But its cheaper option than building dam which can be destroyed due to pak bombing as its close to loc and we lose billions and no I am not talking about nuclear waste but something different.
you are mad.
This is the equivalent of exploding a nuke inside your enemys house in person. he dies, so do you.
When you put radioactive contamination in ground-water, its game over for life wherever that groundwater goes. because every layer of life connected to that radioactive water- from bacterial to tree to animals- will be radioactive and thus suffer from genetic degradation, cancer, aplastic anemia, etc.
You dont screw around with radioactivity. you are better off with millions of tonnes of cyanide - trust me on this one.
The reason is simple - at atomic level, radioactive atoms = AK-47. firing bullets at every direction. These bullets are devastating at atomic level to rna molecular structures, particularly since many of these are weak covalent bonds.
When you come in FRONT of a bit of radioactive uranium for a short time, you pass in front of the gun, which fired bullets at you. yes, its thousands of bullets towards trillion to the power of million targets, so damage is minimal and you survive. stick around long enough, eat enough bullets and you die. Hence exposure limit.
Now, if you have even ONE atom of this uranium or heavy water inside you, now you have a bullet firing inside you- for anywhere between few years to forever of your life ( half life is tricky but thats the range of reality from half-life).
At single-cellular level, this is devastating for life the most, but all levels of life = screwed completely.
Radioactive poisoning is what you do, if you want to permanently kill life on earth.