Radioactive iodine 10,000 X limit


Posted 1 April 2011 [Fools day]

TEPCO data credibility suffers on serious groundwater contamination

TOKYO, April 1, Kyodo

The operator of a crippled nuclear power plant in Fukushima Prefecture suffered another blow to its credibility on Friday over errors found in its radioactive contamination data, including on groundwater at the plant, while workers began test-spraying a resin there to prevent radioactive particles from being dispersed.

Tokyo Electric Power Co. said the concentration of radioactive iodine in the groundwater was 10,000 times the legal limit as it announced earlier, but acknowledged a programming error on a measuring device that affected substances other than iodine.

Hidehiko Nishiyama, a spokesman for the Nuclear and Industrial Safety Agency, said it was ''extremely regrettable'' that TEPCO -- as the utility is known -- had given incorrect radiation data. The agency has strongly warned the operator over the matter and urged it to take steps not to do so again, he added.

''TEPCO 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,'' Nishiyama said.

Earlier in the week, the utility corrected its analysis of radiation levels in water accumulating in the basement of the No. 2 reactor's turbine building.

The agency said the density readings of radioactive substances in groundwater samples taken on Tuesday and Wednesday from around the No. 1 reactor's turbine building may be revised downward, as TEPCO's evaluation programs for materials such as tellurium, molybdenum and zirconium were found to have errors.

But it said the firm's analysis programs for radioactive iodine were confirmed to be correct.

In an effort to prevent radioactive particles from being dispersed from the plant by winds and rain, TEPCO on Friday started test-spraying a water-soluble resin that has coating effects at the plant.

As a result of hydrogen explosions, masses of debris have been strewn around the site, which was ravaged by the March 11 earthquake and tsunami. A total of 60,000 liters of resin will be sprayed over a period of two weeks.

To prevent the risk of more hydrogen explosions, government sources said that the government and TEPCO are considering injecting nitrogen into containment vessels of the plant's reactors.

Workers also continued operations to secure enough space at tanks to store radiation-contaminated water that has been soaking the basements of the reactors' buildings and filling up tunnel-like underground trenches connected to them.

The engineers started transferring fresh water carried by a U.S. Navy barge to tanks at the plant, which will be injected into the reactors to cool them down.

During the operation, a male worker fell into the sea as he tried to move to the barge's tugboat from the shore but was unhurt and not exposed to radiation, TEPCO said, adding that he will be examined for internal exposure to radiation just in case.

TEPCO has been pouring massive amounts of water into the reactors and spent nuclear fuel pools at the plant as a stopgap measure to cool them down, because serious damage to fuel rods from overheating could lead to the release of enormous amounts of radioactive materials into the environment.

However, the measure is believed to be linked to the possible leak of radiation-contaminated water from the reactors, where fuel rods have partially melted.

Removal of the water at the turbine buildings is believed to be essential to restoring the vital functions to stably cool down the reactors and the spent nuclear fuel pools.

Meanwhile, provisional data by TEPCO showed that the Nos. 2, 3 and 5 units at the six-reactor Daiichi nuclear complex experienced an earthquake intensity above the maximum projected level when the northeastern region was struck by the March 11 killer quake.