Abb Reaktor Gmbh

Deutsche Gesellschaft Fur Wiederaufarbeitung Von Kernbrennstoffen Mbh

Brown Boveri Reaktor Gmbh

Franz Potz

Jakob Russ

Leonhard Knierriem

Franz-Wolfgang Popp

Gunter Baro

Dieter Daum

Wolfgang Oswald

Heinz Franke

Heinz Hoffmann

A method and an apparatus for testing, repairing or exchanging nozzles of the bottom of a reactor pressure vessel include inserting individual shielding containers into the reactor pressure vessel. Shafts pass through a shielding container and water-filled cartridges can be inserted into the shafts. Tubes for receiving probes of an in-core instrumentation are embedded into bottom plates of the remaining shielding containers and into bottoms of the cartridges. After removing a cartridge, a carrier for working tools can be introduced into the shaft. In this way the radioactive loading is considerably reduced by the probes inside or outside the reactor pressure vessel.

Method and apparatus for testing, repairing or exchanging the nozzles

After some time incipient cracks may occur in nozzles welded directly into a reactor pressure vessel cover for guiding a control rod, which make it necessary to exchange the nozzles. A method is provided for exchanging the nozzles which changes the structure of the cover little during removal and accomplishes low-stress installation. According to the method, the nozzles are installed with prestressing. An annular surface is introduced from the inside of the cover coaxially to the through-bore and a supporting surface is introduced from the outside of the cover, which surfaces serve for applying the prestressing force and arresting the same.

Method of exchanging a nozzle passing through a cover of a nuclear

Upper and lower core structures of core internals carry a plurality of centering pins which have free ends protruding into recesses in a fuel assembly endpiece. In the case of the upper core structure in particular, the nuts for fixing the centering pins are difficult to access in the event of a subsequent exchange of pins. Therefore, core internals which do not require a nut for securing on the centering pins are preferred. For this purpose, a centering pin is provided with a center bore passing through it. The ends of the center bores facing away from the fuel assemblies are in the form of conically tapering stepped bores. Each stepped bore has a plug which is displaceable in axial direction relative to the centering pin. The peripheral surface of the plug is conically formed in the same direction and with the same pitch as the stepped bore. The centering pin enters into a play-free fitting connection with a bore in a grid plate. The peripheral surface of the centering pin is provided with a grooving at the level of the stepped bore, which enters into a form-locking connection with the wall of the bore in the grip plate, after relative movement of the plug and the centering pin has taken place.

Core internals of a water-cooled nuclear reactor

A hollow plug for blocking a heat exchanger tube includes an expansion zone expanded into a frictional connection with the heat exchanger tube. An outer surface in the expansion zone has a first part with a relatively greater surface hardness and a second part with a relatively lesser surface hardness. The first part has a greater surface hardness than the heat exchanger tube. The second part has a lesser surface hardness than the heat exchanger tube. The first part also has a relief pattern.

Hollow plug for blocking a heat exchanger tube

Process and holding component for repair of a nuclear reactor fuel assembly spacer support. The holding component is formed from a metal strip, on the free ends of which are introduced elastic projections. After removal of the damaged crosspiece, a holding component partly embracing the fuel rod is locked into a slot of a spacer support by means of its projections.

Process and holding component for repair of a nuclear fuel assembly

In containers having latchable covers for closing the container vessel, the overs are rigidly connected to the vessel opening and this condition can be disadvantageous under various load conditions. To attain a flexible yet secure closure, the cover is provided with an annular groove formed in the peripheral edge thereof. The cover is thereby capable of yielding under stress. For tensioning the cover, a device can be fixed in a recess formed in the inner wall surface of the vessel. Upright supports project out from a plate and are in contact engagement with an end face of the cover remote from a shoulder formed in the inside wall surface of the vessel opening. A tensioning unit is subjected to pressure and then presses the cover together in the region of the annular groove. After the latches are inserted into a recess, the tensioning unit is relieved of stress. The latches are then wedged in by the resilient action of the cover to produce a simple and reliable connection.

Growing community of inventors

Heppenheim, Germany

Franz Potz