The technical requirements for detonating nuclear weapons are very high.

In order to clarify the details of detonation, it is necessary to introduce the concepts of chain reaction and critical volume.

When we talk about bomb explosion, we generally refer to chemical reactions, that is, chemical changes between molecules, through the breaking and bonding of molecular bonds, the chemical energy is converted into thermal energy and mechanical energy. This process can be very slow: for example, self-heating instant noodles can be heated by using a built-in heating belt; It can also be very violent: for example, the common lighter ignition is a violent redox reaction; Of course, it can also be more violent: for example, if it happens in a confined environment, the reaction is faster, which is what we usually call an explosion.

From the oldest black powder, to the T*N*T of the last century, to the so-called various high-explosive charges now, as well as the latest types of special bombs...... Although the explosion intensity, lethality, and control ability have changed dramatically, they are all chemical reactions, and they are all energy release processes caused by the breaking and combining of molecular bonds.

They are not fundamentally different and do not change matter from the atomic structure.

It's like hydrogen and oxygen are burned to produce water; Water is also electrolyzed to produce hydrogen and oxygen. Chemical reactions are characterized by reversibility, but they require more or less energy.

That's what chemistry is all about.

But nuclear reactions are different.

A nuclear reaction is a physical change.

In a nuclear reaction, the type of atom changes.

For example, nuclear fission reaction, microscopically speaking, "uranium + neutron = barium + krypton + neutron * 2 + huge energy". And the uranium element has become barium and krypton (barium, which is the stuff full of scum that the doctor asked you to drink when you did a gastrointestinal examination, that thing is called barium sulfate, and you can see what is happening in your intestines through barium sulfate; And krypton is a noble gas, which does not react with any elements, but is widely used in neon lights, and you can see this thing in all kinds of colorful lamps on the road, which is a unique reaction produced by cathode rays hitting inert gas elements in light-emitting diodes, of course, there is also a "superman" from the planet Krypton, you must know this)

Moving on to the energy produced by nuclear fission, how big is this huge energy? We can use the famous mass-energy formula E=MC^2 discovered by Einstein.

Well, while Stephen Hawking once said that every time you write a formula in a book, you have to cut the subscription to the book in half, and I've now written a nuclear fission reaction equation and a mass-energy conversion equation, so it seems like the subscription is going to be cut down to a quarter?

I hope that Hawking's formula of "formula +1, subscription halving" can be overturned by me, but the mood is still very apprehensive. Forehead...... Speaking of which? Continue to calculate the formula to calculate the energy. And this thing is really not easy to calculate, you have to believe that I must not be the number of water words, no writer will use this thing to calculate the number of water words! It's really hard to calculate! It's troublesome!

Well, it was still calculated, and after a series of particularly troublesome unit transformations, it was calculated that this huge energy is 4.3*10^6 electron volts.

So how to intuitively understand the concept of electronvolt? Electron volt refers to the kinetic energy obtained by an electron after being accelerated by a potential difference of 1 volt...... Well, I won't explain. I know you're not going to see this. I'm still talking about people.

In short, this energy is very huge.

This is a human phrase and a nonsense.

Ahem, so how huge is this energy?

For example, if you want to provide a city with the amount of electricity generated, for example, you need to burn 2,000 tons of coal per day, then if you switch to burning nuclear fuel, only one kilogram is enough.

In other words, the ratio of energy released from nuclear fuel and ordinary fossil fuels has reached a staggering 2,000,000:1!

Ok。

The scientists who discovered this shocking fact, yes, mainly said that the scientists who discovered the above two formulas, such as Einstein, Fermi, Oppenheimer, and these scientists that you often listen to, decided to use this ultra-high energy release ratio to create a bomb.

If it's a mild reaction, it's a nuclear power plant.

If it's a violent reaction, it's a nuclear explosion.

What's the difference?

In other words, how can you determine whether a nuclear reaction is mild or violent?

This brings us to the topic of our chapter: chain reactions and critical volumes.

Going back to our formula above, we can see that there is a neutron on the left side of this formula. And on the right side of the equation, there are two neutrons! (Go back to the above and see the formula!) ）

Give one, pop out two!

It's scary!

Imagine that this is roughly like putting a pair of rabbits (one female and one male) on an isolated island, and then ten years later, coming back to the island to see them. You'll find the island full of rabbits! Through consanguineous marriages and ***, they have produced countless rabbits, one gives birth to two, two gives birth to four, and four gives birth to eight......

So, a chain reaction happens.

