Isotopic and Fuel Lattice Parameter Trends in Extended Enrichment and Higher Burnup LWR Fuel Vol I: PWR fuel

A Study on the Characteristics of the Radiation Source Terms of Spent Fuel and Various Non-Fuel Hardware for Shielding Applications

“…The decreasing trend observed from the 3 -4 MeV energy range for all cooling times is consistent with a decrease in 244 Cm concentration with increasing fuel enrichment for a given fuel burnup. A reduction of minor actinides with atomic number higher than 239 Pu occurs as the fuel initial enrichment increases [14].…”

“…The study extends the range of depletion parameters previously analyzed in NUREG/CR-6802 [2] to include depletion parameter values anticipated for increased enrichment and higher burnup fuel operation. This study used the POLARIS PWR and BWR fuel assembly models documented in ORNL/TM-2020/1833 [14] and ORNL/TM-2020/1835 [15], respectively. The PWR fuel assembly analyzed is a Westinghouse (WE) 17 ´ 17 fuel assembly containing 104 integral fuel burnable absorbers.…”

“…This section analyzes trends of the radiation source terms as a function of initial fuel enrichment of a PWR fuel assembly with an average assembly burnup of 80 GWd/MTU. An increase of the fuel initial enrichment causes an increase of the 235 U absorption rate, a decrease of the absorption rates of other nuclides, a reduction of the thermal neutron flux [14], and neutron spectrum hardening. Fuel with higher enrichment will need lower neutron flux to achieve the same power density compared with fuel with lower enrichment.…”

“…An increase of the fuel initial enrichment causes an increase of the 235 U absorption rate and a reduction of the thermal flux [14]. The net effect is a reduction of minor transuranic actinides as the fuel initial enrichment increases.…”

Light Water Reactor LEU+ Lattice Optimization

“…A study investigated lattice physics parameters and used fuel isotopic changes for a conventional GE14 10 × 10 boiling water reactor (BWR) design with GNF-2 part length rod patterns to model a modern BWR assembly design [2]. Another study within phase 1 investigated the difference between a Westinghouse 17X17 PWR assembly design with LEU with the same assembly design with 8 wt% enriched fuel with 80 GWd/MTHM burnup [3]. Finally, the impact of higher-enrichment (> 5%) ATF fuel designs, namely coated cladding, doped UO 2 , and FeCrAl cladding, has been investigated [4].…”