The total energy released by the megaquake in Japan was about a thousand times the combined energy of all the world’s nuclear weapons or 6.7 trillion tons of TNT.
It is a grim reminder of the fact that undersea earthquakes can be so much more devastating than those on the land. They can generate the most destructive of tsunamis, especially those occurring along substantial linear faults off the coast of Japan.
Prime Minister Naoto Kan said that Japan was currently facing its worst crisis since World War II, the Kyodo news agency reported.
In the wake of Japan’s strongest earthquake on record and fears of a meltdown at a nuclear power plant in Fukushima prefecture, anti-nuclear power activists point out that many Japanese plants do not contain the superior modern safety standards of today.
The Fukushima plant was built in the 1970s.
One-third of power in Japan is nuclear. Key nuclear reactors are located in seismic areas. Accidents have plagued the plants over the last decade, leading to deaths among workers and several evacuations.
As Japan buries its dead – in some estimates to be as high as 10,000 and rebuilds its coastal cities, nuclear tension about its plants continue to rise.
Experts in the north-eastern Japanese prefecture of Miyagi have measured radiation levels 400 times above normal, the Kyodo News agency reported.
Japanese officials should brief other nations on the threat posed by quake-damaged nuclear power plants, Australian Foreign Minister Kevin Rudd said.
‘We, and the rest of the international community, need urgent briefings on the precise status of these reactors,’ Rudd said. ‘We are seeking further co-operation on the technical and safety aspects of these from the Japanese government.’
In Helsinki, Paavo Arhinmaki, leader of the opposition Left Alliance, told a party conference that no further nuclear reactors should be built in Finland, citing events in Japan.
Finland is set to hold general elections April 17. Last year, parliament approved building two new nuclear reactors.
At present, it has four reactors, and a fifth is being built although that project has suffered from delays.
In neighbouring Sweden, the Radiation Safety Authority set up a task force that was following events in Japan.
Similar concerns have been raised across the world from India to Southeast Asia and North America.
India which has an ambitious nuclear expansion program said it will “definitely take a relook” at the design features of the operating reactors in the light of what happened to the Fukushima plant of Japan after Friday’s 8.9 magnitude earthquake but there is no reason to think that Indian reactors will face a similar situation.
“Our reactors may not be ready for 8.9 magnitude quake but what is the probability of this happening in India?” asked, K.S. Parthasarathi, who was until recently the secretary of Atomic Energy Regulatory Board.
“This magnitude earthquake may happen only in the Himalayan region and that is one of the reasons we are not going to build any reactor there.
Hideki Ban, a leading Japnese anti-nuclear power activist and head of the Citizen’s Nuclear Information Centre, said that the shocking damage to the Fukushima nuclear power plant points to the need for continued careful monitoring for radioactive leaks, despite government attempts at defusing tension.
“The Fukushima plant explosion symbolises the terrible threat to human safety in Japan that is highly vulnerable to earthquakes. This is another opportunity to stop this dangerous nuclear power build-up,” he told media.
With some press reports hinting at widespread leaks leading as far as Tokyo, the public have been shopping hard for basic food items, leading many supermarkets to report cleaned shelves.
Ban contends hydrogen pressure is rising in the turbine building and the key to containing a major radiation leak is now in the hands of TEPCO (The Tokyo Electric Power Company ) that must work hard to release the pressure.
The Tokyo Electric Power Company owns the nuclear plant.

How a nuclear power plant works

The central part of a nuclear power plant is the reactor, where atoms are split, releasing heat energy.
Fuel rods, usually containing uranium and plutonium, are loaded into the reactor and submerged into water that acts as a coolant. Control rods made up of materials such as boron and cadmium, which soak up neurons produced by nuclear fission, are used to control the rate of the nuclear reaction.
Raising the control rods speeds up the chain reaction and produces more heat, and lowering them produces less.
Water is pumped into the reactor to extract the heat and create steam. In many nuclear plants, the steam runs through a heat exchanger to convert a separate supply of water to steam so the water contaminated with radioactivity is contained and kept away from the rest of the equipment in the plant.
The steam is used to turn a turbine on a generator, which produces electricity. That electricity flows through the power grid to offices, homes and factories.
The steam is then cooled back into liquid and returned to the reactor as water.
Nuclear reactors at two coastal power plants in north-eastern Japan lost their cooling functions after power and backup generators were cut off in last Friday’s magnitude-8.9 earthquake and subsequent tsunami, plant operator Tokyo Electric Power Co said.
Those reactors were built with containment structures in case of accidents. A concrete dome covers the reactor to contain radiation while a steel liner outside it also is designed to prevent leakage of radioactive materials. The complex is enclosed in a concrete building, which serves as a final protective layer.
Insufficient containment structures made the 1986 Chernobyl nuclear accident devastating.