A simple core control code, SCLOF (Simple Core Control Code in Load Following Operation) is developed for the control of a nuclear reactor. The core state equations are described by the one-group diffusion equation with moderator temperature and xenon feedbacks and iodine-xenon dynamics equations.
The control via control rod, boron, and coolant inlet temperature is considered. The control model is formulated as an optimal tracking problem with quadratic objective functional. An optimal solution is obtained by minimizing a quadratic functional of the power distribution and control effort.
In order to avoid the conventional difficulties of two point boundary value problem, the optimal control problem is solved by the direct numerical technique of mathematical programming without the separation of space and time variables. This quadratic programming problem is solved by the Davidon-Fletcher-Powell(DFP) method which is a general unconstrained optimization method. By considering one time step optimization, optimal solutions are obtained with a minimum amount of computing time.
In the cases of the load following operation of Korea Nuclear Unit 7 & 8, the results obtained by using the present model show that the scheduled load demand is successfully followed and power distribution maintains the desired distribution with a minimum amount of control action.
핵 발전소의 부하 추적 운전시, xenon spatial oscillation 을 제어하기 위한 간단한 노심 제어 program,SCLOF 를 개발하였다. 노심 상태 방정식은 moderator temperature 와 xenon feedback 을 고려한 one-group diffusion equation 과 iodine-xenon dynamics equation 으로 구성된다. 또 제어봉, boron, 그리고 냉각수 입구 온도에 의한 노심 제어를 고려하였다. 제어 모델은 quadratic objective functional 을 가진 optimal tracking problem 이 된다.
최적 제어 문제를 푸는데 있어서, mathematical programming 의 직접적인 수치 해석적 방법을 사용함으로서 two-point boundary value problem 의 난점을 피할 수 있다. 또 한 시간 스텝에 대한 최적화를 고려함으로서, 아주 작은 계산 시간으로 최적해를 구할 수 있다.
한국 원전 7&8 호기의 부하 추적 운전에 대해서 계산을 수행한 결과, control action 을 최소한으로 줄이면서 계획된 부하 수요와 원하는 출력 분포를 만족시키는 결과를 얻었다.
