As the name suggests, a nuclear-powered aircraft carrier is an aircraft carrier that uses a nuclear reactor to generate power. Nuclear fuel has a high energy density, and a small amount of nuclear fuel can provide the energy required by an aircraft carrier for a long voyage, which is much more convenient than burning coal or oil.

Until now, most of the nuclear reactors used in aircraft carriers are light water reactors, that is, reactors that use ordinary water as a coolant. The nuclear fuel undergoes a controllable chain reaction in the reactor, which produces a large amount of heat, and the cooling water takes these tropics away, and the water in the other circuit is exchanged in the steam generator, so that the water in the second circuit is converted into steam, and then the steam is used to drive the steam turbine to do work and drive the propeller to run. This is how a light water reactor nuclear-powered aircraft carrier works.

LWRs are small in size and mature in technology, so most reactors, whether they are used for marine reactors or power generation, adopt this design.

LWRs also have some fatal flaws, one is that in order to ensure that the cooling water in the first circuit remains liquid at a high temperature of 320 degrees, the reactor must have extremely high pressure, which puts high demands on the reactor shell. The second is that the core lacks the ability to cool itself, and once the peripheral cooling system fails, the core temperature will continue to rise until the core melts.

In the 80s, the Chernobyl nuclear power plant accident in the former Soviet Union caused the core to melt, and finally the entire nuclear power plant had to be sealed with a large amount of concrete to prevent nuclear materials from continuing to leak. In the 2010 311 earthquake in Japan, the Fukushima nuclear power plant was damaged due to the destruction of the power supply system, which led to the suspension of the cooling water circulation system, which almost caused a tragedy of the reactor melting.

At that time, in order to reduce the temperature of the reactor core, Japan used helicopters to pour water from the air, and introduced seawater for cooling. As a result, while the core was eventually preserved, a large amount of radioactive contaminated cooling water was discharged into the sea, leaving serious ecological concerns.

As a combat weapon, it is inevitable that aircraft carriers will be damaged in war. In the event of damage to the power system, the cooling system of the reactor stops working, and the consequences are very terrible. Even if there is an extreme situation such as a melt pile, even if the cooling water with high radiation leaks out, the impact on the ship's crew is unimaginable.

The gas-cooled reactor is different, its working characteristics are the use of helium instead of ordinary water as the cooling medium, because there is no need to maintain the liquid state of the cooling medium at high temperature like the light water reactor, so the working pressure of the gas-cooled reactor is not large, and the safety is easier to guarantee.

The nuclear fuel in the gas-cooled reactor is encapsulated in small balls with high-temperature resistant ceramics, and the fission reaction takes place inside each ceramic sphere. In the unlikely event that the cooling system stops working, the temperature of the ceramic balls can rise to up to 1,600 degrees Celsius, and then the reactor can be automatically shut down at this temperature without the accident of melting the reactor as in the case of light water reactors with metal cores. In other words, if the Fukushima nuclear power plant were to be a group of high-temperature gas-cooled reactors, there would be no danger of a power outage for many days.

Helium, which is used as the cooling medium in a gas-cooled reactor, is an inert gas that does not carry out contaminants even if there is a leak, which is one reason why a gas-cooled reactor is safer than a LWR.

International research on gas-cooled reactors has been around for decades, starting early in Germany, and later in South Africa, the United States, Russia, Japan and China. China started lagging behind other countries in HTGR, but progress has been very rapid, and by the beginning of the 21st century, China's HTGR technology has reached the world-class level.

The idea proposed by Zhang Yihua is to put the high-temperature gas-cooled reactor that has been experimentally matured on the aircraft carrier as the power source of the aircraft carrier. If this idea can be successful, the nuclear-powered aircraft carrier built by China will be the first aircraft carrier in the world to use a gas-cooled reactor as a power source. As Zhang Yihua previously introduced to Lin Zhenhua, aircraft carriers using air-cooled reactors will have better safety and reduce maintenance pressure than aircraft carriers using light water reactors, which will be of great help to improve the adaptability of aircraft carriers and survivability under war conditions. …,

After Zhang Yihua put forward this idea, Liu Xianghai organized relevant personnel to have a serious discussion, and everyone believed that the advantages of using gas-cooled reactors as the power source of aircraft carriers are very obvious, and since the current gas-cooled reactor technology has been relatively mature, it is completely possible to consider using such a design in China's first nuclear-powered aircraft carrier.

The cooling medium used in a high-temperature gas-cooled reactor is helium, which is heated to about 50 degrees Celsius in the reactor and brought out of the reactor through a circulation system. At this time, there are two modes of converting thermal energy into mechanical energy.

