Pan Zekang did not study atomic physics in college, and there was no such subject at that time, he studied electronics, and after joining the Navy, his main job was actually to assist in the development of new weapons such as radar, sonar, and VT bombs. Because several of his tutors at the university were engaged in atomic theoretical physics, he also had a good foundation in this area. In front of Tan Renhao, Pan Zekang is a scholar who is proficient in theory.

Over the past two days, Tan Renhao not only gained a certain understanding of Pan Zekang, a major technical officer, but also gained a deeper understanding of the new bomb with the help of Pan Zekang.

"You call this bomb an 'atomic bomb.'" Tan Renhao is not engaged in technology, and he has never been very sensitive to technology, so he can't remember many technical words at all.

"Yes, we'll call it the 'atomic bomb' for the time being." Pan Zekang is not only a very humble young man, but also a very responsible teacher, at least in front of Tan Renhao, he has been very patient to explain some basic knowledge to this general. "Because this bomb uses the energy of the atomic nucleus, we call it the 'atomic bomb.'"

"It's very vivid." Tan Renhao smiled and nodded, "So, what technologies are needed to make an atomic bomb?" ”

"Actually, the most basic theory is not complicated." Pan Zekang put a textbook in front of Tan Renhao, "The most basic principle is put forward by Einstein, that is, energy and mass have a certain relationship, and they are mutually balanced. Subsequently, our scientists discovered in the laboratory that most of the mass of atoms is concentrated in the nucleus, which is made up of neutrons and protons. And there are very few elements in the nucleus after being bombarded by neutrons. Fission will occur, forming two, or more, new nuclei ......"

"Can it be simpler?" Tan Renhao felt a little headache. He felt like he was a schoolboy.

"Simply put, it's when the nucleus of an atom is fissioning. Quality varies. The reduced mass will be converted into energy, and then through Einstein's mass-energy balance formula, we can calculate the amount of energy released. ”

Tan Renhao nodded. "I know this formula, but the question is, is there a lot of energy released?"

"It's huge, for sure. Judging by the results of our current experimental calculations, the energy produced by the fission of one kilogram of uranium-235 is equivalent to the energy produced by the explosion of 20,000 tons of TNT explosives. ”

Tan Renhao was secretly startled and looked at Pan Zekang in disbelief.

"These are all theoretically confirmed, and the way to release atomic energy is not only fission, from the current theoretical research, the atomic nucleus can also undergo fusion, that is, two or more nuclei combine into a new nucleus, and in this there will also reduce the mass. As a result, powerful energy is released, and the energy transformed into it is several times, or even dozens of times that of fission......"

"Wait. Major, now this is not the point of view. Tan Renhao stopped Pan Zekang, "We need to know that if we want to make an atomic bomb." What technical support is needed, and what needs to be done? ”

"This ......," Pan Zekang smiled awkwardly, then thought for a while and said, "The main problem is to find the elements suitable for making an atomic bomb. ”

Tan Renhao nodded slightly, motioning for Pan Zekang to continue.

"Not all elements can be fissioned, and the most important thing is that when the nucleus is fissioned, more than one neutron must be produced, so that fission can continue to occur, and the fission will not be suspended because the neutrons are exhausted."

"You've mentioned this, I've already said it before, what is this called a 'chain reaction', right?"

"Yes, that's it. The key to fission is that there must be enough neutrons, and without enough neutrons, the nucleus will not fission. Therefore, when the nucleus is fission, it must produce more than one neutron in order for the chain reaction to continue. Pan Zekang drew a sketch on paper, "This is the approximate way of the chain reaction, as long as it is ......"

"Major, the key, say the key!" Tan Renhao touched his forehead, he felt that all people who were engaged in technology were a little wordy.

"The key is that we have to find the right elements for nuclear fission." Pan Zekang scratched his scalp, he also knew that he was a little wordy. "The only thing we can find in nature is uranium-235, an isotope of uranium that has the ability to react in chains. It is a great pity that uranium-235 is very rare in nature, and in natural uranium ores, uranium-238 accounts for more than 99 percent. ”

"However, one kilogram of uranium-235 can produce that much energy, so it doesn't take much, right?"

"General, the crux of the matter is not here." Pan Zekang hesitated, "Although the proportion of uranium-235 is very small, in the whole of nature, the reserves of uranium-235 are not small. But the most critical problem is that uranium-235 and uranium-238 are isotopes, and their chemical properties are almost identical, and there is no way to chemically separate these two isotopes. ”

Tan Renhao frowned, he had a little headache again.

"The method of separating these two elements is complex, difficult, and very inefficient." Pan Zekang also sighed, "There is only one way, uranium-238 has three more neutrons than uranium-235, and its mass is a little larger, we can use a centrifuge to separate these two elements by high-speed rotation." ”

Tan Renhao didn't ask in detail, but said directly: "In other words, there is still a way to separate these two isotopes?" ”

"Yes, there is a way, but it will cost a lot of money and there will be plenty of time."

"Well, that means we're in a lot of trouble if we start from scratch?"

Pan Zekang nodded. "Fortunately, uranium-235 is not the only element that can undergo nuclear fission."

"Didn't you start by saying that only this element is suitable for nuclear fission?"

"It's an element in nature, and we've made new discoveries in our experiments." Pan Zekang laughed, "The empire already has an experimental reactor. We have already found that when uranium-238 absorbs a neutron, it generates a new element. This element is called plutonium-259, and judging by the results we have now. Plutonium-239 is better suited than uranium-235 for chain reactions, that is, better for making atomic bombs. ”

Tan Renhao touched his forehead. "Major, is there anything else I don't know?"

