TOKYO: Japan hopes to stop pumping radioactive water into the sea on Sunday, which should help ease concerns in neighboring China and South Korea over the spread of radiation from the worst nuclear crisis since Chernobyl. But problems in restoring cooling systems at Japan's crippled nuclear plant, hit by a tsunami on March 11, mean more contaminated water may eventually be pumped into the sea if the complex again runs out of storage capacity. Japan is struggling to regain control of the Fukushima Daiichi nuclear plant after a massive earthquake and tsunami devastated its northeast on March 11, and is facing a major humanitarian and economic crisis. “We cannot say what the outlook is for the next stage,” Hidehiko Nishiyama, a deputy director-general of the Nuclear and Industrial Safety Agency (NISA) said on Sunday. “As soon as possible we would like to achieve stable cooling and set a course towards controlling radiation.” China and South Korea have criticized Japan's handling of the nuclear crisis, with Seoul calling it incompetent, reflecting growing international unease over the month-long atomic disaster and the spread of radiation. Japanese voting in local elections on Sunday are expected to vent their anger over Prime Minister Naoto Kan's handling of the nuclear crisis, further weakening him and bolstering opponents who will try force his resignation once the crisis ends. Results of the vote are expected on Monday. The unpopular Kan was already under pressure to step down before the worst disaster to hit Japan since World War Two, but analysts say he is unlikely to be dumped during the nuclear crisis, which is set to drag on for months. Anti-nuclear protests In Tokyo, around 5,000 people took to the streets in two separate anti-nuclear protests on Sunday. Some carried placards reading ‘No More Fukushima' and ‘No Nukes'; others danced and played musical instruments. One group of demonstrators marched to the offices of the operator of the stricken plant, Tokyo Electric Power Co., (TEPCO) . TEPCO apologized on Saturday for the crisis. “I would like to apologize from my heart over the worries and troubles we are causing for society due to the release of radiological materials into the atmosphere and seawater,” Sakae Muto, a TEPCO vice president, told a news conference. Radiation from Japan spread around the entire northern hemisphere in the first two weeks of the nuclear crisis, according to the Vienna-based Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization. Japan's economy, the world's third largest, is reeling from the triple disaster and several countries have banned or restricted food imports after detecting radiation. More critically, the nuclear crisis and power shortages have disrupted Japan's manufacturing and electronics global supply chains, hitting computer and automakers in particular. Power blackouts and restrictions, factory shutdowns, and a sharp drop in tourists have hit the world's most indebted nation, which is facing a damages bill as high as $300 billion -- the world's biggest for any natural disaster. The government had called for restraint from Japanese to help the recovery effort, but families and friends were out in force at cherry blossom viewing parties, traditional events that herald spring, although some were toning down the usual alcohol-induced revelry in deference to the disaster victims. “It's quieter than usual. There are lots of people but they're a bit subdued,” said one middle-aged woman, strolling beneath the delicate pink blossoms. “The blossoms are in full bloom for us and we should appreciate them,” she said. Radioactive water An unmanned drone helicopter is scheduled to fly over four reactors to video damage and gauge radiation in areas where workers are unable to safely enter. Remote-controlled trucks will be used to remove some of the radioactive rubble. Efforts to regain control of six reactors hit by the 15-metre high tsunami, which caused partial meltdowns to some reactor cores after fuel rods were overheated, has been hindered by 60,000 tons of radioactive water. Japan's Nuclear Industry and Safety Authority said efforts to restore cooling systems were not making clear progress.