Fifteen Minutes to Meltdown Trivia Quiz

Answer: Ukraine

On April 26th, 1986, a systems test of the emergency core cooling experienced a massive spike in output. The cooling system had been deemed unacceptably risky before, and this was the fourth test to see if the emergency coolant system could be improved upon - the previous three tests had all been failures.

When the energy spike occurred, there was not enough coolant to moderate the reaction and the nuclear fission went out of control. The core had to be ejected and the result was that a more extreme energy spike occurred leading to several explosions. This, in turn, caused a massive fire which ejected tons of radioactive dust into the air, rendering the area largely uninhabitable.

Answer: Closed valves in the auxillary system

When the energy increase occurred due to a failure in the water pumps, the core was scrammed (a technical term for an emergency shut-down). This usually means that control rods are inserted between the uranium rods to catch all the excess neutrons and, thus, slow down the reaction. However, there needs to be some medium in place to transport all the built-up heat, and, at Three Mile Island, the mechanism in place was water pumped directly into the core.

At the time of the accident, water was not pumped into the core and the temperature built up. This caused pressure to rise in the core. A pilot valve was opened to let out the excess pressure, but it was supposed to close automatically once the pressure was low enough. Due to a mechanical failure, the valve stuck and remained open leading to a further loss of coolant. A false indicator light did not allow the operators to see that it was still open. This started a further chain of events that led to a partial meltdown of the core.

The accident occurred on March 28th, 1979. Ironically, this was several days after the release of the movie "The China Syndrome", and because of it, the public's reaction to the accident was very negative.

Answer: Submarine

K-431 (previously K-31) was a Soviet nuclear-powered submarine attached to their Pacific fleet. It was an Echo II anti-carrier submarine and was equipped with eight P-6 or P-500 antiship cruise missiles.

While docked in Vladivostok, K-431 was being refuelled. The refuelling was concluded and the lid for the reactor was replaced, only incorrectly. The lid had to be lifted up and repositioned, however, this time with the reactor control rods attached to it. Because the lid was lifted up too high, this set off a reaction and caused an explosion due to built-up steam. Ten people lost their lives directly due to the explosion, and others suffered radiation poisoning.

Answer: Save time

Three Japanese workers at the Tokaimura nuclear plant achieved critical mass on their own by trying to cut corners and to save time in the mixing procedure. They set off a reaction that lasted over 20 hours, and two of the workers lost their lives due to radiation exposure. None of the three workers was properly qualified for the task they were assigned to.

Instead of following procedure and producing the nuclear fuel in a dissolution tank, the three Japanese workers mixed the uranium powder in a stainless-steel bucket along with the nitric acid. They also fed more than the allowed amount of this uranyl nitrate solution into the precipitation tank, about seven times the allowed amount, and this achieved critical mass. Oops? You betcha!

Answer: Cleaning

When tributyl phosphate and nitric acid mix together, they create something known as 'red oil'. This compound can be very unstable and explosive at times, and this was the cause of the explosion at Tomsk-7 (now Seversk) in Russia. A routine cleaning of a paraffin and tributyl phosphate tank with nitric acid resulted in an explosion that ripped apart the building. This occurred on April 6th, 1993. Some of the 8773 kg of uranium and 310 kg of plutonium leaked from the tank and contaminated the area.

This site was used for nuclear weapons production, amongst other things, one of six such sites around Russia. According to official statements, the plant no longer produces weapons-grade uranium.

Answer: graphite

The Windscale reactor was created in post-WWII Britain because of the secrecy act (Atomic Energy Act in 1946) of the US not sharing their nuclear knowledge gained with their allies. As a result, the UK did not want to be left behind and wanted to produce their own nuclear bomb, and, the Windscale piles were built.

The British reactors had a solid graphite core. Graphite is subject to the Wigner effect, meaning, when it's bombarded with neutrons, it displaces the crystal structure enough so that energy is stored in the material. This energy could potentially release at any given moment, and was a danger to the reactor. Luckily, the energy could be released in a controlled method by annealing the graphite to 250 degrees Celsius.

At Windscale, due to a mistake in the measuring of the core temperature, during the annealing process, temperatures were believed to be dropping prematurely. This led the British engineers to restart the reactor and raise the temperature back. However, it was actually already hotter than usual. The resulting explosion and fire released much radioactive material into northern England.

Answer: boric acid

In March 2002, a safety inspection (one that had been delayed well past the December 2001 deadline) discovered that the reactor pressure vessel head had been nearly eaten through by boric acid that was leaking from a cracked pipe above it. The resulting hole was nearly the size of a football, and could have caused a serious accident had the metal ruptured, or had the acid had eaten the rest of the way through.

Davis-Besse has also been subject to a stuck valve, a direct hit by a tornado, and a double-shutdown of the feedwater pumps supplying water to the steam generators.

Answer: Mayak

The 1957 explosion at the Mayak nuclear reprocessing site was caused by faulty cooling of the waste facilities and poor monitoring of them in the case of an accident. A storage tank was not receiving sufficient coolant, and the temperature in it rose steadily. The explosion was equivalent to about 100 tons of TNT and the fallout contaminated over 800 square kilometers over a long period.

Since the Soviet government was secretive, not even the local population was warned to the danger of the fallout. People were slowly evacuated, but, many people (an undisclosed amount) died as a result of the radiation. This is the considered the second-worst nuclear disaster in the history of the world, following Chernobyl.

Answer: Spain

On January 17th, 1966, an American B-52 bomber was on a routine Cold War mission and was attempting a mid-air refuelling. The bomber had originally set out from North Carolina and was to fly close to the Soviet border before returning. On the return leg, the mid-air refuelling went all wrong and the bomber struck the tanker. Both planes were destroyed and only four men ejected from the bomber and were saved.

The payload of the B-52 consisted of four B28 nuclear bombs. Three of these hit the ground not too far from Palomares, a fishing village in Spain. The fourth landed in the Mediterranean Sea. Two of the bombs exploded upon impact, conventionally, and the plutonium contaminated a large area. The US government attempted to clean up much of the mess their bombs had made.

Answer: Jimmy Carter

Surprising, but true. Jimmy Carter was a US Naval officer at the time and was dispatched to help clean up the mess of the accident at Chalk River. On December 12th, 1952, a power spike happened because of a shutoff rod failure and several errors by the operators on duty. Quick thinking by the operators shut down the nuclear reaction, however, the heat already generated was enough to set off explosions that damaged the core of the reactor.

Not six years later, a fire to one of the uranium rods occurred at this same site and contaminated the reactor and the building it was in. Because of a jam, the ventilation was stuck on 'open' and the radioactive ash dissipated throughout the building.