Inner Mongolia Science and Technology and Economic Nuclear Power Plant Autonomous Design Route Compressed Air Production System Project Yu Hongbin (Shenzhen Zhongguang Nuclear Engineering Design Co., Ltd., Shenzhen, Guangdong 518172). A comparative analysis method was used to study the different requirements of the autonomous design route and the compressed air of the pressurized water reactor nuclear power plant. The results show that under the autonomous design route, it is considered that no emergency air compressor is provided.
The Compressed Air Production System (SAP) is an essential utility for nuclear power plants, providing full plant instrumentation compressed air (SAR) and common compressed air (SAT). At present, domestic pressurized water reactor nuclear power plants (CPR units) have set up auxiliary air compressors in accordance with the requirements of the French 90OMWe pressurized water reactor nuclear power plant system design and construction rules KRCC-P) to meet the availability requirements of the units. Under the autonomous design route, with the optimization of the process system, the demand for compressed air has also undergone great changes. It is necessary to analyze and study the design scheme of the compressed air production system from all sides, especially the emergency air. Analysis of the necessity of press setting in order to achieve the purpose of rationally configuring the compressed air production system.
1CPR unit compressed air production system introduction The air compressor of the CPR unit air compressor plant provides the compressed air required by the whole plant. In addition, for each nuclear power unit emergency compressed air production system, two emergency air compressor units are set up. A backup air supply is provided by a compressed air distribution system, as shown in the compressed air production system. The power supply for each emergency air compressor is provided by a low-voltage power supply that is powered by a series of diesel generators. In order to achieve the system autonomous design required for cold shutdown, the route safety related system is required for the compressed air of the instrument. The system name is required for the compressed air under normal operating conditions. The requirements for compressed air under the safety accident conditions are compressed by the instrument. The impact of air failure on the operation of the system The demand for emergency compressed air The system for the use of the system is equipped with a dual-phase phasometer for air conditioning. The cp full-scale air-cooling equipment is kept normally open during normal operation, as long as the RRI is not triggered. The low and low level signals of the wave box do not need to perform the isolation action.
If the accident develops further after the failure of the gas failure, and the valve needs to perform the isolation action, the compressed air production system is required to provide the valve with the gas required to perform a shutdown operation, and the installation of the local pressure storage tank can meet the operation requirements. . After the isolation operation is performed, the nuclear auxiliary plant user DER of the RRI system is isolated and loses cooling. The HVAC system performs the heat dissipation and heat preservation functions of the plant through DEL. Thereafter, if it is handled according to the accident, it is necessary to restart the re-establishment of cooling for the nuclear auxiliary plant user, which can be manually opened by the site, and the compressed air system support is no longer needed.
In the event of a gas loss accident caused by the unavailability of the compressed air production system, the valve can be maintained in situ and has no effect on system operation.
There is no demand for emergency pressure.
CPR unit, this valve uses electric valve.
The water quantity system gives the flow control system the normal operation, the regulating valve needs to be kept open, and the compressed air is continuously supplied.
Under safe accident conditions, the ARE system does not need to be operated and the valve can remain closed. The safety function is guaranteed by the ASG system and no compressed air supply is required to start the ASG system.
In the event of a failure of the compressed air production system, emergency compressed air must be supplied to the ARE system, otherwise it may cause shutdown.
There is no demand for emergency air pressure, and emergency air pressure is used as a backup air source to improve the availability of the unit.
The same self-designed route.
Table 1 Process system analysis of the instrument's auxiliary process system for the demand for compressed air for the instrument.
The overall documentation of the availability of the compressed air system requires the application of the overall document name CPR unit autonomous design route single fault criteria.
Availability.
The compressed air distribution system for the instrument is essential for the operation of the nuclear power unit. Therefore, the compressed air production system in each nuclear power unit is equipped with a 1 main compressor and 2 independent auxiliary compressors, which are powered by diesel generators (one in each series). In addition, the compressed air required for safety-critical drives is not covered by its dedicated backup tank.
