Advanced Analysis of the IAEA Fork Detector Data for
Partial Defect Verification

In recent years, a new advanced analysis approach has been developed for fork detector data, whereby the neutron and gamma radiation measured by the fork detector are compared with the values calculated by the ORIGEN depletion code using the operator’s declaration of the spent fuel assembly history. The IAEA’s Department of Safeguards (SG) has applied this algorithmic analysis procedure on a large set of PWR and VVER-1000-type spent fuel assemblies verified with the IAEA/SG fork detectors. The analysis shows the standard deviation of the difference between the measured and calculated neutron and gamma radiation to be 8% and 6%, respectively. Taking into consideration that the neutron radiation is proportional to the mass of the spent fuel assemblies, the IAEA is pursuing the authorization for field deployment of the fork detector for partial defect verification of PWR-type spent fuel assemblies. Details of the analysis methodology, including the normalization procedure, and the results of the analysis for a population of PWR spent fuel assemblies will be presented.