's where the "nuclear" stuff is going on. They are wrong.
Next to each of these giant towers is usually a much smaller cylindrical shaped building. That's where the nuclear stuff actually is. But that building is not as dramatic looking so it tends to get ignored. The large structure is a "cooling tower" that depends on the "Venturi effect".
Basically, if you shape the structure correctly, air flows (wind) arise automatically that move the air around in useful ways. This air motion that arises out of the shape of the building is used to create a cooling tower that requires no powered fans, etc. Yet it is still capable of cooling a lot of water.
Given the amount of cooling needed by a modern nuclear power plant, the suckers need to be really big. And, to make the Venturi effect work, they need to have that peculiar curved shape. Anything that big is expensive to build. But, once it is built, it has zero operating costs. It also doesn't get radioactive as it is part of the secondary cooling loop.
So once something, a Venturi effect cooling tower or something else equally effective, was tacked on the side of the design they were all set, right? Wrong.
It turns out that the fact that a single bomb was able to kill about 100,000 people at Hiroshima, and then another single bomb was able to kill another 100,000 people at Nagasaki, scared the shit out of people. The power industry countered with the fact that their design was "proven safe by the navy". And that worked well enough for a long time.
The public turned out to be willing to cut the military a little slack when it came to nuclear submarines and aircraft carriers. After all, it was War we're were talking about. And these boats with their nuclear reactors spent most of their time far out at sea. Nuclear power plants would be in our own back yards, metaphorically, and sometimes actually.
And then there were all the monster movies Hollywood was churning out. The deus ex machina for many of them was "some nuclear thing that normal people don't understand goes horribly wrong". It all piled up and people became very afraid of anything nuclear. Arguments that all this could be done safely fell on deaf ears.
So all of the nuclear stuff had to be constructed inside an extremely strong "containment vessel" to keep the public happy. This consisted of a large room with extremely thick walls. And this kind of overdesign drove up costs. And enough was never enough so the overdesign had to be built up even more. This caused schedules to stretch and that too increased the cost.
It might have been possible to overcome the public's resistance to nuclear power if it was cheap enough. But by the time the dust settled, all these factors, and several more I am skipping over, drove the cost up to the point where nuclear power actually ended up being quite expensive.
But plants were built. And by and large they performed as promised. But the anti-nuclear people never gave up. They kept demanding more and more measures that were supposedly intended to increase safety but were actually intended to kill off the nuclear power industry. Ultimately, this "drive for safety" became counterproductive.
Then "Three Mile Island" happened. It was a nuclear power plane near Pittsburgh. At this point the anti-nuclear forces had been at it for decades. As a result, nuclear plants were still using a design from the '50s that was well suited for use on ships.
The anti-nuclear people had made it impossible for the industry to move on to newer and better designs. And that had made it impossible to replace an old plant built to an old design with a new plant built to a newer, much safer, design.
There were several design problems with Three Mile Island. But they all stemmed from deficiencies in what was considered good design in the '50s. It was good design, for the '50s. But technology marches on and we learn things.
The most important problem was with a sensor on a valve. The sensor did not measure whether the valve was open or closed. Instead it measured whether the valve had been instructed to open or close. I am going to skip over why this had been best way to do it when the plant was initially designed and built..
The operators ordered the valve to open. But it got stuck so it stayed closed. But the sensor correctly reported that it had been ordered to open. So the operators erroneously thought the valve was open and took no action until it was too late. This design problem, along with other less directly contributory factors, caused the "core" to overheat.
One of those contributory factors had to do with how the controls worked. State of the art design for the '50s called for a schematic to be put on the wall. Key controls and gages were put beside whatever they controlled or measured.
But something had been "tagged" for some reason. And by chance the tag covered a key indicator that would have told the operators that something was wrong. Nobody noticed so nobody moved the tag.
The reason the controls had not been computerized was opposition by anti-nuclear people. Management correctly felt that they had to be able to say "we stuck with a proven design and did not change anything that could have introduced new failure modes". Any major change, like computerizing the controls, would have been vigorously opposed by the anti-nuclear people on the grounds that it just added new ways for things to go wrong.
