General Electric Company

James Edward Charnley

John Geddes Erbes

Grant Clark Jensen

Robert C Dixon

Louis L Aiello

Gerald A Deaver

Robert James Law

Paul H Tacheron

David O Monserud

David H Bothell

Michael C McDonald

Gunnar V Vatvedt

James A Mees

David E Steele

James H Terhune

Henry Peter Offer

Gerald M Gordon

Robert W Whitling

Barry Hal Koepke

James E Cearley

Robert L Cowan, Ii

Irvin R Kobsa

Lawrence Michael Grycko

Kenneth R Izzo

Beth Ann McAllister

Robert Lee Cowan Ii

Robert J Brandon

Thermal sleeve assemblies for connecting a core spray line to a reactor safe end without welding. In one embodiment the thermal sleeve assembly includes a t-box junction, a thermal sleeve and a finger assembly. The t-box junction is attached core spray lines and the thermal sleeve. The finger assembly is coupled to the thermal sleeve and includes several fingers. The finger assembly includes a ring which is coupled to the thermal sleeve so that an opening in the ring is aligned with a bore extending through the thermal sleeve. The fingers are substantially L shaped and are attached to the ring so that when the ring is welded to the thermal sleeve second end the fingers extend from the thermal sleeve.

Assemblies and methods for coupling piping to a safe end of a nuclear

Pipe connector assembly for replacing a core spray line in a nuclear reactor without field cutting, measuring, or welding such line. In one embodiment, the pipe connector assembly includes a first coupling member, a second coupling member, and at least one locking element. The first coupling member includes a flange, a pipe engaging portion, a spherical convex seat portion, a bore and a stud bore. The second coupling member includes a flange having a spherical concave seat portion for receiving the convex seat portion of the first coupling member, a pipe engaging portion, a bore, and a stud bore. The locking element includes at least one spherical washer and a crimp mechanism and couples the first coupling member and the second coupling member by extending through the flange stud bores. The spherical seat portions allow the coupling members to be rotationally misaligned while remaining to be substantially coaxially aligned thus accommodating additional core spray line length while maintaining a leak tight connection.

Pipe connector assembly

An apparatus for repairing a shroud in which one or more seam welds are cracked. The repair involves the attachment of a splice bracket to the shroud so that the bracket bridges the cracked weld seam and is applicable to both vertical and horizontal weld seams. The bracket is intended to structurally replace the shroud seam weld which is cracked. Multiple splice brackets can be placed along the length of a crack. Each splice bracket is attached to the shroud by a plurality of tapered fastener assemblies. Each tapered fastener assembly includes a first fastener element having a threaded surface and a conical surface coaxial with the threaded surface; a slotted sleeve having an internal surface which matches the conical surface of the first fastener element and an external surface which matches a circular cylindrical surface, and a flange which extends radially outward beyond the external surface; and a second fastener element having a threaded surface threadably engaged with the threaded surface of the first fastener element. The sleeve fits inside aligned holes in the splice bracket and shroud.

Reactor core shroud repair using splice plate to bridge weld seam

An apparatus for stabilizing a shroud against vertical and lateral deflection. The apparatus forms a vertical load path by which the shroud flange can be anchored to the shroud support plate. In the tensioned state, an upper support assembly exerts a restraining force on the top surface of the shroud flange which opposes separation of the shroud at any assumed failed circumferential weld location. The apparatus further incorporates upper and lower restraint springs which oppose lateral deflection at the elevation of the top guide support ring and at the elevation of the core plate support ring respectively. The vertical restraint assembly is made of material having a coefficient of thermal expansion which is less than a coefficient of thermal expansion of the shroud material. A desired differential thermal expansion of the vertical restraint assembly and the shroud can be attained by the selection of member lengths and materials having appropriate coefficients of thermal expansion. In particular, the vertical restraint assembly undergoes a thermal expansion which is less than the thermal expansion of the shroud when the reactor changes from a shutdown state to a fully operative state in which nuclear heat is generated, thereby producing a thermal load. The thermal load during normal operation for a shroud with the limiting combination of cracked welds should be designed to provide a net downward load on the shroud.

