Chapter 645 The Atomic Bomb Is Finalized! (Part 2)

The final form of the atomic bomb.

Hearing these eight words from Lu Guangda's mouth.

"."

Including Li Jue Lao Guo and other base leaders, everyone's breathing stopped for a moment almost at the same time, and an inexplicable atmosphere quickly spread in the room.

The final shape of the atomic bomb

To know.

After this hurdle is passed, all that remains is the application, that is, the problem of parts production technology.

This means that Mao Xiong's theoretical nuclear blockade will completely fail, and the advent of the atomic bomb will also enter the final countdown.

To describe it using examples from later generations.

The god's blood bar was stripped out.

Then under the gaze of everyone.

Lu Guangda took a deep breath first to suppress the excitement in his heart, then picked up the chalk again and said:

"Comrades, now that the parameters we calculated are here, I will use this as a basis to derive the core ZND model."

"The on-site requirements are still the same as before. If there are any abnormal links or parameters, everyone can interrupt me at any time - even if it turns out that the data is not wrong."

Hearing Lu Guangda's words.

Everyone at the scene nodded.

Then Lu Guangda picked up the chalk and started writing on the blackboard.

Students who have watched the movie "Survival of the World" should all know this.

Li Yunlong. Ahem, Lu Guangda, played by Li Youbin, once wrote a chain reaction formula on the blackboard when the project team was first established.

There are eleven steps in the chain reaction, from the initial explosive charge to the final release of energy.

But in fact, in the field of real-life applications, the specific steps of the chain reaction are not eleven steps, but fifteen steps.

Of course.

This is not because the directing team or the screenwriter did not understand the situation - "Survival" is a gift film, and many of the extras are PLAs of the army.

The actual reason for this kind of bug in the plot is mainly because the filming time of "Born Out of the Sky" was 1999.

At that time, the thinking on armaments was relatively conservative, and there was still a lot of information that was far from being declassified, so the crew adopted this blurred method for filming.

But by 2023, none of this is a big secret.

These fifteen steps are: ignition of the detonator → explosion of detonating explosive → guidance of implosion pressure → accumulation of nuclear charge → formation of supercritical state → neutron bombardment → first-generation heavy nuclear fission chain reaction → neutron scattering → second Generation heavy nuclear fission chain reaction → slow neutron refraction → third generation heavy nuclear fission chain reaction → moderator activation → fourth generation heavy nuclear fission chain reaction → ZND model transmits detonation wave → self-sustaining chain fission reaction occur.

What Lu Guangda and the others are working on today is the last step before the nuclear explosion, which is the transmission of detonation waves by the ZND model.

Bah, bah, bah—

Lu Guangda quickly wrote lines of words on the blackboard with the chalk he was holding, and at the same time he was doing analysis:

"The precursor core concentration parameters can be used to derive the electron flow of spontaneous decay, and the effective delayed neutron share can be obtained with the laminar flame boundary equations in a high-density state."

"By combining the two effective delayed neutron shares, the neutron generation time and the density number required for fuel can be obtained."

"Then a part of the neutrons will be absorbed by the fuel and captured by radiation. Comrade Wei Donghang and their calculation results can correct the relative probability of this part."

"Assuming that the average number of neutrons released each time a fission reaction occurs is ν, and we have the probability of fission after a neutron is absorbed, then we multiply the two and we will get the fission rate of the fuel for each neutron absorbed. The number of neutrons is η=νσfσγ+σf=ν11+α”

Lu Guangda writes on the blackboard very quickly and can write a long line of words in the blink of an eye, but most people in the audience can keep up with his thoughts.

Same time as before.

Due to the lack of any early experience, even if Lu Guangda personally took action this time, there were some errors and omissions in the entire derivation process.

Fortunately, the on-site 'reviewers' are all very capable. Basically, within ten seconds after an error occurs in a certain link, five or six hands will be raised at the same time.

Therefore, although these errors and omissions occasionally existed, they were quickly eliminated.

