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Steam Detected at Damaged Fukushima Reactor Steam Detected at Damaged Fukushima Reactor
(35 minutes later)
TOKYO — The operator of the tsunami-ravaged Fukushima Daiichi nuclear power plant stood ready Thursday to inject boric acid into one of its most heavily damaged reactors after it found steam emanating from the reactor building. The preventive measure would stave off criticality, or an uncontrolled nuclear chain reaction, in the reactor’s damaged core. TOKYO — The operator of the Fukushima Daiichi nuclear power plant stood ready Thursday to inject boric acid into one of its most heavily damaged reactors after it found steam emanating from the reactor building. The preventive measure would stave off criticality, or an uncontrolled nuclear chain reaction, in the reactor’s damaged core.
The incident has brought the Fukushima site’s vulnerable state into sharp relief, more than two years after its reactors suffered multiple meltdowns when its cooling systems were overwhelmed by a powerful tsunami. A recent jump in levels of radioactive cesium and tritium in the groundwater at the coastal plant, along with suggestions that the groundwater is leaking into the Pacific, has also raised alarms over the continued environmental threat posed by the plant. The incident has brought the Fukushima plant’s vulnerable state into sharp relief, more than two years after its reactors suffered multiple meltdowns when its cooling systems were overwhelmed by a powerful earthquake and tsunami. A recent jump in levels of radioactive cesium and tritium in the groundwater at the coastal plant, along with suggestions that the groundwater is leaking into the Pacific, has also raised alarms over the continued environmental threat posed by the plant.
Remote camera footage Thursday showed steam escaping from the top of the No. 3 reactor’s primary containment, which houses its fuel vessel, according to the Tokyo Electric Power Company, or Tepco. A worker who checked the footage Thursday morning noticed the steam, said Hiroki Kawamata, a spokesman for the operator.Remote camera footage Thursday showed steam escaping from the top of the No. 3 reactor’s primary containment, which houses its fuel vessel, according to the Tokyo Electric Power Company, or Tepco. A worker who checked the footage Thursday morning noticed the steam, said Hiroki Kawamata, a spokesman for the operator.
Mr. Kawamata said officials were unsure what was generating the steam, and hypothesized that rainwater seeping into the containment may have turned to vapor. Extremely high levels of radiation in the now roofless upper sections of the No. 3 reactor building – destroyed in a hydrogen explosion that rocked the reactor during the early days of the 2011 disaster – make it too dangerous for workers to approach. Mr. Kawamata said officials were unsure what was generating the steam, and hypothesized that rainwater seeping into the containment may have turned to vapor. Extremely high levels of radiation in the now roofless upper sections of the No. 3 reactor building destroyed in a hydrogen explosion that rocked the reactor during the early days of the 2011 disaster make it too dangerous for workers to approach.
But workers are standing by to inject boric acid into the reactor from the outside at any signs of further trouble, such as a rapid rise in temperature or radiation parameters, he said. But workers are standing by to inject boric acid into the reactor from the outside at any signs of further trouble, such as a rapid rise in temperature or radiation parameters, Mr. Kawamata said.
Such spikes would raise the chilling possibility of fission in the reactor’s damaged fuel, most which is thought to have melted and slumped to the bottom of its containment after the hydrogen explosion, one of several at the site in 2011. Boric acid would slow that rate of fission, preventing criticality.Such spikes would raise the chilling possibility of fission in the reactor’s damaged fuel, most which is thought to have melted and slumped to the bottom of its containment after the hydrogen explosion, one of several at the site in 2011. Boric acid would slow that rate of fission, preventing criticality.
Temperature and radiation levels at the reactor appear stable so far, Mr. Kawamata stressed.Temperature and radiation levels at the reactor appear stable so far, Mr. Kawamata stressed.
Any fresh trouble at the No. 3 reactor is especially worrying because it contains highly lethal mixed uranium-plutonium oxide fuel. The upper floors of the reactor also house its fuel pool, which stores over 500 fuel rods. The reactor complex’s basement, meanwhile, is flooded with highly radioactive water. Any fresh trouble at the No. 3 reactor is especially worrying because it contains highly lethal mixed uranium-plutonium oxide fuel. The upper floors of the reactor also house its fuel pool, which stores over 500 fuel rods. The reactor complex’s basement is flooded with highly radioactive water.
The No. 3 reactor’s damaged core, like the cores of two other crippled reactors at the site, is being cooled by water that is pumped into the reactor, filtered and recycled. But in April, the cooling system at No. 3 shut down for hours. Tepco later said a rat had somehow short-circuited a vital switchboard, possibly by gnawing on cables.The No. 3 reactor’s damaged core, like the cores of two other crippled reactors at the site, is being cooled by water that is pumped into the reactor, filtered and recycled. But in April, the cooling system at No. 3 shut down for hours. Tepco later said a rat had somehow short-circuited a vital switchboard, possibly by gnawing on cables.
More than 100,000 people fled their homes in the wake of the meltdowns at Fukushima, the world’s worst nuclear crisis since the Chernobyl disaster in 1986. While many areas are beginning to be repopulated, the residents’ return has been overshadowed by the continued mishaps at the plant. More than 100,000 people fled their homes after the meltdowns at Fukushima, the world’s worst nuclear crisis since the Chernobyl disaster in 1986. While many areas are beginning to be repopulated, the residents’ return has been overshadowed by the continued mishaps at the plant.