LONDON (Reuters) - The government said on Monday it would sell some or all of its 33 percent stake in Urenco, the world's second-largest vendor of nuclear fuel. Three countries hold equal stakes in the security-sensitive uranium enrichment concern - Britain, the Netherlands and Germany, whose share is held by utilities E.ON and RWE. Urenco is estimated to be worth up to 10 billion euros (8.5 billion pounds) and several buyers have been reported to be ready to bid for a stake.