According to Kyodo News, the excavations were carried out using large equipment called shield machines, which attached reinforced concrete walls to every metre excavated, in a process that was repeated about 1,000 times.  It is reported that the initial excavation of about 150 meters is planned to be carefully, and the speed will be accelerated from around late October.  According to NHK, so far, the shield machine has been digging at a rate of about 5 to 6 meters per day, reaching a length of 80 meters on Saturday.  

"The operation is going well," Kyodo News agency quoted a Tepco official as saying.  In order to gain an understanding of the drainage, detailed instructions will be given on the progress of the project and the safety of the equipment."  

Depending on weather and ocean conditions, the project could be delayed and the start of the discharge could be postponed to around next summer.  

On March 11, 2011, a 9.0 magnitude earthquake and massive tsunami occurred off the northeastern coast of Japan, causing heavy casualties.  As a result of the earthquake and tsunami, a large amount of radioactive material leaked from the Fukushima Daiichi nuclear power plant.  

On April 13, 2021, the Japanese government decided to release a large amount of nuclear water from Fukushima into the sea.  Under the plan, the nuclear water will be diluted with seawater and discharged about 1 kilometer offshore through an undersea tunnel.  The move was strongly opposed by the Fukushima Prefecture Fisheries Association and the National Federation of Japanese Fisheries Associations, as well as the international community.