Materials Interactions and Temperatures in the Three Mile Island Unit 2 Core

Effects of interaction between molten zircaloy and irradiated MOX fuel on the fission product release behavior

“…The morphology of the microstructures and elemental distributions of U, Zr and O obtained in this study were quite similar to those of previous literature data of crucible tests and also of three mile island (TMI)-2 specimens [34]. This indicates that we got a good reproduction of the chemical interaction between molten Zry and fuel, which represented the localized heating within the bundle under steam-starved and/or reducing conditions.…”

Overview of experimental programs on core melt progression and fission product release behaviour

“…The melting point of the pure (U,Zr)O 2 ceramic is 2800 K, however, as found in the TMI-2 examination, the transition metal oxides can react eutecticaly with ZrO 2 and lower the liquidus temperature of the ceramic melt by about $100 K [104]. Similarly, the molten pool of the Phebus FPT-0 test had an average composition of U (62 wt%), Zr (22 wt%) and O (14 wt%), with smaller amounts of Fe ($0.6 wt%) (typically as a second phase inclusion or grain boundary precipitate), and traces of Y and Ce from melt interaction with the shroud [20].…”

Fuel and fission product behaviour in early phases of a severe accident. Part I: Experimental results of the PHEBUS FPT2 test

“…The different behaviours of Fe and Ni were already observed in TMI-2. Olsen et al [31] mentioned, as a summary of the state of the oxidation of the various materials in the reactor, that nickel (and tin) were the only elements not oxidised as one would expect from thermodynamic argument. Chromium, iron and molybdenum were partially oxidised.…”