Data Splitter for Joint Use with Oversight Agencies

To establish and verify declarations of nuclear materials, frequently neutron coincidence counting is performed by both the host country and the IAEA to determine the amount of fissionable isotopes. Due to the cost, size and weight of the neutron detection system of neutron coincident counters, the practical practice of jointly using the neutron detector system located at the facility has been adopted. The IAEA has a policy for allowing an authorized joint use of equipment by the facility operators and the IAEA inspectors. The shift register component and controlling computer systems however are not currently shared. Frequently, the facility operator and the IAEA make measurements concurrently where the signals from the joint use neutron detector system are split to each party’s separate and independent shift register and data collection electronics To ensure that neutron pulse streams cannot be maliciously manipulated through the signal splitting connection Savannah River National Laboratory (SRNL), in cooperation with Oak Ridge National Laboratory (ORNL), has developed a Coincidence Counter Signal Splitter (C2S2) that will allow each party to have confidence that the other party is not manipulating the detector system signal to misrepresent the material being measured. While simple in principle, the device employs several design methodologies to make the split output tamper resistant, ensuring that the IAEA receives the same pulse stream that the host country receives. Additionally, the signal is amplified and terminated to allow possible long cable runs and avoid signal reflections which may create erroneous signals. The device also contains a switched power supply that allows the device to be resistant to interruptions which may “cancel” pulses as well as provide a much wider tolerance to input power voltages. Because this device exceeds intended specifications for duplicating a 200 kHz pulse stream from a coincidence counter, it may be used for more than just its intended purpose and serves as a first toward a set of joint use industrial hardware being produced. In this paper we will discuss the importance of joint use measurements, as well as explore the functionality and usefulness of the developed device with regard to splitting other sensor/detector type signals and in unattended and remote monitoring scenarios.