Nuclear update: Leak stopped. Why is Japan injecting nitrogen into reactor?
Workers plugged a leak of highly radioactive water into the ocean from Japan's Fukushima Daiichi nuclear power plant Wednesday, even as they tried to prevent another hydrogen explosion in reactor No. 1 by injecting nitrogen gas.
This satellite image, taken March 18, shows reactors No. 1 to 4 (from R to L) at the Fukushima Daiichi power plant. Officials reported April 6 that highly radioactive water leaking into the ocean had been plugged, and that workers are injecting nitrogen gas into reactor No. 1 (r.) to prevent another hydrogen explosion.
DigitalGlobe / Reuters / File
There was a bit of good news Wednesday from the stricken Fukushima Daiichi nuclear plant, as workers managed to plug a crack in a concrete pit which had been leaking highly radioactive water into the ocean.
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Does this mean the Pacific is now safe from further contamination by the Fukushima complex? Probably not. For one thing, Tokyo Electric Power Company (TEPCO) workers are not sure if there are more leaks. For another, TEPCO continues to pump water with low levels of radioactivity into the sea, to clear tank space for storage of more dangerous wastewater.
“Right now, just because the leak has stopped, we are not relieved yet,” said Chief Cabinet Secretary Yukio Edano at a press conference Wednesday.
Preventing another hydrogen explosion
Meanwhile, TEPCO was also preparing to inject nitrogen into Fukushima’s reactor No. 1 in an attempt to prevent a hydrogen explosion.
Reactor No. 1 has suffered extensive damage to its fuel rods, with upwards of 70 percent melting, according to TEPCO. Scientists have become increasingly concerned that radiation from the damaged fuel could split water into oxygen and hydrogen. The injection of nitrogen, an inert gas, is intended to displace a potentially combustible oxygen-hydrogen mix.
The move does not mean that the reactor is in “immediate danger” of explosion, said Hidehiko Nishiyama, a spokesman for Japan’s Nuclear and Industrial Safety Agency, on Wednesday.
Seawater radiation levels improving
TEPCO’s success in sealing the water leak from the concrete pit did appear to be making a difference in radiation levels near Fukushima. On Wednesday, a seawater sample taken from about 360 yards offshore contained about 280 times the legal limit of radiation. Previous samples from the same point had contained upwards of 4,000 times the legal radiation level.
TEPCO workers had been sure that the hole they plugged was a major problem. Tracer coloring dropped in the water of the concrete pit had shown up offshore.
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