Petrochemical pressure vessels operating in high pressure H₂ at high temperature suffer from hydrogen embrittlement (HE) during repressurization after shutdown cooling to ambient temperature. HE may be mitigated by introduction of hydrogen (H) traps in the steel microstructure to suppress accumulation of H necessary for embrittlement at fracture initiation sites. Experimentally, nanoscale vanadium carbides (VC) significantly improve the HE resistance of bainitic steel specific to closed system H introduced by elevated temperature exposure to H₂. To understand the effect of VC precipitates on HE of 2¼Cr-1Mo-¼V steel, we analyze re-partitioning of H among various trap states, first...