The chain reaction at the atomic nucleus level is different from that of rabbits in that it is faster. The speed of 1 to 2, 2 to 4, 4 to 8 has reached the femtosecond level (10^-15 seconds), many uranium atoms are stacked together, as long as a neutron comes over casually in the environment, or a fixed neutron source such as californium, radium and other elements can be given, it can cause an extremely fast chain reaction, so all uranium atoms explode at the same time! So, the nuclear bomb also exploded!

So, the key question comes out.

Key words: "a lot of uranium atoms stacked together"

It can't be stacked too closely, and if there are too many piles, it is likely to blow up before it is launched.

It is only here that we finally make it clear how a nuclear bomb is detonated.

The larger the volume of the pile, the more likely it is to explode.

The smaller the volume, the more you get it, it won't be fried.

So the final keyword is:

Critical volume.

If the "uranium atoms" of the nuclear reaction are too close and too close to the critical volume, then they can be easily detonated, as long as any neutron source is irradiated, it can be detonated, without the need for conventional explosives, and cannot be detonated by conventional explosives.

Conversely, if the "uranium atoms" are too loose and the total volume is less than the critical volume, then no matter what the conditions are given, the chain reaction cannot occur.

Therefore, the most critical element in the detonation of a nuclear fission bomb is to put together a lot of uranium rods that are less than the critical volume, so that they exceed the critical volume, and give them a neutron source. In this way, the chain reaction can occur spontaneously.

------I'm the dividing line of the key points, and the following content is the key points, knock on the blackboard! ------

And this process of "volume aggregation" is done within an already encapsulated nuclear bomb!

It is an automatic control system!

And the nuclear lockbox controls the critical volume control system inside this nuclear bomb!

Whether or not to launch a nuclear bomb is decided by the commander in charge of launching the missile. For example, the air-based is the current pilot, the road-based is the current silo commander, and the sea-based is naturally the person in the submarine. They can choose to load a conventional warhead on a ballistic missile, as well as a nuclear warhead.

They can control the launch of this nuclear warhead, but whether it can be exploded or not is not up to them.

The only decision is in this lockbox.

And lockbox is unique.

In the case of not being able to disassemble the nuclear bomb, but also to concentrate the uranium rods beyond the critical volume, the lockbox is the only device that can automatically control the critical volume.

That's why there was an embarrassing scene of a ballistic missile that just went directly into the water after it was launched, and it didn't even explode, like a dumb bomb.

That's why there was the previous one, Nie Xing's hesitation and complicated emotions. His decision to drop the lockbox was like a person who died and didn't spend all the money, which was a pity, but it was rational, so he really made a far-reaching decision at that time.

(Chapter 74 Chain Reactions and Critical Volumes...... ENDS)

(The story is not over to be continued!!) ）

……

……

(Self-hilarity chapter.) Hum! Others can use soy sauce to irrigate water, environmental description, dialogue, and psychological activities, so I can't use popular science to irrigate? Just a chapter...... Just one chapter...... Really, this chapter, I was wrong, I was really wrong, I never wrote formulas anymore, I never wrote these things again...... Isn't it okay for me to write more words in the next chapter...... Don't let me cut my subscription to a quarter, really don't...... ）

(Another: I think there should still be someone who will carefully read this chapter of irrigation with popular science, right?) In fact, I still hope that everyone will read it, it is written seriously, and it is necessary to say a very complex change in human terms, there can not be too many scientific and technological terms, and it must be explained clearly, and it is necessary to guess how the lockbox works...... He's aiming at me, and he's not making a lockbox, how do I know if I'm guessing right, don't spray me, okay, huh...... Oh yes, I also did a lot of scientific calculations, and I was really tired...... If you actually read it instead of just reading the part related to the plot and knocking on the blackboard to highlight the highlights, please point out a harmless mistake that I have reserved in the book review section and give me some comfort to let me know that someone else actually read it? Of course, in fact, there are still a lot of logical errors and common sense errors in the whole book that I didn't find...... I also know this, after all, it is going to the real route, so there must be a lot of things that cannot be explained, and I try to make sure that it is too outrageous...... It's full of difficulties, hey, it's all tears, I still write novels, write plots, write stories, and don't write these things, it's really tiring...... ）

(What, ask for support...... ）

(This is the last parenthesis, I promise it is really the last parenthesis: I sprinkled water into the computer motherboard when I got off work tonight, and the motherboard burned directly, so there was no way to update it today.) But in order to keep changing [Invitation Expression] I rode a small yellow car to resist the chassis of the one-ton computer host, and found 4 small repair shops on the street, three of which said that they only repaired notebooks and not desktops, and finally found the docking device between the computer hard disk and the USB port when I found the fourth one...... It's a magical thing called a hard disk socket, so it can finally be updated again...... Hey, today's codeword road is really tortuous...... ）

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Thanks to the book friend for the three tips of 200*********57