Technology Science - Japanese searchers move closer to nuclear plant
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A new glitch in the cooling of used fuel at Japan's crippled nuclear plant prompted a surge in radiation, but an overall decline in leaks allowed police Thursday to search for missing tsunami victims closer to the complex than ever before.
Police in protective gear scoured a 10-kilometre radius around the Fukushima Daiichi for the first time Thursday as part of their search for thousands of victims still missing after the March 11 earthquake and tsunami.
A steel fence is installed to cover a gate to prevent the spread of radioactive water at an intake canal at the Fukushima Daiichi nuclear power plant in this photo taken Tuesday. TEPCO/Reuters"We need to work very carefully so as not to rip our radiation suits with the debris, metal and chunks of concrete scattered everywhere in the zone," a police officer who gave only his surname, Sato, said in a telephone interview.
Although Japanese officials have insisted the situation at the crippled plant is improving, the crisis has dragged on, accompanied by a nearly nonstop series of mishaps and aftershocks of the 9.0 magnitude quake that have impeded work in clearing debris and restoring the plant's disabled cooling systems.
Japan acknowledged this week that overall leaked radioactivity already has catapulted the crisis into the highest severity on an international scale, on a par with Chornobyl, though still involving only a tenth of the radioactivity emitted in that 1986 disaster.
The police, in white suits, picked gingerly through rubble near the plant in a zone where up to 1,000 bodies are believed lodged in tsunami debris, Sato said. Overall, more than 26,000 people are believed to have died March 11, though only about 11,250 bodies have been recovered so far.
"Many families have asked us to search for their missing loved ones. I want to recover bodies as quickly as possible and hand them over to their families," he said.
This week's glitch at the plant involved declining water levels at the pool for spent fuel rods in the Unit 4 reactor building.
Water inadvertently sprayed into an overflow tank prompted a false reading that the main pool was full when it wasn't. That prompted workers to suspend the injection of water into the main pool for several days until Wednesday, when spraying resumed.
Strong aftershocks
Strong aftershocks might also have affected the readings, officials said.
The suspension of spraying allowed temperatures and radiation levels to rise, though the rods were still believed to have been covered with water, said Hidehiko Nishiyama of Japan's Nuclear and Industrial Safety Agency.
"I believe fuel rods in the pool are largely intact, or still keeping the normal shape of what they should look like," Nishiyama said. "If they were totally messed up, we would have been looking at different sets of numbers from the water sampling."
A new burst of radiation this week leaking in Unit 4's fuel pool suggests damage to the fuel rods and complicates efforts to stabilize them, officials said. TEPCO manager Junichi Matsumoto said analysis of the pool's water detected higher levels of radioactive iodine-131, cesium-134 and cesium-137. Normally, those elements would not be found in the pool.
Three of the plant's reactors also have about 20,000 metric tons of stagnant, radiation-contaminated water and it is proving difficult to reduce the amount spilling from the reactors, Nishiyama said.
Workers operate a modified Putzmeister 70Z, the world's largest concrete pump mounted on a truck, to pump contaminated water from the No.4 reactor at Fukushima Daiichi nuclear power plant . TEPCO/ReutersUntil cooling systems can be fully restored, flooding the reactors with water is the only way to help prevent them from overheating, but those many tons of water, tainted with radioactivity, pose a separate threat.
"It is the problem of being stuck with reactors that constantly need to be fed water," Nishiyama said. Setbacks in preparing tanks to store the contaminated water mean new options may need to be considered, he said. He did not elaborate.
The beleaguered plant operator, Tokyo Electric Power Co., or TEPCO, is seeking ways to eventually remove spent fuel rods from reactor storage pools as the plant is closed down for good. The glitch at Unit 4 makes those plans more urgent.
Eventually the rods must be stored permanently in dry, radiation-proof casks, but that process is far off, he said.
TEPCO, meanwhile, is working to stabilize conditions at the plant's No. 1 reactor by pumping nitrogen into its containment vessel to reduce risks of a hydrogen explosion. It also is installing steel plates and silt screens along the coast to help reduce radiation leaks into the sea.
More evacuations
The halting progress at the plant has deepened the misery of residents who were forced to leave their homes and jobs near Fukushima Daiichi.
A 102-year-old man committed suicide Tuesday, a day after the government included Iitate, the village where he had lived all his life, as an area to be evacuated to avoid radiation exposure. A local police official, who declined to be named because he was not authorized to speak to media, confirmed the man had killed himself but would give no further details.
Nearly 140,000 people are still living in shelters after losing their homes or being advised to evacuate them due to the nuclear crisis and March 11 disasters.
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