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US 5,703,916 AGranted
Apparatus and method for loosening a stuck reactor vessel stud
AssigneeWestinghouse Electric Corp.
InventorsJohn J. Wilhelm, Herman Schemberger
Life of this patent
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AssigneeWestinghouse Electric Corp.
InventorsJohn J. Wilhelm, Herman Schemberger
Estimating the term…
Apparatus and method for loosening a stuck reactor pressure vessel stud. A nuclear reactor pressure vessel has a threaded blind bore therein receiving an upright threaded stud having a centrally disposed passage longitudinally therethrough. A pulsar pump is in communication with the passage for supplying a pulsating liquid into the passage and thence into the bore. As the fluid exits the passage, it will push against the bottom of the bore and exert an upwardly directed hydraulic force against the end of the stud for upwardly lifting the stud. A controller is connected to the pulsar pump for controllably operating the pulsar pump. As the hydraulic force of the pulsating fluid lifts the stud, the fluid will migrate between the threads of the stud and the bore for peening or removing any debris from therebetween and washing it upwardly between the stud and bore to a suction pump in communication with the bore. The suction pump suctions the debris-containing liquid from the bore. The apparatus includes a rotation tool connected to the stud for rotating the stud as the liquid is pulsed in order to enhance removal of the debris from the threads. Removal of the debris allows the stud to rotate with reduced resistance to rotation and with the normal amount of torque applied thereto.
For use in association with a nuclear vessel having a thread bore therein and a threaded stud threadably engaging the bore, the stud resisting rotation thereof, an apparatus for reducing the resistance of the stud to rotation, comprising:
For use in association with a nuclear vessel having a threaded bore therein and a threaded stud threadably engaging the bore, the stud resisting rotation thereof, an apparatus for reducing the resistance of the stud to rotation, comprising:
The apparatus of clam 6, wherein said liquid supply pulsar pump pulses the liquid at a frequency of between approximately one and ten pulses per second.
For use in association with a nuclear reactor pressure vessel having a vertically-oriented blind bore therein having first threads and defining a cavity at a proximal end of the bore, the bore receiving an upright elongate stud having second threads threadably engaging the first threads and having a proximal end thereof disposed adjacent the cavity, the stud having a predetermined weight and a centrally disposed passage longitudinally therethrough in communication with the cavity, an apparatus for reducing the resistance of the stud to rotation, comprising:
For use in association with a nuclear vessel having a threaded bore therein and a threaded stud threadably engaging the bore, the stud resisting rotation thereof, a method of reducing the resistance of the stud to rotation, comprising the step of vibrating the stud by supplying a pulsating fluid into the bore.
For use in association with a nuclear reactor pressure vessel having a vertically-oriented blind bore therein having first threads and defining a cavity at a proximal end of the bore, the bore receiving an upright elongate stud having second threads threadably engaging the first threads and having a proximal end thereof disposed adjacent the cavity, the first threads and the second threads having debris residing therebetween resisting rotation of the stud in the bore, the stud having a predetermined weight and a centrally disposed passage longitudinally therethrough in communication with the cavity, a method of reducing the resistance of the stud to rotation, comprising the step of lifting the weight of the second threads of the stud from the first threads of the bore by supplying a pulsating liquid into the passage and to the cavity, the liquid exerting an upwardly-directed hydraulic force against the proximal end of the stud lifting the stud as the liquid is pulsated, the liquid migrating between the first threads and the second threads to loosen the debris as the stud is lifted, so that the stud is capable of being rotated with reduced resistance to rotation as the stud is lifted and as the debris loosens.
Dependencies are inferred from the claim text.