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US 2003/0194041 A1Published application
Test sample removal apparatus and method
AssigneeNone recorded
InventorGrant Clark Jensen
Life of this patent
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AssigneeNone recorded
InventorGrant Clark Jensen
Estimating the term…
In an exemplary embodiment, an electric discharge machining sample removal apparatus for removing a material sample from a structural component in a boiling water nuclear reactor includes a base plate, a motor mounted on the base plate, and an electrode assembly rotatably coupled to the base plate and operatively coupled to the motor. The electrode assembly includes an outer wall defining a substantially semi-cylindrical hollow cavity. The outer wall includes a conductive first arcuate portion a conductive second arcuate portion and a non-conductive third arcuate portion positioned between and coupled to the first and second arcuate portions.
An electric discharge machining sample removal apparatus for removing a material sample from a structural component in a boiling water nuclear reactor, the reactor comprising a reactor pressure vessel and a shroud, said apparatus comprising:
An electric discharge machining electrode assembly for a sample removal apparatus, said electrode assembly comprising an outer wall defining a substantially semi-cylindrical hollow cavity, said outer wall comprising:
An electric discharge machining sample removal apparatus for removing a material sample from a structural component in a boiling water nuclear reactor, the reactor comprising a reactor pressure vessel and a shroud, said apparatus comprising:
A method of excavating a material sample from a structural component in a nuclear reactor, the reactor comprising a reactor pressure vessel and a shroud with an annulus space between the pressure vessel and the shroud, said method comprising:
Dependencies are inferred from the claim text.
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Arrangements for treating, for handling, or for facilitating the handling of, fuel or other materials which are used within the reactor, e.g.…:…
Remote inspection of vessels, e.g. pressure vessels: inspection of the inner surfaces of vessels
Energy generation of nuclear origin: nuclear fission reactors
Nuclear reactors
Term end not estimated
This invention relates generally to inspection of nuclear reactors, and more particularly to an electric discharge machining (EDM) apparatus for obtaining a material sample within a nuclear reactor pressure vessel.
A reactor pressure vessel (RPV) of a boiling water reactor (BWR) typically has a generally cylindrical shape and is closed at both ends, e.g., by a bottom head and a removable top head. A top guide typically is spaced above a core plate within the RPV.
A core shroud, or shroud, typically surrounds the core and is supported by a shroud support structure. Particularly, the shroud has a generally cylindrical shape and surrounds both the core plate and the top guide. There is a space or annulus located between the cylindrical reactor pressure vessel and the cylindrically shaped shroud.
FIG. 1 is a sectional view, with parts cut away, of a boiling water nuclear reactor pressure vessel.
FIG. 2 is a left front perspective view of a sample removal apparatus in accordance with an embodiment of the present invention.
FIG. 3 is a right front perspective view of the apparatus shown in FIG. 2.
An electric discharge machining (EDM) sample removal apparatus that is capable of obtaining material samples from a boiling water nuclear reactor shroud structure is described below in more detail. The EDM sample removal apparatus is easily positioned in the reactor between the shroud and the reactor pressure vessel and is capable of maintaining position in the reactor to complete the process of material extraction from the shroud structure.
Referring now to the figures, FIG. 1 is a sectional view, with parts cut away, of a boiling water nuclear reactor pressure vessel (RPV) 10. RPV 10 has a generally cylindrical shape and is closed at one end by a bottom head 12 and at its other end by a removable top head 14. A side wall 16 extends from bottom head 12 to top head 14. Side wall 16 includes a top flange 18. Top head 14 is attached to top flange 18. A cylindrically shaped core shroud 20 surrounds a reactor core 22. Shroud 20 is supported at one end by a shroud support 24 and includes a removable shroud head 26 at the other end. An annulus 28 is formed between shroud 20 and side wall 16. A pump deck 30, which has a ring shape, extends between shroud support 24 and RPV side wall 16. Pump deck 30 includes a plurality of circular openings 32, with each opening housing a jet pump 34. Jet pumps 34 are circumferentially distributed around core shroud 20. An inlet riser pipe 36 is coupled to two jet pumps 34 by a transition assembly 38. Each jet pump 34 includes an inlet mixer 40, and a diffuser 42. Inlet riser 36 and two connected jet pumps 34 form a jet pump assembly 44.
Heat is generated within core 22, which includes fuel bundles 46 of fissionable material. Water circulated up through core 22 is at least partially converted to steam. Steam separators 48 separates steam from water, which is recirculated. Residual water is removed from the steam by steam dryers 50. The steam exits RPV 10 through a steam outlet 52 near vessel top head 14.