Japanese electrical utility TEPCO has continued to act to reduce the spread of radiation from the damaged Fukushima Daiichi plant.
In addition to the coagulant that engineers injected underneath the unit 2 culvert, they also fixed a rubber plate over the crack. Although the leak appears to now be plugged, the teams are continuously monitoring for leakages. Also, workers have started to build a sandbag dyke around the station's discharge pipe. Furthermore, spillage prevention fences are also being prepared.
Also, a second area was sprayed with a resin (called Kuricoat) to reduce the risk of contaminated dust blowing away from the site. Six hundred square metres was sprayed near the common spent fuel pool. A total of 2400 litres was sprayed on 6 April; 2500 L was sprayed on 5 April and 2000 L was sprayed on 1 April. The trial will last two weeks.
And TEPCO's latest monitoring results underline the need to do so. Iodine and caesium were detected in the unit 2 culvert. In the discharge canal measurements found technetium, cobalt, iodine, caesium, tellurium, barium, lanthanum and molybdenum as recently as 5 April. Samples of air detected iodine, cesium, tellurium and ruthenium as recently as 5 April. Plutonium was detected in the soil as recently as 28 March, although at background radiation levels. Additionally, iodine, caesium, tellurium, barium, niobium, ruthenium, molybdenum, technetium, lanthanum, beryllium and silver were detected in site soil as recently as 28 March, TEPCO said.
In other news, TEPCO said that it has started to inject nitrogen case in the unit 1 containment vessel to prevent the accumulation of oxygen. They suspect that hydrogen gas may have accumulated inside the containment, and are attempting to avert another explosion, as occured at it and also units 2 and 4. A total of 210 m3 of nitrogen was injected as of 9:50am local time 7 April; TEPCO plans to inject a total of 9000 cu m over six days. It is preparing to do the same at units 2 and 3.