By Linda Sieg
TOKYO, May 9 (Reuters) - Unpopular Japanese Prime Minister Naoto Kan has succeeded in his rare bold move to shut down a nuclear power plant due to safety fears, but the decision may not win enough public applause to be a key factor his messy battle to keep his job.
Kan, under fire for his handling of the crisis at another nuclear plant crippled by a huge March 11 quake and tsunami, asked for the shutdown of the Hamaoka plant 200 km (120 miles) southwest of Tokyo on Friday, citing the high risk of another powerful quake.
On Monday, Chubu Electric Power Co reluctantly agreed to shut the plant until defences against a massive tsunami can be improved.
Already Japan's fifth premier in as many years, Kan has seen his ratings sink below 30 percent on concerns about his leadership and faces calls from both inside and outside his own party to step down -- although few expect him to quit easily and there is no obvious successor waiting in the wings.
The political bickering has distracted policy makers from efforts not only to figure out how to fund the massive cost of rebuilding from the triple March 11 disasters, but from tackling the deeper woes of a fast-ageing society and huge public debt.
Japanese mainstream media, which tend to have close ties to Japan's politically influential nuclear power industry, criticised what they called the abruptness of Kan's Hamaoka request, although some analysts said many voters would approve.
"You can say it was sudden, but the chance of a quake affecting the plant is high, so the public will agree with his decision," said political analyst Hirotaka Futatsuki. "But I don't know if this will go so far as to change Kan's image."
An initial poll by broadcaster TBS conducted on the weekend showed Kan's support rate had slipped three points to 29.5 percent, although more than half said Japan should either reduce its number of nuclear plants or close them all.
About 70 percent said that while they were dissatisfied with Kan, they wanted him to stay in his post a while longer.
Experts have long warned about the risk to the Hamaoka plant from a megaquake and the tsunami-triggered accident at Tokyo Electric Power Co's (TEPCO) Fukushima Daiichi plant northeast of the capital has fanned those concerns.
POWER SHORTAGE CONCERNS
The temporary shutdown of Hamaoka, which supplies power to central Japan -- home to many manufacturers including Toyota Motor Corp -- has added to concerns about power shortages in the summer when usage peaks.
"It's good they're closing Hamaoka. They talked a lot about the earthquake risks ... so I'm glad they are going to shut it down. But I'm worried about power shortages in the summertime," said a mother strolling in Tokyo with her two-year-old son.
Kan may also face criticism given that Japanese media and many pundits, while typically professing a longing for decisive leadership, often seem uncomfortable when it is exercised.
"For a change, he took a risk and made a decision that was quite justified, but the way people are so reluctant to give him credit doesn't lead me to believe that this is going to be a game-changer (politically)," said Sophia University professor Koichi Nakano.
Members of the main opposition Liberal Democratic Party (LDP) sniped at what they dubbed a hasty, ill-explained decision, but some outspoken politicians applauded the move.
"The job of elected politicians is to set goals to mobilise the public ... There may be many who oppose the decision but without a doubt, the overwhelming number of people feel that even if there is some burden from halting operations at the dangerous Hamaoka plant, they want to make efforts to achieve that goal," Toru Hashimoto, the popular governor of Osaka in western Japan, said in a televised interview at the weekend.
Even one ally of Kan's heavyweight Democratic Party of Japan rival, former DPJ leader Ichiro Ozawa, expressed approval.
Ozawa's group probably won't abandon attacks on Kan, but prospects they lack the numbers to unseat the premier by backing a no-confidence motion mean Kan could last until his term as party leader expires in 2012, said DPJ lawmaker Hirotami Murakoshi.
Whether Kan follows his Hamaoka decision by outlining a broader energy policy that points to a shift away from nuclear power over time remains in much doubt, especially given the industry's deep tentacles in the DPJ as well as the rival LDP.
A top government official said on Sunday Japan would not back off from nuclear power, which supplies about one-third of Japan's electricity needs, while the trade minister added that a target to raise that to half by 2030 would have to be rethought.
"Utilities are the ultimate in political power," said Murakoshi, who favours gradually weaning Japan from reliance on nuclear power over coming decades. (Additional reporting by Mari Saito; Editing by Nick Macfie)