Is it possible to initiate RACH in SUL of NR?

Answer 1

I think it is possible. 38.300 - 9.2.6 state as follows :

For initial access in a cell configured with SUL, the UE selects the SUL carrier if and only if the measured quality of the DL is lower than a broadcast threshold. Once started, all uplink transmissions of the random access procedure remain on the selected carrier.