KRONOS FUSION ENERGYWHITEPAPER 11 / 40
Publication series 1 — The Machine

When Plasmas Quit: Engineering for the 10.3 GJ Disruption

We sized the worst day in the plant's life before sizing the best one.

At 43 MA, an unmitigated MetroVolt disruption would release 10.3 GJ of stored energy — 4.8 GJ magnetic plus 5.5 GJ thermal — and pull ~590 MN of vertical load. Those numbers are in the deposit because pretending otherwise is how fusion loses trust.

The science

The disruption ledger (KX-24) quantifies the full event: stored-energy partition, a ~23 ms current quench, vertical displacement forces, and a runaway-electron avalanche gain that is flagged 'high' — which is why shattered-pellet injection (SPI) mitigation is a requirement, not an option, with the reduced DREAM deck deposited for flagship confirmation.

Negative triangularity helps twice: the ELM-free edge removes the most frequent disruption trigger class, and the mode-trade study shows the lower-current operating branch eases the ledger to ≈9 GJ. Structural verdicts are computed at ≥2× yield criteria against the ~590 MN envelope.

Why it matters

Utilities do not fear plasma physics; they fear unbudgeted downtime. A disruption case with numbers, mitigation hardware, and structural margins is an insurable event rather than an existential one. Publishing the 'high avalanche' flag is deliberate: it converts our hardest transient into a specified, testable engineering requirement.

The numbers

Unmitigated stored energy10.3 GJ (4.8 magnetic + 5.5 thermal)
Vertical load≈590 MN (≥2× yield structural criterion)
Current quench≈23 ms
MitigationSPI — required, deck deposited (S30)
Eased case≈9 GJ at 37.1 MA branch
Straight answersRunaway-electron avalanche gain is high at this current; the full DREAM confirmation is a Tier-2 deposited deck pending HPC execution. The requirement is stated before the confirmation exists.
Every figure in this paper traces to the openly deposited 81-simulation programme (S01–S81) behind the Kronos MetroVolt four-paper design series — data and code at DOI 10.5281/zenodo.21248916 (CC BY 4.0). Read the series, run the code, check us.
Kronos MetroVolt is a conceptual design study. Quantitative values are simulation-derived and carry the feasibility gates stated in the series; Tier-2 flagship-code confirmations are deposited as runnable decks pending HPC execution. This document is informational and is not an offer of securities. © 2026 Kronos Fusion Energy, Los Angeles.