Apparatus and method for loosening a stuck reactor vessel stud

摘要

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.