Australia will buy nuclear submarines in a major new alliance with the US and Britain to counter the worrying rise of China in the Pacific. Prime Minister Scott Morrison on Thursday morning unveiled Australia's role in a historic tripartite security group, known as 'AUKUS', to switch to nuclear-powered subs with help from its two of its biggest allies. The deal will mean Australia will walk away from its controversial deal to spend up to $90 billion buying French diesel-powered submarines. This is the first time Australia has ever embraced nuclear power after decades of debate – and the first time…