TOKYO (AFP) - Engineers struggled Monday to cool three nuclear reactors at a quake-damaged Japanese power plant hit by two explosions in as many days. The latest blast rocked a building housing the number-three reactor at the Fukushima No 1 plant, 250 kilometres north of Tokyo, and injured 11 people. Officials said the reactor container was not breached and there was no major rise in radiation levels. Chief government spokesman Yukio Edano said that the cooling system at the number-two reactor stopped working after Mondays blast. The WHO said that there is minimal public health risk arising from radioactive leaks from Japans damaged nuclear reactors. The fuel rods in the number two reactor at a quake-damaged nuclear power plant in Japan are again fully exposed, officials said early Tuesday, boosting fears of an eventual partial meltdown. Air pressure inside the reactor at the Fukushima No. 1 plant rose suddenly when the air flow gauge was accidentally turned off, operator Tokyo Electric Power Co (TEPCO) said. Japans govt said another hydrogen explosion is unlikely at a quake-hit nuclear power plant. Japan has officially asked the UN atomic watchdog to send a team of experts to help in the current nuclear crisis, International Atomic Energy Agency (IAEA) chief Yukiya Amano said Monday. Japan has asked the US for help controlling its damaged nuclear power plants after last weeks earthquake and tsunami, the US nuclear regulatory commission said Monday. Nuclear safety agency officials said most serious problem was at the number-two reactor, where pressure was rising and the cooling water level falling. They said operator Tokyo Electric Power Co (TEPCO) was taking steps to release pressure. Jiji news agency said the water levels had fallen far enough to partly expose fuel rods. At the number-three reactor, engineers were unable to pump in cooling water because the explosion damaged the cooling pump. The number-one reactor remained relatively stable.The nuclear safety agency ruled out the possibility of a Chernobyl-style accident at the plant, according to national strategy minister Koichiro Genba.But Frances industry minister said the situation was worrying. It is a serious nuclear accident since there have been radioactive leaks, Eric Besson said on France Inter radio. A US aircraft carrier and other ships deployed for relief efforts repositioned after detecting low-level radiation from the malfunctioning plant. The explosion was caused by a build-up of hydrogen in the number-three reactor building, Edano said, but pressure in that reactor remains stable. Edano said that 11 people were injured in the blast. Officials have been injecting sea water into the reactors to replace lost coolant - a procedure that will render the 40-year-old plant unusable. Authorities have declared an evacuation zone within a 20-kilometre radius of the plant and so far evacuated 210,000 people. Meanwhile, searchers have found 2,000 bodies in Miyagi region, public broadcaster NHK and other media Monday quoted officials as saying. About 1,000 bodies were found on beaches on the Ojika peninsula, the reports quoted police officials as saying.