They can add transmission lines, for cheaper importation.
As fuel synthesis -- ammonia and hydrogen -- comes online and undercuts NG, they can import that instead, at times when their transmission line power capacity or availability is exceeded.
Fuel synthesis from solar in the tropics undercutting NG extraction will be a big business. Synthesis using reliable wind, in other places, likewise.
In the meantime, as minority participants, their contribution to the ongoing climate catastrophe is relatively small.
I am not up to date with ammonia based processed.
Ammonia and hydrogen are attractive because you can sell extra production after your local tankage is full, keeping your synthesis equipment busy whenever you are not drawing down your storage.
There are countries that have been spectacularly failing to provide their own such facilities for decades.
If we propose to allow countries to outsource their nuclear waste disposal, wouldn't it be simpler, cheaper and safer to just skip nuclear entirely and outsource the power generation?
All those countries with apparently not enough access to sunlight or wind will save an awful lot of time and money messing about with nuclear and just buy in their renewable power.
If it works, could the Xlinks Morocco-UK power project could be a template for this kind of solution?[0]:
"A 10.5 gigawatt (GW) solar and wind farm will be built in Morocco’s Guelmim-Oued Noun region, and it will supply the UK with clean energy via subsea cables. The twin 1.8 GW high voltage direct current (HVDC) subsea cables will be the world’s longest."
[0] https://electrek.co/2022/04/21/the-worlds-longest-subsea-cab...
But there's definite risk in outsourcing the majority of your power production, risk that doesn't exist if you're outsourcing long-term storage. If something goes wrong with the storage ecosystem, you can keep it on-site for a few extra months.
I think trusting another country to look after your radioactive waste for a few thousand years might involve a fair amount of risk. It's hard enough trying to look after it yourself.
At the simplest level, what if the storage facility has a design fault or some geological event happens and suddenly loads more work and/or money is required?
Or, in the spirit of bad movie plots:
What happens if the other country changes its mind, perhaps after a major change of government or referendum? "We instruct you to take all your nuclear waste back. Right Now!"
What happens if the other country doesn't maintain the storage properly / fails to keep it safe? Who's to blame for any leak / accident / incident / attack?
It is not like oil stored in a tanker that might spill out because rust has made a hole.
It is a solid substance, vitriefied in a giant block of gas, sealed inside a copper container that never rusts. Then this container is placed hundreds of meters underground, into bedrock, and the tunnel is filled in. Noone walks around to check how it's doing today.
If something goes terribly wrong, these containers can be stored in an ordinary warehouse for years and nothing happens.
Then lets address the misattribution of incentives.
In all your scenarios the coutry housing nuclear waste is the one that's interested in making sure its stored properly. You can't use it for extortion, any kind of returning of nuclear waste by force would likely amount to an act of war.
On the other hand, if another nation is supplying you power, they can extort you by cutting power supply, and that is what Russia is doing to europe today. Europe is very fortunate that Russian leadership is completely retarded when it comes to running the economy, and Russia simply can't afford to cut the supply completely. However it does mean that Europe is sponsoring putin's war in Ukraine.
The primary concerns with nuclear power are those of economic viability, lead times, practicality.
The waste is not killing anyone, we can build containers thay last hundreds, even thousands of years and we have time to figure out this problem.