TOKYO - Workers discovered new pools of radioactive water leaking from Japan's crippled nuclear complex, officials said Monday, as emergency crews struggled to pump out hundreds of tons of contaminated water and bring the plant back under control.
Officials believe the contaminated water has sent radioactivity levels soaring at the coastal complex and caused more radiation to seep into soil and seawater. Crews also found traces of plutonium in the soil outside of the complex on Monday, but officials insisted there was no threat to public health.
Plutonium a key ingredient in nuclear weapons is present in the fuel at the complex, which has been leaking radiation for over two weeks, so experts had expected some to be found once crews began searching for evidence of it this week.
Tokyo Electric Power Co. official Jun Tsuruoka said only two of the plutonium samples taken Monday were from the leaking reactors. The other three were from earlier nuclear tests. Years of weapons testing in the atmosphere left trace amounts of plutonium in many places around the world.
The Fukushima Dai-ichi power plant, 140 miles northeast of Tokyo, was crippled March 11 when a tsunami spawned by a powerful earthquake slammed into Japan's northeastern coast. The huge wave engulfed much of the complex, and destroyed the crucial power systems needed to cool the complex's nuclear fuel rods.
Since then, three of the complex's six units are believed to have partially melted down, and emergency crews have struggled with everything from malfunctioning pumps to dangerous spikes in radiation that have forced temporary evacuations.
Workers on Monday resumed the laborious yet urgent task of pumping out the hundreds of tons of radioactive water inside several buildings at the six-unit plant.
Workers must remove the radioactive water from the floor before new electric cables can be installed to restart the reactor's cooling system, CBS News correspondent Lucy Craft reports. The process is stalled because containment tanks for the water inside the reactor are full.
James Acton, a nuclear expert for the Carnegie Endowment for International Peace, told CBS' "The Early Show" Monday that since the plant has been hit by a series of catastrophes, "We're way beyond the playbook on any of this. Unfortunately, the plant operator is being forced to improvise in order to clean up this mess."
Acton said the Fukushima nuclear crisis can be compared to the BP oil spill. "This crisis does have the potential to go on certainly for weeks, and possibly for months," he said.
"At the moment radiation levels outside the plant are much higher than they should be, but there haven't yet been big, catastrophic releases of radiation," Acton said. "I think this crisis certainly has the possibility just to continue as it is at the moment - you have good days and you have bad days, but taking a long time in order to get this plant under control."
Confusion at the plant has intensified fears that the nuclear crisis will last weeks, months or years amid alarms over radiation making its way into produce, raw milk and even tap water as far away as Tokyo.
The troubles at the Fukushima complex have eclipsed Pennsylvania's 1979 crisis at Three Mile Island, when a partial meltdown raised fears of widespread radiation release, but is still well short of the 1986 Chernobyl disaster, which killed at least 31 people with radiation sickness, raised long-term cancer rates, and spewed radiation across much of the northern hemisphere.
While parts of the Japanese plant has been reconnected to the power grid, the contaminated water which has now been found in numerous places around the complex, including the basements of several buildings must be pumped out before electricity can be restored to the cooling system.
That has left officials struggling with two sometimes-contradictory efforts: pumping in water to keep the fuel rods cool and pumping out and then safely storing contaminated water.
Hidehiko Nishiyama, a spokesman for Japan's Nuclear and Industrial Safety Agency, called that balance "very delicate work."
He also said workers were still looking for safe ways to store the radioactive water.
"We are exploring all means," he said.
The buildup of radioactive water first became a problem last week, when it splashed over the boots of two workers, burning them and prompting a temporary suspension of work.
Craft reports that those men and a third worker hospitalized last week were all released Monday.
But on Monday, officials with Tokyo Electric Power Co., which owns and runs the complex, said that workers had found more radioactive water in deep trenches used for pipes and electrical wiring outside three units.
The contaminated water has been emitting radiation exposures more than four times the amount that the government considers safe for workers.
The five workers in the area at the time were not hurt, said TEPCO spokesman Takashi Kurita.
Exactly where the water is coming from remains unclear, though many suspect it is cooling water that has leaked from one of the disabled reactors.
It could take weeks to pump out the radioactive water, said Gary Was, a nuclear engineering professor at the University of Michigan.
"Battling the contamination so workers can work there is going to be an ongoing problem," he said.
Meanwhile, new readings showed ocean contamination had spread about a mile farther north of the nuclear site than before but is still within the 12-mile radius of the evacuation zone. Radioactive iodine-131 was discovered offshore at a level 1,150 times higher than normal, Nishiyama, a spokesman for the Nuclear and Industrial Safety Agency, told reporters.
Amid reports that people had been sneaking back into the mandatory evacuation zone around the nuclear complex, the chief government spokesman again urged residents to stay out. Cabinet secretary and spokesman Yukio Edano said contaminants posed a "big" health risk in that area. He was responding to reports that people had been sneaking back in.
Gregory Jaczko, head of the U.S. Nuclear Regulatory Commission, arrived in Tokyo on Monday to meet with Japanese officials and discuss the situation, the U.S. Embassy said in a statement.
"The unprecedented challenge before us remains serious, and our best experts remain fully engaged to help Japan," Jaczko was quoted as saying.
Early Monday, a strong earthquake shook the northeastern coast and prompted a brief tsunami alert. The quake was measured at magnitude 6.5, the Japan Meteorological Agency said. No damage or injuries were reported.
Scores of earthquakes have rattled the country over the past two weeks, adding to the sense of unease across Japan, where the final death toll is expected to top 18,000 people, with hundreds of thousands still homeless.
Meanwhile, a strong earthquake shook the region and prompted a brief tsunami alert early Monday. The quake off the battered coast of Miyagi prefecture in the northeast was measured at magnitude 6.5, the Japan Meteorological Agency said. No damage or injuries were reported, and TEPCO said the quake would not affect work to stabilize the plant.
TEPCO officials said Sunday that radiation in leaking water in Unit 2 was 10 million times above normal an apparent spike that sent employees fleeing. The day ended with officials saying the huge figure had been miscalculated and was 100,000 times above normal, still very high but far better than the earlier results.
"This sort of mistake is not something that can be forgiven," Edano said sternly Monday.
TEPCO Vice President Sakae Muto promised better readings.
"We will work hard to raise our precision in our work so as not to repeat this again," he said at a news conference.
The crisis did not interrupt a yearly rite much loved by the Japanese: the start of the cherry blossom season.
Cherry trees typically begin blooming in the south in March, in the capital days later, and in the chilly north in April the signal that spring has arrived.
Pink and white buds appeared at the Yasukuni Shrine in Tokyo on Monday, the country's meteorological agency said.
And in the face of so much adversity, says CBS' Craft, the resilience of the Japanese people still thrives.
Tsunami survivors are taking the lead volunteering in the battered notheastern region.
Seventeen-year-old student Yutaka Takahashi lost five classmates in the tsunami. He told Craft, "I know many people whose homes have drifted away, they have lost everything. So I want to strongly support them."