Three hours later.

When the time came to half past ten in the evening.

Wow——

Lu Guangda used the last half of the chalk tip to draw a circle on the blackboard, and at the same time looked down at the audience:

"Okay, comrades, this is the ZND model we finally built."

"Where the thermal neutron absorption cross section σa=σf+σγ, the effective multiplication coefficient is etafεpPNL, and the constant source is."

Lu Guangda quickly reported seven or eight key parameters and quickly constructed a paper ZND model.

In addition to the previous mathematical calculations, the theoretical logic of this ZND model is actually very simple:

Lu Guangda and others first calculated a constant source equation. When k>1, this equation has no stable solution. When k=1, the stable solution of the above equation is not unique.

But when k < 1, the equation has an asymptotic solution.

At the same time, when Lu Guangda and others were calculating the neutron transport equation, the theoretical team had reached a very important conclusion:

The neutron chain fission reaction device responds very violently to a 0.5% change in the absorption cross section.

On this basis.

Lu Guangda and others deduced an equilibrium equation based on the equilibrium concentration of precursor nuclei, and the expression is dC0dt=0=βνNfσfvN0λC0.

If the cross section changes by 0.5% at time t=0, then at t=0.1s, the proliferation of prompt neutrons is [(1β)k]1000.

In each multiplication interval l, the fission product releases λlC delayed neutrons during decay. The delayed neutron source produces (1β)kλlC in the next first multiplication interval, and [() in the second interval. 1β)k]2λlC delayed neutron.

And so on.

If there is a slow neutron source within the breeding interval of 1000 generations of prompt neutrons, and assuming that the concentration of fission fragments remains unchanged (C=C0), then the number of neutrons after 0.01s is:

N(1000l)=[(1β)k]mN0+λlC0[(1β)k]m1+λlC0[(1β)k]m2++λlC0(1β)k+λlC0 =[[(1β)k]m+[1βk (1β)[1k(1β)]]+β1k(1β)]N0.

Then the detonation equation is introduced, and the ZND model can be obtained.

It's very simple and easy to understand, as long as you have some hands on it.

With the successful establishment of the ZND model, all that remains is.

Introduction and calculation of parameters.

Of course.

At this point, pure manpower is definitely inappropriate or unstable - after all, the stakes are so high.

Therefore, in addition to human calculations, computers are also an indispensable auxiliary item.

So soon members of the theory team extracted these key data and formulas and sent them to the ground to the computer center for simultaneous derivation - when the Taishang project was established, the 104 machine had already been sent to the base.

Now several experts from the Computer Institute are on standby on the ground, ready to input and calculate parameters at any time.

However, Lu Guangda and others did not sit still, but continued to make calculations.

Having more than one party to calculate will provide an additional guarantee. When the time comes, all parties can summarize and compare the results.

Then quickly.

The sound of crackling abacus could be heard in the conference room.

"The small beads advance one, the big beads retreat one."

"Two up, three out, five"

"Three hundred and fifty-seven times four point ninety-nine, the result should be..."

Abacus made of different materials emitted sounds of different frequencies when moved with different strengths, forming a brisk and beautiful movement in Xu Yun's ears.

But soon, Xu Yun realized a "truth":

What struck him was not the sound of the abacus, but the people working on the abacus.

Yu Da, Lu Guangda, Wang Ganchang, Cheng Kaijia. How could the music played by these seniors with their hard work and loyalty not sound good?

Suddenly, Xu Yun remembered a piece of news he saw before traveling through time:

After three years, a certain domestic mobile phone brand developed a domestic 5G chip despite layers of blockade across the sea.

This news may seem like a commercial competition, but behind it is a game between countries.

Although Xu Yun didn't know what kind of story was behind that chip, what was certain was that in that time and space, there must have been a group of people who were equally unwilling to admit defeat, holding up the stars in the sky and driving with faith and passion every night. new road.

