Radioactive gas leaked from the Connecticut Yankee nuclear plant for 10 minutes Monday morning, but no one was injured and there was no danger to the public or employees, a spokeswoman said. The release of xenon-krypton occurred while technicians were taking a test sample, Northeast Utilities spokeswoman Barbara Luce. She said the accident did not affect operations at the plant. The spokeswoman said the release was measured as two-hundredths of a millirem, a unit used to measure radiation exposure. By comparison, she said, a diagnostic chest x-ray involves between 20 and 30 millirems of radiation. Luce also said that there are daily, planned releases of the gas of less than a millirem. The gas is produced during fission. The utility notifed state and government officials of the accident and were investigating, Luce said.