TGLF-EP Predictions for Compact Reactor Use Case Scenarios

We incorporate fusion-alpha transport predictions from the TGLF-EP+Alpha [1] critical-gradient model of energetic particle (EP) transport by Alfvén eigenmodes (AEs) into the STEP [2] integrated workflow for two sample compact-reactor use cases [3]: an inductive (pulsed) compact reactor scenario (UCR-P), and a steady-state compact reactor scenario (UCR-SS). New self-consistent density and temperature profile predictions for fusion alpha particles and thermal species now include the EP transport. The UCR-P case, adjusted profiles showed about 15% reduced performance but still qualitatively consistent with original scenario. The UCR-SS case shows massive profile collapse with nominal fusion performance reduced by 50% even before recomputing pedestal height. Usually neglected physics -- AE suppression by flow shear and MHD pressure gradient stabilization of AEs -- much mitigate alpha transport in the UCR-SS case. Lower current and high bootstrap fraction in the UCR-SS case make these mitigating effects far more important than in modern experiments previously used to validate TGLF-EP.



[1] R.E. Waltz and E.M. Bass, Nucl. Fusion 54 104006 (2014)

[2] O. Meneghini et al., Nucl. Fusion 10 1088 (2020)

[3] C. Holland et al., Journal of Plasma Physics 84 4 (2023)