Abstract Laboratory and loop tests have been carried out in order to investigate the thermal stability of the three amines, morpholine, AMP (aminomethylpropanol) and sarcosine in PWR secondary conditions. Laboratory experiments have been performed in a titanium autoclave at 300° C. The results pointed out high thermal decomposition rates of AMP and sarcosine. A decomposition mechanism is proposed for the 3 amines. Loop tests have ...