Japan enhances efforts to cool nuclear reactor

The truck had originally been scheduled to spend seven hours spraying 3 tonnes of water per minute - a total of 1,260 tonnes - upon the fuel storage pool on reactor number 3 at the nuclear power plant in Fukushima, which was damaged by the March 11 earthquake and tsunami.

The operation has been "successful to some extent", Chief Cabinet Secretary Yukio Edano said, but added that the situation was unpredictable.

Edano said reactor number 4, another part of the six-nuclear-reactor facility was to also be doused Saturday.

Temperatures and pressure have risen at the reactors since their cooling systems failed after the coastal plant was swamped by the tsunami, leading to fears of reactor meltdowns at the plant. Hydrogen explosions, fires and releases of radiation have occurred, and core damage has been confirmed at three of the reactors.

High levels of radiation were detected in milk in Fukushima and spinach in neighbouring Ibaraki prefecture, Edano said Saturday. The government was considering regulating farm products in areas near the nuclear power plant.