253 results about "Boiling water reactor" patented technology

A containment vessel includes a primary containment vessel containing a reactor pressure vessel, an upper secondary containment vessel arranged above the primary containment vessel, and a gas-phase vent pipe linking the primary containment vessel and the upper secondary containment vessel by way of an isolation and connection switching system. The gas-phase vent pipe may be arranged either inside or outside the primary containment vessel and the upper secondary containment vessel. Alternatively, it may be embedded in the wall. An igniter may be arranged in the upper secondary containment vessel. The air in the upper secondary containment vessel may be replaced by nitrogen. A gravity-driven flooding system pool may be arranged in the upper secondary containment vessel and cooling water may be led from the inside of the pool to the inside of the primary containment vessel.

A remotely controlled apparatus (112) for inspecting the core (102) and annulus (104) areas of nuclear boiling water reactors (100) includes a circumferential drive mechanism for propelling the apparatus (112) on the steam dam (108) of the reactor (100). The inspection apparatus (112) uses a set of driver rollers (314) that grip the side of the steam dam (108) and provide propulsion for the apparatus. A pinch-roller assembly with high-tension springs (308) and pneumatic air cylinders (310) is utilized for removably securing a set of pinch rollers (312) to the side of the steam dam opposite the side of the driver rollers (314). A set of rollers (304) are adapted to rest on top of the steam dam (108), supporting the weight of the apparatus (112) and enabling the apparatus to move around the steam dam (108). Two positioning guide rails (306) aid in the balance of the apparatus (112), especially when it is stationary. The apparatus (112) has a watertight main body (202), which houses the electrical control wiring and circuitry. The main body (202) has a front camera (204) and a rear camera (205) used to direct the movements of the apparatus (112). The main body also has two turret-type telescoping mast assemblies (208) with telescoping masts 210 and 212, which are capable of extending at a selected distance above and below the main body (202). The mast assemblies 210 and 212 support inspection equipment such as radiation-shielded EVT-1-capable video cameras and radiation-tolerant fiberscopes. The apparatus (112) and its inspection tools are remotely controlled via control consoles with video monitors from a low-dose, non-contaminated enclosure located remotely from a boiling water reactor.

The invention relates to the fault tree analysis system for a nuclear power plant with advanced boiling water reactor. The full digital instrument control system uses six different modes to simulate the transmission of the digital signals and the analog signals from the detection units. It is to develop the fault tree for various signal transmission modes to support the nuclear power plant in probabilistic risk assessment (PRA) and meet requirements for simulated signal detection, transmission, logic operation and equipment actuation. Thus, the digital instrument control flow process can fit into PRA model and properly reflect its importance in risk assessment.

An apparatus and method for mechanically reinforcing the weld between a riser pipe and riser brace of a jet pump assembly are characterized by first and second attachment members for attachment on a riser brace of the jet pump assembly, and first and second clamp bodies respectively pivotally mounted on the attachment members for movement to a clamping position. In the clamping position, respective abutment surfaces of the clamp bodies are forced against a riser pipe that is attached to a yoke of the riser brace. The abutment surfaces apply radial forces to the riser pipe, and the radial forces are reacted by forces applied against the yoke by respective engagement elements of the attachment members whereby the riser pipe and riser brace are clamped together between the abutment surfaces and the engagement elements.

A reactor containment vessel of a boiling water reactor configured to contain a reactor pressure vessel. The reactor pressure vessel is connected to at least one main steam pipe which penetrates the reactor containment vessel at a main-steam-line penetration point. The main-steam-line penetration point is disposed on a first side of the reactor containment vessel. Distance between outer surface of the reactor pressure vessel and inner surface of the reactor containment vessel on the first side is longer than the distance on a second side which is opposite to the first side.

A zirconium alloy that is resistant to shadow corrosion for a boiling water nuclear reactor fuel assembly component, the alloy being characterized in that:

• • its composition in percentages by weight is as follows:
    • Nb=0.4%-4.5%
    • Sn=0.20%-1.7%
    • Fe=0.05%-0.45%
    • Fe+Cr+Ni+V=0.05%-0.45%, with Nb≦9×[0.5−(Fe+Cr+V+Ni)]
    • S=traces-400 ppm
    • C=traces-200 ppm
    • Si=traces-120 ppm
    • O=600 ppm-1800 ppm
    • the balance being Zr and impurities from processing;
  • in that, during fabrication, after its last hot deformation, it is subjected to one or more heat treatments lying in the range 450° C. to 610° C. for a total duration of at least 4 h, with at least one cold rolling operation with a rolling ratio of at least 25%; and
  • in that a final heat treatment operation is performed at a temperature in the range 450° C. to 610° C. for 1 minute to 20 hours.

