There has been a sharp rise in radioactive iodine in the sea off the Fukushima nuclear power plant, with radioactivity thousands of times higher than the legal limit. The most likely sources of the leaks are Reactors 2 and 3, as detailed here.
It is now believed leaks seeping into the soil, fresh water and the sea are continuous. Radiation has found its way into local produce, milk and tap water as far as Tokyo, 220km (140 miles) to the south.
Radioactive water in a tunnel underneath the reactor and the turbine (see diagram below) is preventing workers from gaining access. This tunnel emerges at the front of the building as a trench - just 55 metres from the sea.
Reactor 3: Uses plutonium in its fuel rod mix - small amounts have been found in soil at the plant indicating this reactor may have suffered a partial meltdown. Sea water is being injected into the spent fuel pool and fresh water is being injected to the damaged core. Highly radioactive water has been detected in reactor.
Reactor 1: Damage to the core from cooling problems. Fresh water is being injected into the core. Highly radioactive water has been detected in reactor.
Once that has been achieved, the next step will be to decomission reactors one to four. This means removing the fuel rods, storing them and then reprocessing them at another plant. Then all non-core buildings will be demolished. Core buildings (which house the reactors) have to remain in tact for at least 40 years because dismantling them would release more radioactive material. Some Japanese nuclear experts are considering whether to cover those core buildings with a special material to stop the spread of radioactive substances.
Reactors 5 and 6 would re-open at some point after consultation with local residents.
Highly radioactive liquid has been found inside and outside several reactor buildings.
Small amounts of plutonium have also been detected in soil at the plant - the latest indication that one of the reactors suffered a partial meltdown.
Prime Minister Naoto Kan said his government was on maximum alert, and the situation remained "unpredictable".
Japan's Nuclear Safety Agency said there was still no confirmation that radioactive water has seeped into the sea from flooded tunnels within the Fukushima Daiichi plant.
Water levels in underground tunnels adjoining reactors 1, 2 and 3 had been stable, the agency said.
Workers from plant operator Tepco have been piling sandbags and concrete blocks around the shafts, which lie between 55m and 70m from the shore, the agency said.
"We need to avoid the fuel rods from heating up and drying up. Continuing the cooling is unavoidable... We need to prioritise injecting water," Chief Cabinet Secretary Yukio Edano told a news conference.
Tepco and the safety agency say the exact source of the radioactive leak is unknown.
But, like the discovery of plutonium, the high levels of radiation found inside and outside reactor buildings are likely to have come from melted fuel rods.
Theories for the leak centre on two possibilities: steam is flowing from the core into the reactor housing and escaping through cracks, or the contaminated material is leaking from the damaged walls of the water-filled pressure control pool beneath the No 2 reactor.
The plutonium - used in the fuel mix in the No 3 reactor - is not at levels that threaten human health, officials said.
Engineers are battling to restore power and restart the cooling systems at the stricken nuclear plant, which was hit by a powerful quake and subsequent tsunami over two weeks ago.
Operator Tepco has been accused of a lack of transparency and failing to provide information more promptly. It was also heavily criticised for issuing erroneous radiation readings at the weekend.
On Tuesday, National Strategy Minister Koichiro Gemba said the government could consider temporarily nationalising the energy giant.
His comments came a day after shares in the company dropped to their lowest level in three decades.
Human suffering The massive 9.0-magnitude quake and the tsunami on 11 March are now known to have killed more than 11,000 people, with at least 16,700 people still missing across north-eastern Japan.
Police are posting information about clothes and physical appearance online, the report said.
Some 190,000 people are continuing to live in temporary shelters, many having to cope with food, water and fuel shortages.
The breakdown of local administration has also left municipal offices struggling to assess the damage and casualties in some coastal areas devastated by the tsunami, national broadcaster NHK reports.
Prime Minister Kan is expected to visit the city of Rikuzentakata, in Iwate prefecture, on Saturday.
http://www.bbc.co.uk/news/world-asia-pacific-12869184
It is now believed leaks seeping into the soil, fresh water and the sea are continuous. Radiation has found its way into local produce, milk and tap water as far as Tokyo, 220km (140 miles) to the south.
Theories on main sources of leaked radiation
Reactor 2: Cooling problems damaged the core. It is thought radioactive steam is flowing from the core into the reactor housing and leaking through cracks. Contaminated material may have escaped through the damaged walls of the water-filled suppression chamber beneath the reactor.Radioactive water in a tunnel underneath the reactor and the turbine (see diagram below) is preventing workers from gaining access. This tunnel emerges at the front of the building as a trench - just 55 metres from the sea.
Reactor 1: Damage to the core from cooling problems. Fresh water is being injected into the core. Highly radioactive water has been detected in reactor.
