How can I prevent a trigerred TNT to explode? [duplicate]
As said in this link, you could try to use :
/gamerule setExplosionDestruction false
This command would prevent any Creeper / TNT blocks to damage others blocks. If you want to re-enable block destruction, use :
/gamerule setExplosionDestruction true
NB : You need to play at least at version 1.4.2 Minecraft to have access to gamerule command