Monitoring neutrons from spent reactor fuel by bubble detectors

In order to eliminate the strong temperature-dependence of bubble detectors used for spent fuel assay, a simple way could be to keep them in the water pond but far from fuel assemblies before exposure for about 20 min, until the detectors warm up. Fast neutrons from fuel assemblies in the Paks Nucle ar Power Plant Hungary, were detected by BD-100R type detectors at 28 degre es C (in winter) and at 35 degrees C in summer). Calibration was performed by a standard Cf-252 source in berated water Burnup monitoring inside fuel assemblies can be provided by smaller diameter detectors prepared from BD-1 00R type ones.