The next step was to plug off one of 2 turbines, after turning off emergency cooling (so they don’t start up between tests), and after shutting off the conduction system.
April 25, 1986: How truthful was the test? Because it was determined that the test was an electrical technical matter, it was therefore conducted by electrical engineers and not specialists on nuclear reactors.
1:00 AM: Starting to scale down reactor performance.
1:05 PM: Scaled down reactor performance by half, and after wards plugged off emergency cooling system.
2:00 PM: The production manager UEC (Ukraine Energetic Concerns) discontinued the tests because it was nearing a holiday (1May), so, the test was abandoned after 9 hours. 4:00 PM: The shift-change.
11:00 PM: The evening shift continues to operate the reduced performance reactor.
The team of electrical engineers are tired, and nearing the end of their shift.
April 26: In the routing tests, the Operator’s detect problems with the Steady Stability reactor.
They turn an the biggest performance reactor, that in turn activates the secondary cooler pump. Performance reactor temperature dips to it lowest.
1:22:30 AM: The Operator checks the computer for the status of the reactor. The answer was horrible. It was only half of the acceptable norm for the performance reactor. The technicians decided to the continue with the test.
1:23:04 AM: Start test. The last step was to block up the emergency control, which closed a steam feeder on the turbine for the automatic reactor to turn off. After closing the feeder, the test began. The Reactor is running on performance of no more than 200 Megawatt.
1:23:40 AM: The performance reactor goes a little haywire from the effect of receiving water. In this moment, the fatal disaster is coming. Leonid Tuponov, the operator that was responsible for the reactor, presses the emergency button to shut off the reactor that was showing regulation bars, but it was inactive. 1:23:44 AM: Then came 2 big explosions. The reactor was filled with pressure weighing up to 1000 tons, which caused it to combust. When the air was released, hydrogen was created from the mixture of red hot graphite and stream, which mushroomed, and caused a radiation fire.
The director of night services Alexander Atimov, and operator Datlov didn’t believe the explosion occurred. They send two operators to check the active zone. The two died at the scene immediately from radiation, but sent a message of what happened.
Atimov and Tuponov died from radiation-related illnesses. Datlov and Uskov lived.
2:20:00 AM: The fire on block 4 is kept under control. For 10 days 5% radiation leaked out
5:10:00 AM: From the explosion about 300 SV of radiation was released. (On actual field lungs, need only 0.035 SV).A cloud arose that the wind wafted above Scandinavia, over Poland and Austria, and back to the Ukraine. April 27th: General Pikalov arrived with radiation proof gear, and mechanisms to detect the levels of radiation that were released.