I use WorldGuard and set flags in regions to disable TNT and other block destruction.
If you want to turn them off for the entire world, you could reference the __global__ region.
Example:
Sir where can i pu the Example you give
Kuya saankuba pweding ilagay ang mga sign na ito?
/rg flag _global_ other-explosionn deny
/rg flag _global_ TNT deny
