Design Of Periodic Test Scheme In Nuclear Power Plant Reactor Protection System

With the development of computer technology,digital reactor protection system has become the mainstream of nuclear power plant protection system.Reactor protection system can trigger timely shutdown or actuate the equipment of Engineered Safety Features Actuation System to restore the reactor to safety state when accidents happen in nuclear power plants.It is an important guarantee for nuclear power plants to operate safely and stably.The reactor protection system has the function of self-diagnosis.In the normal operation of the system,it monitors the running state of its own software and hardware in real time.When the equipment fails,the fault can be detected and alarm.However,due to the limitations of the self-diagnosis function and the multiple redundancy architecture of the safety protection system,some hidden faults within the system are difficult to find.According to the relevant laws and regulations,it is necessary to perform periodic test functions to detect faults that are not detected by self-diagnosis,check the availability of the protection system function,and achieve self-diagnosis and periodic test to cover the failure of the protection system.First,based on the analysis of nuclear safety regulations,standards and relevant design guidelines,the system structure and function of reactor protection system are deeply studied in this paper.Then the periodic test scheme has been applied to provide reference for the design of this paper.The design principles and scope of the periodic test plan have been clarified by studying the standards,regulations and design specifications and other requirements of periodic tests.And a periodic test scheme for reactor protection system is designed based on FirmSys platform.Using the method of piece-wise overlapping scheme will be divided into four sections:(1)T1 channel test;(2)the T2 logic function test: safety shutdown protection function test,safety special protection function test and ESFAS test;(3)T3 test: shutdown circuit breaker test,drive test and interface of test;(4)response time test.And the design principle and method of each section are introduced in detail.Finally,the periodic test scheme designed in this paper is implemented and verified.According to the verification results,this periodic test scheme can improve the efficiency of the test,reduce the risks caused by human factors,and meet the requirements of standards,codes and design.It is a feasible and feasible periodic test scheme.