A thermal nuclear reactor relies on various physical processes to operate safely and efficiently.
Explain why the kinetic energy of neutrons must be significantly reduced in a thermal nuclear reactor.
As a result of a collision with an atom of a particular moderator, a neutron loses 55%55\%55% of its kinetic energy. A neutron initially has a kinetic energy of 2.5 MeV2.5\text{ MeV}2.5 MeV. Calculate the kinetic energy of this neutron after four collisions. Give your answer in eV\text{eV}eV.
The kinetic energy of a neutron in a thermal nuclear reactor is reduced from about 2.5 MeV2.5\text{ MeV}2.5 MeV to about 1 eV1\text{ eV}1 eV. Explain why the number of collisions required to achieve this reduction depends on the nucleon number of the moderator atoms.
One fission process that can occur in the reactor is represented by the following equation:
92235U+01n→54140Xe+3893Sr+301n ^{235}_{92}\text{U} + ^{1}_{0}\text{n} \rightarrow ^{140}_{54}\text{Xe} + ^{93}_{38}\text{Sr} + 3^{1}_{0}\text{n} 92235U+01n→54140Xe+3893Sr+301nCalculate, in MeV\text{MeV}MeV, the energy released in this single fission process.
Data:
128 exam-style questions on AQA A Level Physics Radioactivity (A-level only), covering Rutherford scattering (A-level only), $\alpha$ , $\beta$ and $\gamma$ radiation (A-level only), Radioactive decay (A-level only), Nuclear instability (A-level only), Nuclear radius (A-level only), Mass and energy (A-level only), Induced fission (A-level only), and Safety aspects (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.