The Sichuan earthquake dealt a heavy blow to the nation's military industry but the damage was mainly limited to conventional weapons plants, experts said. The province is a key arms manufacturing base because of its strategic location. Last week's quake laid waste to central Sichuan, home to many weapons facilities. The nation's nuclear weapons design facility is based in Mianyang and Guangyuan is the site of a plutonium processing facility. Both cities were damaged, although the PLA earlier said all nuclear sites were safe and secure. A Shanghai-based military source said that because China stopped making nuclear weapons several years ago, the quake had not hurt nuclear production. There were some conventional weapons plants in Wenchuan county, a hard-hit area. The source said the quake destroyed munitions and tank factories and some old-generation aircraft plants. But he played down the scale of destruction, saying most advanced weapons research and production centres were not in Wenchuan because of its geological instability. The central government spent nearly 15 billion yuan (HK$16.79 billion) setting up military infrastructure and more than 150 arsenals and research institutions, including the Sichang Satellite Launch Centre in Sichuan from 1964 to 1985. The Defence Ministry said the launch centre was not damaged. General Staff spokesman Ma Jian earlier said some military facilities were damaged, but not as seriously as outside observers thought.