China News Service, December 7 (Xinhua) According to Kyodo News, Tokyo Electric Power Company restarted the internal investigation of the reactor containment of Unit 1 of the Fukushima Daiichi Nuclear Power Plant after about half a year on the 6th.
According to reports, in order to take out the molten nuclear fuel (fuel fragments), it is planned to put in four remote-controlled robots in sequence to measure the radiation emitted by the fuel fragments and collect the accumulations accumulated at the bottom.
According to analysis, the nuclear fuel of unit 1 basically melted down into the containment vessel.
During the investigation from February to June this year, massive accumulations of possible fuel debris were confirmed in a large area. It was also found that the base concrete supporting the reactor was damaged and steel bars were exposed, raising concerns about earthquake resistance.
This time, in the second half of the investigation, a robot equipped with radiation detection sensors was put into a containment vessel filled with water, and the sensors were hung down toward the accumulation at the bottom to detect radiation at 8 locations.
The purpose is to detect the characteristic radiation emitted by fuel fragments.
From mid-January next year, the accumulation will be collected by robots equipped with suction devices.
Ultrasound is then used to grasp the three-dimensional structure of the deposits, and in addition to entering the inside of the base that supports the reactor, attempts to photograph internal damage and photograph the reactor from below.
Unit 2 of Yinuo plans to take out fuel fragments in the second half of 2023, while units 1 and 3 are undecided.