The top-level decomposition results of the nuclear power plant availability index for the compressed air production system are priced at 0.00h. Note: 1 This table lists the list of systems that have an important impact on the inapplicability of the existing plant unavailability rate; 2 if the system The unavailability time is less than or equal to the assigned value in the table. The availability rate can meet the target value of the duration of the CPR1000+ nuclear power plant forcible unavailability <5 days/year; 3 the top-level decomposition result is a guiding allocation indicator for the system design. Not the final design goal.
The inapplicable compressed air production and distribution system is a key system affecting the availability of nuclear power plants.
Table 2 Availability Analysis of Compressed Air System Due to space limitations, only the safety-related systems with instrumentation compressed air requirements for autonomous design routes are analyzed here (see Table 1), which mainly includes four aspects: 1 under normal operating conditions The requirements of the process system for compressed air; 2 the requirements of the process system for compressed air under safety accident conditions; 3 the impact of compressed air failure on the operation of the process system; 4 the demand for emergency compressed air in the process system.
From the analysis in Table 1, the 1CPR unit is equipped with an emergency compressed air production system to improve the overall availability of the unit. The safety-related functions are realized through the gas storage tank. 2 The autonomous design route has no function to the emergency compressed air system. It is required that only the eight RE system requires an alternate air source in order to improve the overall availability of the unit.
Comparative analysis of the overall requirements for the availability of compressed air systems for different design routes. Due to space limitations, the availability of compressed air systems is compared based on only the most representative overall documents (see table for analysis from Table 2: 1RCC) ―P clearly requires the installation of an independent auxiliary air compressor to meet the unit availability requirements; the compressed air required for the safety-critical drive unit is guaranteed by its dedicated spare air tank; 2 the overall document of the autonomous design route clearly states the compression The air production and distribution system is a key system affecting the availability of nuclear power plants; however, the unusable hours allocated to the compressed air production system is 000 h, which is only a guiding allocation indicator and is not the final design goal.
Based on the above two aspects of analysis, under the autonomous design route, the process system has no functional requirements for the emergency compressed air production system, and the overall availability of the unit is improved as much as possible while meeting the operating conditions of the unit.
3Autonomous design route The overall reliability analysis of the air compressor plant is based on the analysis of two nuclear power plants sharing the air compressor plant: 13 air compressors in the normal operating state of the unit, one air compressor is in standby state; 2 Air compressor cooling water system has 2 channels of cooling water source (conventional island closed circuit cooling water system, drinking water system) to spare each other; 3 air compressor unit is connected to 2 sets of factory power supply, any one of the factory power supply overhaul, can pass another The plant is powered by the power supply to ensure the normal operation of the air compressor unit; 4 if the control system fails, the linkage state between the air compressors is invalid. The accident signal will be transmitted to the DCS, and the operator will immediately start the local control system of the air compressor to ensure the compressed air consumption requirement for the instrument necessary for the safety related system to operate.
In summary, the air supply reliability of the air compressor plant is relatively stable without considering the failure of the power supply outside the plant, the breakage of the gas supply pipe, and the failure of the air compressor caused by external disasters. The compressed air production system in the air compressor plant has been designed with redundancy in mind, eliminating the need for additional emergency air compressors to increase the availability of compressed air production systems.
Conclusion In the case of meeting the demand for compressed air in the process system, the autonomous design route compressed air production system may not be equipped with an emergency air compressor. Provide a basis for the autonomous standard design of nuclear power plants. Reduce the load of a single emergency diesel generator to 165kW, save the nuclear island plant area of ​​about 160hm2, and save the project cost of about 20 million.
Chen Zhiqi, and so on. French 900MWe pressurized water reactor nuclear power plant system design and construction rules (RCC-P). Beijing: National Nuclear Security Administration, 1991: 81. Su Linsen, et al. 900MW PWR nuclear power plant system and equipment (2). Beijing: Atomic Energy Press, 2007: Wang Jiansheng, et al. Nuclear power plant availability model and indicator decomposition report
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