Abstract: A self-test system for a nuclear power plant, nuclear reactor protection system is disclosed. Nuclear protection systems are the electronic controls, typically including circuit cards, located intermediate between sensors (as for detecting core overheat) and a control (as for providing rod injection to shut down a reactor). Constant surveillance of the nuclear system protection system is provided by a microprocessor that serially addresses protection system circuit cards and loads them at pre-determined input points with test commands. The addressed cards are thereafter simultaneously activated by a system-wide command. The test command is a pulse which is so short in duration that its affect is transparent to the system and cannot cause overall system operation. The pulse passes through the actuating electrical components to verify, on the real actuating path, the operating integrity of the system.

Abstract: In an elongated weak-link supercurrent transmission line, the propagation of mobile flux vortices can be either enhanced or impeded by control means comprising a normal metal segment which interrupts either superconductor in the direction of vortex propagation and a control current source connected to the line at a point in operative relation to the normal metal segment. The control means either enhances or impedes the propagation of a vortex depending on the direction of the control current relative to that of the supercurrent associated with the vortex. The control means may also include a portion of the line in which its width is varied in order to change the velocity of the vortices.