THERE ARE NEW fears of a nuclear meltdown at the stricken Fukushima I nuclear power plant in Japan today, after authorities said they had begun to pump seawater into a second reactor at the plant.

The primary and backup cooling systems at the number 3 reactor were damaged in the aftermath of Friday’s earthquake and tsunami, and the plant’s operator TEPCO now fears that the temperatures in the reactor could result in a second hydrogen explosion, similar to that which destroyed a containment building around another reactor yesterday.

The government has warned that a meltdown at the number 3 reactor is now a distinct possibility.

That blast, at the number 1 reactor, is not thought to have damaged the reactor itself, with TEPCO insisting that the steel casing that houses the reactor itself remaining intact.

In spite of this, however, radioactive leakage has been observed near the site and a total of 19 people have now been hospitalised for radiation exposure.

Further reports suggested that a leak in the reactor had caused the co0ling fluid around the energy rods to leak out, briefly exposing the rods before new water could be pumped back inside.

Though the plant is relatively close to the seafront, thereby making sea water a fairly predictable source of emergency coolant, the tactic is a fairly unusual one – indicating the unprecedented gravity of the situation facing the plant.

Some air has been intentionally vented from the number 3 reactor building, in order to ease the pressure on the containment building and avoid a second explosion in as many days.

The International Atomic Energy Agency have begun distributing iodine tablets to those evacuated from the 20km exclusion zone around the plant, hoping to combat any radiation poisoning of the thyroid gland, which is particularly susceptible to such poisoning.

The exclusion zone remains in effect around the plant. Last night, many of Japan’s symbolically large buildings – such as the Tokyo Tower, the main city call in the country’s capital – turned off their lights in order to preserve power, given the disruptions from power manufacture at the Fukushima plant which supplies the city.

Japan’s meteorological agencies have listed tsunami advisories for the country’s coastal areas, as the number of aftershocks in the waters off the east coast begins to subside.

Authorities fear that the death toll as a result of the first primary 8.9-magnitude quake, and the following tsunamis, could reach 10,000 in the prefecture of Miyagi alone.

As many as 9,500 people are still unaccounted for in the prefecture’s coastal town of Minamisanriku, which had a total population of around 17,000, and which lies around 55 miles from the epicentre of the major earthquake.

Around 7,500 residents from the town were housed in emergency shelters before the main tsunami struck, but authorities say they have not been able to make contact with the rest of the town’s population.

The confirmed death toll at the time of publication was 977, with a further 1683 people confirmed injured.