Environmental disputes around spent nuclear fuel (SNF) have always caused me a slight bewilderment. The storage of this type of "waste" requires strict technical measures and precautions, and must be handled with care. But this is not a reason to oppose the very fact of the presence of spent nuclear fuel and the increase in their reserves.
Finally, why waste? The SNF composition contains many valuable fissile materials. For example, plutonium. According to various estimates, it is formed from 7 to 10 kg per ton of spent nuclear fuel, that is, about 100 tons of spent nuclear fuel generated in Russia annually contains from 700 to 1000 kg of plutonium. Reactor plutonium (that is, obtained in a power reactor, and not in a production reactor) is applicable not only as a nuclear fuel, but also for creating nuclear charges. On this account, experiments were carried out that showed the technical feasibility of using reactor plutonium as a filling of nuclear charges.
A ton of spent nuclear fuel also contains about 960 kg of uranium. The content of uranium-235 in it is small, about 1.1%, but uranium-238 can be passed through a production reactor and get all the same plutonium, only now of good weapon-grade quality.
Finally, spent nuclear fuel, especially that just removed from the reactor, can act as a radiological weapon, and it is noticeably superior in this quality to cobalt-60. The activity of 1 kg of SNF reaches 26 thousand curies (for cobalt-60 - 17 thousand curies). A ton of spent nuclear fuel just removed from the reactor gives a radiation level of up to 1000 sieverts per hour, that is, a lethal dose of 5 sieverts accumulates in just 20 seconds. Fine! If the enemy is sprinkled with a fine powder of spent nuclear fuel, then he can inflict serious losses.
All these qualities of spent nuclear fuel have long been well known, only they encountered serious technical difficulties associated with the extraction of fuel from the fuel assembly.
Disassemble the "pipe of death"
By itself, nuclear fuel is a powder of uranium oxide, pressed or sintered into tablets, small cylinders with a hollow channel inside, which are placed inside a fuel element (fuel element), from which fuel assemblies are assembled, placed in the channels of the reactor.
TVEL is just a stumbling block in the processing of spent nuclear fuel. Most of all, TVEL looks like a very long gun barrel, almost 4 meters long (3837 mm, to be exact). His caliber is almost a gun: the inner diameter of the tube is 7, 72 mm. The outer diameter is 9.1 mm, and the wall thickness of the tube is 0.65 mm. The tube is made from either stainless steel or zirconium alloy.
Uranium oxide cylinders are placed inside the tube, and they are packed tightly. The tube holds from 0.9 to 1.5 kg of uranium. The closed fuel rod is inflated with helium under a pressure of 25 atmospheres. During the campaign, the uranium cylinders heat up and expand, so that they end up tightly wedged in this long rifle tube. Anyone who knocked out a bullet stuck in the barrel with a ramrod can well imagine the difficulty of the task. Only here the barrel is almost 4 meters long, and there are more than two hundred uranium "bullets" wedged in it. The radiation from it is such that it is possible to work with the TVEL just pulled out of the reactor only remotely, using manipulators or some other devices or automatic machines.
How was the irradiated fuel removed from the production reactors? The situation there was very simple. TVEL tubes for production reactors were made of aluminum, which dissolves perfectly in nitric acid, together with uranium and plutonium. The necessary substances were extracted from the nitric acid solution and went to further processing. But power reactors designed for a much higher temperature use refractory and acid-resistant TVEL materials. Moreover, cutting such a thin and long stainless steel tube is a very rare task; usually all the attention of engineers is focused on how to roll such a tube. The tube for TVEL is a real technological masterpiece. In general, various methods were proposed for destroying or cutting the tube, but this method prevailed: first, the tube is chopped on a press (you can cut the entire fuel assembly) into pieces about 4 cm long, and then the stumps are poured into a container where uranium is dissolved with nitric acid. The obtained uranyl nitrate is no longer so difficult to isolate from solution.
And this method, for all its simplicity, has a significant drawback. Uranium cylinders in fuel rod pieces dissolve slowly. The area of contact of uranium with acid at the ends of the stump is very small and this slows down the dissolution. Unfavorable reaction conditions.
If we rely on spent nuclear fuel as a military material for the production of uranium and plutonium, as well as as a means of radiological warfare, then we need to learn how to saw pipes quickly and dexterously. To obtain a means of radiological warfare, chemical methods are not suitable: after all, we need to preserve the entire bouquet of radioactive isotopes. There are not so many of them, fission products, 3, 5% (or 35 kg per ton): cesium, strontium, technetium, but it is they that create the high radioactivity of spent nuclear fuel. Therefore, a mechanical method of extracting uranium with all other contents from the tubes is needed.
On reflection, I came to the following conclusion. Tube thickness 0.65 mm. Not so much. It can be cut on a lathe. Wall thickness roughly corresponds to the depth of cut of many lathes; if necessary, you can apply special solutions with a large depth of cut in ductile steels, such as stainless steel, or use a machine with two cutters. An automatic lathe that can grab a workpiece itself, clamp it and turn it is not uncommon these days, especially since cutting a tube does not require precision precision. It is enough just to grind the end of the tube, turning it into shavings.
The uranium cylinders, being freed from the steel shell, will fall out into the receiver under the machine. In other words, it is quite possible to create a fully automatic complex that will chop fuel assemblies into pieces (with the length most convenient for turning), put the cuts into the storage device of the machine, then the machine cuts off the tube, freeing its uranium filling.
