was repairing the bathroom on Sunday. While the master was working, he watched a movie with his girlfriend.
's movie is called "Unthinkable", which is also translated as "Strategic Secret Service Team" in China.
w Jun has always believed that this is one of the most worth-watching movies in more than ten years. Its essence is to show the conflict between absolute moralism and utilitarianism.
concretely places the views held by the two parties in front of the audience. In fact, it is still the "solution to the trolley problem." However, the point of view given by this film is too profound, and the plot is too scary. It was labeled "restricted". Therefore, the box office has been tepid, so many people do not know this work.
While watching the movie, this scene appeared:
My curious baby asked if this was a nuclear bomb? Why install a gas cylinder?
took a closer look. The Russian text on the bottle said "Dangerous, radioactive material", and the line below said "Phase e plutonium".
sighed, the details of the movie are still very rich. The design of nuclear weapons using gas cylinders to load nuclear materials was proposed in the 1980s, but it has not been realized yet. This is an idea for miniaturizing nuclear weapons. The design idea of the weapon is to store nuclear material powder in a high-pressure gas cylinder. The nuclear material in the cylinder is lower than the critical value of a nuclear bomb explosion. When starting a nuclear bomb, the high-pressure gas in the cylinder is used to blow the nuclear material to a collector. The filter in the collector filters out the nuclear material powder and discharges the gas. In this way, the nuclear material (usually plutonium powder) in the collector ) can reach the critical value in an instant, and the nuclear bomb can be detonated.
In reality, it is difficult for this design to effectively ensure the shape and density of the explosive core. Therefore, it is only a design route for miniaturized nuclear weapons. There have been attempts in this area, but there is still a long, long way to go before it is truly practical. There's still a way to go.
This device was designed in the movie, presumably because such a nuclear weapon might give people a refreshing feeling.
Although this incident is about chatting with my girlfriend at home, it is also a small concept that I can talk about with everyone. This is the "phase" of plutonium material. The "phase" in the movie is actually a small misleading. Most of The writing methods of phase are all Greek letters, and English letters are not used so abruptly mixed in a Russian text.
"Phase e" does not exist, but plutonium does have a "phase".
Today we will talk about the phases of plutonium and how to process plutonium blocks that can actually be used in nuclear weapons.
Generally speaking, when we see a piece of metal, it is a piece of iron, or it is a piece of copper, or it is a piece of aluminum. This is how ordinary people understand metals, and they tend to focus on the material of the piece of metal. But one thing to note is that objects are composed of atoms. When the atoms are arranged in different ways, the characteristics of this "piece" of material will be significantly different. These phenomena of different atomic arrangements showing different characteristics are generally called "allotropes", such as graphite and diamond, or white phosphorus, red phosphorus, black phosphorus and purple phosphorus.
They will all have the same chemical composition, but due to the different internal crystal lattice, they have completely different physical (significant) and chemical (subtle) properties.
Although there is not much difference in appearance between an iron block and a steel block, this characteristic is also very obvious in metals on a microscopic level. Only a small amount of metals do not have allotropes, while most metals do. They have phases determined by different lattice structures. This part was later expanded into a separate subject called metallography.
Back to plutonium, plutonium will form different "phases" under different pressures and temperatures. Plutonium can exist in six phases at room temperature. If high pressure is added, plutonium will actually have a seventh phase.
The characteristics of plutonium itself are different in different "phases". The most obvious is that different phases of plutonium materials have different densities. This is because plutonium with different lattice shapes has different atomic gaps, which results in differences in the mass of plutonium in the same volume.
This is one of the unique physical properties of plutonium. Under different temperature and pressure combinations, pure gold plutonium exhibits six solid-state phase transitions before reaching the liquid state, from α, β, γ, Β, δ, δ-prime passed to epsilon. The density will change in a step-like manner
. At normal temperature and pressure, the plutonium atoms in the α phase present a simple monoclinic crystal arrangement, with a density as high as 19.86 g/cubic centimeter. This is the most common form of plutonium. In comparison, delta-phase plutonium arranged in a face-centered cubic lattice has only 15.92 g/cm3.
δ-phase plutonium can transform from high-phase to α-phase plutonium under extreme pressure. Because of this property, plutonium is a natural implosion nuclear weapon material.
Therefore, in the design of early implosion nuclear weapons, delta phase plutonium was often used to make the core. During the detonation process, high explosives wrapped around the outside of the plutonium core were used to exert great pressure on the plutonium core, completing the transformation of plutonium into the alpha phase. conversion, allowing the plutonium core to be compressed to a critical value.
However, it should be noted that delta phase plutonium usually exists at a temperature of 310 to 452 ° C. If it is lowered to normal temperature, the plutonium will shrink and gradually transform into alpha phase plutonium. In order to prevent the natural conversion of delta phase plutonium to alpha phase plutonium, the role of alloys comes into play at this time. Usually, when making a plutonium core, 1.8% to 3% of metallic gallium is added to pure plutonium. After adding metallic gallium, the lattice of delta-phase plutonium becomes stable and can be maintained normally at room temperature.
At the same time, this plutonium-gallium alloy also exhibits properties similar to aluminum and is easier to cut and process.
