High-Fidelity Modeling and Simulation for a High Flux Isotope Reactor Low-Enriched Uranium Core Design

Key metrics for HFIR HEU and LEU models

“…Cycle length is expressed in days, with a precision of 0.5 days. This precision is considered adequate for EOC estimations in HFIR depletion simulations [2,3].…”

“…Each of these tables includes the flux and the flux per unit power for the HEU and LEU cores, as well as the LEU to HEU flux ratio, for each of the nine energy bins specified in Table 2.1. The EOC time was 26 days [2] for the HEU core and 34 days [3] for the LEU core, as further discussed in Section 3.4. The MOC state point was set as 14 days for the HEU and 18 days for the LEU core [2,3].…”

“…The cycle length was estimated to be 26 days for the HEU representative model [2] and 34 days for the LEU representative model with interim design fuel [3]. The eigenvalue at EOC is 0.99976 (1σ = 0.00013) for the HEU core [2] and 0.99950 (1σ = 0.00015) for the LEU core [3]. The symmetrical control element withdrawal curves in the HEU and LEU models are illustrated in Fig.…”

“…The models used to calculate these key metrics are documented in detail in previous publications [2][3][4]. This report presents a comparison of these key metrics, which were determined for two three-dimensional (3-D) high-fidelity HFIR models.…”

“…The first model [2] considers HEU fuel, an experiment loading representative of HFIR's current operation, and a reactor power of 85 MW. The second model [3] considers an LEU interim design fuel [1] with a reactor power of 100 MW. Except for the fuel region, the two models are consistent and both include an explicit representation [2][3][4] of the HFIR's fuel plate involute geometry.…”