Methods for the verification of input analysis in reprocessing nuclear fuel

The established reprocessing input analysis methods (Pu/U ratio- and volume/concentration methods) are compared with two isotope correlation techniques based on heavy isotopes and fission gas nuclides. The potential of the latter for the verification of reprocessing input data is demonstrated covering various aspects such as accuracy, intrusiveness, additional effort, independence of plant operations, reliability etc. The correlation techniques have the advantage that only one isotope ratio is to be measured; e.g. 241Pu/242Pu or 84Kr/83Kr. The isotope concentration of 240Pu can be calculated on the basis of a single correlation. The 84Kr/83Kr ratio is even not influenced by plutonium feedback. By this way measurements of volume and density as well as isotope dilution can be avoided. The only drawback is the somehow larger statistical deviation of the results. (T.G.)