From the Mainichi Daily News August 10, 2011
TOKYO (Kyodo) — The operator of the crippled Fukushima Daiichi nuclear power plant said Tuesday it will begin in earnest on Wednesday work to install a giant covering over the plant’s No. 1 reactor, with plans to complete it by the end of next month.
The covering, a tent-like structure made of steel frames and air-tight polyester sheets, is meant to prevent radioactive materials from spreading from the crippled reactor and stop rainwater from entering the reactor building, said Tokyo Electric Power Co.
When completed, the covering will be between 42 and 47 meters long and about 54 meters high. About 60 components are being brought to the seaside plant via the Pacific.
On Wednesday, a steel structure about 6.9 meters high that weighs about 30 tons is expected to be pulled up by a crane and installed at the southeast corner of the No. 1 reactor building.