35 Years On, What Caused The Chernobyl Nuclear Disaster?

On April 2, 1986, the worst nuclear disaster in history was quickly unleashed and continues to rage today. Known as Chernobyl, the nuclear disaster turned into the Cold War, in the post-USSR days, and the moment when humanity plunged into the waters of nuclear power.

It became a notorious memory of the dangers of working with nuclear energy, as well as the unfortunate consequences that could result in incidents of human error and bureaucratic incompetence. The catastrophe occurred at the Chernobyl nuclear power plant near the city of Pripyat in Soviet Ukraine at the time. Today, the site is found in northern Ukraine, near the Ukraine-Belarus border.

On Saturday, early April 26, 1986, the plant’s engineers (somewhat ridiculously) were conducting a safety test to see how core of Furnace 4 could be cooled in the event of a power outage. In its simplest sense, a nuclear reactor is a nuclear-powered steam engine: the heat (splitting of atoms) caused by fission is used to heat water to create steam, which spins the turbine to generate electricity. To control the rate of separation, boron carbide control rods are also used to absorb neutrons released during fission in the reactor and to slow down the reaction into pumped cooling water to manage the heat and vapor levels produced.

It gets a lot more complicated than that (it’s not known for the simplicity of nuclear physics), but it’s all you need to know is empty bones. If there is a blackout, the winter pumps are also without electricity and the system could potentially overheat. To solve this problem, the furnace had a few diesel pumps that could cool the core by pumping water around the core but these engines took about 1 minute to go. The purpose of this experiment was to show how to maintain adequate cooling while waiting to kick backup diesel pumps.

The test was spread through this mismanagement driven by untrained trained personnel and vital safety precautions were taken. During the test, the operators went against the safety rules and turned off the automatic control system. It was further noted that the test was initially planned for the previous afternoon but after some delay, it fell into the hands of less experienced night time workers. At the end of April 25, just before midnight, the grid controller agreed that the furnace could reduce its power. 

Although the power was low, Xenon was still made and work began on making it. Xenon is a byproduct of the fission reactions carried in the reactor and it is particularly difficult to absorb neutrons and further reduces the action as the reactor is formed.