Framatome Gmbh

Framatome & Cie.

Groupement Atomique Alsacienne Atlantique

Groupement Pour Les Activities Atomiques Et Advancees 'gaaa'

Groupement Pour Les Activites Atomiques Et Avancees 'gaaa'

Jean Martin

Albert C Wiart

Paul Petit

Rene Peletan

Jacques Defaucheux

Jacques Jolly

Jean-Louis Ollier

Gilbert Pasqualini

Claude LaFosse

Device for operating a cluster of neutron absorber elements in a pressurized water nuclear reactor, comprising two coaxial control shafts (2, 3), the central shaft (3) being rigidly joined to the cluster of absorber elements. A widened part (22) of this shaft (3) forms a piston (22) which is fitted with segments (35). A pressure difference on either side of a segment (35) permits the clusters of absorber elements to be lifted by acting on the piston (22). The segment (35) is radially expandable and the leaktight sealing of the segment is initiated by entry of the piston (22) into the reduced diameter zone (10) of the shaft (2). The invention applies, in particular, to nuclear reactors with spectral shift employing clusters of fertile elements.

Device for operating a cluster of neutron absorber elements in a

The mechanism has at least one carrier sprocket wheel (18-19) fixed on a horizontal shaft (15) mounted on the body of a grab (4) with pivoting fingers. An apparatus (14) for actuating the pivoting fingers connected to the shaft allows them to open and close to take up or, alternatively, release the absorbent unit. Drive chain wheels (25-26) allow the portions (20-21) of a chain supporting the carrier pulley (18-19) to be moved, either in synchronism to move the absorbent assembly or with a differential movement to actuate the pivoting fingers of the grab (4). A single differential pinion apparatus (31-32) allows the two kinds of movement to be carried out. The invention can be applied particularly to the control and emergency shutdown of pressurized water nuclear reactors.

Differential movement chain mechanism for controlling a nuclear reactor

Apparatus for controlling a nuclear reactor by vertical displacement of a unit absorbing neutrons, comprising, inside a sealed enclosure (1) in communication with the interior of the reactor, a movable magnetic piece (6) connected to a control shaft (3) which is itself connected to the absorbent unit. This magnetic piece (6) has at least two radial projections (7). The magnetic piece (6) is displaced by an inductor (10) with at least two pole shoes (16) corresponding to the projections (7) on the magnetic piece (6) and allowing magnetic coupling between the inductor (10) and the magnetic piece (6). The inductor (10) and its displacement device (30, 32, 33) are disposed outside the sealed enclosure (1). A control means (38) allows the control shaft (3) to be uncoupled from a member (36, 37) assuring its suspension so as to drop the absorbent unit in the event of emergency shutdown. The apparatus is particularly applicable to control rods of pressurized water nuclear reactors.

Apparatus for controlling a nuclear reactor by vertical displacement of

A rack and pinion mechanism for vertical up-and-down movement of neutron-absorbing control elements to control the power and to shut down a nuclear reactor in case of emergency. The upper portions of the elements constitute the rack, engaging a rotatably driven pinion perpendicular thereto and having teeth on a lateral face engaging corresponding teeth of a clutch pinion. The rack and pinion remain on continuous enagement, while the clutch pinion selectively engages and disenages the pinion, the translatory axial movement of the clutch pinion being controlled by a vertically moving actuating member controllable from the upper part of the apparatus.

Rack and pinion mechanism for moving a unit absorbing neutrons in a

A finger mechanism for controlling vertical displacement of a neutron-absorbing assembly in a nuclear reactor for power adjustment and emergency shut-down of the reactor comprises two hooks each having a body carrying pivotable fingers which are engageable in circular notches provided in a control bar which supports the neutron-absorbing assembly from its lower end. The hook bodies are movable vertically relative to the control bar in opposite directions to alternately engage and move the control bar vertically. The fingers are pivoted synchronously with movements of the hook bodies and movements of the hook bodies and fingers are controlled by rotatable cams driven by a common drive so that the control rod is displaced in a continuous movement during rotation of the cams. Means are provided for maintaining the cams controlling the fingers in operative position, said means being releasable for causing all the fingers to release the control bar so that the neutron-absorbing assembly suspended from the control bar can drop immediately into a position of maximum engagement for shut-down of the reactor.

Finger mechanism, with a cyclic movement, for controlling a nuclear

Method and device enabling the injecting in the cutting groove of a gas coming from a nozzle at a supersonic speed, brought to a temperature which may probably be very high. A device for injecting an auxiliary gas ensures the protection of the front lens of the laser. Increase in the cutting speed.

High energy laser beam cutting method and apparatus

Rotating seal sealing by viscous effect, intalled on a rotating shaft crossing through a bore separating, from the outside medium, an enclosure containing a fluid kept under pressure, comprising at its center two threads having an unequal length and having reverse pitches, separated by a groove and two lip seals for a rotating shaft of the conventional type on either side of the threads. The gap between the two lip seals is fed with viscous fluid by two tanks, one of which is at the pressure of the fluid for which sealing is to be provided. Application to the passing of shafts rotating at a high speed for all types of enclosures containing a gas or a liquid under pressure which can reach several tens of bars.

Rotating seal

Partly melting rotating seal assembly surrounding a rotating shaft crossing through a wall limiting a volume of fluid kept under pressure, constituted by a solidified sleeve of the fluid to be sealed or of an intermediate fluid, contained in an external metallic sleeve fast with the wall, provided with cooling means. A very thin thread, fast with the shaft, maintains during the rotation of the shaft, a thin liquid film between the shaft and the solidified sleeve, ensuring sealing along said shaft.

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Chatillon, France

Jean Martin