1. 2002. 7. 22. KIM, UNG-SOO Dept. of Nuclear and Quantum Engineering
Axially Variable Strength Control Rods for The Power Maneuvering of PWRs
KIM, UNG-SOO
Dept. of Nuclear and Quantum Engineering

2. Table of Contents Introduction Optimization of AVSCRs
Conclusion and Further Study

3. Introduction
Optimization for the axially varying strength of the AVSCRs
Obtaining the optimal performance for power maneuvering
Minimizing AO variation and power deviation during power maneuvering
Objective function for optimization of the AVSCRs
Relationship between AO variation(or power deviation) and worth shape
Analytic objective function does not exist.
Response for input can only be evaluated by computer simulation.
Simulation optimization

4. Optimization of AVSCRs
The optimization indexes are modified and improved.
In order to reflect the requirements of AVSCRs
Do the indexes have consistency with optimization objectives?
Correspond to objectives !
Correspond to past index !

5. Optimization of AVSCRs
Optimization of AVSCRs through simulation optimization
Response surface methodology as an optimization strategy
3-in-a-row stopping rule is used.
Objective function (Optimization index)
The degree of violation of AO target boundary
Power deviation from reference target power
Initial AO (for AVSCR1)

6. Optimization of AVSCRs
Evaluated by computer simulation (ONED94)

7. Optimization of AVSCRs
Multiple objectives (The use of many responses)
Desirability function
The researcher’s own priorities and desires on the response value are built into the optimization procedure.
One- and two- sided functions are used.(maximization, minimization, assigned target value)
For assigned target value,

8. Optimization of AVSCRs
For maximization,
For minimization,

9. Optimization of AVSCRs
Single composite response
Geometric mean of the desirabilities of the individual responses
Maximization of D implies that all responses are in a desirable range simultaneously.

10. Optimization of AVSCRs
In this experiment
Optimization of AVSCR1
Index1 : The degree of violation of AO target boundary
Index2 : Initial AO

11. Optimization of AVSCRs
Single composite response

12. Optimization of AVSCRs
Results of Optimization (AVSCR1)
Optimized shape of AVSCR1 : [3.1903, 0.5, ]

13. Optimization of AVSCRs
Results of Optimization (AVSCR1)

14. Optimization of AVSCRs
Results of Optimization (AVSCR1)
At initial shape
After optimization

15. Optimization of AVSCRs
Application to the power maneuvering
Initial power variation vs. the step of the AVSCR1
Initial step of AVSCR1 = 20

16. Optimization of AVSCRs
Initial AO variation vs. the step of the AVSCR1
Desirable AO line

17. Optimization of AVSCRs
Initial AO variation vs. the step of the AVSCR2 with the AVSCR1 on the initial position
Desirable AO line
Initial step of AVSCR2 = 73

18. Optimization of AVSCRs
Application to the power maneuvering : %, h

19. Optimization of AVSCRs
Application to the power maneuvering : %, h (cont’d)

20. Conclusion and Further Study
Obtaining optimum worth shape of AVSCRs
Safety related analysis
Enhancement of the operation strategy for the AVSCRs
to extract optimal performance of the AVSCRs to be developed
applying T_avg signal