In the general environment of everything being under a microscope nobody thought to worry about the bad design of the sensor. And, of course, if a new plant had been built to replace the old plant, it would have fixed both of these problems (and many others).
Three Mile Island was another milestone. It was a "China Syndrome" class of failure. The entire "core", the part with all the Uranium, completely melted down. This was supposed to be an "as bad as it gets" type of accident. (We would learn differently later.)
This was called a China Syndrome event because if the core melted down we were told it would melt through the reactor vessel, the containment building, and pretty much everything else as it kept going all the way through the earth until it got to China.
A movie called "The China Syndrome", speculating on this sort of thing, had just opened a few months before Three Mile Island happened. But, in spite of the total meltdown of the core, the reactor vessel remained completely intact. It came nowhere close to failing.
And the rest of it was nonsense too. In fact, after the initial failure, everything worked exactly the way the experts said it would. The safety measures built into the design kept everyone safe even though a "catastrophic failure" had occurred.
Three Mile Island was an economic disaster. It was not a health disaster. No one's health was significantly harmed. But you couldn't tell that from the press coverage. In fact, we learned something very interesting from Three Mile Island. It turns out that granite is radioactive. It also emits Radon gas, which is highly radioactive.
No one even suspected this before studies that were done as a result of Three Mile Island. People in the vicinity of Three Mile Island were exposed to more radiation if they cowered in their basements than if they instead stood on their roofs basking in the "radioactive glow" we were told was emanating from Three Mile Island.
And it's a national problem. Many people living far away from Three Mile Island (or any nuclear power plant) are getting far higher doses of radiation from the granite their house is built on than they ever would from a nuclear power plant.
For a while, contractors were making a bundle by first radiation checking people's basement and then selling them expensive "remediation" packages. Fortunately, this particular scam soon died out and few now remember it.
Chernobyl is the anomaly. It was a design similar to that used under the squash court. The British built a small reactor along these lines in the '50s at a place called Windscale. Things went wrong but it was small and the damage was contained relatively easily, But Windscale convinced the nuclear industry to stay away from this design. Except the Russians.
The Russians built a number of nuclear power plants using this design. They did this in spite of the fact that, in the right circumstances, the reactor would "run away" (just as bad as it sounds). They figured that everything would be fine if they did two things.
The first thing they did was to add a bunch of safety equipment so that the it was impossible to put the reactor in the "right circumstances". The second thing they did was to train all the operators. "Don't do this. If you do, very bad things will happen." Their "human nature" calculations turned out to be fatally flawed.
A group of operators decided they didn't believe their training was correct. So they carefully disconnected all of the safety equipment. Then they carefully put the reactor in the "right condition". It turns out that the experts were right. Bad, bad, very bad things happened.
It turns out that Chernobyl is the only example of a nuclear power reactor going south and killing and injuring a lot of civilians. Chernobyl is also the only 100% human error event. It was 100% caused by a bunch of people who knew better going out of their way to do a really stupid thing.
Chernobyl makes a strong case for not building nuclear power plants to this design. But that's all. And even Russia abandoned this design after Chernobyl. Pretty much all nuclear plants use a minor variation on the the navy submarine design from the '50s. It works pretty well. But it can be improved upon. Any doubt about this was delivered by the Fukushima disaster.
Fukushima delivers perhaps the weakest case for abandoning nuclear power. It happened in the midst of a massive earthquake and an epic tsunami. Absent either, it would not have happened. And absent anti-nuclear agitation it also would not have happened. Let's review the circumstances.
A magnitude 9.4 earthquake happened a few miles offshore from the Japanese main islands. The Fukushima nuclear power plants survived the earthquake just fine even though they weren't designed to handle an earthquake that large. In fact, all of the more than 50 Japanese nuclear power plants rode through this gigantic earthquake just fine.
But then came a tsunami of epic proportions. Fukushima was hit the hardest. In spite of the fact that the plant was not designed to handle a tsunami nearly as large the plant itself survived with little damage. Other nuclear power plants that were not hit as hard came through with flying colors.
What did the Fukushima nuclear power plants in was a small thing, the siting of their emergency generators. Guess who had a big hand in this decision?
