IE38956L - Detecting temperature faults in nuclear reactors - Google Patents

Abstract

1468373 Monitoring nuclear reactors; fuel elements EUROPEAN ATOMIC ENERGY COMMUNITY 6 March 1974 [8 March 1973] 9986/74 Heading G6C A nuclear reactor includes a plurality of probes each having a temperature threshold and associated with a respective fuel element and temperature faults are detected and localized by monitoring the probes sequentially to determine the radial loci of any faults and, subsequently, determining the locus, along the length of a probe which has given a fault indication, of the fault. The probes 1 are scanned sequentially by a multi-way switch 8, the radial loci of indicated faults being stored in a position register 15. Subsequently, a reflectometer 18 determines the axial position of origin of signals from only the fault-indicating probes, the axial position being stored in a second register 20. A digital and/or chart form display can be provided. Each probe 1 is wound spirally about a fuel rod 2 of a bundle, the turns of the spiral being in alternation with turns of a larger-diameter spacer 6. Where the fuel rod 2 is supported by grids (7), (Figs. 4, 4a, not shown), the pitch of the probe's turns is at least twice the intergrid distance. Each probe comprises one or more electrical conductors spaced from a conductive envelope by (a) first zones of material whose resistance decreases, to render the material electrically conductive, at a specific temperture, these zones alternating axially with (b) second zones of insulating material. [GB1468373A]