Damning report in New York Times, online today.
"Culture of Complicity Tied to Stricken Nuclear Plant"
N. Onishi and Ken Belton, April 26, 2011.

"Given the fierce insularity of Japan's nuclear industry,...fitting that an outsider exposed the most serious safety cover-up in the history of Japanese nuclear power. .......Fukushima Daiichi....."
In 2000, Ken Sugaoka, Japanese-American nuclear inspector who had worked for General Electric...told Japan's nuclear regulator about a cracked steam dryer that he believed had been concealed. If exposed, it could have forced TEPCO to undertake costly repairs.
The regulator, NISA, divulged Sugaoka's name to TEPCO, effectively blackballing him from the industry.
The agency instructed Tepco to deploy its own investigators to inspect Daiichi. Regulators allowed the company to keep operating its reactors for the next two years even though, an investigation ultimately revealed, its executives had hidden far more serious problems, including cracks in the shrouds that cover reactor cores.
Inconsistent, inconsistent or uninforced regulations played a role in the accident....
A ten-year extention for the oldest of Daiichi's reactors suggests that the regulatory system was allowed to remain lax by politicians, bureaucrats and industry executives single-mindedly focused on expanding nuclear power...... despite warnings about its safety and subsequent admissions by Tepco that it had failed to carry out proper inspections of critical equipment.
"In Japan, the web of connections between the nuclear power industry and government officials is ....referred to as the "nuclear power village.""

A long history of coverups, push to expand nuclear power, despite discovery of active fault lines under plants, danger of tsunami and safety coverups.
It has been considered political suicide to even discuss the need to reform the industry. "...a taboo, so nobody wanted to touch it," said Mr. Oshima, a Democratic Party member, who talks freely because he is backed by one of Japan's largest lay Buddhist movements.

Collusive practices between bureaucrats and industry, long practiced in Japan, are the rule. The article discusses these practices, and the names for them- amagaari or ascent to heaven and amakaduri or descent from heaven.
Interesting reading.