Vertical and lateral restraint stabilizer for core shroud of boiling

A welded bracket for use in repairing a shroud in which one or more shroud girth seam welds have experienced stress corrosion cracking. A plurality of the welded brackets are placed around the outer circumference of the shroud at a plurality of azimuthal positions at the elevation of the top guide support ring. Each bracket is constructed by welding curved plates. Welding productivity is increased by using an extremely thin weld joint design with a non-circular cylindrical, thin welding electrode having an elongated cross-sectional shape. During welding, the elongated dimension is aligned parallel with the length of the weld joint. This combination enables joining of the welded bracket parts with both the initial weld joint preparation and the completed weld having a uniquely thin width and with a high aspect ratio of depth to width. This high aspect ratio reduces the number of weld beads needed to build the weld joint. The high aspect ratio, in combination with torch travel speeds of 12 or more inches per minute, increase welding productivity, thereby reducing reactor downtime resulting from shroud repair.

Reactor core shroud repair with welded brackets

A method and an apparatus for repairing a shroud in which one or more shroud girth seam welds have experienced SCC. The method involves the placement of a plurality of brackets around the outer circumference of the shroud at a plurality of azimuthal positions. Each bracket has circular holes for receiving respective tapered pin assemblies. Corresponding circular holes are machined in the shroud wall at positions which will align with the holes in the bracket. Each tapered pin assembly is inserted and then manipulated remotely from outside the shroud. Each tapered pin assembly consists of three types of parts: a threaded tapered pin, a slotted sleeve with a tapered bore, and a threaded nut. When fully installed, the tapered pin is encased by the sleeve. As the tapered pin is tensioned, the sleeve exerts a radially outwardly directed contact pressure on the cylindrical surface of the aligned circular holes respectively formed in the bracket and shroud.

Reactor core shroud repair with tapered pins

An apparatus for cleaning inlet mixers while they remain in their operating position within a nuclear reactor. A cleaning tool is inserted by remote control into the inlet mixer via a secondary inlet opening. Following insertion of the cleaning tool, the internal surfaces of the inlet mixer are cleaned with a waterjet created from an ultra-high-pressure source and directed by controlled positioning of a cleaning head having a nozzle which scans the cleaning waterjet across the surface to be cleaned. The cleaning system includes a nozzle cleaning tool, a throat/barrel/flare cleaning tool, pumping systems for supplying ultra-high-pressure equal to at least 20,000 psi and low-pressure water to an installed cleaning tool, a launching system located at the top of the opened reactor vessel for feeding the water conduits (power), control cables, monitoring cables (instrument) and cleaning tool into and out of the inlet mixer, and a computerized process monitoring and control system.

In situ inlet mixer cleaning system

A catalytic recombiner device for reacting two or more molecular species having dilute concentrations in fluids flowing in pipes at elevated temperatures. The species are stable in the bulk fluid, but because of a high electrochemical potential, the species create conditions favorable to stress corrosion cracking in the pipe walls. If the pipe forms a portion of a coolant system, as in a nuclear power plant, the dissolved chemical species are transported and distributed throughout the system with undesirable consequences. To reduce the electrochemical potential, a cartridge having catalytic surfaces is installed in the flow upstream of the component to be protected against stress corrosion cracking. The catalytic surfaces of the cartridge form a small amount of benign reaction product (e.g. water), thereby reducing the concentration of undesirable species. The presence of a compact catalytic recombiner at strategic locations substantially reduces the electrochemical potential and protects both the piping and the vessels and internals connected to the piping from corrosive attack.

