1. lead or concrete
2. lead and tin
3. graphite or cadmium
4. thick galvanized sheets
lead or concrete
1. X-rays
2. infra-red rays
3. a, P, and y rays
4. neutrons and gamma rays
neutrons and gamma rays
1. return the neutrons back into the core
2. shield the radioactivity completely
3. check pollution
4. conserve energy
return the neutrons back into the core
1. 1 MeV
2. 2.4 MeV
3. 4.3 MeV
4. 7.8 MeV
7.8 MeV
1. U233 and Pu239
2. U238 and Pu239
3. U238 and Th239
4. none of the above
U238 and Pu239
1. the most fissionable material
2. the basic fuel for nuclear paints
3. basic raw material for nuclear plants
4. the material which absorbs neutrons and undergoes spontaneous changes leading to the formation of fissionable material
the material which absorbs neutrons and undergoes spontaneous changes leading to the formation of fissionable material
1. % of U235 has been artificially in-creased
2. % of U has been artificially increased
3. % of U234 has been artificially increased
4. extra energy is pumped from outside
\% of U235 has been artificially in-creased
1. nucleus
2. electron
3. proton
4. meson
electron
1. neutron
2. proton
3. atom
4. electron
atom
1. any type of moderator can be used
2. graphite is used as the moderator
3. heavy water is used as the moderator
4. moderator is dispensed with.
moderator is dispensed with.