Development of pid controller algorithm over fpga for motor control in failed fuel location module in Indian fast reactors

Nuclear fuels in fast reactors are provided with a leak tight metal cladding for containment of the fission products of the nuclear reaction. Cladding tube failures are unavoidable despite careful fabrication and testing. In case of fuel clad failure, the fuel might be lost into the coolant, with potential consequences. In view of the above it is necessary that there shall be a system designed for identifying failed Fuel Sub Assembly (FSA) in the core at the earliest possible juncture immediately after detecting the presence of failed fuel. Failed fuel location module is required to find out the fuel sub assembly which has developed a wet rupture. Failure of fuel pin in central FSA is detected by indirect method and is inferred when there is no indication from any other FSA. This is done by finding out the delayed neutrons in the sample of the sodium jet coming out of from all fuel sub assemblies. This requires a sampling system, and uses a dc servomotor to select the different jets. This is done by reading from the optical encoder which senses the position of the selector valve. This system requires a smooth and accurate control of the motor to align the selector valve to the required fuel sub assembly from the initial position. Presently it is done manually, in the experimental assembly. An accurate and fast embedded system is proposed to be designed using a digital pid controller. The digital pid controller is implemented on a field programmable gate array on a parallel architecture giving us very high speeds. The simulations are performed using Xilinx 8.1 ISE and MODELSIM 6.4C tools. Communication protocol is developed with the plant wide system using RS232C protocol and local display with the help of a LCD. This paper discusses regarding the tuning of PID controller for the DC servo motor.