For OPG, you are not going to need any NEU study guide. Don't even look at it. It has NOTHING to do with CANDU reactors or Canadian RP practices.
Study Tritium. Know eveything there is to know about Tritium. Figure whole body dose rates based on Tritium concentration in air. (i.e. 1 MPC = 2.5 milliRem/hr). Know the thumbrules about Tritium concentrations in the Heat Transport and Moderator systems. (Spilling one liter of moderator water yields 1000 MPC, Heat transport yields 100 MPC per liter... look those up - I may have them backwards.)
Be able to do simple calculations involving air sampling, dose rates (inverse square and the like), stay times, contamination levels, ...etc.
OPG usually trains their tradesmen to do RP. The emphasis is more on procedures than on theoretical knowledge of radiation. Be able to read and follow procedures. Most of the test will be concentrated in this area.