Abstract: Upper internals for a nuclear reactor comprise an upper core plate and a plate which supports cluster guides tubes connecting the two plates together. The cluster guides project above the support plate. A bottom wall of the support plate is situated at a level just higher than the outlet nozzles of the reactor vessel and each guide is supported by the bottom wall of the support plate by abutment of a shoulder formed in a passage of the bottom wall, in the lower half thereof.

Abstract: The invention provides a safety device for an electric installation protection apparatus, comprising a residual differential current detector through which pass a phase conductor and a neutral conductor, and a processing circuit supplied by a rectifier bridge and connected to the phase and neutral conductors. It further comprises biasing and safety circuits formed by a static bidirectional switch connected between a ground connection and the AC terminals of the rectifier bridge.

Abstract: The disclosure relates to a static power switch circuit having a power switch member having a bidirectional power switch with at least one controlled semiconductor of the thyristor or triac type with power terminals connected to an AC source in series with a load and a circuit for controlling the power switch member having a first control switch whose current path is connected to the gate of the power semiconductor through a full wave rectifier bridge, this switch being connected to a circuit able to generate control energy of the switch in response to an input signal.

Abstract: A protection device has first and second differential transformers each with a toroidal magnetic core through which pass the neutral and phase conductors of an alternating current distribution network, and a secondary winding. The secondary winding of the first transformer is coupled to the input of an amplifier followed by a rectifier, a threshold comparator and a control device adapted to release a circuit-breaker. The secondary winding of the second transformer is coupled to the output of the amplifier. The improvement is constituted by an auxiliary amplifier inserted between the output of the first amplifier and the terminals of the secondary winding of the second differential transformer.