PLD based protection system [for nuclear power plants]

The potential value of the application specific integrated circuits (ASICs) in safety systems of nuclear power plants (NPPs) is being increasingly recognized because they are essentially hardwired circuitry on a chip, the reliability of the system can be proved more easily than that of software based systems which is difficult in point of software V&V (verification and validation). There are two types of ASIC, one is a full customized type, the other is a half customized type. The PLD (programmable logic device) used in this paper is a half customized ASIC which is a device consisting of blocks of logic connected with programmable interconnections that are customized in the package by end users. This paper describes a PLD-based RPS (reactor protection system) which provides emergency shutdown of the reactor to protect the core and the pressure boundary of RCS (reactor coolant system) in NPPs. An RPS using PLDs is composed of five logic blocks, each of them implemented in one PLD, as follows: 1) bistable logic; 2) matrix logic; 3) initiation logic; 4) MMI (man machine interface) logic; and 5) test logic. In this paper, an RPS using PLDs is designed and simulated.