Authorities are investigating a fire at a California nuclear plant that forced a reactor to be shut down. Diablo Canyon Nuclear Power Plant spokeswoman Sharon Gavin said Monday that there was no danger of a radiation leak after a fire the day before. The blaze was in a non-nuclear part of the plant. Gavin said one of two reactors was shut down as part of standard safety procedures. She didn't know when it would be restarted. The plant started supplying electricity in 1985 and generates power for about 3 million homes in northern and central California.