The first mode is to heat the water or other medium in the second circuit with high-temperature helium through a heat exchange system, and then use the formed water vapor or other high-temperature gas to drive the steam turbine to do work. This method is similar to the light water reactor, and the technology is relatively mature, but the defects are also obvious: first, two circuits are required, which makes the volume of the whole system larger, the number of equipment increases, and the maintenance cost is increased; The second is to add a heat exchange process, in which losses will inevitably occur, resulting in a decrease in thermal efficiency

The second mode is also the model proposed by Zhang Yihua, that is, to cancel the second circuit and directly use high-temperature helium to drive the steam turbine to do work, which not only simplifies the structure, but also improves the thermal efficiency, which is a very promising model. In this mode, a steam turbine that is directly driven by helium is a helium turbine. Or, strictly speaking, a helium turbine used in the first circuit of the nuclear island. Up to now, the helium turbines that exist in the world can only be used in the second circuit, and the helium turbines used in the first circuit are still experimental.

Zhang Yihua is a technical idiot, since his research direction from aircraft engines to industrial steam turbines and gas turbines, he began to dabble in a wide range of related technologies, and the technology of helium turbines also entered his field of vision at this time.

At the beginning, Zhang Yihua felt that there was still a gap between this kind of technology representing the world's top level and China's national conditions, so he just paid attention to it, and did not expect that he would be able to impact this technology in his lifetime. As China's economic strength became stronger and stronger, and the gap between China and the international advanced level in technology became smaller and smaller, Zhang Yihua's heart began to move. In his opinion, if you can have the opportunity to participate in a world-leading technology research, it will be in vain.

Lin Zhenhua has some understanding of these things, and Zhang Yihua has said the word helium turbine more than once at the group's office meeting. The group has studied the feasibility of this project, and the final conclusion is that there are too many technical links involved, and the future market prospects are not clear enough.

What Lin Zhenhua didn't expect was that after the Hanhua Group vetoed the project, Zhang Yihua actually took a path of "saving the country by curve" and pulled the navy to put the project again.

"Mr. Lin, this time is different from the past." Zhang Yihua explained to Lin Zhenhua, "In the past, we didn't have the support of the state, and it was definitely not possible to rely on our Hanhua family to do it, and the technical talents and technical accumulation in many aspects were insufficient." But this time it was different, Hong Feng, deputy director of the Commission of Science and Technology, said that it is necessary to mobilize the country's elite troops to overcome this problem in the future. In the early stage, the professors of the Institute of Nuclear Energy Technology of Huaqing University have done a lot of pioneering work, as long as the strength of the production department is put into it, it is completely certain to break through this technical difficulty. ”

"Lao Liu, what do you think?" Lin Zhenhua turned his head to look at Liu Xianghai.

Liu Xianghai said with a smile: "I am engaged in thrusters, and I have no say in nuclear energy and heat engines. However, I have participated in several technical demonstration meetings organized by the Commission of Science and Technology, and from the opinions of experts, the conditions for our country to break through helium turbine technology are ripe, and now it is almost a fire. ..., Lin Zhenhua also smiled: "Hehe, in this way, I am the fire?" Tell me, what do you need me to do? ”

"People, money, things." Liu Xianghai stretched out three fingers.

"People, money, and things, I've all come out, so what do you want you to do?" Lin Zhenhua asked with a smile.

Liu Xianghai said: "Of course, it can't let you out." People, mainly Lao Zhang's team, may need to be requisitioned during this time.

Over the years, Hanhua has accumulated a lot of experience in industrial steam turbines and gas turbines, and your elite team is indispensable for helium turbines. ”

Lin Zhenhua nodded and said, "This is no problem." However, Lao Zhang, you have to leave half of the team, and the company's R&D and technical services for industrial steam turbines and gas turbines can't be stopped, understand? ”

"Mr. Lin, don't worry, I have already arranged it." Zhang Yihua replied.

Lin Zhenhua handed Liu Xianghai a helpless expression and said, "Lao Liu, look at it, Lao Zhang's heart has already flown to you, can I keep it if I want to?" ”

"It's all for the country, what is yours and mine." Liu Xianghai said with a big grin, he didn't feel distressed at all when he used other people's teams to work for himself, "In terms of people, there is also the hope that Hanhua can support some of our excellent technicians, the trial production of helium turbines needs to be completed by high-quality workers, and in this regard, Hanhua's strength is also unmatched by other enterprises." ”

"I also have some senior technicians recruited from Europe, and I have inquired that they have experience in processing similar products, and I can let them play some role when the time comes." Lin Zhenhua said.

"That's great." Liu Xianghai said, "I'll just say, Xiaolin is by no means a stingy person, when it comes to national affairs, you will definitely not hide your selfishness." ”

"Okay, everyone has promised you, so it's none of my business, right? I'll go first..." Lin Zhenhua made a turn to leave, but the soles of his feet didn't move. He remembered that Liu Xianghai was talking about "people, property, and property", and now he just finished talking about "people".