The tracer injection began on the 20th January with the circulation of the 0.5 litre of cocktail in the equipment sorption stage.

Circulation of 0.5 litres of tracer injection cocktail during the equipment sorption stage

Radiation Protection staff monitor the injection area during the circulation of the 0.5 litre equipment sorption cocktail.

However, extreme weather in the area forced the postponement of the next stages for one week until conditions improved. Even leaving Guttannen was difficult!

After postponing the injection, the cars had to be dug from the car park in Guttannen.

This was easier said than done.

The following week the injections re-started. Firstly, the 5 litre spike input stage was successfully carried out.

GTS manager Toni Bär prepares to dance with joy as the Final Injection continues the following week.

Then the first 30 litre tank was connected and the top hat input stage began.

The team from PSI (Max Rüthi and Marc Grämiger) examine the data from the on-line gamma spectrometers which monitor the inflow and outflow of radionuclides

The tank is placed in a large watertight tray and shielded with thick plexiglass. The mass of injected tracer is monitored by the balance connected to the Data Acquisition System

Leaving Handeck after the successful injection

The Final Tracer Test continues. On 17th February the field crew successfully replaced the tracer solution with another 30 litres. The weather was much improved from the previous visits.

There is still a considerable depth of snow at the entrance to the KWO tunnels.

The radioactive tracers are injected from a large tracer tank coated with Teflon to minimise sorption of the tracers onto the tank. The lighter material on the inside wall of the tank is a result of condensation.

Urs Mäder (Uni. Bern) and Karam Kontar (Solexperts) prepare the second 30 litre injection tank. The long input of safety relevant tracers will continued for another 4 weeks.