Fuel Debris Retrieval at Fukushima No. 1 Nuclear Power Plant
On October 30th, a retrieval device was deployed in the No. 2 reactor of the Fukushima No. 1 nuclear power plant. This marked a significant step in the ongoing efforts to remove fuel debris that melted down during the 2011 disaster.
On November 5th, the operator, Tokyo Electric Power Co. (TEPCO), reported that the radiation level of the retrieved fuel debris was within safe handling limits. This positive development paves the way for the completion of the trial removal on or after November 7th.
Following the retrieval, the device containing the fuel debris was placed in an isolation box outside the containment vessel on November 2nd. On November 5th, TEPCO measured the radiation level at approximately 0.2 millisievert per hour at a distance of 20 centimeters from the box. This level is well below the safety threshold of 24 millisieverts per hour, ensuring the safety of workers involved in the process.
The next step involves placing the debris in a box-shaped container within the isolation box on November 6th. Subsequently, a window on the side of the box will be opened on or after November 7th to transfer the container into a bucket-shaped container, marking the completion of the trial retrieval.
The Fukushima No. 1 plant houses an estimated 880 tons of fuel debris across its No. 1, No. 2, and No. 3 reactors. These reactors suffered meltdowns following the Great East Japan Earthquake and tsunami in March 2011, which crippled the plant's cooling systems.
This trial retrieval aims to collect up to 3 grams of fuel debris from the No. 2 reactor for analysis. This analysis will provide valuable insights into the composition and characteristics of the debris, aiding in the development of future retrieval methods. The successful completion of this trial represents a crucial step towards the decommissioning of the Fukushima No. 1 nuclear power plant.