Contaminated water heightens concerns over nuclear plant

By Peter Eisler, USA TODAY

Updated |


The discovery of pools of highly radioactive water at Japan's ruined Fukushima Dai-ichi nuclear power plant raised concerns Friday about the possible breach of reactor containment walls that are supposed to prevent the release of nuclear material in accidents.

  • A young evacuee is screened at a shelter Thursday for leaked radiation from the damaged Fukushima nuclear plant.

    By Wally Santana, AP


By Wally Santana, AP


That prospect caused new speculation about the potential for long-lasting environmental contamination in areas around the plant.

Engineers cautioned that there could be other sources for the tainted water, which was reported by the Japanese Nuclear and Industrial Safety Agency to have radiation levels up to 10,000 times what would be normal for water in or around a reactor.

Some of those possibilities would carry far less risk of extensive off-site contamination. But the mere presence of water with such high levels of contamination suggests serious challenges remain in containing radiation and minimizing public health risks from the damaged plant.

Conditions at the site remain "very grave and serious," Prime Minister Naoto Kan said. "We are not in a position where we can be optimistic. We must treat every development with the utmost care."

The contaminated water was discovered after two workers suffered radiation burns from wading through it as they pushed to finish restoring power at reactor Unit 3 in the plant, which has a total of six reactors. News organizations reported Friday that water with similar radiation levels was found in reactor Unit 1, and contaminated puddles were found in reactors 2 and 4. Tokyo Electric Power, which owns the plant, later reported that there was no evidence of coolant water in reactor 4.

Radiation has been leaking from the plant since its cooling systems were knocked out March 11 by a massive magnitude-9 earthquake that triggered a huge tsunami. Engineers have struggled since then to find ways to cool both the nuclear fuel rods inside three damaged reactors and the "spent" fuel rods submerged in four storage pools. Radioactive steam has vented repeatedly from the plant, and explosions and fires at the site have pumped more contamination into the air.

As the crisis at the plant became evident, the Japanese government ordered evacuations of residents within 12 miles and advised those up to 19 miles away to stay indoors. Officials continued to insist Friday that those steps were sufficient, but the government offered to move residents who had been sheltering indoors to other areas, in part because they had diminishing access to food and water. The U.S. government has warned its citizens to stay 50 miles away.

The Japanese government has halted the sale or distribution of milk and various types of produce from farms near the plant, and it has warned that radiation levels in tap water in some areas are too high for consumption by infants. Adults are not at significant risk, the government says.

If the discovery of the contaminated water at the plant ultimately reveals a reactor breach, it increases the risk that radioactive material could escape into the environment, both as airborne contamination and by seeping into surrounding soil and groundwater. The levels of radioactivity in those releases could be far higher than what has escaped into the atmosphere so far.

Engineers noted that there could be other sources for the water, including some that would be much less worrisome.

"It's very hard to know what is happening or where (the water) came from," said Alexander Sich, a nuclear engineer and associate physics professor at Franciscan University of Steubenville, Ohio. "There are so many possible sources and ... so many unknowns, to speculate treads into dangerous territory."

Possibilities include a spill or leak from a spent fuel pool or a cracked pipe in one of the reactors' cooling systems, said Sich, a former Energy Department official involved in nuclear safety programs. Or it's possible that water dumped onto the reactors as part of the cooling effort washed over contaminated debris from one of the explosions at the site.

Some of the answers will become clearer with further analysis of the radiation in the water, Sich said, noting that the presence of certain isotopes could help determine whether the contamination came from the reactor core or a spent fuel pool.

"We need to see the chemical analysis of the water," he said. "That's the fingerprint."

The amount of radiation released from the plant goes far beyond the very low levels measured offsite in the accident in 1979 at the Three Mile Island nuclear plant in Pennsylvania, according to an analysis released Friday by the Institute of Energy and Environmental Research. The analysis found that the contamination in Japan still falls far short of what was generated in Ukraine by the Chernobyl reactor meltdown in 1986, the world's worst nuclear accident.

The analysis focuses on two forms of contamination: radioactive iodine, which can cause thyroid cancer but dissipates in weeks or months, and cesium, which causes various cancers and can linger in the environment for hundreds of years.

The institute's report notes that new estimates by France's radiation protection agency suggest that releases of radioactive iodine at the Japan plant are roughly 150,000 times what was seen at Three Mile Island, but about a tenth of what was recorded at Chernobyl. For cesium, which was not emitted in measureable quantities at Three Mile Island, the French agency found that releases in Japan amount to about 10% of what was emitted at Chernobyl.

"This accident has long since passed the level of Three Mile Island," said Arjun Makhijani, president of the Institute for Energy and Environmental Research. "While the releases are still considerably below Chernobyl, they have already reached a level that could affect the region around the site for a prolonged period."


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