The operator of Japan's Tsunami stricken Fukushima nuclear power plant says it has suspended an operation to clean-up radioactive water only five hours after it had begun. Tokyo Electric Power Company (TEPCO) says the suspension was prompted by a sharp rise in radiation in a part of the system intended to absorb caesium. The company had undertaken the operation at the plant, disabled by the March 11 earthquake and tsunami, to avert spillage into the sea of large growing pools of radioactive water. The official says teams working at the plant believe that the radiation rise may be linked to sludge flowing into the machinery intended to absorb caesium. Another cause could be pipes surrounding it. But resumption, he says, is critical to deal with the highly radioactive water. The official says TEPCO foresaw no delay in its overall plan to bring the Fukushima Daiichi plant fully under control by the end of the year. The clean-up operation got underway yesterday after being delayed by a series of glitches at the plant, 240 kilometres north-east of Tokyo.