Japan has ordered increased inspections of marine life and sea water after detecting elevated levels of radiation in Pacific waters adjacent to a tsunami-damaged nuclear plant.
The Japanese government said Tuesday levels of radioactive iodine in sea water samples near the Fukushima nuclear plant were at least 80 times higher than normal. But, officials said the elevated radioactivity does not pose a threat to human health even if contaminated sea food is ingested for a year.
Experts have noted that the fishing industry has been devastated in areas affected by the March 11 earthquake and tsunami, reducing the risk of contaminated marine life entering the food supply.
The operator of the Fukushima plant says workers reconnected power lines to all six reactor units at the complex on Tuesday, a major step toward restoring cooling systems that prevent nuclear fuel rods from overheating and emitting radiation.
But, Tokyo Electric Power Company said repair crews must do more work to check the safety of electrical equipment before turning the power back on.
Steam and smoke continued to rise from two of the reactor buildings Tuesday, but officials said the emissions do not appear to be a serious hazard. An official with Japan's Nuclear and Industrial Safety Agency said he no longer sees any chance of a total meltdown of the reactor cores.
Fire crews resumed spraying water into one of the reactor buildings where the roof was blown off by an earlier explosion. Plant workers were preparing to use special equipment to spray water into another building where the roof is still intact.
Investors reacted positively to the improved prospects for averting a catastrophe, driving the benchmark Nikkei stock index up by more than 4 percent during the day.
Still, massive problems remain, with more than 22,000 people dead or missing and more than 300,000 living in poorly equipped shelters after the earthquake and tsunami. The World Bank has estimated the cost of the twin disasters at up to $235 billion, more than twice as much as Japan's 1995 Kobe earthquake.
Problems at the plant began when the earthquake and tsunami knocked out the main and auxiliary systems for pumping water into the reactors and adjacent cooling ponds where used fuel rods are stored. If the rods become too hot, they can burn off their outer casings and release dangerous radiation into the air.
Fuel rods in the inner core of two or three of the reactors are believed to have partially melted, but their radiation is contained by heavy concrete chambers. There are fears that the earthquake and several subsequent explosions may have damaged two of the containment chambers as well as one or more of the cooling ponds.
Japanese authorities suspended shipments of raw milk and spinach from areas surrounding the plant Monday, after finding unacceptably high radiation levels in samples of the foodstuffs. Officials said contamination of those products also does not pose an immediate health risk.