The Senate voted Tuesday evening to approve legislation banning the import of enriched uranium from Russia, sending the measure to the White House which has said it supports efforts to block the Kremlin’s shipments of the reactor fuel

The Prohibiting Russian Uranium Imports Act, approved by unanimous consent, would bar US imports 90 days after enactment while allowing temporary waivers until January 2028. Biden must sign the bill before it becomes law.

Russia provided almost a quarter of the enriched uranium used to fuel America’s fleet of more than 90 commercial reactors, making it the No. 1 foreign supplier, according to US Energy Department data. Those sales provide an estimated $1 billion a year to Russia, but replacing that supply could be a challenge and risks raising the costs of enriched uranium by about 20%.

The White House had called for a “long-term ban” on Russian imports, which is needed to unlock some $2.7-billion to stand up a domestic uranium industry made available by Congress earlier this year, contingent on there being limits on the import of Russian uranium in place.

“This is a national security priority as dependence on Russian sources of uranium creates risk to the US economy and the civil nuclear industry that has been further strained by Russia’s war in Ukraine,” the White House said earlier in a fact sheet. “Without action, Russia will continue its hold on the global uranium market to the detriment of US allies and partners.”

The House bill was approved by voice vote in December amid growing congressional support to cut off Russia in the wake of its invasion of Ukraine. The US has banned imports of Russian oil and worked with Group of Seven allies to impose a price cap on seaborne exports of crude and petroleum products.

The legislation, which expires at the end of 2040, does permit the Department of Energy to issue waivers authorizing the entire volume of Russian uranium imports allowed under export limits set in an anti-dumping agreement between the Department of Commerce and Russia through 2027.

Without those waivers, an approximate 20% jump from the current enrichment spot price of $165 per separative work unit to a record high of as much as $200 per SWU, according to Jonathan Hinze, president of nuclear fuel market research firm UxC.

Enriched uranium is measured in separative work units, or SWU, which account for the volume and enrichment density of the radioactive metal.

It’s possible Russia will respond with a unilateral export ban if the US bars imports, which could end deliveries of enriched uranium from the country immediately and render the waiver allowances moot.

An import ban will take some time to affect operators of US nuclear power plants. Reactors are typically refueled every 18 months to 24 months, and fuel purchases are negotiated long in advance. That means most but not all utilities have already lined up enough uranium to keep their reactors running for at least the next few years.