摘要:
A fuel assembly is provided with a coolant ascending path for making coolant rise and a water rod having a coolant descending path for conducting the coolant.A ratio of a flow area in a coolant inlet port of the smallest in coolant ascending path 13 on the downstream side than large diameter tube portion 3E to a flow area of the largest in the axial direction of coolant ascending path 13 in large diameter tube portion 3E is set to be 0.2-20%.In the normal operation, the declination degree from the liquid level in the coolant ascending path, corresponding to the coolant flow rate of the liquid level formed in the coolant ascending path can be controlled. Further, at the time of the excess the change speed of the liquid level can also be controlled.
摘要:
A device for guiding a nuclear reactor control cluster comprises guide tubes provided in the fuel assemblies, and in the upper internals, a tubular casing having an upper closure with a hole for passing the cluster drive shaft, horizontal guide plates spaced apart along the casing and cut out so as to let the spider pass and to guide the elements of the cluster, and split tubes for guiding individual elements for protecting the elements from the action of the coolant. Openings are provided immediately below the plates at the top of each internal between the guide plates. The guide tubes in a lower portion of the casing are devoid of openings other than to a slit for passage of a spider carrying the cluster.
摘要:
The present invention discloses an improved methodology for achieving the desirable feature of recirculation flow control in a sparger-type natural-circulation BWR, enabling reactors utilzing the method to perform in load-following and/or spectral shift modes of power operations. In its broadest aspects, the invention is based on locating the feedwater sparger at an elevational level which is about water level established during normal operation of the BWR. One or more of load following or spectral shift can be performed by controlling the feedwater fed to said BWR through the feedwater inlet and into the sparger to vary the water level to be above, at or below the elevational level of such sparger.
摘要:
Slender water displacer rods for use in water reactors are provided with rings of a wear resistant coating spaced along the length of the rod. Each coating contains Cr.sub.2 C.sub.3 and is metallurgically applied and bonded to the zirconium base alloy forming the outer portion of the rod by electrospark-deposition (ESD) technique.
摘要:
A method of operating a pressurized water nuclear reactor comprising determining the present core power and reactivity levels and predicting the change in such levels due to displacer rod movements. Groups or single clusters of displacer rods can be inserted or withdrawn based on the predicted core power and reactivity levels to change the core power level and power distribution thereby providing load follow capability, without changing control rod positions or coolant boron concentrations.
摘要:
A nuclear reactor including, in the upper internals, a guide structure capable of effectively accommodating and guiding without binding the large number of neutron-absorber rods included in modern reactors of improved efficiency. The neutron-absorber rods include control rods, gray rods, and water-displacement rods. All rods are suspended in clusters from spiders or vanes. The upper internals of the reactor includes cruciform guides for the control-rod and gray-rod clusters. Each of these guides is composed of a plurality of vertical guide sections of transverse cruciform cross section. Plates extending throughout the cross-section of the reactor are supported between each pair of successive guide sections. The plates are perforated, the perforations in each plate being patterned to pass the water-displacement rod clusters. The plates are oriented so that the patterned perforations are aligned to serve as guides for the water-displacement rod clusters. The plates are of very large diameter and, as perforated, would not be self-supporting unless they were very thick. To overcome this drawback, each plate is formed of separate plate sections which are, when assembled nested together, like the parts of a "jig-saw puzzle".
摘要:
Apparatus is disclosed for introducing a low neutron moderating fluid into the reactor vessel of a spectral shift pressurized water nuclear reactor and for distributing the moderating fluid through the lower core support plate into the fuel assemblies in the core.
摘要:
A nuclear reactor system in which the neutron-energy spectrum is displaced towards lower energy (enthalpy) by a control selectively operable by commands outside of the reactor. The core of the reactor contains, in addition to fuel assemblies, sealed tubes filled with helium. The selective control of the neutron energy spectrum includes a master cylinder having a master piston. The master cylinder is immersed in the coolant and admits the coolant through a check valve. The admitted coolant serves as hydraulic fluid of the cylinder. When the external command to shift the neutron-energy spectrum is entered, the master piston compresses the coolant in the master cylinder. The compressed coolant flows into slave cylinders displacing their slave pistons. The slave pistons carry piston rods which drive rupturing tools into engagement with the tubes rupturing the tubes and admitting the coolant which is a neutron moderator and enhances the moderaton of the neutron energy.
摘要:
A nuclear fuel assembly is described for producing tritium in a light water moderated reactor. The assembly consists of two intermeshing arrays of subassemblies. The first subassemblies comprise concentric annular elements of an outer containment tube, an annular target element, an annular fuel element, and an inner neutron spectrums shifting rod. The second subassemblies comprise an outer containment tube and an inner rod of either fuel, target, or neutron spectrum shifting neutral.