If you master the disassembly of the "death tubes", then you can use spent nuclear fuel both as a semi-finished product for the isolation of weapon isotopes and the production of reactor fuel, and as a radiological weapon.
Black deadly dust
Radiological weapons, in my opinion, are most applicable in a protracted nuclear war and, mainly, for causing damage to the military-economic potential of the enemy.
Under a protracted nuclear war, I am raising a war in which nuclear weapons are used at all stages of a protracted armed conflict. I do not think that a large-scale conflict that has reached or even began with the exchange of massive nuclear missile strikes will end there. Firstly, even after significant damage, there will still be opportunities for conducting combat operations (stocks of weapons and ammunition make it possible to conduct sufficiently intensive combat operations for another 3-4 months without replenishing them with production). Secondly, even after the use of nuclear weapons on alert, large nuclear countries will still have a very large number of different warheads, nuclear charges, nuclear explosive devices in their warehouses, which, most likely, will not suffer. They can be used, and their importance for the conduct of hostilities becomes very great. It is advisable to keep them and use them either for a radical change in the course of important operations, or in the most critical situation. This will no longer be a salvo application, but a protracted one, that is, a nuclear war is acquiring a protracted character. Third, in the military-economic issues of a large-scale war, in which conventional weapons are used along with nuclear weapons, the production of weapons-grade isotopes and new charges, and the replenishment of nuclear weapons arsenals will clearly be among the most important priority tasks. Including, of course, the earliest possible creation of production reactors, radiochemical and radio-metallurgical industries, enterprises for the manufacture of components and the assembly of nuclear weapons.
It is precisely in the context of a large-scale and protracted armed conflict that it is important not to let the enemy take advantage of his economic potential. Such objects can be destroyed, which will require either a nuclear weapon of decent power, or a large expenditure of conventional bombs or missiles. For example, during the Second World War, in order to ensure the destruction of a large plant, it was required to drop from 20 to 50 thousand tons of aerial bombs on it in several stages. The first attack halted production and damaged equipment, while subsequent attacks disrupted restoration work and exacerbated the damage. Let's say the Leuna Werke synthetic fuel plant was attacked six times from May to October 1944 before production fell to 15% of normal production.
In other words, destruction alone does not guarantee anything. A destroyed plant is amenable to restoration, and from a heavily destroyed facility, the remains of equipment suitable for creating a new production in another place can be removed. It would be good to develop a method that would not allow the enemy to use, restore, or dismantle an important military-economic facility for parts. It seems that a radiological weapon is suitable for this.
It is worth recalling that during the accident at the Chernobyl nuclear power plant, in which all attention was usually focused on the 4th power unit, the other three power units were also shut down on April 26, 1986. No wonder, they turned out to be contaminated and the radiation level at the 3rd power unit, located next to the exploded one, was 5, 6 roentgens / hour that day, and a half-lethal dose of 350 roentgens ran up in 2, 6 days, or in just seven working shifts. It is clear that it was dangerous to work there. The decision to restart the reactors was made on May 27, 1986, and after intensive decontamination, the 1st and 2nd power units were launched in October 1986, and the third power unit - in December 1987. The 4000 MW nuclear power plant was completely out of order for five months, simply because the intact power units were exposed to radioactive contamination.
So, if you sprinkle an enemy military-economic facility: a power plant, a military plant, a port, and so on, with powder from spent nuclear fuel, with a whole bunch of highly radioactive isotopes, then the enemy will be deprived of the opportunity to use it. He will have to spend many months for decontamination, introduce a rapid rotation of workers, build radio shelters, incur sanitary losses from overexposure of personnel; production will stop altogether or will decrease very significantly.
The method of delivery and pollution is also quite simple: finely ground uranium oxide powder - deadly black dust - is loaded into explosive cassettes, which in turn are loaded into the warhead of a ballistic missile. 400-500 kg of radioactive powder can freely enter it. Above the target, the cassettes are ejected from the warhead, the cassettes are destroyed by explosive charges, and fine highly radioactive dust covers the target. Depending on the height of the missile warhead operation, it is possible to get a strong contamination of a relatively small area, or to get an extensive and extended radioactive trail with a lower level of radioactive contamination. Although, how to say, Pripyat was evicted, since the radiation level was 0.5 roentgens / hour, that is, the half-lethal dose ran up in 28 days and it became dangerous to live permanently in this city.
In my opinion, radiological weapons were wrongly called weapons of mass destruction. It can hit someone only in very favorable conditions. Rather, it is a barrier that creates obstacles to access to the contaminated area. The fuel from the reactor, which can give an activity of 15-20 thousand roentgens / hour, as indicated in the "Chernobyl notebooks", will create a very effective obstacle to the use of the contaminated object. Attempts to ignore radiation will lead to high irretrievable and sanitary losses. With the help of this obstacle, it is possible to deprive the enemy of the most important economic objects, key nodes of transport infrastructure, as well as the most important agricultural land.
Such a radiological weapon is much simpler and cheaper than a nuclear charge, since it is much simpler in design. True, due to the very high radioactivity, special automatic equipment will be required to grind uranium oxide extracted from the fuel element, equip it into cassettes and into a rocket warhead. The warhead itself must be stored in a special protective container and installed on the missile by a special automatic device just before launch. Otherwise, the calculation will receive a lethal dose of radiation even before launch. It is best to base missiles for delivering radiological warheads in mines, since there it is easier to solve the problem of safely storing a highly radioactive warhead before launch.
