At Fukushima Daiichi Nuclear Power Station, we are working on the
stabilization of the reactor of Unit 1 by continuing the nitrogen gas
injection to the reactor containment vessel and adjusting the water
injection rate to the reactor monitoring several parameters.
In order to solidify these efforts, we need to install and calibrate a new
reactor water level gauge. Also, we need to install a circulating cooling
system to improve the status of the reactor to a more stable cooled
condition. To do so, we have to improve the working environment inside the
At this moment, in preparation for the improvement, we are conducting the
visual inspection and measuring the radiation dose and the density of
radioactive substances by a remote controlled robot inside the reactor
building. From now on, we will install an ambient air filtration system*,
circulate air inside the reactor building for a while, filter the
radioactive substances and lower the density. After that, in order for
workers to enter the reactor building and conduct necessary works, we will
open the airlock. Before opening the airlock, we will monitor the density
of the radioactive substances within the reactor building and confirm that
the influence to the outside is low enough.
We will announce beforehand in opening the airlock of the reactor
building. At the same time, we will closely monitor figures at monitoring
posts and announce these.
On May 2nd, we received the instruction from the Minister of Economy,
Trade and Industry to report the work detail of the Improvement of the
working environment inside the reactor building of Unit 1, Fukushima
Daiichi Nuclear Power Station, as well as the evaluation of the impact
outside due to radioactive materials.
On May 3rd, we organized the information based on this instruction, and
reported to the Minister of Economy, Trade and Industry. The detail of the
report is as attached.
- Improvement of the environment within the Reactor Building of Unit 1
* Ambient air filtration system
This system vacuums up the ambient air at the work area by a fan, filters
impurities and cleans the air.