If the generators had been sited high up in the facility. everything would have been fine. But anti-nuclear people argued for siting them low down to avoid hurricane (or Typhoon, as they are called in that pert of the world) considerations. So they were.
And water got into all of the lower areas of the plant as a result of the tsunami. Some of that water got into the emergency generators and wrecked them. BTW, the high areas stayed dry.
So why did they even matter? When the earthquake hit the reactors SCRAMed, just like they were supposed to. From then on, theoretically, the reactors were shut down. So what went wrong? It turns out that reactor cores contain a lot of heat. And, although the nuclear reaction is tamped way down, it is not stopped completely. Heat is produced at a low rate for about four days.
Normally this heat is not a problem. The amount produced is way less than is produced in the course of normal operation. All that "cooling tower" business can easily handle it. The problem is getting the heat out of the core and into the cooling tower. Normally, you just pump a little water and everything is cool.
It doesn't take much electric power to run the pumps. But it takes some. Normally, the Fukushima plants would get this from the Japanese power grid, which is very robust. But the earthquake knocked out the whole power grid. And that's where the backup generators are supposed to kick in. But they were flooded out so they didn't.
And that meant that the water did not move. And that meant that heat built up in the core. And that resulted in a mini Three Mile Island. Eventually the reactor cores melted down. Only this time there was nothing anybody could do about it. So the roofs literally blew off the reactor buildings and a substantial amount of radiation was spread around.
Fukushima turned out to be much worse than Three Mile Island. This was because the earthquake/tsunami wiped out all the resources around Fukushima. At Three Mile Island they never lost power from outside the plant. Additional resources could be brought in promptly. That allowed the damage to be contained.
At Fukushima the problem was not the triggering event. It was that resources from outside the plant were literally unavailable. And much of the plant was trashed, not just the reactor room. It was what happened after the initial event that made the event so destructive. Three Mile Island was an "inside the fence" event. Fukushima was not.
And it is important to remember that at Fukushima there were no civilian casualties. Some plant employees were exposed to massive amounts of radiation as they tried to manually get things under control while they worked in horrific conditions. After a few days the damage was extensive and that made things much more difficult and much more dangerous. I believe there have been fatalities but I actually don't know.
And, absent an aggressive anti-nuclear movement, the Fukushima power plants would have been replaced by new plants that did not contain the deficiencies that it only took a massive earthquake combined with a massive tsunami to bring to light.
Many tens of billions of dollars worth of damage was caused by the non-Fukushima part of the disaster. More than 20,000 lives were lost in the non-Fukushima part of the disaster. But all most people remember is what happened at the power plant. Yet, measured either by the cost in dollars or the cost in lives, Fukushima was a small part of a much larger disaster.
Fukushima lit a rocket under the anti-nuclear movement. Nuclear power plants have been shut down all over the world. Nuclear power is carbon free. For the most part, carbon free nuclear power has been replaced by carbon heavy fossil fuel powered sources of electric power. Carbon heavy power generation kills people. We just choose to ignore that fact.
Wind and solar are coming on like gangbusters. I'm all for that but they are both "intermittent". Wind farms generate no electricity if the air is calm. Solar generates no electricity if it's dark out. There are ways to deal with this intermittency but we have talked about it a lot and done little.
Meanwhile, nuclear is just sitting there. New designs are safer and more efficient. But the anti-nuclear people have gotten very good over the decades at slowing things down and making them more expensive. They are also very good at scaring the shit out of people and keeping them scared. So the plans sit on the shelf.
These new designs do not suffer from the problems exposed by Three Mile Island and Fukushima. We know to measure what's happening and not what's supposed to happen. New designs are designed to be "passive". Cooling is maintained even if there is no power available and even if the operators do nothing. We ignore the many failings of fossil fuel power plants and obsess on the perceived failings of nuclear plants.
Nuclear is good at what wind and solar are bad at. It is perfect for "base load", needs that are always there whether the wind is blowing or not and whether the sun is shining or not. It pairs very nicely with wind and solar.
But, instead of taking advantage of nuclear, we worry incessantly about theoretical fears that never materialize and focus on wildly exaggerated fears that we are told are based on actual events but aren't. It is another example going with "gut instinct" then wondering why things are so screwed up.
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