Recreational Nuclear Physics

Wall Street Journal: Radiation Spkes in Sea Near Japan Plant
TOKYO—The regulator overseeing Japan's Fukushima Daiichi nuclear complex on Saturday announced a sharp elevation in radioactive contamination had been detected in nearby seawater, furthering signs of distress at a plant where officials had cautioned of radioactive leaks near hobbled reactors the day before.

A spokesman said the spike in radioactive iodine—to 1,250 times the legal limit—didn't pose an immediate threat to human health or the area environment, since the material quickly dissipates in the tides and would become diluted before reaching fish and seaweed.

"Because nobody is engaged in fishery in the evacuation area within a radius of 20 kilometers [from the plant], there will be no immediate impact on people in the area," added Hidehiko Nishiyama, spokesman for Japan's Nuclear and Industrial Safety Agency told reporters at a news conference Saturday morning.

But the news underscores the fact that, for all the progress claimed by officials over the past week, they have a long way to go in bringing Tokyo Electric Power Co.'s reactors under control and understanding exactly what is happening inside the compound.

Saturday's report came a day after efforts to repower key cooling systems at the plant bogged down amid reports of highly radioactive water in puddles at the plant's troubled reactor No. 3. Workers who came into contact with the water on Thursday had to be hospitalized.

Mr. Nishiyama on Friday linked the radioactive puddles in plant No. 3 to a possible breach in pipes or ventilators leading to, but not inside, the vessels that surround the core at plant No. 3. Plant officials said later Friday that puddles at Nos. 1 and 2 also contained high levels of radiation.

The precise source of the radiation in the seawater—by air or by water—could yield clues about whether there is new, unanticipated damage in the complex.

Mr. Nishiyama on Saturday said officials weren't sure what caused the latest surge. "Radioactive substances may have been transmitted through the air, or contaminated water could have drained from the plant somehow," he said. "I don't have further ideas."

He also said officials were crafting a plan to deal with the contaminated puddles. "I have heard that [the operator] has an idea about a place to store water and is preparing" for drainage, he said.

The results released Saturday were from samples collected Friday morning in seawater about 330 meters south of the plant. In addition to heightened levels of iodine-131, the seawater contained 117 times Japan's legal limit of cesium-134 and 80 times the threshold for cesium-137, the Nuclear and Industrial Safety Agency.

The iodine-131 reading compared with an earlier report that showed the radioactive isotope at 126 times the legal limit. A person drinking half a liter of water with the latest level of contamination would be consuming 1 millisievert, the equivalent of a full year's acceptable consumption.

Samples gathered Friday north of the reactors 5 and 6—which have been the least worrisome since Japan's March 11 earthquake and tsunami knocked out cooling systems at the complex—were also high, but roughly one-quarter of the levels to the south. NISA is scheduled to disclose the result of Saturday morning's tests on Sunday.

The plant's regulator said Saturday it had begun to drain puddles with high levels of radioactivity at the turbine building connected to the No. 1 reactor.

The agency and Tokyo Electric Power, or Tepco, are mulling ways to drain puddles in Nos. 2 and 3, Mr. Nishiyama said.

Workers started spraying fresh water on a reactor pressure vessel at No. 2 reactor Saturday, switching from a last-resort measure in which seawater had been used to cool reactors. The continued use of seawater had led experts to worry about the accumulation of crystallized salt in cooling pumps. Workers began using freshwater to cool Nos. 1 and 3 on Friday.

Among the plant's most immediate concerns is reactor No. 3, where the basement of the turbine building has partially flooded with water that officials said contained radiation levels 10,000 times as high as normal, according to official briefings.

"The situation at the Fukushima Daiichi nuclear power plant is still very grave," said Prime Minister Naoto Kan at a news conference. "We are still not at a stage where we can be optimistic."

Early Friday, Mr. Nishiyama said the radiation levels in the water at reactor No. 3 appeared to suggest there had been a breach to the reactor.

Later that day, he amended that view to say there was no indication that the structures around the fuel rods—the pressure vessel and the containment vessel that surrounds it—had been damaged. Rather, he said, damage to ventilators or pipes leading to those structures was believed to be responsible for the leak.

While a breach involving reactor No. 3 would already appear to represent the most significant radiation leak thus far at the plant, it would be less severe than any damage closer to the fuel rods.

Even so, Friday's report from the No. 3 complex foiled the completion a top-priority job, as officials sought to pinpoint where workers are being exposed to hazardous levels of radiation.

Workers at the six-reactor complex had hoped to connect the control room of the No. 2 unit to outside power and start cooling systems at the Nos. 1, 3 and 4 reactors by the end of Friday. Returning the plant's cooling pumps to stable functioning by Friday had been a priority for the government and Tepco.

"Radiation levels in some parts of the facilities are just stunning," said one official at Japan's nuclear regulator. "The work to fix the cooling system was made all the more difficult by the lack of information about where radiation is high inside the complex."

Officials said Friday they didn't know now when the cooling systems would come online. "We cannot say with certainty at this point in how many days all the reactors will be brought to a state of cold shutdown," or the cooling of a nuclear reactor to safe levels, said Mr. Nishiyama said Friday.

The setbacks came after a week in which workers at the plant appeared to make slow progress toward stabilizing the plant. High radiation levels, as well as difficulties in assessing and fixing damaged cooling equipment, have slowed efforts.

A week ago, much of the plant was still without power, control rooms were dark and temperatures were out of control in the pools holding spent nuclear fuel. Now, all the units are hooked up to the electric grid, all but one have lights on, and the temperatures in the pools have fallen. Mr. Nishiyama said he wanted to have the lights turned on at the last remaining dark control room Saturday.

"The amount of heat being generated by the core is declining.... Now physics is on their side. Last weekend it was against them," said Murray Jennex, an associate professor at San Diego State University, who worked in the commercial nuclear industry for 17 years. "The longer they go without anything major happening, the better."

Japanese Defense Minister Toshimi Kitazawa said Friday the U.S. has offered to provide fresh water for the cooling operations. A U.S. military spokesman in Japan said that as an initial step, the U.S. military plans to ship 525,000 gallons of fresh water on two Navy barges from a base in Yokosuka, south of Tokyo.

Japan's government also said Friday it would begin helping evacuate people who live just beyond the "no-go" zone that surrounds the plant. The government has said it isn't considering officially broadening its 12-mile evacuation zone around the nuclear complex.

But a state monitoring body this week released estimates that suggested radiation in some areas just outside the zone had reached levels deemed harmful to infants in the long term. People in the zone from 12 to 18 miles (20 to 30 kilometers) of the plant are also suffering shortages of everyday goods.

The U.S. government has recommended a 50-mile (80-kilometer) exclusion zone.

More than a quarter million people have been evacuated overall in Japan following recent twin natural disasters. On Friday, Japan's National Police Agency said 10,102 people had been confirmed dead and 17,053 were missing.