April 18, 2022
On April 18, at a meeting of the Nuclear Regulation Authority to review the status of the accident at the Fukushima Daiichi Nuclear Power Plant, TEPCO announced that it had changed its target date for the completion of work to “the first half of FY2022 (April to September)” regarding the removal of pipes between Units 1 and 2 that were contaminated with high concentrations of radioactive materials. Previously, the target was “within FY 2009. The scope of the removal work includes the areas that interfere with the installation of rainwater inflow countermeasures in the waste treatment buildings of Units 1 and 2 and the installation of a large cover in Unit 1.
The removal work began on February 24, but has not progressed at all due to a series of problems with the cutting equipment. The timing for the resumption of work is not clear, as investigations are still underway to determine whether the cutting equipment and method used to lift the pipes up by a large crane are appropriate.
The pipes to be removed were used in the venting process immediately after the accident to release contaminated air inside the reactor to prevent the containment vessel from rupturing. The pipes are 30 cm in diameter and measure 65 meters on the Unit 1 side and 70 meters on the Unit 2 side. The current plan is to cut the piping into 26 sections and remove them. The surface dose at the connection with the exhaust stack is 4 sievert per hour, which is high enough to kill a person if he or she stays there for several hours. For this reason, all work will be carried out remotely. (Shinichi Ogawa)
April 18, 2022