Neutron Flux
Measure of neutron density times velocity, in neutrons/cm²/s, driving fission rate in reactor core.
Thermal flux ~10^13-10^14 n/cm²/s in operating PWRs; monitored by in-core detectors for power distribution. Flux shapes via control rods, burnup. High flux accelerates material damage, limits cycle length.
Why it matters now
Neutron flux management key for 2025-2026 high-burnup fuels in SMRs, extending refuels for data center economic PPAs.