Year
2018
Abstract
As new nuclear facilities are constructed around the world, the international safeguards community is burdened with the task of monitoring and inspecting the nuclear materials and activities. With limited resources, it is essential to improve the effectiveness and efficiency of monitoring systems to ensure adequate coverage. The concept of safeguards by design has addressed this need through the customization of monitoring systems within a specific facility. Often one of key features of these systems is the ability to perform unattended, continuous monitoring. However, this is only effective if the system is sustainable over time and requires little maintenance. Los Alamos National Laboratory (LANL) has designed a Glovebox Unattended Assay and Monitoring (GUAM) system for a newly planned MOX fuel production facility in Japan. The detector assembly will include over 800 3 He tubes and amplifiers built into the shielding of the gloveboxes and will perform measurements for both hold-up and process monitoring. To evaluate individual components of the GUAM system, an independent study was conducted to assess the long term performance of the Precision Data Technology (PDT) amplifiers. The purpose of this evaluation is to determine the failure rate of individual amplifiers before long-term installation in a permanent structure. A test set-up with 42 3He tubes and PDT amplifiers in a well counter geometry has been in continuous operation since 2009, measuring background and was regularly tested with 252Cf neutron sources. Data was acquired for each individual amplifier, or pair of amplifiers, to allow independent assessment. During the period of evaluation, none of the PDT amplifiers failed and one amplifier was effected by a low level of noise. The results of this testing indicate that the PDT amplifiers exhibit a good long term stability performance.