摘要:
The present invention relates to a nuclear reactor, in particular a pool-type nuclear reactor cooled with liquid metal (for example, a heavy metal such as lead or lead-bismuth eutectic) or with sodium or molten salts, having a core formed by a bundle of fuel elements and immersed in a primary fluid circulating between the core and at least one heat exchanger; the fuel elements extend along respective parallel longitudinal axes and have respective bottom active parts immersed in the primary fluid to constitute the core, and respective service parts that extend at the top from the active parts and emerge from the primary fluid; the fuel elements are mechanically supported via respective top end heads anchored to supporting structures and can be operated via handling machines.
摘要:
An assembly of the type having a water channel extending along a longitudinal axis and having an upper section of larger cross-section area than a lower section and at least one fuel rod receiving groove extending longitudinally on the outer surface of the lower section, fuel rods extending longitudinally and disposed around the water channel and fixing members for fixing at least one fuel rod to the water channel in the at least one groove below the upper section.According to one aspect of the invention, the at least one groove extends along the upper section such that a fuel rod received in fixing members is longitudinally extractable or insertable from the upper end side of the fuel assembly.
摘要:
A method and apparatus for securely fastening a pipe collar or a bracket to a riser pipe of a boiling water reactor (BWR) jet pump assembly. A pipe plug assembly includes an angled pipe plug that acts as a wedge to expand a bushing assembly as the pipe plug is drawn into the overall pipe plug assembly. Expansion of the bushing assembly allows a tight tolerance to exist between an outer diameter of the pipe plug and an inner diameter of the collar/bracket and riser pipe. Expansion of the bushing assembly allows a straight hole to be match drilled into the collar/bracket and riser pipe, thereby avoiding a more complicated tapered hole to be drilled into the collar/bracket and riser pipe. An ensuing tight fit between the pipe plug assembly, the collar/bracket and the riser pipe mitigates vibration of components and minimizes leakage to acceptable levels for use in the flooded environment of the annulus region where the jet pump assembly exists in the BWR.
摘要:
A plate mounted fuel assembly hold-down system that provides a defined channel for both the insertion and removal of reactor head mounted, fixed in-core detector instrumentation, provides a guided path for the fixed in-core detector during insertion, and shields the instrument shroud against coolant cross flow. The hold-down assembly includes a base plate that seats on the adapter plate of the fuel assembly and has openings that align with the control rod guide thimbles. A hollow sleeve extends through and below a central opening in the base plate to mate with the fuel assembly instrument thimble. The sleeve extends above the base plate and through and above an upper core plate of the reactor. A hold-down bar is slidably mounted on the sleeve and is restrained below the top of the sleeve. A spring is positioned around the sleeve and is captured between the hold-down bar and the base plate.
摘要:
A method of repairing a vessel bottom head penetration of a nuclear reactor is presented, said penetration comprising a tube fastened to the internal wall of the vessel bottom head by an internal weld bead and emerging outside the vessel bottom head, forming a groove. The method consists inter alia in preparing a mock-up representative of the vessel bottom head penetration to be repaired and in depositing this mock-up on site in an irradiation-free zone, in fastening two half-inserts to this mock-up in the groove, each half-insert having a profile corresponding to the half-profile of the groove, in forming, again on this mock-up, automatically and by remote control, a weld bead in the groove, in carrying out a dimensional check and, after validation of this weld bead, in carrying out the steps of fastening the two half-inserts and forming a weld bead automatically, directly in the groove of the vessel bottom head penetration to be repaired.
摘要:
A particle therapy system that includes at least one irradiation chamber, in which an object is irradiated with a treatment beam, an antechamber, which is screened off from radiation occurring in the irradiation chamber and from which access is made to the irradiation chamber, and an access area, which leads to the irradiation chamber and connects the irradiation chamber to the antechamber, is provided. A support for a patient moves along a path of travel from the antechamber, through the access area, to the irradiation chamber. A radiation protection door is arranged in the access area, and the access area is configured geometrically in such a way that the path of travel in the access area is substantially rectilinear.
摘要:
An apparatus and method for determining terminal solid solubility temperature in materials capable of forming hydrides, such as reactor pressure tubes. An inspection device is positioned within the reactor pressure tube under test and a pair of annular seals are radially deployed to seal a section of the pressure tube. Any water within the sealed section is displaced through the injection of gas and the heating of the sealed section to dry the tube and the device. A probe assembly on the device is deployed to contact the interior surface of the pressure tube and measure resistivity changes in the pressure tube wall as a function of temperature. The probe assembly includes a thermocouple probe for measuring temperature and transmit and receive coils for inducing eddy currents within the pressure tube wall. The pressure tube is allowed to cool at a predetermined rate, is reheated at a predetermined rate, and is allowed to cool again. Discontinuities within the temperature coefficient of resistivity indicate terminal solid solubility temperatures of precipitation or dissolution, which may be used to determine the hydrogen concentration of the sealed section of reactor pressure tube.
摘要:
A fuel rack for supporting radioactive fuel assemblies in an underwater (or other submerged) environment that reduces the depth required for the pool to effectuate the fuel rack loading procedure. The fuel rack is specially designed to afford lateral loading. In one embodiment, the fuel rack comprises a body structure comprising at least one substantially vertically oriented elongated cell for receiving a nuclear fuel assembly, the body having a top, a bottom and a first lateral side; at least one elongated slot in the first lateral side of the body structure that forms a passageway into the cell through which a vertically oriented fuel assembly can be loaded; and means for supporting a fuel assembly within the cell in a substantially vertical orientation. In another embodiment, the invention is a method of laterally loading a fuel rack that utilizes rotation of the fuel assembly to secure the fuel assembly within its designated cell.
摘要:
A tool assembly provides for brushing circumferential welds in a restrictive access area between a cylindrical inner member and a cylindrical outer member such as the shroud and vessel in a nuclear reactor. The tool assembly includes a circumferential plate sized larger than an outside diameter of the inner member and smaller than an inside diameter of the outer member. At least one renew brush is coupled with the circumferential plate, and a motor is coupled with the renew brush that rotates the renew brush. A driving assembly mounted between the inner member and the outer member engages the circumferential plate and circumferentially drives the circumferential plate in the restrictive access area.
摘要:
A jet pump diffuser weld repair device includes a lower ring section and an upper ring section respectively sized to fit around a circumference of the diffuser on opposite sides of the weld to be repaired. The lower and upper ring sections are provided with a plurality of aligned gripper slots. A corresponding plurality of grippers are fit into the gripper slots, where at least one of the gripper slots and the grippers defines cam surfaces shaped to drive the grippers radially inward as lower and upper ring sections are drawn toward each other. A plurality of connector bolts are secured between the lower ring section and the upper ring section. Tightening of the connector bolts draws the lower and upper ring sections toward each other.