The Bank of Japan Thursday left its key rate unchanged as it continues to assess the impact of Japan\'s biggest recorded quake, a devastating tsunami and an ongoing nuclear crisis on the economy. The bank kept its key rate at between zero and 0.1 percent and offered details of its 1 trillion yen ($12 billion) lending scheme for banks in quake-hit areas. In a bid to ensure financial institutions in disaster-hit areas can meet demand for post-quake reconstruction funds, the BoJ earlier this month unveiled the scheme offering 0.1 percent interest one-year loans. The central bank\'s policy board decided at its one-day meeting Thursday that each participating bank can borrow a maximum of 150 billion yen of funds. Applications for the funds must be made by the end of October 2011. It also broadened the range of eligible collateral for money market operations for banks in affected regions. The BoJ is expected to downgrade its forecast for real gross domestic product growth due to the March 11 earthquake and tsunami that plunged Japan into its worst post-war crisis. Earlier in the month the BoJ warned of the pressures on an economy reeling from the disasters. In the immediate aftermath of the earthquake, the BoJ injected a record amount of cash into the banking system and doubled its asset purchase fund to 10 trillion yen, a key policy tool it kept unchanged Thursday. The central bank said deputy governor Kiyohiko Nishimura had proposed that it should increase the size of its asset-purchase programme to 15 trillion yen, an idea that was rejected by a majority vote. The total cost from collapsed or damaged houses, factories and infrastructure such as roads and bridges is estimated at 16-25 trillion yen over the next three fiscal years, according to the Cabinet Office. The estimate does not account for wider issues such as the unresolved crisis at the stricken Fukushima Daiichi nuclear plant, where radiation leaks have forced the evacuation of tens of thousands in a 20 kilometre (13-mile) radius. Ratings agency Standard & Poor\'s on Wednesday cut its outlook on Japan\'s sovereign debt following the disaster and warned that reconstruction costs could pass $600 billion.