TRACY and SILENE Benchmark Phase II evaluation by TRACE code

Following the Benchmark Phase I on the criticality excursion organized by the OECD NEA Working Party on the Nuclear Criticality Safety (Expert Group on Criticality Excursion), the Phase II of the benchmark was launched by selecting three experiments (R159, R76, R61) conducted at Japanese TRACY facility and one (LE1-641) from French SILENE facility. The main features of the Phase II of the benchmark are the ramp reactivity insertion generated by pumping fuel solution into the core tank (TRACY) or slow withdrawal of central transient rod (SILENE), and the use of both low enriched uranium (10 w/o, TRACY) and high enriched uranium (93 w/o, SILENE) for the uranyl nitrate fuel solution. As in the Phase I, TRACE code was used for the Phase II and the benchmark evaluated results were presented and discussed. The kinetic parameters, reactivity temperature and void coefficients for the benchmark were prepared using SRAC code system (PIJ, ANISN, CITATION and TWOTRAN modules) with JENDL-3.3 library. In general, the code benchmark results for the TRACY cases show excellent agreement with the measured data. However, for the SILENE case, overestimation of the power profile was observed.