gnu, there was an article in Japan Times about liability. I mentioned it a while back but cannot refind it.
Japanese law with regard to liability and damages seems to bear little relationship to the law we know.

As I recall, the article was very clear about the liability, the burden being that in Japanese law, once the title was transferred to the operator, TEPCO, it would bear sole responsibility for liabilities.
A General Electric statement said that this is the case.
This would leave General Electric (designer), Hitachi and Toshiba (reactor builders) free of the costs (General Electric and Hitachi have a relationship, I don't know the share relationship).

Japanese bankers are urging the government to bail out TEPCO. "No one wants to see TEPCO go bankrupt," said Ben Westmore, a Tokyo-based analysist at MF Global Securities.
One option "may be that TEPCO would issue enormous amounts of new shares and the government would then buy most of them. The government can hold them for a while until the price of TEPCO shares stabilizes and then sell them to other investors."
Thurs, April 7, Japan Times, "Bankers Urge Aid for TEPCO." (The subtitle says no new loans to TEPCO until bailout)

The Japanese law requires the utility to carry liability insurance of about 120 billion yen. The government also compensates victims if an accident is caused by a natural disaster.

Engineers are estimating decommission costs at 1 trillion yen.
An economist estimates the electricity shortfall and adverse effects from radioactivity and contamination will cut 1.7 trillion yen from GDP.
Tepco's supplying area covers 40 percent of the country's gross domestic product.