  In this work the development results of the TRITIUM project is presented. The
main objective of the project is the construction of a near real-time monitor
for low activity tritium in water, aimed at in-situ surveillance and
radiological protection of river water in the vicinity of nuclear power plants.
The European Council Directive 2013/51/Euratom requires that the maximum level
of tritium in water for human consumption to be lower than 100 Bq/L. Tritium
levels in the cooling water of nuclear power plants in normal operation are
much higher than the levels caused by the natural and cosmogenic components,
and may easily surmount the limit required by the Directive. The current
liquid-scintillation measuring systems in environmental radioactivity
laboratories are sensitive to such low levels, but they are not suitable for
real-time monitoring. Moreover, there is no currently available device with
enough sensitivity and monitoring capabilities that could be used for
surveillance of the cooling water of nuclear power plants. A detector system
based on scintillation fibers read out by photomultiplier tubes (PMTs) or
silicon photomultiplier (SiPM) arrays is under development for in-water tritium
measurement. This detector will be installed in the vicinity of Almaraz nuclear
power plant (Spain) in Spring 2019. An overview of the project development and
the results of first prototypes are presented.
