TREAT Transient Analysis Benchmarking for the HEU Core

Analysis of the TREAT LEU Conceptual Design

“…Its use requires a set of core-specific parameters: delayed neutron fraction and prompt generation lifetime, temperature reactivity feedback and core average and peak temperature values as a function of core energy, and transient rod bank available reactivity as a function of axial position. Historically this information came from measurements made in the HEU core, but a method of generating the information with MCNP has been developed and evaluated against the reported data available from the M8CAL and ANCAL historic experiments [8,[11][12][13]. Temperature reactivity feedback was evaluated using temperature-dependent neutron cross-sections for a series of hot-core temperature zones corresponding to increasing core energy steps.…”

“…The control/shutdown bank was positioned as needed for approximately critical conditions with the transient bank inserted. The calculated worth values were then multiplied by 0.95, the average ratio of the measured-to-calculated transient rod bank worth for the HEU core, for use in TREKIN (consistent with the approach taken in the previous studies [12]). The values used in the TREKIN calculations are shown in Table 2-20.…”