TEPCO investigates inside fuel pool of Number 3

February 18, 2013

http://photo.tepco.co.jp/en/date/2013/201302-e/130213-02e.html 

http://www.simplyinfo.org/?p=9728

SimplyInfo » The Latest » Analysis: Unit 3 Mast In Pool Inspection

Analysis: Unit 3 Mast In Pool Inspection 

TEPCO released a new video and handout of the unit 3 mast that fell deeper into the spent fuel pool.

We have processed the video into about 200 still images that can be found here.

The full video of the inspection can be found on our Youtube channel.

TEPCO estimates one end of the mast landed along the east wall with the end resting on a control rod drive rack. The other end appears to be resting tangled in concrete and rebar debris on top of the fuel racks. Portions of the middle of the mast can be seen spanning above the fuel racks by a few inches. What appears to have been the structure that originally held the mast into the fuel crane can be seen partially down the mast.

What is of particular note in the findings from this inspection is that the control rods housed along the east (sea side) wall of the pool. These control rods have considerable damage,with one laying mangled under the mast. The control rods contain halfnium in a steel shell. This damage could have caused them to leak.

This diagram shows the structure of a normal control rod with cracks, an ongoing problem in reactor operation. CNIC has reported in the past about control rod cracking problemsat Fukushima Daiichi

200 still images from TEPCO’s video : http://www.flickr.com/photos/simplyinfo/sets/72157632785914272/with/8479956315/