Fast neutron detection for spent PWR fuel in dry storage

Nuclear safeguards is of fundamental importance for any country operating nuclear power plants. The management of spent nuclear fuel (SNF) recently became important concern in S. Korea due to nuclear-free energy policy and out of pool storage capacity. These would lead to require the accelerated plan how to secure SNF in dry storage. SNF in dry storage is notoriously difficult to accurately verify with nondestructive methods, so it is necessary to develop nondestructive techniques for ensuring and verifying the integrity of spent nuclear fuel. Several techniques based on gamma and thermal neutron detection have been developed and applied for the monitoring and certification of SNF. However, there are very limited technologies available due to the influence of shielding materials and interference of background radiation. Therefore, Korea Institute of Nuclear Nonproliferation and Control (KINAC) currently proposed a novel SNF monitoring technique using He-4 scintillation fast neutron detectors. Currently, the new proposed study for SNF neutron monitoring is ongoing at KINAC. Based on the proposal, the present authors have designed, optimized, and built an experimental apparatus and computation tool capable of verifying SNF integrity in a dry cask or storage. The groundwork such as energy discrimination, gamma rejection, and others for a new approach has been laid. The next step will be sensitivity studies of parameters which have non-negligible contributions