| 摘要 |
<p>1. Device for measuring the local power in a nuclear reactor, comprising a gamma sensor (10) positioned within a tubular guide (18) of a fuel assembly, said sensor having an elongated gamma heated body (12) provided with relatively hot and cold regions, an outer sheath (11 or 46) in thermal contact with the body (12) along the cold region to establish symmetrical heat distribution in response to uniform external cooling of the outer sheath within an annular gap (33) between said outer sheath (11 or 46) and the tubular guide, and means constituting centering means and a thermal bridge (36, 40; 42; 44; 52) which thermally connects the outer sheath and the tubular guide at the same axial level as the cold junction (30) of a measuring thermocouple whose hot junction is located in the hot region, characterized in that the hot junction of the thermocouple is located midway in the hot region and in that the thermal bridge is located at the axial level of the cold region of the body (12), as close as possible to the boundary with a hot region (14) which is constituted, in a known per se manner, by a part of reduced diameter of the body, at a location which however corresponds to a flat portion of the axial temperature distribution curve, wherein local centering by said means prevents occurence of an unsymmetrical temperature distribution.</p> |