Time can change many things, but it cannot change many things.

Then Xu Yun suddenly thought of something and quietly pushed his wheelchair to Li Jue's assistant Zhou Cai:

"Assistant Zhou, do you have a camera with you?"

"camera?"

Li Jue was slightly startled, seemingly surprised by Xu Yun's words, but he quickly nodded:

"I have it with me. I'm responsible for taking photos for many news about the base. Consultant Xu, what's wrong?"

Upon hearing this, Xu Yun turned around and pointed to the calculation room where the abacus was being clicked, and said:

"Assistant Zhou, can you take some photos of the scene? - Although our project is still top secret now, maybe it will be gradually declassified in a few years?"

"If we take some photos now, if we can't preserve them all, they will just be precious historical images."

"In case someone questions something then. For example, we don't actually use a lot of calculations to calculate the data. Then we will have evidence to counterattack."

When he said these words, Xu Yun's tone contained a subtle emotion that he had not even noticed.

In his future life after traveling through time.

The so-called "Rabbits didn't use much calculation in the atomic bomb project" can often be seen. Xu Yun recalled these things earlier.

Xu Yun thought he was used to these remarks, but what he didn't expect was

With the release of a movie called "Oppenheimer", the enthusiasm about the rabbits' development of the atomic bomb has also been aroused.

Some of them are positive news, such as the deeds of senior science popularizers like Lu Guangda, or introducing the difficulty of developing nuclear weapons at that time.

But there are still some so-called "reasonable guests":

Suddenly there are a lot of people on the Internet who forcefully "popularize science" rabbits. People who had computers back then said [the abacus is just a propaganda tool, and the difficulty of abacus calculation is xxxxx].

Faced with those remarks, Xu Yun was really helpless.

The Rabbits' 104 machine indeed made a great contribution to the research of the atomic bomb. He has never denied this.

But the problem is that the computing power of the 104 machine is only 50,000 times per second. Even if the 104 machine was fully loaded at that time, it could not afford the data calculation of the atomic bomb.

It is not that they do not know that the efficiency of the abacus is definitely lower than that of the computer, nor that they are looking for trouble, but the conditions at that time forced them to use the abacus to assist.

Just like many working people now go to work on the subway or ride a small electric donkey. Ask them if they are afraid of heights and are unwilling to take a helicopter?

The answer is obvious.

But the logic of those people now is equivalent to focusing their attention on those who can take a helicopter.

Then they say [the technological conditions in 2023 have already popularized some helicopters, for example, xxx of xx Group went to work by helicopter].

In fact, it is not just Rabbit. At that time, Xu Yun also saw someone under a video of the drama "Oppenheimer" saying that the other side of the sea used a computer with a computing power of 1 million per second when developing nuclear weapons.

Perhaps for some people, changing the way to deny the ability of the strong will give him some pleasure.

Therefore, in order to shut those people up, Xu Yun suddenly had an idea:

Why not take a photo at this most critical moment?

You know.

In 2023, when Xu Yun traveled through time, there were many photos and materials of Base 221, but they were basically in the same format:

There were one or two tractors or other equipment parked in the back of an open space, and three or four men and women in shirts stood on the open space. The men put their hands behind their backs, and one foot (usually the right foot) was slightly extended forward in a posture similar to "at ease" but more casual. The women crossed their left and right hands in front of their bodies, with a bright but slightly restrained smile on their faces.

In addition to these "formats", there are very few images related to computing.

At present, in addition to the 11 related photos exhibited in the Atomic City, there are only about five or six photos circulated through different channels (such as the person being photographed).

The reason why these data are scarce is not because of the high level of confidentiality, but because people at that time did not realize that these data would be so precious. It is no exaggeration to say that when the base was first built, many people were not very confident about whether they could make an atomic bomb.

Besides, even with the brains of Lu Guangda and Da Yu, I am afraid they would not have thought that someone in the future would use the abacus to make a fuss.

