Steam in the primary circuit
Steam in the primary circuit
Patch notes: V 0.2.07.051
In a pressurized water nuclear reactor, the primary circuit is where the nuclear fuel is located and where the neutrons that drive the fission reaction are produced. It is critical that the primary circuit remain filled with water, as water acts as a coolant to dissipate the heat generated by the fission reaction. If, for some reason, water in the primary circuit becomes vapor, there can be serious and even catastrophic consequences.
There are several reasons why it is important that no vapor is formed in the primary circuit of a pressurized water nuclear reactor:
1. Cooling capacity is reduced: Liquid water is a much more effective coolant than vapor. If vapor forms in the primary circuit, the cooling capacity is significantly reduced and the nuclear fuel can overheat. If the fuel overheats, there can be damage to the fuel elements and the release of radioactive products.
2. Loss of pressure: When vapor forms in the primary circuit, the pressure decreases. Loss of pressure can negatively impact the effectiveness of the cooling system and the ability to control the fission reaction. If the pressure continues to decrease, there can be a leak in the primary circuit and the release of radioactive substances.
3. Risk of explosion: If vapor forms in the primary circuit and the pressure continues to decrease, there can be a risk of explosion. This is because when water turns into vapor, its volume increases dramatically. If the pressure in the primary circuit is not properly controlled, the increase in volume of the vapor can cause an explosion and the release of radioactive products.
Therefore, it is crucial that an adequate amount of water is maintained in the primary circuit of a pressurized water nuclear reactor to ensure effective cooling and prevent the formation of vapor. Various safety systems are used to ensure this does not happen, including safety valves and emergency cooling systems.
How can I check for the presence of vapor in the primary circuit, and what are the consequences if vapor is detected?
To check for the presence of vapor in the primary circuit, a new indicator has been installed on the control console, which will illuminate in yellow if vapor is detected and red if the value detected is critical for the normal operation of the reactor.
If vapor is detected in the primary circuit, the core will heat up more than normal and become difficult to cool. The volume of coolant will decrease, the evaporators will lose temperature, and the generating turbines will lose power.
To address the issue, if the vapor concentration is low, the internal pressure of the circuit can be increased. If the concentration is high, the ventilation valve of the reactor core should be opened, and an emergency shutdown initiated. In both cases, it will be necessary to inject coolant into the primary circuit.
The pressurizer is a crucial component in the safe operation of a pressurized water nuclear reactor. Its main function is to maintain the proper pressure in the reactor's primary circuit, preventing the formation of steam.
Pressurizer
When heat is generated in the reactor core, the water circulating through the primary circuit becomes heated and can turn into steam. The pressurizer prevents steam from accumulating in the primary circuit, maintaining the system pressure at a constant and safe level. If the pressure in the primary circuit drops, the pressurizer injects water to increase it, thus preventing the formation of steam.
The importance of the pressurizer lies in the fact that if it fails to operate correctly, the primary circuit could lose pressure, leading to the formation of steam. This, in turn, could cause a reduction in cooling capacity and the release of radiation into the environment, posing a serious risk to the health and safety of people and the environment.
Therefore, the pressurizer is a critical component in the safety system of a pressurized water nuclear reactor, and its proper functioning is essential to prevent the formation of steam in the primary circuit and avoid possible radiological accidents.