Chapter 6

Phase 3: Protocols

Standardized operational protocols for plasma startup, steady-state operation, shutdown, and emergency procedures ensure safe and reproducible fusion operations.

Operation Protocols

A fusion plasma shot involves carefully orchestrated sequences of events, from initial vacuum preparation through plasma termination. WIA-FUSION defines standard protocols for each phase.

Startup Sequence (STARTUP-001)

The startup protocol brings the reactor from cold standby to burning plasma conditions:

T-60s to T-0s: Pre-conditioning

Verify vacuum (<10⁻⁶ Pa), activate wall conditioning, check diagnostics

T+0s to T+5s: Magnetic Field Ramp

Toroidal field: 0 → 5.3 T at 1 T/s, establish poloidal shaping

T+2s to T+3s: Gas Injection

Puff 10²⁰ deuterium atoms, achieve 0.1-1 Pa pressure

T+3s to T+5s: Plasma Breakdown

ECRH pre-ionization (1-2 MW), loop voltage 10-20 V, achieve Ip > 100 kA

T+5s to T+15s: Current Ramp

Ramp to target current (15 MA at 1 MA/s), monitor flux consumption

T+10s onwards: Auxiliary Heating

Activate NBI, tune ICRH/ECRH, reach steady-state conditions

Steady-State Operation (STEADY-001)

During steady-state, the AI control system maintains plasma parameters within target ranges:

STEADY-STATE CONTROL TARGETS:
├── Core Temperature: 10-15 keV (±10%)
│   └── Feedback: ECRH power modulation
├── Density: 1.0×10²⁰/m³ (±15%)
│   └── Feedback: Pellet injection rate
├── Plasma Current: 15 MA (±5%)
│   └── Feedback: Inductive + bootstrap
└── Beta: 2.5% (limit < 3.5%)
    └── Feedback: Heating power reduction

AI Control Loop:
├── Cycle time: 1 ms
├── Inputs: 50+ diagnostic signals
├── Optimization: Maximize Q, minimize disruption risk
└── Actions: Heating, shape, fueling adjustments

Shutdown Sequence (SHUTDOWN-001)

Controlled shutdown ("soft landing") safely terminates the plasma:

T+0s to T+30s: Heating Reduction

Reduce all heating at 50%/minute while maintaining plasma control

T+30s to T+60s: Current Ramp-down

Reduce plasma current at 0.5 MA/s, maintain vertical stability

T+45s: Fuel Cutoff

Stop gas puffing and pellet injection

T+60s to T+90s: Field Reduction

Ramp down toroidal and poloidal fields

T+90s onwards: Post-shot Analysis

Archive data, inspect components, log performance

Safety Protocols

Emergency Shutdown (EMERGENCY-001)

EMERGENCY SHUTDOWN TRIGGERS:
T+0 ms: Emergency Signal

System receives emergency trigger

T+10 ms: MGI Triggered

Massive gas injection activated

T+100 ms: All Heating OFF

NBI, ECRH, ICRH immediately terminated

T+500 ms: Plasma Terminated

Plasma extinguished via radiative collapse

T+5000 ms: Safe State

Magnetic field dumped, facility in safe state

Tritium Management (TRITIUM-001)

Tritium Inventory Limits:

AI Control Protocol

The AI control protocol defines how machine learning systems interact with the plasma:

AI DISRUPTION PREDICTION (AI-DISRUPT-001):
├── Latency: < 10 ms (data to action)
├── Inputs: Ip, li, β, locked modes, radiation, q95, etc.
├── Model: LSTM + Attention (50,000+ training shots)
├── Accuracy: > 95% detection, < 5% false positive
└── Thresholds:
    ├── GREEN (< 30%): Monitor at 100 Hz
    ├── YELLOW (30-70%): Alert, prepare mitigation
    └── RED (> 70%): Execute mitigation immediately

Key Takeaways: