Where is Satan during the thousand-year reign of Christ and how long is he bound there?
During the thousand-year reign of Christ, Satan is bound in an abyss of some kind, held under spiritual chains. He remains there until the thousand years have run their course, after which he is released. He is still alive but restricted during that period.
Les explains that old Satan is still alive during the millennium, but he is merely bound up in an abyss of some kind and held there under spiritual chains of one sort or another until the thousand years has run its course. Because Satan has not been put away forever, the final setting away of Satan cannot take place until the thousand years have finished. At the end, Satan will once again be released and will cause the nations to follow him and reject the sovereignty of the King and of God. During Christ's absolute rule as King of Kings and Lord of Lords, there will be nothing of Satanic power to oppose Him.