If we look at the binding energy versus atomic number graph, we see that in the start its increasing up until iron, then it starts decreasing.
CloseUsually, naturally occurring substances contain very low percentages of the fissile atoms we want, but by enriching it, we increase the percentage of fissile atoms in our substance so we get a better fuel.
CloseThe purpose of the moderator is to slow down the neutrons. If they are too fast, they will not cause fission, hence it enables the chain reaction. However, if we remove the moderator, the chance of fission happening will greatly decrease, and the reaction would slow down.
CloseControl rods can absorb neutrons and are placed around the fissile material. If the reaction speeds up too much, these rods can be inserted to absorb some neutrons, hence slowing down the reaction.
CloseThese rods are still radioactive and can half-lives of hundreds of years, hence they are still dangerous for a very long time.
CloseFission is a form of nuclear energy, and an AC generator produces electrical energy.
CloseThe correct answer is: B.
In neutron-induced fission, a neutron is absorbed by a uranium-235 nucleus, making it unstable. This causes the nucleus to split into smaller nuclei, releasing a significant amount of energy in the process. The fission also produces additional neutrons, which can initiate further fission reactions in a chain reaction.
CloseThe correct answer is: A.
In a self-sustaining chain reaction, each fission event produces enough neutrons to cause additional fission reactions, thus maintaining the process. Control rods are used to regulate the reaction by absorbing neutrons to prevent the reaction from becoming uncontrollable.
CloseThe correct answer is: B.
Control rods are made from materials that absorb neutrons, such as boron or cadmium. By absorbing some of the neutrons produced in the fission process, they reduce the number of neutrons available to sustain the chain reaction, effectively controlling the rate of fission.
CloseThe correct answer is: B.
Fission products are typically highly radioactive and include a variety of isotopes, which can have long half-lives. These products must be carefully managed to prevent radiation exposure. They are often stored in specially designed containers and facilities until they decay to safer levels.
CloseThe correct answer is: B.
In nuclear fission, the total mass of the fission products is less than the mass of the original nucleus. This "missing" mass is converted into energy according to Einstein's equation \(E = mc^2\), which explains the release of energy during fission.
CloseThe correct answer is: C.
A moderator is used to slow down fast neutrons to thermal neutrons, which are more likely to cause fission in the reactor fuel. Graphite is commonly used as a moderator in many reactors because of its ability to slow down neutrons efficiently without absorbing too many of them.
CloseThe correct answer is: B.
Shielding is used in nuclear reactors to absorb harmful gamma radiation and reduce the exposure of workers and the environment to radiation. Materials such as concrete, lead, or water are often used for this purpose.
CloseThe correct answer is: C.
The products of nuclear fission, such as cesium-137 and iodine-131, are typically highly radioactive and have relatively long half-lives. Therefore, they must be carefully handled, stored, and monitored to ensure that radiation exposure is minimized.
Close| Option | Explanation |
|---|---|
| A | The neutron causes the nucleus to absorb energy, making it more stable. |
| B | The neutron splits the nucleus into smaller nuclei and releases energy. |
| C | The neutron is absorbed but does not directly cause fission. |
| D | The neutron causes the nucleus to emit gamma radiation. |
| Option | Explanation |
|---|---|
| A | The chain reaction is self-sustaining when each fission event causes exactly one more fission. |
| B | The chain reaction ceases after the first fission event. |
| C | The chain reaction requires an external source of neutrons to continue. |
| D | The chain reaction slows down exponentially without the use of control rods. |
| Option | Function of Control Rods |
|---|---|
| A | To reflect neutrons back into the reactor core to increase fission. |
| B | To absorb neutrons and reduce the number of fission events. |
| C | To provide a source of additional neutrons for fission reactions. |
| D | To cool the reactor by absorbing heat produced during fission. |
| Option | Statement |
|---|---|
| A | Fission products are typically harmless and do not require any special handling. |
| B | Fission products are highly radioactive and must be carefully managed and stored. |
| C | Fission products are stored in water, which neutralizes their radioactivity. |
| D | Fission products are reused as fuel after being separated from the reactor core. |
| Option | Explanation |
|---|---|
| A | The mass of the fission products is greater than the mass of the original nucleus. |
| B | The energy released is due to the conversion of mass into energy according to \(E = mc^2\). |
| C | The energy released is due to the splitting of the nucleus into two large fragments. |
| D | Energy is released because the proton-proton interaction decreases during fission. |
| Option | Material Used as Moderator |
|---|---|
| A | Uranium-235 |
| B | Boron |
| C | Graphite |
| D | Cadmium |
| Option | Purpose of Shielding |
|---|---|
| A | To prevent the release of neutrons into the environment. |
| B | To prevent the release of gamma radiation and reduce the risk of radiation exposure. |
| C | To absorb neutrons and prevent a chain reaction. |
| D | To cool the reactor and maintain optimal operating temperature. |
| Option | Statement |
|---|---|
| A | Fission products have long half-lives and are typically safe after a short period. |
| B | Fission products are usually stable and do not pose any long-term radiation risks. |
| C | Fission products are often highly radioactive and must be carefully handled and stored. |
| D | Fission products are beneficial and can be used directly as energy sources. |