TEPCO shares fall 16% despite plant progress

TOKYO - Shares in the power company at the centre of the world's worst nuclear crisis for 25 years continued to tumble on Wednesday despite signs of progress in stabilising its stricken Fukushima Daiichi plant.

Tokyo Electric Power was down 16.29 per cent at 303 yen on renewed selling in defiance of news that it had stopped the accidental leakage of highly radioactive water into the ocean from a cracked pit at the number two reactor.

TEPCO shares plunged to their lowest ever close on Tuesday at 362 yen amid expectations the company will face a mounting compensation bill that some estimates put at around 10 trillion yen (S$149 billion).

More than three weeks on from the March 11 earthquake and tsunami, the crisis at Fukushima Daiichi remains unresolved after reactor cooling systems were knocked out, triggering explosions and fires, and releasing radiation.

The plant northeast of Tokyo has emitted radioactive materials into the air, contaminating farm produce and drinking water.

Radioactive water has seeped into the Pacific Ocean but officials stress there is no imminent health threat.

To stop the long-running leak from the Fukushima plant on the Pacific coast, operator TEPCO had injected sodium silicate, a chemical agent known as "water glass", to solidify soil near a cracked pit where the water had been escaping.

However, the company continued a separate operation to release lower-level radioactive water into the sea to free up urgently needed storage space for water so toxic that it is hampering crucial repair work.

Japan has battled to prevent full reactor meltdowns at the tsunami-hit plant and poured thousands of tons of water onto overheating fuel rods, a stop-gap measure that has created highly radioactive run-off.

It insisted the release of the water into the sea - at 11,500 tons it is the equivalent of more than four Olympic sized swimming pools - would not harm marine life or seafood safety.

But amid growing unease about water contamination, Japan has imposed a legal limit for radioactive iodine in fish and may widen tests to cover a larger area, after elevated levels were discovered in a fish caught off Ibaraki prefecture, south of the crippled plant.

"There is still plenty of work to do," a senior strategist at a Japanese brokerage told Dow Jones Newswires. "The dumping of radioactive water into the ocean (since Monday night) has also had deep repercussions, intensifying selling interest among overseas investors," he adds.