The main job of a reactor is to house and control nuclear fission—a process where atoms split and release energy. … Inside the reactor vessel, the fuel rods are immersed in water which acts as both a coolant and moderator. The moderator helps slow down the neutrons produced by fission to sustain the chain reaction.
How is a nuclear reaction started and controlled in a reactor?
A nuclear reactor is driven by the splitting of atoms, a process called fission, where a particle (a ‘neutron’) is fired at an atom, which then fissions into two smaller atoms and some additional neutrons. … The fissioning of atoms in the chain reaction also releases a large amount of energy as heat.
What controls the chain reaction in a nuclear reactor quizlet?
By control rods and the moderator. They absorb neutrons allowing the reactor to produce energy at a steady rate. In a controlled chain reaction, on average only one neutron from each fission will strike another nucleus and cause further stimulated fission to occur.
How do you control the rate of a nuclear reaction in a reactor?
Answers. In a fission reactor, control rods absorb neutrons to control the rate of a reaction. Lowering the rods into the reactor decreases the rate of fission and removing them increases the rate.
How do operators control the nuclear reaction?
In a nuclear energy plant, the nuclear chain reaction takes place inside the reactor vessel. Raising the control rods speeds up the chain reaction and lowering them slows or even stops it. …
How does a nuclear chain reaction start?
major reference. Nuclear chain reactions are series of nuclear fissions (splitting of atomic nuclei), each initiated by a neutron produced in a preceding fission. For example, 21/2 neutrons on the average are released by the fission of each uranium-235 nucleus that absorbs a low-energy neutron.
How many control rods are in a nuclear reactor?
Typical reactors can contain around 50 of these clusters with 20 individual control rods in each cluster. The ability of a control rod to absorb neutrons to control the fission chain reaction requires a choice of material that has high neutron-absorbing abilities.
What is the purpose of control rods in a nuclear reactor?
A rod, plate, or tube containing a material such as hafnium, boron, etc., used to control the power of a nuclear reactor. By absorbing neutrons, a control rod prevents the neutrons from causing further fissions.
What do moderators do in nuclear reactors?
Slow neutrons strike nuclei of uranium-235, causing the nuclei to fission, or split, and release fast neutrons. The fast neutrons are absorbed or slowed by the nuclei of a graphite moderator, which allows just enough slow neutrons to continue the fission chain reaction at a constant rate.
What is the purpose of the chain reaction in a nuclear power plant?
A chain reaction refers to a process in which neutrons released in fission produce an additional fission in at least one further nucleus. This nucleus in turn produces neutrons, and the process repeats. The process may be controlled (nuclear power) or uncontrolled (nuclear weapons).
How do control rods slow down nuclear fission?
The control rods can be moved down into the reactor, which slows the reaction down by absorbing more of the neutrons, or moved up so that fewer of the neutrons are absorbed, which means that the reaction remains constant and explosions do not occur.
How does a nuclear power plant operate?
Nuclear power plants use heat produced during nuclear fission to heat water. … The heat produced during nuclear fission in the reactor core is used to boil water into steam, which turns the blades of a steam turbine. As the turbine blades turn, they drive generators that make electricity.