Over the next 30-40 years, more than 1 million metric tons of water need to be released from the 1,000 tanks constructed by TEPCO. Yet, the company's greater challenge lies in addressing a substantial amount of melted fuel debris present within the nuclear reactors.
(Photo : PHILIP FONG/AFP via Getty Images)
TOPSHOT - A shoreline is pictured from Futaba-machi, Fukushima Prefecture, around 5 km away from the crippled Fukushima-Daiichi nuclear plant on August 24, 2023, the day on which Japan's government plan to begin releasing wastewater from the stricken plant into the Pacific Ocean.
Facing Larger Concerns Beyond Water Release Effort
Following approval from the International Atomic Energy Agency (IAEA), Japan has begun the process of discharging wastewater from the Fukushima nuclear plant into the ocean.
TEPCO, the operator of the plant, initiated the release on August 24, starting with a batch of 7,800 tons sourced from 10 of the group B tanks. This water is recognized as being among the least radioactive at the facility.
In the upcoming 30-40 years, a substantial volume of over 1 million metric tons of water must be gradually released. Currently contained within the 1,000 tanks constructed by TEPCO, this water represents a significant challenge to address.
However, TEPCO faces even larger concerns beyond this water release effort. Within the nuclear reactors, Interesting Engineering reported that a notable quantity of melted fuel debris is present.
According to a statement from a TEPCO spokesperson, approximately 880 tons of radioactive melted nuclear fuel still reside within the reactors.
Despite employing robotic probes to collect data, the status of the molten debris remains largely uncertain, with the possibility that the actual amount might be even greater.
During the incident, Units 1 to 3 of the nuclear plant were in operation, each containing fuel rods within their reactors.
Restoring Process from Reactors
The subsequent loss of emergency power hindered the cooling process, leading to the overheating and melting of the fuel. TEPCO explained that the term "fuel debris" encompasses the melted fuel and other substances that re-solidified once they had cooled down.
In an effort to mitigate the potential risks posed by this fuel debris, Associated Press reported that TEPCO is actively preparing for the retrieval process from the reactors.
The initial focus is on commencing retrieval operations from the first unit, Unit 2, and progressively expanding the scope of retrieval efforts. TEPCO plans to store the retrieved fuel debris in a newly constructed storage facility situated on the premises.
Due to its high radioactivity, the fuel debris removal process at the plant is expected to span several years. In March of this year, TEPCO conducted a robotic study that visually confirmed the breach of a pressure vessel at Unit 1, where the meltdown is assessed to be more severe than in Units 2 and 3 reactors.
As per Asahi's report, the International Research Institute for Nuclear Decommissioning's report suggests that the Unit 1 reactor building holds an estimated 279 tons of melted fuel debris.
Robots will play a key role in debris removal, with a trial using a large remote-controlled robotic arm scheduled for Unit 2 this year, as per a TEPCO spokesperson. While the treated water release will span 30-40 years, complete decommissioning of the plant is projected to take 50-100 years.
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