Westinghouse Electric Corporation

Westinghouse Electric Company LLC

Richard E Schwirian

David E Boyle

David R Forsyth

Daniel Merkovsky

Theo Van De Venne

James R Chrise

James A Rex

Naugab E Lee

John F Kielb

Vincent A Perone

A pressurized water reactor vessel having a flow skirt formed from a perforated cylinder structure supported in the lower reactor vessel head at the outlet of the downcomer annulus, that channels the coolant flow through flow holes in the wall of the cylinder structure. The flow skirt is supported at a plurality of circumferentially spaced locations on the lower reactor vessel head that are not equally spaced or vertically aligned with the core barrel attachment points, and the flow skirt employs a unique arrangement of hole patterns that assure a substantially balanced pressure and flow of the coolant over the entire underside of the lower core support plate.

Pressurized water reactor flow skirt apparatus

A nuclear reactor vessel has a baffle-barrel assembly for supporting the fuel assemblies in its core region and guiding coolant flowing through the core region when the reactor vessel is in service. The baffle assembly includes a baffle plate fastened to a former plate by a bolt. The baffle plate has a countersunk hole extending to a smaller diameter baffle plate hole. The former plate has a bolt hole aligned with the baffle plate hole. The bolt has a head portion disposed in the countersunk hole and a shank extending from the undersurface of the head portion into the aligned bolt holes and threadedly engaged with the former plate. A hole or slot extending through or along the bolt head and externally of the shank is formed in the bolt head itself or between the bolt head and the baffle plate for flowing coolant past the undersurface of the bolt head and the crevice it forms with the baffle plate so that steam which may form under the bolt head will be readily vented, deposited particulates from stagnant coolant and precipitates from the steam will be washed from the underside of the bolt head and the adjacent crevice, and the bolt head will be cooled. Because the shank does not have an axial bore or other passageway for coolant flow, the shank can be readily untrasonically tested and its strength is not compromised. Operational reactor vessels may be backfit without having to remove and disassemble the baffle assemblies.

Nuclear reactor vessel

A pressurized water nuclear reactor pressure vessel has an upper core support plate with passageways for the passage of coolant, an upper support plate above the upper core support plate, and peripheral hollow support columns extending upwardly above the passageways in the upper core support plate for supporting the upper support plate above the upper core support plate and for guiding coolant from the passageways into the plenum. Each peripheral support column has a peripherally slotted upper portion for guiding the coolant in the peripheral support column into the plenum and an unslotted lower portion.

Pressurized water reactor vessel with slotted support columns

A new system is provided for control rod guidance support with wear mitigating features in a nuclear reactor pressure vessel. The upper guide tube and the lower guide tube structures house the control rod when it is withdrawn from the fuel core. The upper guide tube has a top enclosure plate with a drive rod opening therethrough sized to provide a predetermined clearance space between the drive rod and the top enclosure plate and to direct coolant flow between the upper and outlet plenums and through the guide tube assembly to allow transmittal of upper plenum bypass cooling flow to the outlet plenum. Structure is provided for restricting coolant flow through the top plate clearance space to reduce control rod wear. A coupler secures the drive and control rods in end-to-end relation within the guide tube assembly. The coupler is located just below the top guide tube enclosure plate with the control rod fully withdrawn. The coolant restricting structure includes a flow restricting sleeve secured to the coupler and extending upwardly over the drive rod through the top guide tube enclosure plate. A flow restrictor is located above and secured to the top guide tube enclosure plate, and it has an upper portion disposed about and spaced from the flow restricting sleeve to provide a flow gap having a flow area substantially equal to the clearance space. The flow restrictor is otherwise structured to provide at least one contraction-expansion loss above the top guide tube plate for guide tube coolant flow through the flow gap.

System providing improved guidance support with restricted coolant flow

A new design for nuclear reactor internals resulting in reduced fast neutron leakage to the reactor vessel. The first step of the two-stage process reflects high energy or fast neutrons back into the core, by placement of a reflector made of tungsten, stainless steel, or zirconium oxide in the baffle barrel region. The second stage involves reducing the energy of any fast neutrons that may pass through the reflector by the use of a neutron energy reducer, composed of an hydrogenous material such as titanium hydride, surrounding the core barrel in the areas of high neutron flux. In addition to protecting the reactor vessel wall and increasing the operating life of a nuclear reactor, the neutron economy in the core, and hence the operating efficiency of a nuclear power plant, are significantly increased.

Low neutron fluence nuclear reactor internals

A thimble guide assembly for use in a nuclear reactor includes a lower element which can be screwed into a bore in a core plate and an upper element which can be screwed to the lower element. One of the screw-connections is right-handed while the other is left-handed. The length of the upper element is selected so that the exposed portion of a thimble tube, which extends through the thimble guide assembly and into a fuel assembly above it, is relatively modest, thereby minimizing the turbulence to which the thimble tube is exposed. The lower element of the thimble guide assembly is provided with a sleeve portion which extends through the bore in the core plate, and the tip of the upper element terminates in a planar, annular lip. Both elements are provided with surfaces for engagement by wrenches or other tools. The lower element has annular grooves for engagement by a lower spring clip which is welded to the core plate and an upper spring clip which is welded to the upper element.

Growing community of inventors

Pleasant Hills, PA, United States of America

Richard E Schwirian