Off-line test method and system for low pressure differential operation of No. 1 main pump seal

Abstract

The invention discloses an off-line testing method and system of low-pressure-difference operation of a No.1 seal of a main pump. The method comprises the following steps: S1, a static pressure reduction disc dynamic test is carried out; S2, a sealing boosting test is carried out; S3, a pressure reduction test is carried out; and S4, a boosting test is carried out. In the off-line testing method and system of low-pressure-difference operation of the No.1 seal of the main pump, under conditions of starting torque under different pressure differences, whether a liquid film exists between seals or not is verified through the static pressure reduction disc dynamic test; initial sealing performance under a normal working condition is verified through the sealing boosting test; the sealing characteristics under various pressure differences including the situation that the pressure difference is lower than a minimum pressure difference is verified through the pressure reduction test; and whether sealing performance can be restored to an initial state after operation is carried out under the situation that the pressure difference is lower than a minimum pressure difference is verified through the boosting test. The various tests can be completed, and sealing integrity of the pressure-bearing boundary of the main pump is ensured. Huge economic losses brought by non-planned shutdown repair of the unit due to lack of relevant experience and theoretical analysis after accidents are reduced, and evaluation analysis basis of equipment availability is improved.

Description

technical field [0001] The invention relates to the field of rotating machinery, in particular to an off-line testing method and system for the No. 1 seal of a main pump running under low pressure difference. Background technique [0002] The reactor coolant system (RCP) is the primary loop system of a nuclear power plant. The CPR1000 (China's million-kilowatt pressurized water reactor nuclear power plant) nuclear power unit has three loops, and each loop is equipped with a reactor coolant pump (main pump) , which is used to drive the coolant to circulate in the primary circuit system, and continuously transfer the heat generated in the core to the secondary side feedwater of the steam generator. The main pump ensures proper flow of coolant through the core to keep the reactor core cool and prevent film boiling. [0003] The main pump is a vertical, single-stage centrifugal pump with a controlled leakage shaft seal. The mechanical seal of the main pump is the most fragile ...

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Problems solved by technology

[0004] The main pump is the CCM equipment of the nuclear power plant. If the safe operation of the main pump seal cannot be guaranteed, the No. 1 seal of the main pump needs to be shut down for inspection and replacement, which involves unit disassembly, reactor cover opening, unloading, and water level inspection and replacement of the No. 1 seal. The whole process needs to be shut down for at least 12 full-power equivalent days, and the direct economic loss is about 110 million yuan; in addition, a set of No. 1 sealing components needs to be replaced, and the spare parts are about 2 million yuan , will also produce a large amount of radioactive waste

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