GB1017401A - Locating device - Google Patents

Abstract

1,017,401. Fuel elements. ENGLISH ELECTRIC CO. Ltd. June 8, 1962 [June 9, 1961], No. 20889/61. Heading G6C. Two fuel elements are located one above the other, in predetermined relative angular orientation about a common axis, by means of a locating member fixed to one end of each fuel element and comprising at least one sloping guide surface and at least one thrust surface, the guide surfaces of the two elements cooperating to guide the elements towards the desired relative angular orientation and the thrust surfaces co-operating to maintain this orientation when the upper element is supported on the lower. Referring to Figs. 1 and 2, locating members 10, 11 screwed into the corresponding end portions of fuel elements 12, 13 each have three helical guide surfaces 18 joined by flat thrust surfaces 19, the member 10 also having a conical protrusion or cone 29 and the member 11 a corresponding conical depression or cup 28. The fuel element 12 is lowered on to the fuel element 13 in a vertical fuel channel of a nuclear reactor until the surfaces 18 of the member 10 engage those of member 11, this occurring before the cone 29 engages the cup 28, and is caused by its own weight on further lowering to turn with respect to the element 13 until the cone 29 is fully home in the cup 28. At this stage there is a slight clearance between the thrust surfaces 19 of the two locating members but this is taken up if coolant flowing past the helical cooling fins of the element 12 exerts a torque on the element, the guide surfaces 18 then being out of contact with each other. In either case the weight of the element 12 is taken by the cup 28 and the cone 29. The relative angular orientation of the fuel elements is determined so as to give the best heat transfer characteristics between the fuel elements and the coolant and the least loss of pressure in the coolant, preferably also to minimize vibration or movement of the elements caused by the coolant flow. In order to adjust the orientation of the locating members with respect to the fuel elements, shims 16, 17 may be inserted between them.