gas cooled
liquid metal cooled
pressurised water
boiling water
lead or concrete
lead and tin
graphite or cadmium
thick galvanised sheets
X-rays
infra-red rays
a, P, and y rays
neutrons and gamma rays
return the neutrons back into the core
shield the radioactivity completely
check polllution
conserve energy
1 MeV
2.4 MeV
4.3 MeV
7.8 MeV