Loading patent…
AssigneeWestinghouse Electric Corp.
InventorsFrank J. Baloh, James A. Sparrow
Estimating the term…
A fuel assembly in a nuclear reactor has a spectral shift apparatus including a plurality of displacer rods for controlling reactivity in the assembly and an apparatus for refurbishing the displacer rods for reuse. Each displacer rod contains a quantity of water equivalent to a small fraction of the rod volume. Also, the spectral shift apparatus includes a manifold with a central plenum and a rupturable disk connected to the manifold. The manifold is connected in flow communication with the displacer rods. The disk which seals the displacer rods as well as the manifold plenum is rupturable at a given pressure differential thereacross so as to allow entry of the moderator/coolant liquid into the manifold and rods. Also, a screen adjacent the disk restricts it to rupturing in one direction only. The spectral shift refurbishing apparatus includes a charging tool insertable within the manifold plenum and separate air and water conduits interconnecting the manifold and upper and lower portions of the respective displacer rods in flow communication so as to provide respective entrance paths for air under pressure from the charging tool to the upper rod portions and separate exit paths for liquid from the lower rod portions to the charging tool such that introduction of air under pressure along the entrance paths will force liquid from the rods along the exit paths until the level of the liquid within the rods lowers to the level of the conduits in their lower portions.
In combination with a nuclear reactor spectral shift mechanism having at least one elongated hollow water displacer rod being substantially filled with a moderator/coolant liquid, a refurbishing apparatus comprising:
In combination with a nuclear reactor spectral shift mechanism having at least one elongated hollow water displacer rod being substantially filled with a moderator/coolant liquid, a refurbishing apparatus comprising:
In combination with a nuclear reactor spectral shift mechanism having at least one elongated hollow water displacer rod being substantially filled with a moderator/coolant liquid, a refurbishing method comprising the steps of:
Dependencies are inferred from the claim text.
Drawings are temporarily unavailable. Open the PDF at USPTO
No related US applications are recorded in the indexed filing history.
By displacement of the moderator or parts thereof by changing the moderator concentration: spectral shift control
Construction of control elements: clusters of control rods; Spider construction
Energy generation of nuclear origin: nuclear fission reactors
Nuclear reactors
Term ended 1 Mar 2005 (estimated)
USPTO file history isn’t available for this patent, so only indexed dates are shown.
Reference is hereby made to the following copending applications dealing with related subject matter and assigned to the assignee of the present invention:
1. "Moderator Control Apparatus For A Nuclear Reactor Fuel Assembly" by D. B. Lancaster et al, assigned U.S. Ser. No. 623,744 and filed June 22, 1984 now U.S. Pat No., 4,657,726.
2. "Nuclear Fuel Assembly With Improved Specral Shift Rods" by H. M. Ferrari, assigned U.S. Ser. No. 638,333 and filed Aug. 6, 1984.
In the course of the following detailed description, reference will be made to the attached drawings in which:
FIG. 1 is an elevational view of a conventional fuel assembly with the refurbishing apparatus of the present invention and the spectral shift apparatus of the invention claimed in the third patent application cross-referenced above disposed in operative relationship to the fuel assembly, the latter being shown in a vertically foreshortened form with a portion of its top nozzle broken away to more clearly show the components of the refurbishing and spectral shift apparatuses.
FIG. 2 is an enlarged, partially sectioned, elevational view of the refurbishing and spectral shift apparatuses being removed from the fuel assembly of FIG. 1.
In the following description, like reference characters designate like or corresponding parts throughout the several views of the drawings. Also, in the following description, it is to be understood that such terms as "forward", "rearward", "left", "right", "upwardly", "downwardly", and the like, are words of convenience and are not to be construed as limiting terms.
Referring now to the drawings, and particularly to FIG. 1, there is shown an elevational view of a fuel assembly, represented in vertically foreshortened form and being generally designated by the numeral 10. The fuel assembly 10 is the type used in a pressurized water reactor (PWR), being illustrated diagrammatically in a simplified form in FIG. 10 and designated by the numeral 12. The fuel assembly 10 basically includes a lower end structure or bottom nozzle 14 for supporting the assembly 10 on the lower core plate (not shown) in the core 16 of the PWR 12, and a number of longitudinally extending guide tubes or thimbles 18 which project upwardly from the bottom nozzle 14. The assembly 10 further includes a plurality of transverse grids 20 axially spaced along the guide thimbles 18 and an organized array of elongated fuel rods 22 transversely spaced and supported by the grids 20. Also, the assembly 10 has an instrumentation tube 24 located in the center thereof and an upper end structure or top nozzle 26 attached to the upper ends of the guide thimbles 18. With such an arrangement of parts, the fuel assembly 10 forms an integral unit capable of being conventionally handled without damaging the assembly parts.
As mentioned above, the fuel rods 22 in the array thereof in the assembly 10 are held in spaced relationship with one another by the grids 20 spaced along the fuel assembly length. Each fuel rod 22 includes nuclear fuel pellets (not shown) and the opposite ends of the rod 22 are closed by upper and lower end plugs 28,30. The fuel pellets composed of fissile material are responsible for creating the reactive power of the PWR 12. A primary liquid moderator/coolant such as water, being held under high pressure such as 2250 psi so that it remains in liquid form, is pumped through the fuel assemblies 10 of the core 16 in order to extract heat generated therein. The primary coolant is circulated by a primary pump 31 around a closed primary path 32 which leads through a first chamber 33 of a heat exchanger 34 where the extracted heat is given up to a secondary flow of water circulated by a secondary pump 35 around a closed secondary path 36 which leads through a second chamber 37 of the heat exchanger 34. The secondary water turns to steam in the second heat exchanger chamber 37 and drives a turbine 38 which generates electricity for the production of useful work.