What caused the Chernobyl Incident
The Chernobyl disaster was caused by a combination of flawed reactor design and human error during a safety test. A sudden power surge, triggered by the test, led to a steam explosion that destroyed the reactor core and released significant amounts of radiation.
Here’s a more detailed breakdown:
1. Flawed Reactor Design:
The RBMK-type reactor used at Chernobyl had a positive void coefficient, meaning the reaction rate increased as the coolant (water) turned to steam.
The control rods, designed to absorb neutrons and slow down the reaction, had a dangerous design flaw. Their graphite tips initially displaced coolant, causing a surge in power before the absorbing material could be effective.
2. Human Error:
During a safety test, operators intentionally disabled safety systems, including the emergency core cooling system and power regulation systems.
The operators also removed most of the control rods, allowing the reactor to operate at a dangerously low power level.
These actions, combined with the reactor’s flawed design, created a situation where a small power surge could rapidly escalate into a catastrophic event.
3. The Accident Sequence:
The test initiated a power surge due to the positive void coefficient and the flawed control rod design.
The rapid increase in temperature and pressure caused a steam explosion that ruptured the reactor core and the reactor building’s roof.
A second explosion, possibly involving hydrogen, followed shortly after, further damaging the reactor.
The explosions and subsequent fire released large amounts of radioactive material into the atmosphere, contaminating a wide area.
In essence, the Chernobyl disaster was not caused by a single factor, but rather by a combination of a flawed reactor design that was operated unsafely during a test.
Frequently Asked Chernobyl Questions | IAEA
On April 26, 1986, the Number Four RBMK reactor at the nuclear power plant at Chernobyl, Ukraine, went out of control during a test at low-power, leading to an …
International Atomic Energy Agency