TOKYO (AFP) - Flammable gas has been detected inside a pipe linked to a nuclear reactor at Japan's crippled Fukushima atomic power plant, its operator said Saturday. Tokyo Electric Power Co was unable to identify the gas but nonetheless said it was unlikely there would be an explosion in the reactor. The company has been injecting nitrogen into the reactor so that the level of oxygen inside becomes low enough to prevent blasts. But a TEPCO spokesman said workers at the Fukushima Daiichi nuclear plant measured a 100-percent flammable gas in a pipe connected to the power station's reactor number one. "It is not clear exactly where and how this gas was created,". the spokesman told AFP. "We are considering ways to deal with it. "It is likely that we will continue the survey the gas to identify it and use nitrogen to bring its level low enough" to avoid explosions, he said. There were explosions at the reactors at the Fukushima nuclear plant after they went into meltdown following the March 11 earthquake and tsunami, which hit its cooling systems. In the world's worst atomic disaster since Chernobyl, the Fukushima plant has since sent radiation into the air and sea, forcing tens of thousands of residents to evacuate and consumers to avoid food from the region. Japan has promised to achieve a cold shutdown of the plant by the year-end.