He signed the Prohibiting Russian Uranium Imports Act on Monday, two weeks after the bill was passed unanimously by the US Senate. The law bans the import of Russian-produced unirradiated LEU, including LEU that has been swapped for banned uranium.

The prohibition on imports of LEU comes into effect 90 days after the date of the enactment of the bill and will last until the end of 2040. Waivers may be granted to allow the import of limited amounts of LEU, under exceptional circumstances, until 1 January 2028.

US National Security Advisor Jake Sullivan said: “Today, President Biden signed into law a historic series of actions that will strengthen our nation's energy and economic security by reducing – and ultimately eliminating – our reliance on Russia for civilian nuclear power.

“This new law re-establishes America's leadership in the nuclear sector. It will help secure our energy sector for generations to come, and – building off the unprecedented $2.72bn in federal funding that Congress recently appropriated at the President's request – it will jump-start new enrichment capacity in the United States and send a clear message to industry that we are committed to long-term growth in our nuclear sector.”

Since the outbreak of the war in Ukraine, western nations have sought to reduce reliance on Russian nuclear fuel, but this is the first time formal legislation has been implemented.

US nuclear company Westinghouse has been at the centre of the US’ drive to move countries away from dependence on Russian nuclear resources. In April, Westinghouse and Ukrainian state-owned utility Energoatom started the construction of the first AP1000 reactor in Western Ukraine, where existing reactors are Soviet-era VVER (water-water energetic reactor) models.