Good progress was made on both the experimental and process modelling fronts during the past quarter. All experimental tests used the fixed-bed laboratory reactor to study the sulfidation of CeO{sub 2} with H{sub 2}S and the regeneration of Ce{sub 2}O{sub 2}S using SO{sub 2}. A number of experimental problems were solved (or at least alleviated) during the quarter including malfunctioning mass flow controllers, excessive bed pressure drop, and elimination of the H{sub 2}S plateau during early stages of sulfidation tests. Most CeO{sub 2} sulfidation tests were carried out a 800{degrees}C and 5 atm using a sulfidation gas containing 1% H{sub 2}S, 10 % H{sub 2}, balance N{sub 2}. At these conditions sulfidation of CeO{sub 2} was rapid and complete. Sulfur material balance closure was satisfactory, and, except for the unexpected H{sub 2}S plateau during the prebreakthrough period, the sulfidation results were as expected. Near the end of the quarter, the cause of the H{sub 2}S plateau was tentatively identified as being due to reaction between H{sub 2} and elemental sulfur deposited downstream of the sorbent in the bottom of the reactor and in tubing leading to the gas chromatograph. The sulfur deposits occurred during regeneration tests, and chemically cleaning the lines between regeneration and sulfidation coupled with reducing the temperature of the transfer line during sulfidation greatly reduced the H{sub 2}S plateau. A brief examination of the effect of sulfidation temperature between 700 and 850{degrees}C showed relatively little temperature effect, although the slope of the active portion of the breakthrough curve was somewhat smaller at 700{degrees}C, which is consistent with a smaller reaction rate at this temperature.