Question EXE.2.SL.TZ0.18
| Date | Example questions Example questions | Marks available | [Maximum mark: 8] | Reference code | EXE.2.SL.TZ0.18 |
| Level | SL | Paper | 2 | Time zone | TZ0 |
| Command term | Calculate, Discuss, Outline | Question number | 18 | Adapted from | N/A |
One possible fission reaction of uranium-235 is
Outline, with reference to the decay equation above, the role of chain reactions in the operation of a nuclear power station.
[3]
The four neutrons released in the reaction may initiate further fissions ✓
«If sufficient U-235 is available,» the reaction is self-sustained ✓
Allowing for the continuous production of energy ✓
The number of neutrons available is controlled with control rods «to maintain the desired reaction rate» ✓
The following data are given:
Binding energy per nucleon of = 7.591 MeV
Binding energy per nucleon of caesium-137 = 8.389 MeV
Binding energy per nucleon of rubidium-95 = 8.460 MeV
Calculate, in MeV, the energy released in the reaction.
[2]
✓
169 «MeV» ✓
Two nuclides present in spent nuclear fuel are and cerium-144 (). The initial activity of a sample of pure is about 40 times greater than the activity of the same amount of pure .
Discuss which of the two nuclides is more likely to require long-term storage once removed from the reactor.
[3]
«For the same number of nuclei,» the activity is inversely related to half-life ✓
Thus has a longer half-life and will likely require longer storage ✓
Half-lives of their decay products need also be considered when planning storage ✓