nuclear power Flashcards
nuclear fission
The process of splitting a heavy nucleus into two fragments. certain heavy nuclei can be split with addition of an extra neutron. the nucleus becomes unstable and spontaneously fissions. creates heat, radiation and neutrons as byproduct
nuclear reactor critical state
neutron byproducts from one fission go on to cause only one additional fission reaction. number of fissions will remain constant over time
nuclear reactor subcritical state
there are not enough neutrons to sustain continued fission reaction. fission neutrons will go on to be absorbed in non-fissile materials
nuclear reactor supercritical state
an increasing number of fissions over time. reactors are often slightly ___. The rate at which fissions increase can be dangerous
control rods
____ absorb neutrons, preventing them from initiating additional fissions. Made out of material that more readily absorb neutrons than the surrounding fuel
nuclear steam plant
isolated primary and secondary systems
primary system
radioactive. water absorbs heat produced in reactor. cooling reactor provides heat to secondary system
secondary system
nonradioactive. steam travels to turbine, condenses and is fed back to steam generator
shielding
the reactor and reactor compartment are covered in dense materials (commonly lead) lead blocks radiation
speed changes on nuclear ship
manually opening & closing of throttle valves controls amount of steam admitted to the turbine
nuclear advantages
unlimited range, no fuel for propulsion, submarines can operate submerged for months, frees up fuel tanks for aircraft
father of the nuclear navy
Admiral Rickover
USS NAUTILUS (SSN 571)
first nuclear powered submarine
How do we limit exposure to radiation onboard nuclear powered vessels?
shielding, protect personnel health, limit contaminated waste
