Patent GB-933475-A (GB)
Title: Improvements in or relating to nuclear reactors
Inventor: KISTRUCK JOHN ROGER SCRIVENER
IPC: G21C17/10
Filed: 1959-08-07
Abstract: 933,475. Nuclear reactors. BABCOCK & WILCOX Ltd. Aug. 8, 1960 [Aug. 7, 1959], No. 27100/59. Class 39 (4). In a nuclear reactor of the kind having a core with fuel channels arranged to be traversed by a coolant having a low electrical conductance and means for measuring temperatures of fuel elements in the channels, the electrical circuit of a temperature responsive device mounted on a fuel element in a channel includes fixed first contacts at the wall of the channel mutually circumferentially displaced and second complementary contacts carried by the fuel element, and fixed guide means provided at the periphery of the channel are adapted during longitudinal movement of the fuel element to its operative position in the channel to effect such orientation of the fuel element in the channel that the second contacts engage respective first contacts. The fuel element may be enclosed in a can provided with cooling fins and with four splitters 25, Fig. 1, which are held in place by a brace 57 which passes through gaps provided in the splitters. Each splitter carries a pair of spring contacts secured to a support extending across these'gaps, the upper contacts 51X extending clockwise in Fig. 1 from the splitters and the lower contacts (not shown in Fig. 1) extending anti-clockwise. The upper contacts are electrically connected to each other and to one side of a thermocouple 23 attached to the fuel can, and the lower contacts are similarly connected to the other side, the connection being made of wires of the same materials as those forming the thermocouple. The contacts may be of stainless steel and are adapted for connection to fixed contacts 33, respectively of the same metals as the thermocouple so that the contacts link two conducting parts of the same metal and no net e.m.f. is set up by these junctions. The contacts 33 may be vertical wires embedded in a guide member 7 and connected to terminals 41 on the other side of the guide member, from which terminals wires extent to the outside of the reactor. Guide member 7 lines one quadrant of a fuel channel, the remaining part of the channel being lined with a graphite sleeve 5. At the junction of member 7 and sleeve 5 are raised portions 9 forming abutments and, as shown in Fig. 3, member 7 is provided with a raised portion 7A of which the boundaries 7C form guide surfaces extending from abutments 9 to points 27. Thus when a fuel element is lowered into a channel, one of its splitters 25 will contact surface 7C and rotate the element as it is lowered until it is correctly orientated with a splitter 25 adjacent each abutment 9 and the contacts on the splitters engaging the respective fixed contacts 33. Similarly, if a lower fuel element is to be raised past guide member 7, its splitters rotate it to the correct orientation by engaging the lower surfaces 7C. In another arrangement, Fig. 6, not shown, each splitter 25F carries a pair of plates 51FX and 51FY which are generally flat but curve away from the splitter in their central regions; the plates 51FX are connected to one lead from the thermocouple and the plates 51FY to the other, and they are adapted to make contact with fixed contacts 97 and 99 respectively which are attached to the guide member 7F. The guide member is provided with converging ridges 103 and 105, Fig. 7, not shown, to guide the splitters 25F as the fuel element is lowered into position or raised from a lower position.