Paladin Energy Ltd (ASX: PDN) shares are falling on Wednesday.

In morning trade, the uranium producer's shares are down 3% to $11.44.

This follows the release of an update on its proposed acquisition of Fission Uranium Corp. (TSX: FCU).

Fission Uranium is the owner of the Patterson Lake South uranium property. It is a proposed high-grade uranium mine and mill in the Athabasca Basin region of Saskatchewan, Canada.

This is a great location to be in, with the Athabasca Basin consistently ranking as one of the world's top mining investment jurisdictions.

Fission Uranium notes that its Patterson Lake South project is backed by a feasibility study highlighting elite economic potential, making it one of the few projects advanced enough to enter production this cycle.

In June, Paladin Energy announced a deal to acquire Fission Uranium via an all-scrip deal. The two parties agreed on 0.1076 Paladin Energy shares per Fission Uranium, which was the equivalent of C$1.30 per Fission Share at the time. This represented an implied equity value of C$1,140 million (A$1,220 million).

What's the latest?

This morning, Paladin Energy was given a small boost in its quest to complete the deal for Fission Uranium.

It advised that Fission Uranium has obtained a final order from the Supreme Court of British Columbia approving the arrangement.

However, that doesn't mean a deal is done. Far from it. Unfortunately, the completion of the arrangement "remains uncertain" according to Paladin Energy, which may explain why its shares are falling today.

This is because it needs to also obtain Investment Canada Act (ICA) clearance, which may not be as easy as first thought.

Last week, Fission Uranium received a notice from the Minister of Innovation, Science and Industry ordering a national security review of the arrangement under section 25.3 of the ICA.

Paladin Energy and Fission Uranium advised that they are continuing to engage with the minister. But warned that "in light of the national security review of the Arrangement, there can be no certainty that Fission will be able to obtain ICA clearance in a timely manner or at all. Failure to obtain ICA clearance would prevent the Arrangement from being successfully completed."

This would be a big blow to Paladin Energy and its ambitions. Paladin advised that it will continue to keep the market informed of all material developments.

Paladin Energy's shares are down 25% over the past six months despite a recent (very strong) rally.