Attempts to plug a crack in reactor unit 2 at Japan's stricken nuclear plant were unsuccessful Saturday, and have left officials seeking new alternatives to stop the leakage of radioactive water into the Pacific Ocean, the company that runs the plant said.
A representative for the Tokyo Electric Power Co. (TEPCO) said attempts to plug the crack with fresh concrete did not reduce the amount of water leaking from the reactor.
The representative said a second attempt to plug the crack using a polymer will begin after a TEPCO representative analyzes the site on Sunday and decides which type of polymer to use.
Radioactive water has been spilling into the Pacific Ocean from a crack in a maintenance pit discovered Saturday at the distressed nuclear complex.
Once a type of polymer is decided upon, it will be injected into a pipe connected to the pit. TEPCO is also devising a third plan in case the polymer injection does not plug the crack.
The crack was discovered on the edge of the plant, according to Nuclear and Industrial Safety Agency spokesman Hidehiko Nishiyama. It was most likely caused by the March 11 earthquake and tsunami that ravaged the coast of Japan and the Fukushima Dai-ichi nuclear complex, according to The Associated Press.
"This could be one of the sources of seawater contamination," Nishiyama said. "There could be other similar cracks in the area, and we must find them as quickly as possible."
The air above the radioactive water in the pit is measuring 1,000 millisieverts of radiation per hour, according to Nishiyama. Risk of cancer is greatly increased by exposure to 500 millisieverts over a short period of time.
According to TEPCO, the water is coming from a pit holding power cables near the water intake inside the reactor. TEPCO is trying to pour concrete to seal the 8-inch-long crack.
Even large amounts of radiation have little effect on a body of water as vast as the Pacific Ocean, and experts have said the radiation from the Fukushima Dai-ichi complex will be quickly diluted.
Radiation has spread into water 25 miles south of the plant, according to measurements released Saturday. Over a week ago, iodine-131 at concentrations higher than the legal limit was detected in waters close to the facility.
Plant workers racing to stabilize the facility are the most likely to have been exposed to radiation. Residents within 12 miles of the plant have been evacuated.
Meanwhile, international nuclear experts believe that melted fuel in reactor No. 1 has caused a "localized criticality," which is a small, uncontrolled chain reaction that occasionally emits a burst of heat, radiation and a blue flash of light.
It is not a threat to the area at large, officials say, but could be deadly for workers.
One worker from inside the plant spoke anonymously about safety concerns, such as not having enough radiation-detection devices available for workers. The devices alert workers of too much exposure.
"Since the number of monitors is limited, only one or two devices are handed to each group," the worker said. "But sometimes you have to move away from that person and in that case you'll never know the level of your exposure."
He said workers are worried about their health.