nuclear fission/ half life/ dangers of radiation

Question 1

what is half life?

Answer 1

the time taken for the activity of a radioisotope to fall by half and the time taken for half of the original nuclei to decay

Question 2

what is nuclear fission?

Answer 2

splitting of atomic nucleus

Question 3

fissionable substances used in nuclear reactors:

Answer 3

uranium- 235

plutonium-239

Question 4

what needs to happen for nuclear fission to occur?

Answer 4

nucleus needs to absorb slow-moving neutron

Question 5

what happens to the nucleus when it undergoes fission?

Answer 5

it splits into two smaller daughter nuclei and 2 or 3 neutrons with kinetic energy

Question 6

what do controls rods do?

Answer 6

absorb some neutrons to prevent self -sustaining chain reactions so each fission only triggers one more

Question 7

what do moderators do?

Answer 7

slow down neutrons to trigger fission

Question 8

why is ionising radiation dangerous?

Answer 8

damages cell structure which triggers chemical reactions

Question 9

what can radiation cause to body?

Answer 9

burns
destruction of cells
mutation of DNA

Question 10

how can we prevent damage to body?

Answer 10

handle sources carefully
use tongs/ gloves
exposure time kept to a minimum

Question 11

where are fuel rods kept?

Answer 11

under water to cool radiation

then put into glass case (vitrification)