We need to do a full scale(Yield) test of Thermo-Nuclear weapon (hyderogen bomb) before we can deploy our new designs validated in 1998 tests. With out tht proof test we will not be able to deploy light weight high yied weapons on our missiles. No light weight weapons results in heavy, less efficient, low yield weapons constraining us. We will need low weight thermo-nuclear weapons to use our missiles efficiently.
Light weapons = more number of high yield weapons for same amount of plutonium.
If we don't do a proof test it will be a capping our techinical capabilities in weapon design. Some people may argue we can do simulations. The answer is you can you simulations and optimize a weapon but with out testing you can never be sure. And there is no scope for error in yield when we have to demonstrate our deterrance.
You can write control laws (FBW- Fly by Wire) for an fighter aircraft and simulate the laws on test bed but, you still need to fly the aircraft with those control laws to validate and refine them. Its the same thing with nuclear weapons too.
Simulations are like reading theory and weapon explosions are like hands on experience. There is no substuite for hands on experience unless you have pleanty of experience like US or RUSSIA even france signed CTBT only after proof testing all their latyest weapons and validating them.
