Work to cover the Fukushima Daiichi intake canal (in front of units 1-4) have begun. A crane barge is pouring two layers of grout-cement mixes on the sea floor in front of the station to reduce the possibility of radioactivity spreading.
At unit 4, TEPCO is planning to use a robot submersible to survey the unit 4 spent fuel pond debris in mid-March. The self-propelled ROV, supplied by Hitachi-GE nuclear energy, holds a camera and a light. The fuel pool is about 11.5m deep, and the fuel rods stored at the bottom of the pool are about 4.7m high. The pool is currently covered by floats to prevent the ingress of other contaminants. The ROV will be passed through this slit to reach the bottom of the tank.
It is also planning to survey the bottom of the empty reactor vessel (which is under about 25m of water) with a camera and a light. It would aim to survey the bottom of the reactor well, the top of the control rod drive housings, and the shroud supports. This work prepares the way for workers to shift control rods currently stored in the cask pit to the bottom of the reactor during fuel removal from the spent fuel pond.
On the anniversary of the crisis, TEPCO published an overview of work on the site, available on www.youtube.com/neimagazine
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