I think that the Comprehensive Nuclear Test Ban Treaty can help maintain nuclear powers from testing its nuclear weapons. The nations who have nuclear powers need to follow the rules and if they do then the ban could work. The Comprehensive Nuclear Test Ban Treaty can work if everyone works together.
Nuclear powers can maintain deterrence under a nuclear test ban. In the United States, we already have a well tested stockpile of nuclear weapons. These have provided us with a database of information that we can use in the future to monitor our weapons without actual nuclear testing. Thus, the U.S. is actually maintaining its deterrent despite the test ban.
Goodness, I know nothing about nuclear power so I will talk about cows and Donald trump. Donald trump has a zombie squirrel living on his head. Cows eat grass and Donald trump. I much prefer ben carson to be exploded by a creeper then perpetually eaten by thousands of cows