A laboratory degradation test system for testing degradation of a test specimen in a test fluid flow includes a reactor assembly, which reactor assembly comprises: a reactor vessel, the reactor vessel having a reaction space, an inlet and an outlet and a specimen holder for retaining a test specimen inside the reactor vessel, a heater for heating the reactor vessel, a fluid circulation system generating a test fluid flow over the test specimen, which fluid circulation system comprises: a circulation line which extends between the outlet of the reactor vessel and the inlet of the reactor vessel, which circulation line is arranged outside the reactor vessel, a pump for providing fluid circulation through the circulation line and the reactor vessel, which pump is arranged in the circulation line. The volume available to the test fluid inside the reaction space after insertion of the degradation test specimen is less than or equal to 10 ml.