DEVICES FOR THE DETERMINATION OF A CONCLUSION IN A CAPITAL ROOM OF A FUEL STATE

摘要

Apparatus for precisely positioning the seam on an end of a nuclear reactor fuel rod opposite from a welding electrode in a weld chamber. The circumferential seam is formed by abutting surfaces at the end plug-fuel tube interface, and it is important that the seam be located in an exact position relative to the welding electrode tip. This is accomplished by providing a stop member against which the fuel plug rests during the time an end plug is welded. The distances are chosen such that when the end plug is fully seated in the stop member, the electrode tip and seam will be located in optimum positions to effect the making of high quality welds. Open communication is established between the inside of the fuel rod and vacuum equipment which is used for evacuating the fuel rod of air or other gases during the welding operation through an axial passageway in the stop member. When evacuation is complete and the pressure drops to a predetermined low value, a vacuum switch responding to fuel rod pressure acts to close an electrical circuit which energizes the welding electrode. If the end plug is not properly seated in the step member, the desired vacuum cannot be drawn, the vacuum switch will not close, thus precluding initiation of the welding process.