Tokyo Electric Power Co. (Tepco) said an operation to reduce the risk of a hydrogen explosion at the crippled Fukushima Daiichi nuclear plant’s No. 1 reactor by injecting it with nitrogen has been a success.
According to Japan’s Kyodo newswire, pressure in the reactor's containment vessel has risen as expected, indicating the success of the operation. Tepco also continued to dump into the Pacific Ocean water tainted with low-level radiation to make room to store highly radioactive water that has been hampering the plant's restoration work.
Japan’s nuclear safety agency said most of the water will be released by Thursday afternoon and the remaining amount will be discharged by Saturday. The move has sparked concern over sea contamination among neighbouring countries and strong protests from the domestic fishing industry.
In its operation to prevent a hydrogen explosion at the No. 1 reactor, Tepco plans to insert nearly 6000 cubic meters of nitrogen, an inert gas, into the reactor over six days and estimates that about 200 cubic meters were injected between 1:30 a.m. and 9:50 a.m. on Thursday.
The firm and the government's Nuclear and Industrial Safety Agency said they believe chances are slim that another hydrogen explosion will occur immediately or that high volumes of radioactive substances will be emitted following the nitrogen injection operation..
To prevent further contamination of the sea from radiation leakage, TEPCO will install iron sheets as well as ''silt fence'' barriers close to the No. 2 reactor water intake and other areas near the plant. The utility will also put 100 tons of sandbags at a breakwater, Nishiyama said.
According to estimates by TEPCO, nuclear fuel rods in the No. 1 reactor core are the most damaged compared with those in the Nos. 2 and 3 reactors. Cooling functions of all three units were lost after a magnitude 9.0 quake and tsunami ravaged the plant on March 11.
The company estimates that 70 per cent of the fuel rods in the No. 1 reactor core have been damaged, compared with 30 per cent at the No. 2 and 25 per cent at the No. 3.