Weeds were the culprit that poked holes in vinyl chloride hoses for transporting radioactive water under treatment at the crippled Fukushima No. 1 nuclear power plant, Tokyo Electric Power Co. said Feb. 9.
Weeds were the culprit that poked holes in vinyl chloride hoses for transporting radioactive water under treatment at the crippled Fukushima No. 1 nuclear power plant, Tokyo Electric Power Co. said Feb. 9.
Twenty-two cases of water leakage were reported between July and December 2011.
The hoses make up a 4-kilometer conduit to purify radioactive water that is used to cool nuclear reactors and pump it back into the reactors.
Most of the conduit is outdoors and connects equipment with tanks of the purification system.
Experiments conducted by TEPCO confirmed that sharp and pointed buds of cogon grass (Imperata cylindrica) penetrated the four-layered structure of the hose surface. Buds that penetrated the hoses likely died and fell out of the hoses, generating the water leakages, TEPCO officials said.
TEPCO has already replaced the hoses with polyethylene pipes that are more resistant.