Process, judgment and treatment of national inspection-free steam generator accidents

The national inspection-free steam generator is an efficient automatic device that regulates steam temperature as needed. The national inspection-free steam generator includes a water tank, a steam chamber, an insulation layer, a temperature sensor and a safety valve. The water inlet valve is connected with a water pump and a solenoid valve in sequence, and a steam chamber is arranged in the water tank, and the steam chamber is opened under the steam chamber. The water inlet is connected to the temperature control device, and the upper part of the steam chamber is connected with the steam chamber. There is a partition between the steam chamber 1 and the water tank. The water tank is equipped with a liquid level sensor. The upper part of the steam chamber is equipped with a solenoid valve and a water tank. A liquid level sensor is provided inside to connect with the alarm device.

This patent is a highly efficient automatic electric heating device that can supply the required superheated steam and can regulate the steam temperature as needed. At present, the steam generators used in industrial production use fixed pressure as an important technical index, and in the production, the temperature index is required. This index is the main indicator affecting the quality of the product, and the temperature of different products is required. The range index is also different, so it is inconvenient to use fixed pressure as the main technical indicator.

Process, judgment and treatment of national inspection-free steam generator accidents

(1) The main basis for the judgment of the accident is: the condenser exhaustor monitoring, the steam generator sewage monitoring, and the 16N monitoring outside the main steam pipeline all show a sharp rise in the radioactive concentration and an alarm.

(2) When the heat transfer tube is broken, since the primary side pressure of the steam generator is much larger than the secondary side pressure, the primary side water enters the secondary side. Due to the loss of the primary side water, the water level of the regulator is lowered, and the pressure of the primary circuit also decreases as the volume of the vapor in the regulator expands. Figure 1 and Figure 2 show the change of the water level and pressure of the regulator with time, and the two curves reflect the damage of the two heat exchanger tubes.

(3) Due to the low voltage and low water level alarm of the regulator, the flow of the upper charge pump will increase automatically, and the electric heating in the voltage regulator will be energized to stabilize the pressure and water level in the regulator. If the leakage exceeds the flow rate of the upper charge pump, the primary circuit water will continue to decrease, resulting in automatic shutdown and automatic shutdown of the turbine. When the water level of the regulator reaches a low water level, the safety system fills the first circuit.

(4) Since the primary side water leaks into the secondary side of the broken pipe steam generator, the pressure and water level on the secondary side rise, and the amount of water supply decreases, and the amount of steam and the amount of water supply mismatch. When the water level reaches the high water level setting value, the main water supply is isolated and the auxiliary water supply is input.

(5) If there is an off-site power supply at this time, the steam bypass system is used to discharge the steam into the condenser, so that the temperature and pressure of the primary circuit are rapidly reduced.

(6) If there is no off-site power supply, the main pump cannot be operated, and the condenser cannot be used. At this time, the steam generator discharges the residual heat of the core by natural circulation.

(7) The steam pressure of the broken pipe steam generator rises rapidly. When the setting value of the release valve or the safety valve is reached, the radioactive steam will be discharged to the atmosphere through these valves, causing environmental pollution.

(8) The auxiliary feed water and the water injection are used as heat traps to absorb the residual heat of the core. Therefore, the amount of steam discharged into the atmosphere is gradually reduced, and the pressures on the primary and secondary sides are gradually equal.

(9) Isolation of the broken pipe steam generator and isolation of the condenser exhaust to the atmosphere.