Reactor-Sim/CONTEXT_NOTES.md

Session Context Notes

• Reactor model: two-loop but tuned to RBMK-like pressures (nominal ~7 MPa for both loops). Loop pressure clamps to saturation baseline when pumps are off; pumps ramp flow/pressure over spool time when stopping or starting.
• Feedwater & level: secondary steam drum uses shrink/swell-aware level sensing to drive a feedwater valve; makeup flow scales with steam draw toward the target level instead of instant inventory clamps.
• Chemistry/fouling: plant tracks dissolved O2/boron/sodium; impurities plus high temp/steam draw increase HX fouling (reduces UA) and add condenser fouling/back-pressure. Oxygen degasses with steam; impurity ingress accelerates when venting.
• Reactivity bias: boron ppm now biases shutdown reactivity; a very slow trim nudges boron toward the power setpoint after ~300s of operation.
• Turbines: produce zero output unless steam quality is present and effective steam flow is >10 kg/s. Turbine panel shows steam availability (enthalpy × quality × mass flow) and steam enthalpy instead of loop pressure; condenser pressure/temperature/fouling shown with nominal bounds.
• Generators: two diesel units, rated 50 MW, spool time 10s. Auto mode default False; manual toggles b/v. Auto stops when no load. Relief valves toggles l (primary) / ; (secondary) and displayed per loop.
• Pumps: per-unit controls g/h (primary), j/k (secondary). Flow/pressure ramp down over spool when pumps stop. Pump status thresholds use >0.1 kg/s to show STOPPING.
• Maintenance hotkeys: p (core, requires shutdown), m/n (primary 1/2), ,/. (secondary 1/2), B/V (generator 1/2), y/u/i (turbine 1/2/3).
• Dashboard: two-column layout, trends panel for fuel temp and core power (delta and rate). Power Stats show aux demand/supply, generator and turbine output. Turbine panel shows steam availability/enthalpy instead of loop pressure. Core/temp/power lines include nominal/max.
• Thermal updates: primary/secondary inlet temps now back-computed; when secondary flow is near zero, loops cool toward ambient over time. Relief venting removes mass/enthalpy with a multi-second ramp toward ~1 MPa and quenches superheat toward target-pressure saturation. Pumps cap target pressure when reliefs are open. Condenser modeled with vacuum pump drawdown, cooling-sink temperature, and fouling-driven back-pressure penalty.
• Meltdown threshold: 2873 K. Auto rod control clears shutdown when set to auto and adjusts rods. Control rod worth/tuning currently unchanged.
• Tests: pytest passing after all changes. Key regression additions include generator manual mode, turbine no-steam output, auto rod control, and passive cool-down.
• Coolant demand fixed: demand increases when primary outlet is above target (sign was flipped before), so hot loops ramp flow instead of backing off.
• Pump spin-down: pressure/flow ramp down over pump spool time with STOPPING->OFF threshold at 0.1 kg/s; prevents instant drop when last pump stops.
• Steam pressure display shows 0 unless steam quality ≥0.05 and flow ≥100 kg/s to avoid showing pump head as steam pressure.
• Passive cool-down: when secondary flow ~0, loops cool toward ambient; primary inlet/outlet back-propagated from transferred heat and ambient.
• Relief valves: l (primary) and ; (secondary) vent with mass/enthalpy loss, ramp pressure toward ~1 MPa over several seconds, cap pump targets while open; status displayed per loop.
• Generator behavior: starting/running only produce power when load is present; auto off by default; manual toggles b/v; auto stops with no load; base aux drops to 0 when idle/cold.
• Pressure tying: loop pressure floors to saturation(temp) when pumps off; pump targets aim for ~7 MPa nominal RBMK-like setpoints.
• Turbines/governor: require meaningful steam flow/quality; otherwise zero output. Steam supply pressure in turbine panel reads 0 when no steam. Throttle now biases toward load demand with a governor term, and overspeed/overload >105% rated electrical trips a unit and spools it down.
• Rod control now supports three banks with weighted worth; xenon/iodine tracked with decay and burn-out; new UA·ΔT_lm steam-generator model and pump head/flow curves.
• Dashboard shows heat-exchanger ΔT/efficiency and protections; pumps and HX changes documented in FEATURES.md / TODO.md.