system
Given the following post, respond as if you're commenting on Reddit:
human
Does nuclear fusion occur in the accretion disc of a black hole?

I was having a discussion about this recently, and I haven't been able to find conclusively whether or not it does. The articles i've read elude to fusion not occuring, but don't seem to say concisely that this is the case for the entirety of the matter's descent into the black hole.

From Wikipedia's "accretion disc" page:

 "The large luminosity of quasars is believed to be a result of (the frictional heating of) gas being accreted by supermassive black holes. This process can convert about 10 percent to over 40 percent of the mass of an object into energy as compared to around 0.7 percent for nuclear fusion processes."

If this amount of heat and pressure is present, why isn't the matter fusing?
gpt
I may be wrong but from your description it seems as though there is a higher conversion of mass to energy in an accretion disk than in fusion. This would suggest that perhaps fusion is occurring, but even it if is, the energy released from the fusion reaction is much less than some other process generating much higher levels of energy from the destruction of mass. It's a bit like trying to look for a match that's next to a fire from across a room.