Method and apparatus for local protection of piping systems from stress

A method and an apparatus for repairing a shroud in which the top guide support ring has been subjected to stress corrosion cracking. The method involves the placement of a plurality of clamps around the outer circumference of the shroud at a plurality of azimuthal positions between jet pump assemblies. The clamps structurally replace the welds that join the top guide support ring to the upper and lower shroud walls. The shroud repair clamps support the top guide, the fuel bundle assemblies and the shroud head. The shroud repair clamps are bolted to the shroud above and below the top guide support ring in a manner which will prevent relative movement across the top guide support ring welds during all normal and upset conditions.

Shroud repair clamp

A method for cleaning inlet mixers while they remain in their operating position within a nuclear reactor. A water-powered cleaning tool is inserted by remote control into the inlet mixer via a secondary inlet opening. Following insertion of the cleaning tool, the internal surfaces of the inlet mixer are cleaned with a waterjet created from an ultra-high-pressure source and directed by controlled positioning of a cleaning head having an nozzle which scans the cleaning waterjet across the surface to be cleaned. The cleaning system for carrying out the method includes a nozzle cleaning tool, a throat/barrel/flare cleaning tool, pumping systems for supplying ultra-high-pressure equal to at least 20,000 psi and low-pressure water to an installed cleaning tool, a launching system located at the top of the opened reactor vessel for feeding the water conduits (power), control cables, monitoring cables (instrument) and cleaning tool into and out of the inlet mixer, and a computerized process monitoring and control system.

Method for in situ cleaning of inlet mixers

An internal passive catalytic device operating in the water phase of a boiling water reactor vessel downstream of the steam/water separator location. The device consists of catalytic material arranged and situated such that all (except perhaps a small leakage flow) water phase exiting the water/steam separator device flows over the surface of the catalytic material. The catalytic surfaces decompose dissolved hydrogen peroxide into water and oxygen. When the substrate of the catalytic material is plated or alloyed with a water recombination catalyst such as a noble metal, the catalytic surfaces also catalyze the recombination of dissolved hydrogen and oxygen molecules into water. The passive catalytic device is constructed to ensure that the pressure drop of the reactor water across the device is very small. The device includes a stainless steel flow-through housing packed with catalytic material, which could take the form of tangled wire or strips, crimped ribbon, porous sintered metal composite or any other structure having a high surface area-to-volume ratio.

Internal passive water recombiner/hydrogen peroxide decomposer for a

A passive decomposer operating in the water/steam mixture exiting the core of a boiling water reactor. The decomposer comprises a catalytic material arranged and situated such that substantially all of the water/steam mixture entering the water/steam separator device flows over the surface of the catalytic material. The catalytic decomposing surfaces decompose hydrogen peroxide molecules dissolved in the liquid phase to form water and oxygen molecules. The passive catalytic decomposer is constructed to ensure that the pressure drop of the reactor water across the device is very small. The decomposer can include a plurality of stainless steel flow-through housings packed with stainless steel catalytic decomposer material, which could take the form of tangled wire or strips, crimped ribbon, porous sintered metal composite or any other structure having a high surface area-to-volume ratio.

Internal passive hydrogen peroxide decomposer for a boiling water reactor

An apparatus and process for the construction of a cruciformed section control rod is disclosed. The control rod is characterized by having square exterior sectioned tubes with central cylindrical volumes for the containment of neutron absorbing poisons. In the process, these tubes are welded together at the corners of the square sections to form the planar members of the cruciformed shaped rods. An apparatus and process is disclosed in which the rods are all held by a jig in the same configuration as is ultimately fabricated. Thereafter, the jig is drawn through fixtures, which fixtures accurately guide the rods to be joined by welding past paired and opposed laser welding heads. By the expedient of positioning the laser and rapidly drawing the braced together tubes by the laser, control rod fabrication occurs. There results a solid, integral control rod constituting a suitable pressure vessel for neutron absorbers for control of nuclear reactions.

Growing community of inventors

Nevada City, CA, United States of America

James Edward Charnley