[en] Transients analysed for MSBR and AMSTER Molten Salt Reactor Concept are: 1. ULOF: loss of flow (i.e. loss of a primary pumping); 2. ULOHS : loss of heat sinks (i.e. HXs); 3. UOC : overcooling of primary fuel because of secondary side malfunction 4. UTOP : sudden reactivity insertion (actinide fuel agglomerated in piping system. Dislodged fuel particle then sweeping through core). Observations are made as regards the AMSTERIncinerator Molten Salt concepts as follows: 1. Above 800 deg. C the graphite reactivity coefficient of the AMSTERIncinerator becomes negative without Er-167. 2. Adding Er-167, the graphite coefficient becomes negative > 600 deg. C. 3. Negative graphite coefficient will stabilize system long-term. Thus recommend that Er-167 is also added in the AMSTER-Incinerator. 4. The large thermal inertia associated with graphite makes the transient behaviour very 'sluggish' of this reactor concept. 5. This 'sluggish' transient behaviour allows sufficient grace time for effective operator intervention