High Temperature gas-cooled Reactor Pebble-bed Module (HTR-PM) is a high temperature gas-cooled reactor demonstration plant with a structure of two modules feeding one steam turbine. Compared with the structure of a single reactor feeding a turbine, there are more devices shared between these two modules. When they are operated, the shared components are prone to introduce collisions or even logical deadlocks for different technical processes. The future commercial HTR-PM plants are supposed to comprise more modules for a larger turbine, thus the collision problem and potential deadlocks introduced by the shared components will become severer, which may impact the efficiency or even the functions of the related systems. Therefore, how to design suitable control policies in the distributed control system (DCS) to relieve the collisions and avoid the deadlocks during using these shared devices is a new and also a very important problem. In this paper, the classifications of the shared devices are first addressed, and then how to identify the shared objects of nuclear power plant (NPP) is proposed. Furthermore, a general model for the control logic design is proposed, taking into consideration the collision avoidance, time delay and fairness. Moreover, a scheme for deadlock avoidance is proposed. The example of how to apply the schemes to relieve the conflicts and deadlocks in the processes of using the shared devices in fuel element cycling system is illustrated.

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