NLO's (called Nuclear Equipment Operators, NEO's) and RO's are part of the bargaining unit and are paid according to the union contract.
The 2013-2015 Contract is available on the IBEW website
http://www.ibewlu220.com/doc/contract/CPNPP2013-2015.pdf (pg 29-31)
Most fully-qualified NEO's make about $41-43 / hour (once you include the base pay, plus the fire brigade adder, plus the instructor adder).
Most RO's make about $45 / hour, plus a license bonus of $750 / month.
There is a small increase in pay ($1 / hour) for hours worked on nights. Overtime is 1.5x. There is no holiday pay.
SRO pay is a bit different because they are salaried and not part of the bargaining unit. Generally an SRO gets paid similar to an RO, except the SRO annual bonus is considerably larger. My best guess for typical SRO annual compensation: $140k