0
Please log in or register to do it.



    

    The Three Mile Island Nuclear Generating Station is a decommissioned nuclear power plant located on Three Mile Island in the Susquehanna River, near Harrisburg, Pennsylvania. While it is no longer operational, the decommissioning process is far from complete, as such efforts require an extensive amount of time. Originally constructed by the General Public Utilities Corporation, the plant was operated by its subsidiary, the Metropolitan Edison Company (Met-Ed).

Construction of the plant’s first reactor, TMI-1, began in 1968 and proceeded smoothly, without major complications. In contrast, the second reactor, TMI-2, faced numerous challenges. Construction of TMI-2 began in 1969 and was intended to be completed within six years, but delays extended the timeline to nine years, with completion in 1978. Once operational, TMI-2 experienced a series of unscheduled shutdowns, highlighting ongoing technical problems. To avoid government scrutiny, plant workers falsified performance data submitted to the Nuclear Regulatory Commission (NRC), setting the stage for a catastrophic failure.

On March 28, 1979, the cooling system for TMI-2 failed when a pump responsible for transferring hot water to the reactor’s steam generator malfunctioned. Although the exact cause remains uncertain, possible factors include a stuck valve or water intrusion into an airline. The turbine shut down as a safety measure, releasing a plume of high-pressure steam, but without the steam generator, the reactor’s feedwater pump also failed. This pump played a critical role in cooling the reactor core. Without adequate cooling, the reactor core overheated, initiating a chain of events that led to a partial meltdown.

The plant’s emergency shutdown protocols kicked in, but complications arose. A relief valve meant to release pressure became stuck in the open position, allowing steam to escape and depleting the water needed to cool the core. Although backup systems were in place, they failed due to human error. Days before the incident, the emergency pump’s valve was tested and left closed, preventing the backup system from engaging. This oversight, combined with faulty control room instruments, meant operators were unaware of the water loss and believed the reactor was functioning normally.

Operators inadvertently worsened the situation by shutting down the flow of water to prevent perceived flooding, unaware that the reactor was already critically low on coolant. As a result, the nuclear fuel rods, made of zirconium (which melts at 1,850°C), began to overheat and melt. By the time workers realized the gravity of the situation, significant damage had occurred.

The meltdown resulted in approximately 60% of the reactor core being destroyed. Fortunately, the reactor’s steel containment held, preventing a full-scale disaster. However, it wasn’t until two days later that officials advised residents near the plant to stay indoors. Eventually, Pennsylvania’s governor called for the evacuation of children and pregnant women within a five-mile radius. While no immediate health effects were reported, the delayed response could have had dire consequences in a more severe incident.

The aftermath of the Three Mile Island accident included extensive cleanup efforts that lasted until August 1993, requiring the disposal of 2.3 million gallons of contaminated water. TMI-2 was permanently shut down, while TMI-1 resumed operation in 1985, despite public opposition. TMI-1 continued to operate until its final shutdown on September 20, 2019, primarily due to economic factors rather than technical issues.

The decommissioning of TMI-1 is expected to take nearly 60 years and cost over $1 billion. The Three Mile Island incident remains a pivotal moment in the history of nuclear energy, raising questions about safety, regulation, and the future of nuclear power.



What is Retrograde Motion? Do Planets Actually Move Backward?
What I’ve Learned As a Failed Crypto Developer

Reactions

0
0
0
0
0
1
Already reacted for this post.

Reactions

1

Your email address will not be published. Required fields are marked *