Bremsstrahlung — braking radiation from electron-ion collisions — carries 29.9 MW, about 15% of fusion power, at the reference point. The design computes it two ways and reports the lower, so the ledger is mildly optimistic in a stated, bounded direction.
The burner's bremsstrahlung form truncates its temperature series and omits the electron-electron term, so it under-estimates above ~100 keV. A published 2024 fit (Xie) is carried as a cross-check and runs 8% higher, at 32.3 MW. The reference uses the lower 29.9 MW value, and says so.
Carrying a cross-check and naming which value is used — and in which direction it errs — is the difference between a number and an audited number. The 8% optimism is small, bounded, and disclosed, which is exactly how a design earns trust on the numbers that are not disclosed as uncertain.
| Bremsstrahlung (used) | 29.9 MW (15.2% of fusion) |
| Cross-check (Xie 2024) | 32.3 MW (+8%) |
| Value used | the lower one |
| Bias direction | mildly optimistic, stated |
| Under-estimates above | ~100 keV |