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Radiation Seen Spreading to Japan Plant Groundwater
Radioactive contaminants have probably seeped into groundwater at Japan's Fukushima Daiichi nuclear power plant, though erroneous measurements by the plant's operator might have overstated the extent of the leakage, the Japanese Nuclear and Industrial Safety Agency said on Friday (see GSN, March 31).
Tokyo Electric Power said levels of radioactive iodine in the water were 10,000 times greater than the level allowed by law, but added it was reassessing a radiation analysis made public yesterday after it was found to be problematic, Kyodo News reported (Kyodo News I, April 1).
The company's conflicting announcements have raised safety concerns and undermined faith in the firm's capacity to contain damage from the six-reactor site, which was crippled by the 9.0-magnitude earthquake and devastating tsunami that hit Japan on March 11. The death toll from last month's events could reach 25,000 people, according to authorities (Associated Press I/Washington Post, April 1).
The company "faces a grave situation as it is failing to live up to the expectations of people who are very worried by the company. Its data should be trustworthy," Kyodo News quoted Japanese atomic safety agency spokesman Hidehiko Nishiyama as saying (Kyodo News I). The plant operator earlier this week revised radiation measurements for water collecting in the No. 2 reactor's turbine area.
“We have suspected their isotope analysis, and we will wait for the new results,” AP quoted Nishiyama as saying.
Tokyo Electric Power contended its erroneous computer calculations applied only to two contaminants, and not to radioactive iodine (Associated Press I). Still, the company indicated it would re-evaluate its readings for the isotope, the Wall Street Journal reported (Juro Osawa, Wall Street Journal I, April 1).
Contaminated groundwater might reach public water supplies by spreading to wells or tributary rivers, though specialists have played down the probability of such a development, AP reported. Operations have been suspended at two water treatment sites within the evacuation area extending 12 miles from the plant.
“When people return to the area we will test the water to make sure it is safe,” said Masato Ishikawa, an official with Fukushima prefecture’s government.
A shortage of radiation sensors prevented the utility from supplying detection gear to all plant personnel, but authorities on Friday said a new shipment had been completed and all workers would have the equipment (Associated Press I). The responders' effort to prevent reactors and spent fuel at the plant from overheating has been hampered by the spread of radiation-tainted water through portions of the facility. Uncooled nuclear material could melt down, potentially resulting in much larger radioactive material releases than have been seen so far from the plant.
Workers on Monday began a process to make condensers at the plant available to hold contaminated water, and personnel were also seeking out containers from other facilities for storing the fluid, the Asahi Shimbun reported (Asahi Shimbun I, April 1).
The No. 1 reactor's condenser was filled to capacity on Monday with water from the site's underground turbine area, the International Atomic Energy Agency said, referring to updates by the Japanese government. Preparation of the No. 3 reactor's condenser to store contaminated water commenced on Monday, and workers began readying the No. 2 reactor's condenser the following day (International Atomic Energy Agency release, March 31).
Tokyo was mulling potentially tapping tanker vessels or establishing fully closed-off pools for holding contaminated water, the Asahi Shimbun reported (Asahi Shimbun I).
Authorities and the plant operator were weighing the possibility of transferring nitrogen into reactor containment vessels in a bid to prevent new hydrogen explosions, Kyodo News reported. Several such detonations have already damaged containment structures at the facility, according to previous reports (Kyodo News II, April 1).
Personnel on Thursday were readying a trial deployment of adhesive material intended to bind radioactive detritus to surfaces, potentially preventing its spread for 6-12 months.
The two-week trial would focus on a flooded underground area at the site's No. 4 reactor and on a location north of reactors No. 5 and No. 6. A spray truck is expected to disperse nearly 16,000 gallons of the material, which is employed at garbage dumps and in industrial applications (Asahi Shimbun II, April 1).
Japan should anticipate a costly process of distinguishing which areas around the plant are capable of again accommodating human life, the New York Times quoted a U.S. radiation-removal specialist as saying.
Radiation-tainted soil could be gathered and moved to an isolated location, added Lawrence Boing, special projects head at the Argonne National Laboratory in Illinois. Conventional cleaning methods could remove all but the most deeply embedded radioactive particles from walls and pavement, according to the Times (Henry Fountain, New York Times, March 31).
The Japanese government on Friday said follow-up tests had turned up no radioactive material in beef from Fukushima prefecture, Kyodo News reported. Tokyo on Thursday announced the discovery of a radioactive cesium concentration exceeding legal limits in beef from the jurisdiction (Kyodo News III, April 1).
Meanwhile, authorities on Friday detained a man said to have intruded on the grounds of the Fukushima Daiini nuclear power plant, which neighbors the severely damaged Daiichi facility, Kyodo News reported. It was unclear why the 25-year-old had allegedly broken open the facility's western gate and driven his car through the area for around 10 minutes (Kyodo News IV, April 1).
Elsewhere, Spain detected a marginal elevation in concentrations of airborne iodine and cesium, United Press International reported. The increase was too small to affect human health, ThinkSpain quoted the Spanish Nuclear Safety Council as saying (United Press International, April 1).
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