The Role of Non-quantifiable Aspects in Nuclear Safeguards

Nuclear material accountancy is a fundamental and unchallenged pillar of the EURATOM and IAEA safeguards systems. Nuclear material accountancy measures have also traditionally been used to derive quantifiable safeguards conclusions. While the accomplishment of certain quantifiable conclusions is unquestionably an advantageous feature of nuclear material accountancy, it should not be overlooked, that the achievement of the safeguards objectives depends also to an increasingly large degree on so-called non-quantifiable aspects and their appropriate evaluation and follow up. Since there appears to be almost no literature available on the subject, the aim of this paper is threefold; firstly to define and to present examples of non-quantifiable aspects and their use in safeguards, both at the facility and at the headquarters level. Secondly to discuss and analyse such aspects in view of their usefulness and conclusiveness for safeguards purposes. As illustrated in the history of safeguards, the way in which such nonquantifiable information is treated, judged and followed up both inside and outside the safeguards organisations, is of fundamental importance for the detection of diversions. Third and last, ways are considered how such nonquantified aspects, wherever identified to be useful, could be better integrated in the implementation and evaluation of safeguards activities.