When the Starch in the rice (powdery) turns into a GEL..
So.... according to this graph..
Your rice will Certainly be gelatinizing anywhere between 60 and 80..
The key takeaway is, the rice does NOT need to be constantly heated to 100C to be COOKing..
The temperature only needs to be raised to 100C momentarily such that it kills bacteria..
Once your mixture has been fully gelatinized, it is cooked.. additional cooking time does NOTHING..