They actually used adhesive duct tape for this.

http://voiceofrussia.com/news/2014_01_05/Fukushima-worker-confessions-adhesive-tape-used-to-deal-with-increase-of-radioactive-water-5945/

Fukushima worker confessions: adhesive tape used to deal with increase of radioactive water

In the first days of January 2014, Tokyo Electric Power Company (TEPCO) launched preparations for cleaning the drainage system of the crippled Fukushima Daiichi nuclear power plant holding more than 20,000 tons of highly radioactive water.

Meanwhile, a Japanese worker says he is not surprised at so many radioactive water leaks from Fukushima water storage tanks.

Yoshitatsu Uechi, 48, an auto mechanic and tour bus driver, was sent to work at the Fukushima plant along with other workers from the Okinawa Prefecture for six months in 2012, according to the Asahi Shimbun newspaper.

 The workers were set various areas of the devastated plant, including highly contaminated ones code-named H3.

Uechi was part of a team tasked with building new tanks for radioactive water. He and his fellow workers were under such pressure to do it quickly that they did not wait for dry conditions to apply anti-rust coating over bolts and around seams as they were supposed to.

Uechi was part of a team tasked with building new tanks for radioactive water. He and his fellow workers were under such pressure to do it quickly that they did not wait for dry conditions to apply anti-rust coating over bolts and around seams as they were supposed to.

Uechi recalled with disgust the disregard for worker safety, the makeshift plans and the cost-cutting measures, including the use of adhesive tape on key equipment.

“I couldn’t believe that such slipshod work was being done, even if it was part of stopgap measures,” the man told the newspaper.

 One rainy October day, Uechi and another worker were instructed to cover the openings of about six storage tanks that lacked their top lids. They put on yellow raincoats over their protective gear and headed for the E sector close to an H3 area.

When Uechi climbed to the top of a 10-meter-tall storage tank, he saw white adhesive tape covering an opening about 30 centimeters across. The tape was all that separated him from radioactive water only 50 cm below. As he used the blade to remove the tape, his legs trembled at the sight of raindrops hitting the water surface, Uechi said.

Uechi applied a sealing agent on the opening, fit a steel lid he had brought with him, and fastened it with four bolts as he had been instructed to, but he saw that there were eight bolt holes.
Read more: http://voiceofrussia.com/news/2014_01_05/Fukushima-worker-confessions-adhesive-tape-used-to-deal-with-increase-of-radioactive-water-5945/

Uechi’s colleagues told him that the use of adhesive tape was part of makeshift measures devised to deal with increasing water leaks. But he saw signs of cost-slashing shoddy work all around him. For example, wire nets were used instead of reinforcing bars during the construction of concrete foundations for water storage tanks, and waterproof sheets were applied along the joints inside flange-type cylindrical tanks in order to save on sealing agent. Little wonder that some of those tanks began leaking radioactive water.

Uechi also claimed that many second-hand materials were in use.

Workers were told to keep away from the water storage tanks which had high radiation levels, so Uechi wore a raincoat even on sunny days to block radiation when he had to go near highly radioactive water.

Taisei Corporation, the prime contractor for the work project, declined comment. “We are implementing and supervising work projects in an appropriate manner,” it said.

 But Uechi, who had been hired by Taisei’s third-tier subcontractor, claims he received work instructions from foremen of the first-tier and second-tier subcontractors of Taisei Corp.

Voice of Russia, Asahi Shimbun
Read more: http://voiceofrussia.com/news/2014_01_05/Fukushima-worker-confessions-adhesive-tape-used-to-deal-with-increase-of-radioactive-water-5945/

Read more: http://voiceofrussia.com/news/2014_01_05/Fukushima-worker-confessions-adhesive-tape-used-to-deal-with-increase-of-radioactive-water-5945/