China Sealcon Company

The Application of Shaft Seal In Nuclear Power

The pressurized water reactor is one of the light water reactors. According to statistics, about 60% of the world's nuclear power plants use pressurized water reactor, which uses pressurized boron containing water as reactor coolant and moderator. At present, there is a good balance between the safety and the economy of the nuclear power plant of the million kilowatt - class PWR. At present, the third generation of pressurized water reactor is mainly multi-million kilowatts.
The reactor coolant pump (main pump) is the only large rotating equipment in the circuit system of the pressurized water reactor. Its main function is to provide it that allows the coolant to be forced in a loop system. The heat generated by the core is passed through the coolant to the steam generator, generating steam from the steam turbine for generating electricity. At the same time, the pump shell and other pressure-containing members also bear the safety function of preventing radioactive material from leaking into the containment.

The shaft seal is the key component of the shaft seal pump. Its long-term reliable operation will not only affect the normal production of the nuclear power plant, but also directly affect the safety of the nuclear power plant. The function of shaft seal is to ensure that the leakage amount of the reactor coolant is basically zero from the primary pump shaft to the containment space environment during the normal operation of the power plant. It is required to be in a high pressure differential condition for a long time and maintain a controllable leakage rate. The non-failure operation time is at least 20000hm. Once the shaft seal of the main pump fails, the integrity of the pressure boundary of the primary loop of the nuclear power plant will be lost. If the leakage rate exceeds the capacity of the water replenishment system, it will lead to the occurrence of the potential small fracture water loss, which will eventually lead to the melting of the core.

At present, the main pump of the world's million-kilowatt nuclear power plant can be divided into three-bearing main pump of American style and four-bearing main pump of European style. Among them, the American style main pump is equipped with a hydrodynamic seal, while the European style main pump is equipped with a hydrostatic type. The 2 types of shaft seals are in a non-contact state through the hydrodynamic pressure effect and hydrostatic pressure effect respectively, and the controllable leakage is formed to ensure the long life and reliable operation of the shaft seal.

Related News
  • Sealing Sense

    Sealing Sense

    November 29, 2017Thermal growth rate differences of head flanges, tube-sheets, bolts and gaskets create an upset of the gasket-flange interface and a loss of seating stress on the gasket that can cause flanges to leak...view
  • Classification Of Rubber Seal Ring

    Classification Of Rubber Seal Ring

    May 4, 2018There are all kinds of rubber seal rings in rubber seal factory. According to the ssutting shape, it can be divided as follows:O seal ring series (DSH seal series)It has many kinds of products, such a...view
  • Leakage Analysis And Maintenance Of Mechanical Seal

    Leakage Analysis And Maintenance Of Mechanical Seal

    May 4, 2018Leakage analysis and maintenance of mechanical seal1. Repair of mechanical sealMechanical seal flygt pump do not need special tools and materials for maintenance. Generally speaking, mechanical seals ...view
  • Common Problems In Mechanical Seal Pump

    Common Problems In Mechanical Seal Pump

    May 4, 2018The following are several common failure about the seal of mechanical seal flygt pump:(1). Leakage during installation of static test. After the mechanical seal is installed and debugged, the static p...view
  • The Mechanical Seal Of The Pump

    The Mechanical Seal Of The Pump

    May 4, 2018The mechanical seal of the pump is the material or part that prevents the leakage of fluid or solid particles from the adjacent surface and prevents the external impurities, such as dust and water, in...view
  • Sealing Technology

    Sealing Technology

    May 4, 2018Sealing technology mainly refers to the use of a certain combination of sealing materials, sealing elements and the corresponding seal structure form, to prevent or cut off the mass transfer process b...view