Tokyo (PTI):cJapan’s quake-devastated northeast faced a fresh tsunami alert today after a massive 7.4 magnitude temblor shook the region, as engineers pumped in nitrogen into a reactor at the Fukushima nuclear facility in their desperate bid to prevent another hydrogen blast.
The powerful earthquake jolted the Miyagi prefecture, 118km north of Fukushima. The quake that hit 40 kilometres under the water, prompted an immediate tsunami alert with authorities warning that it could trigger waves up to three feet high.
The quake was felt as far away as Tokyo and Japan’s national broadcaster NHK asked those in the quake-hit areas to evacuate to higher ground. Kyodo reported no immediate casualties or damage.
A magnitude 9.0 earthquake on March 11 devastated northeast Japan and damaged the atomic facility at Fukushima that is presently the centre of the country’s worst nuclear crisis since World War II.
Officials said the earthquake caused no further damage to the crippled plant.
The fresh quake struck Japan as authorities here mulled extending the evacuation zone around the radiation-leaking plant.
For the first time since the March 11 quake and tsunami, police in protective gear launched a search for around 2,500 people missing within the 10-20 km radius of the crippled plant, where such an operation had not been carried out before due to high levels of radiation.
A day after registering rare progress by plugging a 12-inch crack leaking highly radioactive water into the sea, the plant’s operator Tokyo Electric Power Company (TEPCO) said its workers injected chemically-stable nitrogen into the No.1 reactor, where a build-up of hydrogen gas had raised concerns about a possible radiation-leaking explosion.
Last month’s hydrogen blasts at the No.1 and No.3 reactors following the quake and tsunami destroyed reactor buildings, causing release of radioactive steam.
TEPCO said the operation to reduce the risk of a blast has gone smoothly, Kyodo reported.
The utility said it plans to pump nearly 6,000 cubic metres of nitrogen, an inert gas, over a 6-day period, nearly four weeks after the twin disaster left over 27,000 people dead or missing.
TEPCO also continued to dump low-level radioactive wastewater from the plant into Pacific Ocean to create storage for more highly contaminated water. Around 6,000 tonnes of water have been discharged so far.
As Japan battled to cool its overheating reactors, the number of foreign nationals, who left Japan in the week after the earthquake, was reported to be 240,000, up 100,000 from the previous 7 days.
Japan’s immigration bureau said the number of foreigners entering the country dropped to one third after the disaster compared to the number before. Some 160,000 foreigners entered Japan in the week before the quake, while the number fell to 60,000 in the first week after the disaster, and to 50,000 in the second week, national broadcaster NHK said.
With the atomic crisis at the crippled plant dragging on, Chief Cabinet Secretary Yukio Edano said authorities may look into widening the evacuation zone around it.
He said the current 20-km zone, which was based on the assumption of short-term exposure, may need to be extended.
“Current evacuation orders apply to areas where people are in danger of having received 50 millisieverts,” Edano said. “We are now looking into what to do with other areas where, with prolonged exposure, people may receive that amount.”
The government’s nuclear safety agency said most of the low-level toxic water will be released soon, amid concerns among neighbouring countries over sea contamination and strong protests from the domestic fishing industry.
After TEPCO successfully stopped leakage of highly radioactive water into the sea from a cracked pit, it detected a temporary rise in the level of tainted water in an underground trench connected to the No. 2 reactor building, from which the toxic liquid is believed to have originated.
Hidehiko Nishiyama, a spokesman for the nuclear regulatory body, said the water level which rose about 4 cm and then returned to the previous level, suggests that highly radioactive water may have begun leaking again from somewhere else, Kyodo reported.
He said that TEPCO was expected to boost monitoring of seawater radiation levels.
TEPCO yesterday again reported detecting a very small volume of plutonium in soil samples from the disaster-stricken Fukushima plant.
The plant’s operator had collected samples from four locations at the compound of the plant on March 25 and 28 for analysis by an outside organisation.
It said the radioactive substance was detected on the soil about 500 metres west-northwest of the No.1 reactor and a site near a solid waste storage facility 500 metres north of the reactor, NHK reported.
Radiation in seawater near the No.2 reactor also remains high, even after the leakage of contaminated water into the sea was stopped.
TEPCO said it detected 5,600 bequerels of radioactive iodine-131 per cubic cm in seawater samples collected around the water intake of the reactor yesterday morning.
That’s about half the level detected on the previous day, but still 140,000 times higher than the safety limit under the government’s standards.
US Secretary of State Hillary Clinton is planning to visit Japan to underline American support for its efforts to overcome the devastation caused by the March 11 twin disaster, NHK said.