"Actually, I also know these things from a few mentors." Pan Zekang is a bit innocent. "Now we have two elements that can be used to make an atomic bomb, and the most direct way is to use uranium-235 as a raw material, and the most effective way is to use plutonium-239 as a raw material. Of these, plutonium-239 can only be produced in experimental reactors, and this requires an extremely important condition. ”

Tan Renhao nodded, motioning for the major officer, who had given him a little headache, to continue.

"Fast neutrons are used to induce the reverse chain reaction, while plutonium-239 is produced in the experimental reactor is supposed to be slow neutrons."

"What is a fast neutron and what is a slow neutron?"

"This ......," Pan Zekang hesitated, "do you need me to explain in detail?" ”

"Forget it, let's get to the point!" Tan Renhao also laughed.

"So. We have to find a way to slow down the neutrons so that we can get plutonium-239. And now we know that the best moderator is water. ”

"Water!?" Tan Renhao was a little surprised.

"It's not what we usually call water. It's heavy water. ”

"What do you mean?" Tan Renhao sighed secretly, it seems that there is time to make up for the basic physics knowledge.

"Ordinary water molecules are made up of two elements, hydrogen and oxygen, while heavy water is made up of heavy hydrogen or super heavy hydrogen. That is, the water molecule composed of the two elements deuterium or tritium and oxygen, which is heavy water. ”

Tan Renhao nodded, he already had a headache.

"So, to keep the reactor running, you need a lot of heavy water. In nature, the proportion of heavy hydrogen to super-heavy hydrogen is quite small, and fortunately, it is much easier to make heavy water than to refine uranium-235. ”

"In other words, heavy water is the key?"

"Yes, that's the key of the keys." Pan Zekang smiled and nodded. "From the intelligence we have now, the United States, Germany, the United Kingdom and other countries are expanding the scale of heavy water production."

"So, is there any other use for heavy water?"

"No, the main purpose is to keep the nuclear reactors running, and these reactors are definitely used to produce plutonium-239."

Tan Renhao immediately wrote this down, although he didn't understand technology, but he was able to keenly grasp the key issues.

"We are also working hard to increase the production of heavy water, but ......"

"There must be a problem, isn't it?"

Pan Zekang nodded. "Actually, there are three main problems. The first is funding, and all kinds of related research require a lot of capital investment. As far as we know, there are a large number of talented people in the United States and Germany who are carrying out related work. The third is infrastructure and power supply. ”

"Electricity supply?" Tan Renhao frowned.

"No one can build an atomic bomb without enough electricity."

"Well, I've written these things down, and we'll figure them out together." Tan Renhao put down his pencil, "Then, do you think now that if we only rely on the support of the army, we may be able to make that ...... before other countries?"

"Atomic bomb."

"Yes, can we build an atomic bomb before other countries do?"

"General, do you want to listen to the truth, or do you want to lie?"

"Major, I'm not asking you to compliment the Navy, tell the facts, remember, the point!" Tan Renhao picked up the teacup.

"The truth is, if we only had the support of the Army, we would certainly not have been able to build an atomic bomb before the United States, or even Germany."

Tan Renhao nodded slightly, motioning for Pan Zekang to continue.

"Xiaguan has been in contact with his previous mentor, and from what Xiaguan knows, the army is not very enthusiastic about this task assigned by the Prime Minister, and the funds have not been in place, and the relevant talents and infrastructure are also very imperfect, so the development progress has been very slow. If we continue to develop as we do now, I am afraid that within three years, we will not be able to build an atomic bomb. Pan Zekang hesitated, "That's why Xia Guan wrote a letter to the general." As far as the lower officer knows, the general also served in the Naval Equipment Technical Office before, right? ”

Tan Renhao nodded. "It's barely enough, I only stayed for a short time, and I mainly dealt with the affairs of the navy and the fleet, and didn't involve too much basic research."

"So Xiaguan hopes that the general can fully support this project, and we must build the atomic bomb before other countries!"

Tan Renhao didn't rush to speak, this was not something he had the final say.

"General ......" Pan Zekang also gradually calmed down.

"Say what else you want." Tan Renhao glanced at the major officer, "'I'll keep an eye on it,' and the principal has already put me in charge of this matter, if it is finally determined that the navy needs to participate, the principal will contact the prime minister directly." ”

"Then please forgive the general for being rude." Pan Zekang licked his lips, "Xia Guan believes that the atomic bomb will become the ultimate weapon, and if the empire lags behind other countries in this regard, then the survival of the empire will become a problem." Xiaguan believes that no matter what the cost, we must build an atomic bomb before all other countries! ”

"I know that." Tan Renhao sighed, "Okay, then we have to do our job first, so that more people, especially the Prime Minister, can realize the importance of the atomic bomb, right?" ”

"In fact, there are many related issues, such as how to drop the atomic bomb, and related supporting facilities, etc., but the lower officials think that the most convincing thing is not our report."

"What's that?" Tan Renhao glanced at Pan Zekang in surprise.

"It should be the report of the best scientists in the Empire." Pan Zekang hesitated for a moment, "If all the atomic physicists of the empire suggested the manufacture and production of atomic bombs, then the prime minister would definitely recognize the seriousness and urgency of this problem, and the report submitted by these scientists would certainly be more convincing than the report submitted by our navy!" ”

Tan Renhao pondered for a moment, then laughed. "It's really more convincing, but the question is, how do we contact these scientists?"

"If the general agrees, the subordinate can go to the help of the three mentors, and they will come forward to contact the other scientists and write a joint letter to the prime minister."

"Very good, you can do this immediately!" Tan Renhao no longer hesitated, "I will immediately go to the Chief of the General Staff and ask him to give you all the privileges, your task is to write this joint letter as soon as possible, and then send it to the Prime Minister, and I will be in charge of the report on the Navy's side!" ”

The two of them did what they said, and they didn't think much about it, of course, they didn't delay a little time.