Pennsylvania Occupational Health Nurse Exam Questions and Correct Answers 2026 – COHN/COHN-S Practice Test, Rationales & Certification Prep

PENNSYLVANIA NUCLEAR ENGINEER EXAM B B B




QUESTIONS AND CORRECT ANSWERS (VERIFIED
B B B B B




ANSWERS)PLUSRATIONALES2025|2026Q&A|
B B B B B B




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B B B




1. Theneutron lifecyclein areactor includes allthefollowingEXCEPT:
B B B B B B B B B B B




• a)Fission neutron production
B B B




• b) Fastneutron slowingdown
B B B B




• c)Thermalneutron absorption
B B B




• d) Moderation B




Rationale:Fissionneutronproductionis partof thecycle,notaseparatelifestage; the life
B B B B B B B B B B B B B B B




cycle refers to neutron behavior after production.
B B B B B B B




2. Theeffectivemultiplicationfactor keff=1keff=1indicates:
B B B B B




• a)Subcriticalreactor
B B




• b) Critical reactor
B B




• c)Supercriticalreactor
B B




• d)Reactor shutdown
B B




Rationale:keff=1keff=1means eachfissionleads toexactlyonesubsequentfission on
B B B B B B B B B B B




average.
B




3. Whichmaterialis commonlyused asamoderator in lightwaterreactors?
B B B B B B B B B B B




• a)Water B




• b) Graphite B




• c) Heavy water
B B




• d) Boron carbideB B

,4. Thedelayedneutron fractionisimportantfor:
B B B B B B




• a) Fuel enrichment
B B




• b)Reactor control and stability
B B B B




• c) Waste disposal
B B




• d) Heat transfer
B B




5. Theprimary fissileisotopeused inmostcommercialreactors is:
B B B B B B B B B




• a)U-235
B




• b) Pu-239 B




• c) Th-232
B




• d) U-238 B




6. Fastreactorsprimarily relyon:
B B B B




• a)Moderationbylightwater
B B B B




• b)Fast neutrons withoutmoderation
B B B B




• c) Graphitemoderation
B B




• d) Heavy water moderation
B B B




7. Neutronflux isdefined as:B B B B




• a)Energy released per fission
B B B B




• b)Rateof fission reactions
B B B B




• c)Number of neutrons perunit area perunit time
B B B B B B B B B




• d) Totalneutronpopulation
B B B




8. Controlrods in anuclearreactor primarily:
B B B B B B




• a)Increasethermalconductivity
B B B




• b)Increase fuel enrichment
B B B




• c) Absorb neutrons
B B

, • d) Slow down neutrons
B B B




9. Areactoris consideredsupercriticalif keffkeff is:
B B B B B B B




• a) <1 B




• b) >1 B




• c) =1
B




• d) ≤0 B




10. In a PWR, theprimary coolant loop:
B B B B B B




• a)Directlydrives turbines
B B B




• b)Transfersheattothesecondaryloop
B B B B B B




• c)Is open totheatmosphere
B B B B B




• d) Containsboron only in trace amounts
B B B B B B




11–20:Thermodynamics &HeatTransfer
B B B B




11. TheRankinecycleisused in nuclear powerplants for:
B B B B B B B B B




• a)Convertingthermalenergytoelectricalenergy
B B B B B B




• b)Enriching fuel
B B




• c)Reactor cooling
B B




• d)Controllingneutron flux
B B B




12. Theboilingpoint ofwater increases in a pressurized reactor dueto:
B B B B B B B B B B B




• a)Neutron flux
B B




• b) Elevated pressure
B B




• c)Moderatorpresence
B B




• d)Control rods
B B




13. Theheattransfer in afuel rod isprimarilyby:
B B B B B B B B B