Japan's nuke plants not ready for quake, reports warn

Two official studies predicted higher waves and earthquakes that could bigger that its nuclear power plants are prepared for.

Thus it got more difficult for Japan to persuade the public on restaring nuclear reactors.

The government is keen to get some of the reactors running after surging fuels imports resulted in a rare trade deficit, raising worries about its declining ability to fund a huge public debt with domestic savings.

But it must first persuade wary locals that the plants are safe.

Japan's defences against a major tsunami and the safety of its nuclear plants were thrown into further doubt after two official studies predicted much higher waves could hit and that Tokyo quake damage could be bigger than it was prepared for.

One report said a quake as big as the one that rocked Japan in 2011 could trigger waves topping 34 metres, almost double its previous estimate made in 2003 when its worst scenario forecast tsunami of no more than 20 metres.

The Cabinet Office panel which authored the report, revised its predictions after one of the biggest tremors on record struck Japan last year, setting off a tsunami that topped 20 metres in the worst-affected areas and triggering the world's worst nuclear crisis in 25 years.

"We won't be able to contain a massive tsunami with the (current) embankments," said Masaharu Nakagawa, disaster prevention minister.

Waves at the now off-line Hamaoka nuclear plant in Shizuoka prefecture, operated by Chubu Electric Power, could reach 21 metres, breaching the 18-metre breakwater that the operators are currently building, the report said.