Operator of Fukushima nuke plant admitted to faking repair records

The revelation raises fresh questions about both Tokyo, the scandal-tainted past of the Electric Power Co (TEPCO), and the Japanese government's perceived soft regulation of a key industry.

The operator of the Fukushima No 1 plant submitted a report to the country's nuclear watchdog 10 days before the quake hit on March 11, admitting it had failed to inspect 33 pieces of equipment in its six reactors there.

A power board distributing electricity to a reactor's temperature control valves was not examined for 11 years, and inspectors faked records, pretending to make thorough inspections when in fact they were only cursory, TEPCO said.

It also said that inspections, which are voluntary, did not cover other devices related to cooling systems including water pump motors and diesel generators.

The report was submitted after the regulator ordered operators to examine whether inspections were suitably thorough.

"Long-term inspection plans and maintenance management were inadequate," the nuclear safety agency concluded in a follow-up report two days after TEPCO's admission.

"The quality of inspection was insufficient."

The safety agency ordered the operator to draw up a corrective plan by June 2.

But on March 11 the 9.0-magnitude earthquake unleashed a 10-metre tsunami, knocking out back-up generators hooked to the plant's cooling system aimed at keeping fuel rods from overheating and releasing dangerous radiation.

A nuclear safety agency official who declined to be named said: "We can't say that the lapses listed in the (February 28) report did not have an influence on the chain of events leading to this crisis.

"We will conduct thorough research on TEPCO's activities up until this crisis but that will come afterwards. For now we are only working on saving the plant."

Firefighters, policemen and troops are hosing the damaged reactors in a desperate bid to stop them overheating, and trying to restore electricity that would kick-start cooling systems.

Images of the exploding plant triggered global alarm, but for many in Japan, TEPCO's track record of safety issues and attempts to cover them up add to suspicion over a flow of opaque, erratic information about Fukushima.

In 2002, TEPCO admitted to falsifying safety reports which led to all 17 of its boiling-water reactors being shut down for inspection, including Fukushima.

The revelation forced the then TEPCO chairman and president to resign.

And in an eerily familiar event, a 2007 earthquake paralysed its Kashiwazaki-Kariwa nuclear plant - the world's biggest - and more radiation leaked than TEPCO initially acknowledged.

TEPCO later said it underestimated the potential impact of an earthquake on the facility.

"People don't trust TEPCO, they don't expect TEPCO to tell the truth," Philip White of the Tokyo-based Citizens' Nuclear Information Centre, a group of scientists and activists against nuclear power, said.

"The problem is one of a culture of denial - denial that this could occur, denial Japan could be subject to a big quake and the scale of the wave that could come."

Parallels with how TEPCO has handled Fukushima and BP's dealing with the Gulf of Mexico oil spill disaster have been drawn.

TEPCO has lost 1.93 trillion yen ($A24.6 billion) in market value since the disaster.

Prime Minister Naoto Kan was heard by a stray microphone furiously berating TEPCO officials after they took an hour to notify the government of the first explosion to hit the plant.

"What the hell is going on?" Kan was heard to say.

When the February report was released, the local Fukushima government also demanded redress, saying the "problem threatens the foundation of trust", media reported at the time.

TEPCO had issued the report after a fresh inspection at its Kashiwazaki Kariwa plant also revealed oversight.

"They had submitted the report because they were afraid they would get in trouble if they didn't," another nuclear safety official said.