For various reasons, the rabbits did have very few images of the calculation process.

Now that there is this opportunity, how can Xu Yun not seize it?

Although Zhou Cai could not understand Xu Yun's inner thoughts, and could not know some controversies decades later, he personally did not dislike Xu Yun's suggestion.

After all, from a purely commemorative point of view, it is no problem to take a few photos of the scene.

So he quickly made a gesture to Xu Yun to wait, came to Li Jue and whispered a few words to him.

Li Jue raised his eyebrows slightly and nodded quickly.

Zhou Cai then returned to Xu Yun and slowly took out a small bag from the side of his seat:

"Advisor Xu, the factory director has agreed to take photos. Please wait a moment while I adjust my baby first."

Xu Yun had no objection to this.

Zhou Cai then put the small bag on the chair, unzipped it, and carefully took out a camera.

This camera is completely different from the SLR cameras of later generations. It is a rectangle with a width of about 7 cm and a height of nearly 15 cm.

Its sides and back are black, and the front is silver-white. There are also two lenses on the front.

The upper lens has only one lens, and the lower lens has some scales, which seems to be able to rotate and adjust.

Seeing Xu Yun staring at the camera with some curiosity, Zhou Cai couldn't help but smile:

"How is it, Consultant Xu, does my treasure look good?"

"To be honest, this is the Brownie camera produced by Eastman Kodak Company across the sea. It has a two-lens structure, three apertures: large, medium and small, and two shutters: 1/25 and B."

"In order to import this camera, the capital spent a lot of foreign exchange. There are only about ten in the country."

Looking at Zhou Cai who was talking freely, Xu Yun suddenly felt a sense of déjà vu of meeting a SLR enthusiast in the future.

Then Zhou Cai walked to the front of the calculation room and took pictures.

The flash of the camera slightly affected the calculations of some project team members, but no one said anything about it. After all, it was acceptable to keep some images during such a critical period.

At the same time, Li Jue slipped to Dayu's side without knowing when, pretending to be discussing something, and deliberately asked Zhou Cai to take a close-up photo.

This operation inexplicably reminded Xu Yun of Dean William Whewell in the 1850 copy, who seemed to have done a similar operation in the night of Pluto.

After Zhou Cai took a few photos, Xu Yun suddenly thought of something - his face seemed to be photographed.

But Xu Yun quickly shook his head and threw this idea behind his mind.

Just take the photos, anyway, his face has been disfigured, what else can go wrong?

Impossible!

More than ten minutes later.

Zhou Cai adjusted the camera and returned to Xu Yun:

"Consultant Xu, the rubber ring has been taken, do you want to continue?"

Xu Yun glanced at him:

"How many photos did you take in total?"

"The capacity of the film is 36 photos. I took seven photos with this roll of film the day before yesterday, so I took a total of 29 photos today."

"29 photos!"

Xu Yun touched his chin after hearing this:

"That's enough. If there are more, it will easily affect the calculation efficiency of all comrades. Let's stop here."

"Okay!"

Then Xu Yun and Zhou Cai and others waited obediently in the back, no longer affecting the calculations of the big guys in front.

More than four hours passed.

When the time came to nearly three o'clock in the morning, Dayu submitted his data first.

Followed by Chen Jingrun

Then Cheng Kaijia, Zhou Guangzhao and others

Four o'clock in the morning.

All project team members summarized all the data to Lu Guangda.

At 4:20 in the morning, the reply from the computer group also came back from the ground.

Afterwards, Lu Guangda, Peng Mengxiong, Zhou Guangzhao and others worked together to sort out the information, and finally at 6:17 in the morning.

A complete atomic bomb design drawing was officially released!

At the same time.

Across the distant ocean.

A man who looked very happy looked at the dark night outside the window and couldn't help scratching his hair.

The weather has been good recently, so it seems that I can find a chance to go out for a ride in a convertible.

Note:

I have typed 5,000 words in the hospital, please give me some monthly votes.