Breeder Shot Lifecycle

One tokamak shot from arming to post-shot analysis, and the control decisions the stack makes in each window.

A shot is a bounded experiment

The breeder (Hyperion) operates in discrete shots even at commercial intent, because a spherical tokamak drives current inductively and thermally cycles the plasma-facing components. Each shot is a bounded window with an arm, a ramp, a flat-top, a ramp-down, and a recovery. The stack treats the flat-top as the productive phase where the Q_sci 3.076 / 85.0 MW scenario is held and 14 MeV neutrons drive the breeding blanket.

Flat-top control

During flat-top the controller holds current near 9.66 MA, regulates shape and vertical position, manages fueling and heating to the target profile, and watches for disruption precursors. The tritium breeding ratio - treated as a design lever across 1.1/1.5/1.8 - is a slow accounting quantity computed shot-over-shot from neutron diagnostics, not a fast loop.

def flattop_supervise(state, twin):
    if twin.disruption_risk(state) > THRESH:
        return mitigate()               # see disruption page
    if twin.vertical_margin(state) < VMIN:
        boost_vertical_gain()
    log_neutron_yield(state)             # feeds TBR accounting 1.1/1.5/1.8
    return 'nominal'

Ramp-down and recovery

Controlled ramp-down avoids a current-quench by bleeding current within actuator limits and managing halo currents into the structure. Recovery captures the full shot record for the twin to reconcile prediction against measurement, feeding predictive maintenance and postmortem. Many shots chained together form a campaign; see Campaign Lifecycle.