Nuclear disaster at Three Mile Island

At 4 a.m. on March 28, 1979, the worst accident in the history of the U.S. nuclear power industry begins when a pressure valve in the Unit-2 reactor at Three Mile Island fails to close. Cooling water, contaminated with radiation, drained from the open valve into adjoining buildings, and the core began to dangerously overheat.

The Three Mile Island nuclear power plant was built in 1974 on a sandbar on Pennsylvania’s Susquehanna River, just 10 miles downstream from the state capitol in Harrisburg. In 1978, a second state-of-the-art reactor began operating on Three Mile Island, which was lauded for generating affordable and reliable energy in a time of energy crises.

Three Mile Island accident | nuclear accident, Pennsylvania, United States  [1979] | Britannica

After the cooling water began to drain out of the broken pressure valve on the morning of March 28, 1979, emergency cooling pumps automatically went into operation. Left alone, these safety devices would have prevented the development of a larger crisis. However, human operators in the control room misread confusing and contradictory readings and shut off the emergency water system. This was the first big mistake they made. The reactor was also shut down, but residual heat from the fission process was still being released. By early morning, the core had heated to over 4,000 degrees, just 1,000 degrees short of meltdown. In the meltdown scenario, the core melts, and deadly radiation drifts across the countryside, fatally sickening a potentially millions of people.

As the plant operators struggled to understand what had happened, the contaminated water was releasing radioactive gases throughout the plant. The radiation levels, though not immediately life-threatening, were dangerous, and the core cooked further as the contaminated water was contained and precautions were taken to protect the operators. Shortly after 8 a.m., word of the accident leaked to the outside world. The plant’s parent company, Metropolitan Edison, downplayed the crisis and claimed that no radiation had been detected off plant grounds, but the same day inspectors detected slightly increased levels of radiation nearby as a result of the contaminated water leak. Pennsylvania Governor Dick Thornburgh considered calling an evacuation.

Finally, at about 8 p.m., plant operators realized they needed to get water moving through the core again and restarted the pumps. The temperature began to drop, and pressure in the reactor was reduced. The reactor had come within less than an hour of a complete meltdown. More than half the core was destroyed or molten, but it had not broken its protective shell, and no radiation was escaping. The crisis was apparently over.

Two days later, however, on March 30, a bubble of highly flammable hydrogen gas was discovered within the reactor building. The bubble of gas was created two days before when exposed core materials reacted with super-heated steam. On March 28, some of this gas had exploded, releasing a small amount of radiation into the atmosphere. At that time, plant operators had not registered the explosion, which sounded like a ventilation door closing. After the radiation leak was discovered on March 30, residents were advised to stay indoors. Experts were uncertain if the hydrogen bubble would create further meltdown or possibly a giant explosion, and as a precaution Governor Thornburgh advised “pregnant women and pre-school age children to leave the area within a five-mile radius of the Three Mile Island facility until further notice.” This led to the panic the governor had hoped to avoid; within days, more than 100,000 people had fled surrounding towns.

At the height of the crisis, plant workers were exposed to unhealthy levels of radiation, but no one outside Three Mile Island had their health adversely affected by the accident. Nonetheless, the incident greatly eroded the public’s faith in nuclear power. The unharmed Unit-1 reactor at Three Mile Island, which was shut down during the crisis, did not resume operation until 1985. Cleanup continued on Unit-2 until 1990, but it was too damaged to be rendered usable again.

The public began to come forward with their concerns about what them and their families might have been exposed to. Mainly due to conflicting statements from media, government officials, and scientists. Officials continued to measure radiation levels, they again said it wasn’t a threat to society. This industry immediately was trying to exonerate itself after the incident. Many of the monitors were not even capable of picking up the accurate amount of radiation being released. This again was a technical flaw. No one actually knows the true numbers of the amount of radiation that was released, we simply didn’t have the proper equipment to measure such numbers.

People began to come back to their homes, they all thought the immediate threat was over. After this, radioactive iodine was found everywhere even in the milk being produced in the surrounding areas. Fish couldn’t even survive in the near by water, they began to wash up on the shores and frighten the once happy citizens. Children and young adults started to get sick. Lesions, diarrhea, projectile vomiting all signs of radiation poisoning. The community came together at this point, they no longer trusted the government officials and with good reason. Again officials confirm the residents have nothing to worry about, these people knew better.

6 months later: a trial of sorts was put in place, all operators were told to recite exactly what they did that caused a bad accident to become worse. Miscommunication and untrained employees all played a big part. This particular reactor had only been in service for about 3 months. The NRC wasn’t hearing what the staff and other officials had to say. Bottom line was they had to make this power plant profitable. Many many mistakes were made during this entire process. No one really knew how much damage was done to the reactor. Talk of the plant opening back up didn’t sit well with citizens od Middletown PA. They made that know in many ways. Then things got scary, people were being followed, phones were being tapped. The people of the nearby towns knew something fishy was going on.

3 years later, they sent a radiation detector and camera down into the core to see the actual damage. What they saw was a molten mess that was once the top half of the reactor, but it had collapsed in on itself. Massive core damage was seen, when they lost cooling the core then melted. They were 30 minutes away from an entire reactor exploding and blowing the top off. The rest was left up to the government, 1 billion dollars were spent to safely clean the area up for years to come. They had to remove all materials around the reactor and even contaminated water surrounded the area. The people still have no idea just how much themselves and their children have been exposed. Till this day people still are suffering with the effects of being exposed to so much radiation. This incident could’ve been prevented and many lives could have been saved had they had proper training and equipment during this time.