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SG Chief Road To Prevent Foreign Body Block





SG (steam generator) is a heat exchanger of the PWR nuclear power plant, which transfers the heat generated by the reactor from one side to the two side, making the water in the two loop into steam to drive the turbogenerator to generate electricity.
During the maintenance and maintenance of the evaporator, the inlet and outlet of the evaporator must be added without the pressure of the system, in order to prevent the one side pipe from entering the foreign body during the construction. However, the primary medium of the evaporator is boron containing water, and the radiation dose, temperature and humidity in the chamber are very high. In order to minimize the radiation to the operator, the design of the blockage board should be suitable for single person operation and make the operation simple and fast.
The original shutoff plate of 300MW of Qinshan factory is imported, with a weight of 30Kg, complicated structure, complicated disassembly and disassembly, 2 people need to operate together, and it is easy to hook the rope, and the safety is poor.
Three nuclear power has been fortunate to undertake the development task of blocking board upgrade. After repeated demonstration, the key points of the technology are as follows:
1, the circular three plate folding structure, the mouth and block positioning, without careful calibration, fast and time-saving.
2. TC4 titanium alloy with high rigidity, high strength, low density and corrosion resistance will be controlled below 20Kg. The parts are resistant to impact and do not have to be treated with surface treatment.
3, the installation process is only placed, without screw fixation; after the installation of the plugging plate is airtight, and the dirt generated during the SG maintenance process will not enter the pipeline.
Application effect: blockage board installation test proves that the effect is improved significantly. The average installation time is shortened to 35 seconds, and the fastest time is only 28 seconds, which greatly reduces the radiation level of the personnel. It is easy to operate, quick in installation, reasonable in structure, safe and reliable after being in place, and has been praised by the user in terms of structure, weight, strength and use effect. Not only can it replace the import blockage completely, it is innovative in many ways, and has great application value.

MR. Hu:
The evaporator plugging plate is installed on site today, the effect is very good, the fastest personnel process (from the entry to out) only used 28 seconds, greatly reduced the degree of exposure of the personnel.
The complete effect evaluation needs to wait until the blockage plate is removed.
Thank you, Mr. Hu, General Wang and Qin general for their support.
Attitude decides everything!
Bei Qiusheng, a mechanical team of overhaul Department