What was computed
GPU fleet: expanded Ta-free PFC family (A37a/b/c) all NEAR-NEUTRAL & viable: divertor -0.002, first-wall -0.002, DEC -0.015 eV/atom; removing Ta keeps/improves stability; entropy-stabilized refractory HEAs (dense 8x8x8 landing)
Reproduce this
# Reproduce BR-L2-A37 against the frozen record pip install kronos-toolkit # github.com/KronosFE/kronos-toolkit python -c "from kronos_toolkit.verify import run_regression; run_regression()" # BR-L2-A37 is anchored in the 2026-08-27 freeze spine (verdict: reproduced).