[1A06-13] Contamination Measurement Techniques

3:00 PM - 3:15 PM JST(6:00 AM - 6:15 AM UTC)

[1A07] Development of analysis and estimation techniques to determine the properties of fuel debris(2) Development of active neutron method

*Yosuke Toh¹, Makoto Maeda¹, Masao Komeda¹ (1. JAEA)

Keywords:

Active neutron method,Fukushima Daiichi Nuclear Power Plant,Non-destructive assay,Nuclear fuel material,Decommissioning

This report presents the evaluation results of the applicability of the Fast Neutron Direct Interrogation (FNDI) method and the Fast Fission Neutron Coincidence Counting (FFCC) method for fuel debris sorting. The FNDI method utilizes fission reactions induced by thermal neutrons to measure fissile material, providing the total amount of fissile material. The FFCC method uses fission reactions induced by fast neutrons to measure the total amount of uranium. The results of simulations showed that while the FNDI method is difficult to measure debris containing neutron absorbers, the neutron die-away times obtained could potentially be used to correct FFCC measurements. Additionally, the FFCC method was found to be capable of measuring debris even in the presence of neutron absorbers.