3.4: nuclear fission and fusion

nuclear fission is

the splitting of a large, unstable nuclei to form more stable smaller nuclei and also emitting spare neutrons

a fissionable isotope is

uranium-235

usually, to induce a fission reaction

an unstable nuclei must absorb a neutron, spontaneous fission is rare

alongside two smaller nuclei, what else is emitted from fusion

two or three neutrons, gamma rays, energy

all fission products have

kinetic energy

during a chain reaction in a nuclear reactor

an unstable nucleus absorbs a neutron and undergoes fission, emitting 2 or 3 neutrons inducing more fission reactions resulting in a chain reaction

consequences of an uncontrolled chain reaction are

rate of fission becomes too high and there is too much energy which can lead to a nuclear explosion

in the core of a nuclear reactor there is

fuel rods, control rods,moderator

the role of a moderator in a nuclear reaction is

to slow down neutrons so they are at an absorbable rate or fissile nuclei

chain reactions in a fission reactor are kept under control by

control rods

control rods are

positioned in-between the fuel rods and the rate of fission is controlled by the rods moving up and down, the lower the rods are inserted, the slower the rate of fission

a nucleus that can undergo fission is a

fissile nuclei

the only fissionable isotopes are

uranium-235 and plutonium-239

nuclear fusion is

the joining of two smaller nuclei combine to create a nucleus with a greater mass and energy is released in the process

two common isotopes (of hydrogen) used in nuclear fusion are

deuterium and tritium (1 neutron,1 proton and two neutrons,1proton)

what releases more energy, nuclear fission or fusion

fusion

it is difficult to generate energy through nuclear fusion because

it requires very high temperatures and pressures and casings which can withstand them

nuclear fusion is currently ………….. on earth because

not a viable way to produce energy, with our current equipment energy required is greater than energy created resulting in energy loss

products of nuclear fusion are

a helium atom, a neutron and energy

similarities of nuclear fusion and fission are

they both release energy, both make changes to the nucleus, both been achieved on earth

differences between nuclear fission and fusion are

fission splits a single nucleus and fusion combines two separate nuclei to make a single nucleus, fusion requires high temperatures and pressure, fission doesn't, fission products can produce a chain reaction, fission is used to generate electricity but there isn’t the technology for fusion yet

the requirements for nuclear fusion naturally occur

in the core of stars