Chapter 1064: Chapter 1062: The Necklace of Truth (Popular Science Edition, Skip if Uninterested)
Richard appeared at the Spell Test Field at the bottom of the Eden Garden Heavenly Pit.
This was already the seventh day since the start of nuclear weapon construction.
After a week, he had completed the first four key processes of nuclear weapon construction and many subsequent tedious ones, advancing progress to 60 percent, with 40 percent remaining to be completed.
And now, what he had to do was a relatively important step among the remaining 40 percent: the experiment on the explosives for triggering the nuclear weapon.
As mentioned before, a nuclear weapon like an atomic bomb consists of a detonation control system, high-energy explosives, reflector layer, nuclear components containing nuclear fuel, neutron source, and shell.
Among these, high-energy explosives are the energy source that drives and compresses the reflector layer and nuclear fuel. In other words, the high-explosive compresses the previously manufactured "Crystal Heart" metallic uranium component together harshly to reach a supercritical state, and then triggers a nuclear explosion.
If it were a gun-type atomic bomb, the setting of high-energy explosives would be extremely simple, as long as it explodes.
However, to avoid waste and save the hard-to-come-by Uranium 235 nuclear material, the atomic bomb Richard built is not a gun-type but an implosion-type.
This requires the high-explosive not only to explode but also to explode according to standards.
What does it mean to meet standards?
Generally, the implosion-type high-explosives are installed in tens or hundreds of pieces arranged in an elliptical shape inside the nuclear weapon, resembling a pearl necklace.
And to ensure that the metallic uranium component can be compressed to the maximum extent, it is necessary to ensure that every "pearl (explosive block)" on this "pearl necklace" can detonate simultaneously, and then transmit the explosive shock force through the Re-W alloy component to act on the metallic uranium component at the same instant.
Most important is simultaneously.
It must happen simultaneously.
The error cannot exceed one microsecond, that is, one millionth of a second.
Because the speed of explosive detonation is very fast.
Even a low-grade explosive like mercury fulminate can reach a blast speed of several kilometers per second, while advanced explosives like "Hexogen," "Taian," and "Octogen" can have blast speeds approaching ten kilometers per second.
Monsters like "CL-20 (Hexanitrohexanitrazine)" and "DNAF (4,4’-dinitro-3,3’-dinitrodiazofurazan)" directly exceed the ten kilometers per second threshold, with extremes like five imidazole anion salt and metallic hydrogen existing further up.
Even if the blast speed of explosives is controlled at eight kilometers per second, a microsecond difference amounts to eight millimeters, nearly one centimeter.
This distance may not matter elsewhere, but in a nuclear weapon, it is fatal, so it must detonate simultaneously.
And simply detonating the explosives simultaneously is just the beginning.
You must understand, the propagation of explosion and release of power expands from a point to a sphere. Even if it can truly guarantee all explosives detonate simultaneously, it is still using countless "spherical pressure surfaces" to compress the metallic uranium component.
Like using countless inflated basketballs to squeeze a large raw dough, it is impossible to ensure no dents appear on the dough’s surface.
A dent means a defect.
Therefore, even if the detonation time error of all explosives is strictly controlled within one microsecond, it is still far from meeting the implosion-type atomic bomb design requirements.
According to the implosion-type atomic bomb design requirements, the spherical pressure must become planar pressure, using a plane to compress the metallic uranium component. Only in this way can the metallic uranium component be squeezed tightly enough to achieve a higher supercritical state and utilize the hard-to-come-by nuclear material to a greater extent.
But how does a spherical surface turn into a plane?
Explosives will not listen, they will not propagate as dictated by others, they will only faithfully release power according to physical rules.
The shortest path between two points is a line segment.
As long as under the framework of classical mechanics, without considering space distortion, according to the shortest path principle, spreading power from a point to the surroundings ultimately forms a spherical surface.
It’s always a sphere.
Sphere!
To solve this spherical issue, there is only one way, that is to use compound explosive blocks.
Yes, compound explosive blocks.
Compound explosive blocks, as the name implies, are composed of various different explosives.
It is well known that different types of explosives have different blast speeds, then it is entirely feasible to design explosive blocks like this: low-speed explosives in the middle, medium-speed explosives outside, and the fastest explosives on the outermost layer.
When the explosive is detonated, the low-speed explosive spreads slowly, the medium-speed explosive spreads next, and the high-speed explosive very quickly. Thus, the originally spherical spread pressure surface would show a certain degree of concavity, forming a planar in a specific direction.
In actual operation, it is also possible to optimize a bit.
For instance, only two types of explosives with different blast speeds are necessary. In each explosive zone, adjust the ratio of low-speed explosives to high-speed explosives to control blast propagation speed.
For example: if the blast speed of high-speed explosives is 3, and the blast speed of low-speed explosives is 1, in the central explosive zone, make an explosive column with the top one-third filled with the low-speed explosive, and the lower two-thirds filled with the high-speed explosive, thus the speed of the entire explosive column will balance to 2.
For the outer explosive zone, an explosive column can be made with the top one-sixth filled with the low-speed explosive, and the lower five-sixths filled with the low-speed explosive. Thus, the speed of the entire explosive column will balance to about 2.7, creating a difference from the central explosive zone, and finally producing a pressure plane.
What Richard is doing now is using different explosives and adjusting different proportions to test which types of explosives are most stable and which explosive ratios meet the requirements.
Richard stands at the Magic Test Field, taking out one explosive column after another from the Space Iron Ring, and begins to carefully arrange them around a fist-sized test target.
After arranging, he decisively detonates.
"Boom, boom, boom!"
Explosions sounded continuously in the Spell Test Field as Richard continuously tested.
It must be said, finding the most suitable explosives for triggering a nuclear weapon requires very tedious testing. Moreover, every test demands absolute precision with no room for error.
Because under the high blast speed of explosives, every mistake will be magnified a hundredfold or more, resulting in complete failure.
Fortunately, with mathematical guidance, more than 99 percent of erroneous options can be eliminated in advance, and only those correctly calculated need to be repeatedly tested to find the optimal solution.
"Boom, boom, boom!"
Time keeps passing.
...
In the blink of an eye, three more days passed.
In three days, Richard conducted dozens or even hundreds of explosive tests at the Magic Test Field. He finally resolved the issue with the triggering explosives, identified the most suitable composite triggering explosives, and prepared enough quantities.
In other words, in three days, a significant step was taken towards the full success of nuclear weapons manufacturing.
...
Note①: For knowledge about explosive speed, please refer to Chapter 386 "Five Imidazole Anion Salt" of this book.