A fuel assembly component made of the alloy, a fuel assembly including the component, and the use thereof.

A method and apparatus for providing a Boiling Water Reactor (BWR) jet pump slip joint internal seal in the interface between an inlet mixer and a diffuser of a jet pump assembly. The internal seal provides an effective means of mitigating leakage and slip joint flow induced vibration (FIV) between the inlet mixer and diffuser to reduce damage to many of the jet pump assembly components that may otherwise be damaged by FIV. A metallic seal of the slip joint internal seal flares out to conform the internal seal to a range of gap sizes, and may be compressed or spring back to nominal dimensions as thermal expansion and contraction occurs. The internal seal is also self-expanding/self-tightening, as the internal seal flares further outward as a result of the internal pressure caused by flowing fluids in an operating jet pump assembly.

An electric power plant, e.g., a boiling water reactor nuclear power plant supplies steam generated in a nuclear reactor to a high-pressure turbine and a low-pressure turbine. The steam discharged from the low-pressure turbine is condensed with a condenser. Water generated with the condenser, used as feed water, flows through a feed water pipe, is heated with a low-pressure feed water heater and a high-pressure feed water heater, and then supplied to the nuclear reactor. The steam extracted from the high-pressure turbine is supplied to the high-pressure feed water heater. The steam extracted from the low-pressure turbine is compressed with a steam compressor, and the steam whose temperature has been increased is then supplied to the high-pressure feed water heater. The feed water to be directed to the nuclear reactor is heated in the high-pressure feed water heater by both the steam extracted from the high-pressure turbine and the steam compressed with the steam compressor. Because the feed water is heated by both the extracted steam and the compressed steam in the high-pressure feed water heater, the amount of plant service power consumed by the steam compressor can be reduced. Therefore, it is possible to increase thermal efficiency in the electric power plant when increasing the power output.

A method and apparatus for a fret resistant fuel rod for a Boiling Water Reactor (BWR) nuclear fuel bundle. An applied material entrained with fret resistant particles is melted or otherwise fused to a melted, thin layer of the fuel rod cladding. The applied material is made of a material that is chemically compatible with the fuel rod cladding, allowing the fret resistant particles to be captured in the thin layer of re-solidified cladding material to produce an effective and resilient fret resistant layer on an outer layer of the cladding.

The invention refers to a nuclear fuel, a fuel element, a fuel assembly and a method of manufacturing a nuclear fuel. The nuclear fuel is adapted for use in a water cooled nuclear reactor, including light water reactors LWR, such as Boiling Water Reactors BWR and Pressure Water Reactors PWR. The nuclear fuel comprises an uranium-containing compound consisting of UN. The uranium content of the uranium-containing compound comprises less than 10% by weight of the isotope ²³⁵U. The nuclear fuel comprises an additive substantially consisting of at least one element, in elementary form or as a compound, selected from the group consisting of Zr, Mo, Si, Al, Nb and U.

A nuclear power plant is provided including a BWR, a reactor cooling system cooling the BWR, an HWC hydrogen injection system connected to the reactor cooling system and an alcohol injection system connected to the reactor cooling system. Methods for providing methanol and hydrogen are also provided.

A new type of coated component for use in boiling water reactor (“BWR”) fuel assemblies, particularly Zircaloy spacers, having protective coatings applied to selected surfaces of the spacers in order to prevent the formation and propagation of “shadow corrosion” on adjacent zirconium alloy structures. In its broader aspects, the coating material is applied to those surfaces of the BWR components having electro-chemical characteristics that differ from zirconium alloys, such as Inconel spacers or springs. The new coatings impart an electro-chemical potential to the surfaces of the components that is substantially similar to the adjacent zirconium alloy, thereby preventing or significantly inhibiting shadow corrosion.

