High Count Rate, High Temperature Neutron/Gamma Detector for Advanced Reactors

One of the goals of DOE’s MPACT program is to develop nuclear material accounting (NMA) methods for next generation, advanced fuel cycles such as Molten Salt Reactors (MSR). There are several challenges for NMA of MSR, for example, the high temperature and high dose rates, at which the measurements need to be performed. The goal of the proposed research is to develop high-count-rate, high temperature neutron/gamma-ray detectors that can operate in an MSR environment. We will utilize dual-mode sensors developed at RMD that provide excellent gamma spectroscopic capabilities and high sensitivity to neutrons. A robust detector using an advanced scintillation material integrated within a high-temperature design and interfaced with custom, digital readout electronics to perform pulse shape discrimination (PSD) for independent gamma ray spectroscopy and neutron detection under high radiation fields will support NMA at MSR. In our ongoing Phase II research, we successfully demonstrated the prototype instrument by developing a high temperature detector (HTD) with a CLLBC scintillator. The HTD that can operate up to 175?C was designed, developed, and constructed at RMD and shows excellent gamma-ray and neutron detection performance at elevated temperatures. The development of FPGA electronics that can perform gamma spectroscopy at high count rates is underway. Currently the system is at the laboratory stage at TRL 4. The Phase IIA plan is an extension of Phase II research where development efforts will be carried out to upgrade the instrument to commercial quality for MSR monitoring, with the goal of advancing it to the TRL 5-6. These efforts will include (1) develop a new revision of electronics (2) develop software/UI for data retrieval and analysis (3) design, build, and evaluate the instrument with special nuclear materials. A radiation detection system capable of simultaneous detection of gamma-rays and neutrons at high count rates and temperatures, with good gamma-ray resolution and neutron efficiency will easily find its application in nuclear power plant management, decommissioning, well logging, dosimetry, and homeland security.