Development of a real-time tritium-in-water monitor

Abstract

In this paper, we report the development and performance of a detector module envisaging a tritium-in-water real-time activity monitor. The monitor is based on modular detection units whose number can be chosen according to the required sensitivity. The full system is being designed to achieve a Minimum Detectable Activity (MDA) of 100 Bq/L of tritium-in-water activity which is the limit established by the E.U. Council Directive 2013/51/Euratom for water intended for human consumption. The same system can be used as a real-time pre-alert system for nuclear power plant regarding tritium-in water environmental surveillance. The first detector module was characterized, commissioned and installed immediately after the discharge channel of the Arrocampo dam (Almaraz nuclear power plant, Spain) on the Tagus river. Due to the high sensitivity of the single detection modules, the system requires radioactive background mitigation techniques through the use of active and passive shielding. We have extrapolated a MDA of 3.6 kBq/L for a single module being this value limited by the cosmic background. The obtained value for a single module is already compatible with a real-time environmental surveillance and pre-alert system. Further optimization of the single-module sensitivity will imply the reduction of the number of modules and the cost of the detector system.

Acquiring Gamma-Ray Energy Spectrum Using a Plastic Scintillation Optical Fiber Detector

“…Additionally, in February 2020, the Tokyo Electric Power Company (TEPCO) implemented a PSOF detector in the FDNPP drainage system to monitor 90 Sr, commencing operations [5]. The PSOF detector can be used to monitor daughter nuclides of 238 U for process control in mining operations and to assess tritium levels for onsite monitoring in rivers adjacent to nuclear facilities [6][7][8].…”