Vacuum Test for the Tank Bottom PlateWe will specify the location of the opening through which bubbles are vacuumed, by applying bubbles to the

flange parts etc. and conducting suction from the lower side of the bottom plate.On September 20, vacuum test for the tank bottom plate was conducted, and we found leak from caulking

and mortar installed around the bottom-plate (in-leak), therefore we found no bubble suction.On September 25, after treating the accumulated water under the tank bottom plate, and re-conducting

sealing, we found the two adjacent bolts through which bubbles were vacuumed up.We continue the investigation into leakage.

Bottom plate

Side plate

Inside Outside

Bottom-plate flange partsBottom-plate reinforcement member

Suction from the lower side of the

bottom plate(0.03MPa)

Bottom plateBottom plate

Water-expandable waterproof materialWater-expandable sealing materialSealing material

Concrete foundation Concrete foundation

Sealing*

Suction from the lower side of the bottom plate

Bubbles

Bubbles are vacuumed up through an opening.

Sealing

*We replaced caulking and mortar with sealing of water-proof tapes

180

90270

0

Bubble suction was found here.

September 25, 2013

Tokyo Electric Power Company

Bolts where bubble suction was found.

Approx.

10m

Approx. 12m