Earth Watch Report - Nuclear Event
Fukushima's damaged reactor building at the Japanese nuclear plant. Photograph: Yoshikazu Tsuno/AP
| 19.07.2013 | Nuclear Event | Japan | Prefecture of Fukushima, [Fukushima Daiichi Nuclear Power Plant] |  |  |
Nuclear Event in Japan on Thursday, 18 July, 2013 at 07:58 (07:58 AM) UTC.
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Steam has been spotted in a reactor building at the crippled
Fukushima nuclear plant in Japan, its operator said Thursday, but
stressed there is no sign yet of increased radiation. The incident,
which Tokyo Electric Power (TEPCO) said was not "an emergency
situation", is the latest event serving to underline how precarious the
plant remains more than two years after it was wrecked by a tsunami.
"Steam has been seen around the fifth floor of the Reactor 3 building," a
spokesman at TEPCO said. The roof of the building was blown off in a
hydrogen explosion in the days after the March 2011 meltdowns, sparked
when cooling systems were flooded with seawater after a huge undersea
quake. "(The steam) was drifting thinly in the air and it's not like a
big column of steam is spurting up," the spokesman said. "Neither the
temperature of the reactor nor readings at radiation monitoring posts
have gone up. "We do not believe an emergency situation is breaking out
although we are still investigating what caused this." The pool is on
the fifth floor and stores devices and equipment removed from the
reactor before the disaster as part of regular operations. TEPCO said it had confirmed the reactor remained subcritical at 9.20am (0020 GMT), one hour after the steam was first spotted. Criticality is the term used for reactors in which there is a self-sustaining nuclear chain reaction. Workers were continuing to pump water into the reactor and fuel pool as part of on-going cooling efforts, the company said, adding it would measure dust near the building as well as the air above it to gauge radiation levels. A 9.0 earthquake and the resulting massive tsunami in March 2011 knocked out cooling systems at Fukushima Daiichi, causing the meltdowns of reactors. Tens of thousands of people were forced from their homes by the threat of radiation in the planet's worst nuclear accident for a generation. TEPCO is struggling to manage the clean-up, which scientists say could take up to four decades to complete. The steam is the latest in a growing catalogue of mishaps that have cast doubt on the utility's ability to fix the world's worst atomic disaster in a generation. A series of leaks of water contaminated with radiation have shaken confidence, as did a blackout caused by a rat that left cooling pools without power for more than a day. The company has admitted in recent weeks that water and soil samples taken at the plant are showing high readings for potentially dangerous isotopes, including caesium-137, tritium and strontium-90. Japan's nuclear watchdog said last week the Fukushima reactors are very likely leaking highly radioactive substances into the Pacific Ocean. Members of the Nuclear Regulation Authority voiced frustration at TEPCO, which has failed to identify the source and the cause of spiking readings in groundwater. NRA officials are urging TEPCO to offer more detailed and credible data and make efforts to better explain to the public what it knows. Most of Japan's nuclear reactors remain off-line, largely due to public distrust of the industry. Prime Minister Shinzo Abe's Liberal Democratic Party, as well as utilities, are hoping to restart them. |
Steam seen in Fukushima reactor 3 building
Unit still subcritical, Tepco assures; vapor on fifth floor near MOX in fuel pool
AFP-JIJI, Kyodo
Steam has been spotted in the reactor 3 building at the Fukushima No. 1 power plant, but there was no sign yet of increased radiation, Tepco said Thursday, speculating the vapor was just evaporated rainwater hitting a hot metal surface.
The incident, which Tokyo Electric Power Co. said was not “an emergency situation,” is the latest event underlining how precarious the plant remains more than two years after it was wrecked by tsunami and subsequently suffered three meltdowns. One of them, reactor 3, is the only one at the plant to use the highly lethal mixed uranium-plutonium oxide (MOX) fuel, some of which is in its spent-fuel pool near the top of the reactor.
“Steam has been seen around the fifth floor of the reactor 3 building,” a Tepco spokesman said. The spent-fuel pool is on that floor.
The roof of the building was blown away in a hydrogen explosion at the beginning of the crisis in March 2011, sparked when cooling systems were flooded by tsunami after the huge March 11 undersea quake.
“(The steam) was drifting thinly in the air and it’s not like a big column of steam is spurting up,” the spokesman said. “Neither the temperature of the reactor nor readings at radiation monitoring posts have gone up.
“We do not believe an emergency situation is breaking out, although we are still investigating what caused this,” he said.
The temperature readings on reactor 3 pretty much stayed the same as before the steam was found, as have the radiation figures around it.
As of 6 p.m. Thursday, the steam was still coming out, Tepco said.
What is creating the steam is unclear, but Tepco said the best explanation is that rainwater, which had fallen from Wednesday night, dropped onto the containment vessel’s lid and evaporated.
The steam appears to be emanating from a seal over the top of the reactor.
The lid of the containment vessel is just below that seal and the rainwater is dropping onto the lid from some inner space, Tepco speculated.
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Fukushima rainfall caused steam above reactor, says Tepco
Firm says radiation levels are stable after video images showed steam rising from damaged building housing reactor No 3
Fukushima's damaged reactor building at the Japanese nuclear plant. Photograph: Yoshikazu Tsuno/AP
The operator of the crippled Fukushima Daiichi nuclear power plant said on Thursday that radiation levels were stable after vapour was detected coming from one of the three reactors that went into meltdown after the triple disaster in Japan in March 2011.
Video images showed the vapour, which is thought to be steam, rising from the damaged building housing reactor No 3.
Tokyo Electric Power (Tepco), reeling from recent criticism of its handling of contaminated water at the plant, said the reactor's spent fuel pool was stable, adding that there had been no significant rises in radiation levels in the vicinity.
A worker monitoring live camera images noticed that what appeared to be steam was hovering just above the primary containment vessel at 8.20am on Thursday. The vapour was still visible two hours later, reports said.
Tepco said rainfall on Wednesday night could have been the cause.
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