Decommissioning the plant
The good news is that mains electric power has finally been restored, which brings effective cooling of the fuel rods one step closer.Once that has been achieved, the next step will be to decomission reactors one to four. This means removing the fuel rods, storing them and then reprocessing them at another plant. Then all non-core buildings will be demolished. Core buildings (which house the reactors) have to remain in tact for at least 40 years because dismantling them would release more radioactive material. Some Japanese nuclear experts are considering whether to cover those core buildings with a special material to stop the spread of radioactive substances.
Reactors 5 and 6 would re-open at some point after consultation with local residents.
Highly radioactive liquid has been found inside and outside several reactor buildings.
Small amounts of plutonium have also been detected in soil at the plant - the latest indication that one of the reactors suffered a partial meltdown.
Prime Minister Naoto Kan said his government was on maximum alert, and the situation remained "unpredictable".
Japan's Nuclear Safety Agency said there was still no confirmation that radioactive water has seeped into the sea from flooded tunnels within the Fukushima Daiichi plant.
Water levels in underground tunnels adjoining reactors 1, 2 and 3 had been stable, the agency said.
Workers from plant operator Tepco have been piling sandbags and concrete blocks around the shafts, which lie between 55m and 70m from the shore, the agency said.
FUKUSHIMA UPDATE (29 MAR)
- Reactor 1: Damage to the core from cooling problems. Building holed by gas explosion. Highly radioactive water detected in reactor
- Reactor 2: Damage to the core from cooling problems. Building holed by gas blast; containment damage suspected. Highly radioactive water detected in reactor and adjoining tunnel
- Reactor 3: Damage to the core from cooling problems. Building holed by gas blast; containment damage possible. Spent fuel pond partly refilled with water after running low. Highly radioactive water detected in reactor
- Reactor 4: Reactor shut down prior to quake. Fires and explosion in spent fuel pond; water level partly restored
- Reactors 5 & 6: Reactors shut down. Temperature of spent fuel pools now lowered after rising high
- Plutonium: Found at five locations in soil - levels said to represent no danger to human health
Water in the tunnel linked to the No 2 reactor was measured at more than 1,000 millisieverts an hour, a dose which could cause radiation sickness. Radiation levels in water in tunnels adjoining reactors 1 and 3 were much lower.
Work to safely remove the contaminated water is a priority, government officials said, but stressed more water would need to be used to continue to cool fuel rods. "We need to avoid the fuel rods from heating up and drying up. Continuing the cooling is unavoidable... We need to prioritise injecting water," Chief Cabinet Secretary Yukio Edano told a news conference.
Tepco and the safety agency say the exact source of the radioactive leak is unknown.
But, like the discovery of plutonium, the high levels of radiation found inside and outside reactor buildings are likely to have come from melted fuel rods.
Theories for the leak centre on two possibilities: steam is flowing from the core into the reactor housing and escaping through cracks, or the contaminated material is leaking from the damaged walls of the water-filled pressure control pool beneath the No 2 reactor.
The plutonium - used in the fuel mix in the No 3 reactor - is not at levels that threaten human health, officials said.
Engineers are battling to restore power and restart the cooling systems at the stricken nuclear plant, which was hit by a powerful quake and subsequent tsunami over two weeks ago.
Operator Tepco has been accused of a lack of transparency and failing to provide information more promptly. It was also heavily criticised for issuing erroneous radiation readings at the weekend.
On Tuesday, National Strategy Minister Koichiro Gemba said the government could consider temporarily nationalising the energy giant.
His comments came a day after shares in the company dropped to their lowest level in three decades.
Human suffering The massive 9.0-magnitude quake and the tsunami on 11 March are now known to have killed more than 11,000 people, with at least 16,700 people still missing across north-eastern Japan.
Continue reading the main story
“Start Quote
End Quote Karen Mueller Red Cross, northern JapanDuring the day, these frail, crumpled people sit bundled up in blankets around the space heater that is inadequate to warm the large common room”
The authorities are struggling to identify about 4,000 bodies in Iwate, Miyagi and Fukushima prefectures.
''They were collected at places far from their residential areas (due to being swept away by the tsunami), or their families as a whole must have been washed away by the tsunami,'' a senior official at the National Police Agency was quoted by Kyodo news agency as saying.Police are posting information about clothes and physical appearance online, the report said.
Some 190,000 people are continuing to live in temporary shelters, many having to cope with food, water and fuel shortages.
The breakdown of local administration has also left municipal offices struggling to assess the damage and casualties in some coastal areas devastated by the tsunami, national broadcaster NHK reports.
Prime Minister Kan is expected to visit the city of Rikuzentakata, in Iwate prefecture, on Saturday.
http://www.bbc.co.uk/news/world-asia-pacific-12869184
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