Year
1996
Abstract
An Ultra– Violet Image Intensifier (W–II) type Improved Cerenkov Viewing Device (ICVD) is used for the identification of LWR spent fuel assemblies stored in a pond However, it is difficult or impossible to apply the ICVD to low bumup or long cooling time assemblies, so the UV– II type Advanced CVD (ACVD) has been developed The ACVD uses a proximity focused type UV– II, a CCD camera and an image processor to improve the image quality. In this paper, the performance limit of the ACVD is discussed based on a specific comparison between the ICVD and ACVD and the characteristics of human eyes. The observation range of the ACVD is more than twice that of ICVD with the real time operation mode of the CCD camera (30 frameslsecond). When an image is integrated for 1 second in the CCD camera, the observation range of the ACVD is extended more than 4.5 times. Moreover, when an image processor is used with the CCD cmnera, the performance limit becomes more than 10 times that of the ICVD. As a result, this ACVD system can detect Cerenkov glow images radiated from spent fuel assemblies with a burnup of more than 4,000 MWD/MTU and a cooling time of less than 30 years.