A method and apparatus for providing a Boiling Water Reactor (BWR) jet pump three point slip joint clamp to mitigate sleep joint leakage flow induced vibration of a BWR jet pump assembly. A collar, provided as one seamless component or in separate portions, is installed on the upper crown of a diffuser. The collar includes a lower set of fasteners and an upper set of fasteners that contact the inlet mixer and diffuser, respectively, to horizontally stabilize the inlet mixer in a fixed position inside of the diffuser. The upper fasteners may be anchored by bosses that ensure a light-weight design of the collar. An optional cantilevered seal (including a cantilevered overhang and a lip) may mitigate leakage from the slip joint interface.

The invention discloses a passive heat removal system of a boiling-water reactor based on the characteristics of a nanometer fluid and belongs to the technical field of equipment and safety of nuclear power stations. The system consists of a valve controller, a water tank, a circulating pipeline, a valve and the like. In the case of unavailability of a station power supply, the quick removal of heat in the boiling-water reactor is realized by using the higher heat transfer characteristic and lower viscosity coefficients of the nanometer fluid and higher natural circulation capacity. The aims of preventing radioactive materials from being discharged and protecting the public and environments are fulfilled. When a severe accident occurs, a safety assurance function is executed and realized. The system is good in backup safety, simple in flow, stable in performance, high in reliability, convenient for implementation and simple to control.

A method and apparatus for providing a Boiling Water Reactor (BWR) jet pump inlet-mixer integral slip joint clamp to constrain the inlet mixer and diffuser to mitigate inlet mixer flow induced vibration of a BWR jet pump assembly. The slip joint clamp includes horizontally projecting flanges with vertical sidewalls that protrude toward a lowest distal end of the inlet mixer. Fasteners penetrating the flanges provide a biasing load on the diffusers by being tightened to press against an upper crown on the diffuser. One or more flanges may be used. Laterally disposed gaps between the flanges may provide a clearance for guide ears of the diffuser to fit between the flanges.

A method for retrofitting a boiling water reactor is provided. The method includes removing a mixing chamber from a slip joint defined by a diffuser and the mixing chamber, the mixing chamber having an inner surface and a bottom edge directing flow to the diffuser such that a recirculation zone at an entrance to the slip joint creates a diverging effective path for the leakage flow entering the slip joint. The method also includes providing a new inner surface and new bottom edge, the new inner surface and the new bottom edge being reshaped to decrease the size of the recirculation zone. A jet pump is also provided.

A slip joint clamp is disclosed which structurally replaces cracked welded joints in the core spray downcomer slip joint coupling, which is part of the lower portion of internal core spray piping internal to a reactor vessel of a Boiling Water Reactor plant. The internal piping delivers core spray cooling water to the reactor core region. The clamp assembly consists of a primary clamp housing and a secondary clamp housing, which are rotationally joined together by a hinge assembly including a hinge pin. The clamp assembly is installed at a desired elevation relative to the downcomer slip joint, and then secured to the downcomer piping by installing coupling bolts and associated coupling bolt keeper nuts that hold the primary and secondary clamp housings in a facing relationship to one another around the downcomer slip joint.

A zirconium alloy suitable for forming reactor components that exhibit reduced irradiation growth and improved corrosion resistance during operation of a light water reactor (LWR), for example, a boiling water reactor (BWR). During operation of the reactor, the reactor components will be exposed to a strong, and frequently asymmetrical, radiation fields sufficient to induce or accelerate corrosion of the irradiated alloy surfaces within the reactor core. Reactor components fabricated from the disclosed zirconium alloy will also tend to exhibit an improved tolerance for cold-working during fabrication of the component, thereby simplifying the fabrication of such components by reducing or eliminating subsequent thermal processing, for example, anneals, without unduly degrading the performance of the finished component.

The invention discloses a boiling water heater, which includes a barrel shape internal tank body, a water inlet pipe, a water outlet pipe and a exhaust pipe, the upper end of the tank body, fixedly and hermetically connect to the first upper cover, the first upper cover is fixedly and hermetically connected to the second upper cover. One cavity is formed between the first and second upper covers, water inlet pipe passes through the second upper cover. An exhaust hole is set on the inner wall of water inlet pipe to connect to the cavity, a separation plate extended to the middle which is above the exhaust hole on water inlet pipe's internal wall. The invention has the characteristics of convenient installation and disassembly, convenient cleaning, and can ensure the quality of water flows out, and the production cost is low, and very safe for use.