REVIEW OF EVALUATION OF HOLD UP MEASUREMENTS

The purpose of this work is to assess the importance of hold up determination in nuclear fuel cycle facilities and to discuss the present status and future development of holdup measurements. It is shown that the measurement uncertainty of holdup contributes significantly to LEMUF in the mixed oxide fuel fabrication plant. In other cases like the reprocessing plant, the contribution is insiginificant. The nuclear material signatures available for holdup measurements are reviewed. The possibility of using the more penetrating gamma rays emitted by traces of fission products such as Zr95-Nb95 and Rhl06-Rul06 is suggested. A variety of recent holdup measurements indicate that systematic errors between 20% to 50% are attainable. The lower values are obtained under more favorable conditions. For many applications the higher error is acceptable and can be easily achieved even in the present industrial environment.