u/gioangi

The K340A was the true "digital brain" of the Duga radar. Designed in 1966, it was, for its time, a masterpiece of Soviet computer engineering. It was built specifically to handle the enormous amount of data transmitted and received by the radar's gigantic antennas. Its operation and structure were based on extraordinary technical features: A unique mathematical trick: The Residue System. Normal computers calculate using the binary system (made up of 0s and 1s), one operation at a time. The K340A instead used the Residue Number System (RNS), a mathematical system based on the remainders of divisions. Parallel calculations: This trick allowed the computer to perform multiple complex calculations simultaneously. Record speed: It could perform 1 million operations per second. It was considered the fastest second-generation computer in the world. Less energy and more endurance: This logic system consumed less electricity and allowed the computer to function even if some hardware parts failed. Physical structure and aesthetics (Hardware) The K340A did not resemble modern computers at all. It was a huge industrial facility: Gigantic dimensions: A single K340A computer took up entire rooms and consisted of 15 or 17 large metal cabinets (racks) for data, plus another 4 cabinets just for electricity. Memory: Inside, there were cabinets dedicated only to RAM memory and others for storing the army's fixed programs. Colossal cooling: Since the thousands of electronic boards produced hellish heat, the Duga building had an entire upper floor dedicated to a very powerful air conditioning system to prevent the circuits from melting. The control console: The military operator sat in front of a dashboard full of colored light bulbs and writing, with two giant built-in printers to read the data. What was its purpose in the Duga radar? The computer had to perform three vital tasks in just a few seconds: Filtering out noise: The radio signal traveled for thousands of kilometers, bouncing off the ionosphere (the upper atmosphere). The computer had to clean the signal from thunderstorms, civilian radios, and space noise. Find the missiles: It had to recognize the faint radio waves reflected by the exhaust fumes of newly launched American ballistic missiles. Calculate the route: If it detected danger, it instantly calculated the missile's trajectory toward Russia to raise the alarm. Today, the destroyed and rusting remains of these secret supercomputers still lie abandoned inside the technological buildings in the fenced-off forest of Chernobyl.

Historical Reality and Radar Problems: Astronomical Costs: The Duga system cost the Soviet Union approximately 7 billion rubles. A staggering sum, roughly double the cost of building the entire Chernobyl nuclear power plant. The Frequency Problem: The radar suffered from a serious design flaw. It operated on short waves, and its signal (the famous "Russian Woodpecker" clicking sound) jammed civilian, commercial, and military radio frequencies worldwide. Northern Lights Interference: The biggest problem was that the radar had to look toward the United States by passing over the North Pole. The Northern Lights and the unstable ionosphere in that area jammed the signals, rendering the Duga-1 radar nearly "blind" and ineffective at accurately detecting missiles. No Trial: Despite these enormous flaws and the wasted money, the Soviet Politburo did not open a criminal investigation against chief designer Franz Kuzminsky or his team. The project simply remained secret and continued to be modified in attempts to fix it.Historical Reality and Radar Problems: Astronomical Costs: The Duga system cost the Soviet Union approximately 7 billion rubles. A staggering sum, roughly double the cost of building the entire Chernobyl nuclear power plant. The Frequency Problem: The radar suffered from a serious design flaw. It operated on short waves, and its signal (the famous "Russian Woodpecker" clicking sound) jammed civilian, commercial, and military radio frequencies worldwide. Northern Lights Interference: The biggest problem was that the radar had to look toward the United States by passing over the North Pole. The Northern Lights and the unstable ionosphere in that area jammed the signals, rendering the Duga-1 radar nearly "blind" and ineffective at accurately detecting missiles. No Trial: Despite these enormous flaws and the wasted money, the Soviet Politburo did not open a criminal investigation against chief designer Franz Kuzminsky or his team. The project simply remained secret and continued to be modified in attempts to fix it.

These drawings by Konstantin Checherov (from Nikolai Karpan’s book Chernobyl: Revenge of the Peaceful Atom) show a speculative reconstruction of the two explosions in Unit 4.
Key problems:

Fig. 14 (First explosion, Phase A, 01:23:46)
There is a large empty gap between the lower biological shield (Сх.ОР) and the reactor vessel / Scheme L. This is incorrect — the RBMK was hermetically sealed. No such open space existed before the explosion.
Fig. 15 (First explosion, Phase B, 01:23:47)
Already shows molten Corium lava flowing down through the steam relief channels during the first explosion. This is highly unrealistic. The scientific consensus is that the fuel needed hours to days to heat up enough to form significant amounts of Corium.
Fig. 16 (Second / upper explosion, 01:23:49)
This one is more plausible. The upper explosion lifted the biological shield (“Elena”) together with a large part of the core and scattered debris across the site.

Bottom line:
Checherov’s drawings are historically interesting but not accurate. The sudden gap under the lower lid and especially the instantaneous Corium lava contradict both the reactor’s design and the established timeline of the accident.

DIAGRAMS OF MAJOR RBMK AND UGR STRUCTURES

Diagram of the main structural components of the RBMK-1000 reactor and a cross-section of the primary metal structures located between the "Scheme E" bottom plate and the graphite stack: 1 — bottom grid (Scheme E); 2 — flange assembly; 3 — top shield plate; 4 — adapter (steel-to-zirconium); 5 — graphite block; 6 — channel section.

Aleksandr Fyodorovich Akimov (6 May 1953 – 11 May 1986) was the Unit 4 shift leader.

He was at the reactor control panel at the moment of the explosion. Believing the reactor was still intact, he and Leonid Toptunov stayed for hours trying to restore cooling water flow, receiving a fatal dose estimated at over 15 Gy (≈1,500 rad).

He died of acute radiation syndrome in Moscow Hospital No. 6 and was posthumously awarded the Order For Courage.

The destroyed Reactor Unit 4 – April 27, 1986. Photo by V. Yevtushenko.

Almost 40 years ago, on October 2, 1986,

Alexander Yungkind, Leonid Khristich, Nikolai Ganzhuk, and Vladimir Vorobyov were involved in an accident in which all of them lost their lives.

The pilot struck a crane cable and consequently crashed.

In 2017, during preparatory work for the dismantling of Block 4, the tail rotor of the helicopter that crashed in 1986 was discovered.

The propeller had crashed onto the roof of the turbine hall of Block 4, but it was so heavily contaminated that it was immediately walled up with a large amount of concrete.

Rest in peace, heroes.

Computing complex "SKALA" of the three unit, today.

Rosatom's Fuel Division has developed and successfully tested the new OS-5 fuel assembly for a Generation IV reactor. For the first time, metallic sodium was placed under a steel cladding, enveloping fuel pellets made of a uranium-plutonium composite. Research has shown that the use of a liquid metal sublayer will improve the performance of fuel rods with nitride fuel. This fuel is expected to operate at a lower temperature while maintaining coolant parameters, and the uranium-plutonium pellet will reduce the pressure on the fuel rod cladding. This will improve both the fuel's economic efficiency and operational reliability. The development of the OS-5 is part of a large-scale program to improve the efficiency of SNUP fuel for the innovative BREST-OD-300 reactor, which is being built in Seversk, Tomsk Oblast, as part of the "Breakthrough" strategic industry project.

A pebble of uranium in a cloud chamber (or Wilson chamber), a scientific instrument that makes ionizing radiation visible like an X-ray. The different trails: The thick, short lines are caused by alpha particles, while the longer, thinner ones indicate beta particles. The gamma particles are not visible because they have neither mass nor electric charge, but electromagnetic charge, and they even expand through walls, just as the telephone company can't imagine tons of these expelled from reactor 4.