TOKYO—Highly contaminated water is escaping a damaged reactor at the crippled Fukushima Dai-ichi Nuclear Power Station in Japan and may soon leak into the ocean, the country’s nuclear regulator warned on Monday.
The discovery raises the danger of further radiation leaks at the stricken power plant and also poses a further setback to efforts to contain the nuclear contamination crisis as emergency workers find themselves in increasingly hazardous conditions.
Engineers have been battling to control the six-reactor Fukushima complex since it was damaged by a March 11 earthquake and tsunami that also left more than 27,000 people dead or missing across northeast Japan.
Radiation measuring 1,000 millisieverts per hour was detected in water in an overflow tunnel outside the nuclear plant’s Reactor No. 2, Japan’s nuclear regulator said at a news conference.
That is the same as the radiation level discovered on Sunday. The US Environmental Protection Agency says a single dose of 1,000 millisieverts is enough to cause hemorrhaging.
The tunnel leads from Reactor No. 2’s turbine building, where contaminated water was discovered on Saturday, to an opening just 60 meters from the sea, said Hidehiko Nishiyama, deputy director general for the Nuclear and Industrial Safety Agency.
The contaminated water level is now about a meter from the exit of the vertical, U-shaped tunnel and rising, Nishiyama said.
Unsure about overflow
Contaminated water also was found at tunnels leading from Reactor No. 1 and Reactor No. 3, though at much lower levels of radiation.
“We are unsure whether there is already an overflow” of the contaminated water out of the tunnel, Nishiyama said.
He said workers were redoubling efforts to first remove the water from the turbine building.
Government officials have said that the water is likely leaking either from broken pipes inside the reactor, or from a breach in the reactor’s pressure vessel, which houses the nuclear fuel.
Monday’s disclosure about the escaping contaminated water came as workers pressed their efforts to remove highly radioactive water from inside buildings at the Fukushima plant.
Alarmingly high
Attempts to contain the contamination at the plant suffered a setback on Sunday when alarmingly high radiation levels were discovered in a flooded area inside the complex.
The operator of the plant, Tokyo Electric Power Co. (TEPCO), said the elevated radiation levels in the water, which had flooded the turbine buildings adjacent to the reactors, were at least four times the permissible exposure levels for workers at the plant and 100,000 times greater than water ordinarily found at a nuclear facility.
TEPCO earlier announced on Sunday that the radiation was 10 million times the normal level. The operator later apologized over the erroneous radiation reading.
Alarm over the radiation levels grew on Thursday when two workers were burned after they stepped into highly radioactive water inside Reactor No. 3.
Over the weekend, a worker trying to measure radiation levels of the water at Reactor No. 2 saw the reading on his dosimeter jump beyond 1,000 millisieverts per hour, the highest reading on the device. The worker left the scene immediately without taking a second reading, according to a TEPCO spokesperson.
The average amount of radiation workers at the Fukushima plant are exposed to in a year is at most 50 millisieverts. In emergency situations, the limit is usually raised to 100 millisieverts but it has been raised to 250 millisieverts during the crisis.
No evacuation
There was no evacuation of the roughly 1,000 workers stationed at the Fukushima plant after the high radiation levels were discovered. Since the crisis began on March 11, 19 workers had been exposed to radiation levels of 100 millisieverts.
Despite the new problem, workers on Monday were still trying to determine a way to approach the turbine building of Reactor No. 2 to extract the contaminated water.
The nuclear safety agency reported that radioactive iodine 131 was detected on Sunday at a concentration 1,150 times the maximum allowable level in a seawater sample taken about 1.6 km north of the drainage outlets of Reactor Nos. 1, 2 3 and 4.
Nishiyama said there were no health concerns because fishing would not be conducted in the evacuation-designated area within about 20 km of the plant.
The Fukushima plant has been leaking radiation since a 9.0-magnitude quake and monster tsunami struck northeastern Japan’s coastline on March 11. The tsunami knocked out power to the plant’s system that cools the nuclear fuel rods.
Uncertain operation
TEPCO has conceded it faces a protracted and uncertain operation to contain the overheating fuel rods and avert a meltdown.
“Regrettably, we don’t have a concrete schedule at the moment to enable us to say in how many months or years (the crisis will be over),” TEPCO vice president Sakae Muto said in the latest of round-the-clock briefing the company holds.
Chief Cabinet Secretary Yukio Edano, the government spokesperson, said on Monday it was too early for people to return to homes within a 20-km radius of the Fukushima plant.
“We cannot guarantee safety at the moment as the situation is still under evaluation,” he said.
The nuclear crisis has compounded Japan’s agony after the earthquake and tsunami devastated its northeast coast, turning whole towns into apocalyptic-looking landscapes of mud and debris.
6.5-magnitude tremor
Residents there have been repeatedly rattled by aftershocks from the strongest earthquake in Japanese history, including Monday’s 6.5-magnitude tremor that triggered a tsunami warning.
“I lived through World War II, when there was nothing to eat and no clothes to wear. I’ll live through this,” Mitsuharu Watanobe said, sitting cross-legged on a blanket in an evacuation center in Fukushima.
“But the scary thing is the radiation. There is a gap between what the newspapers write and what the government is saying. I want the government to tell the truth more,” he added.
The latest death toll was placed 10,804 people, with 16,244 people missing 17 days after the disaster.
About a quarter of a million people are living in shelters, and the damage could top $300 billion, making it the world’s costliest natural disaster. Reports from New York Times News Service and Reuters