Dynamic Compensation of Vanadium Self Powered Neutron Detectors for Use in Reactor Control

The slow response characteristics of Vanadium SPNDs precludes their direct use for reactor protection and regulation applications. On the other hand, benefits offered by Vanadium SPNDs like better life span, simple response characteristics, easiness in handling the replaced SPNDs etc., make them desirable candidates for such applications. Therefore, a method to improve the response time of Vanadium SPNDs would enable them to be utilized for reactor control applications as well as to fulfill core monitoring and surveillance requirements. In this paper, two different dynamic compensators are designed for response improvement of Vanadium SPNDs using a mathematical model of the SPND derived from first principles. The model as well as the compensators are validated using the plant data collected from the 540 MWe PHWR units. It is established that the compensated Vanadium SPND signals are in very good agreement with the prompt Cobalt SPND signals. It is further demonstrated that the compensated Vanadium SPNDs can be used for computation of reactor bulk power as effectively as the Cobalt SPNDs. This puts forth the possibility of using Vanadium SPNDs in lieu of Cobalt SPNDs for reactor protection and regulation applications.