Devlog & release notes

When main feedwater stops, the reactor still needs a heat sink. The new auxiliary feedwater board gives you motor-driven and steam-driven backup pumps, independent feed valves to both steam generators, measured flow and a finite 300-tonne tank.

• Different supplies, different decisions. Motor-driven AFW needs safety AC. Steam-driven AFW uses reactor-plant steam and control DC, consumes steam, and can run without the main condenser while its supplies last.
• Emergency power has a specific job. Automatic diesel standby restores safety loads, including motor-driven AFW and RHR. It cannot restart the reactor coolant, main feedwater or circulating-water pumps; those require normal AC. Natural circulation follows actual pump coastdown.
• Practise a complete recovery. Choose Loss of Feedwater on Shift. One fixed fault removes both main feed flows; live guidance on Respond helps you diagnose, trip, establish AFW and hold stable hot shutdown for two continuous minutes. Show control brings each action into view.
• Earn the recovery. The lesson debrief scores stable cooling and reports water used, without penalizing its required trip or scoring market dispatch. Low-tank, unavailable-pump and low-battery alarms make the remaining supplies visible.

AFW is manually operated in this simplified educational model. Compatible saved shifts gain the new controls on reload, and the remaining AFW tank water persists.

The main turbine now carries a deeper shaft hum and casing rumble, with a softer blade whine and air rush. Its pitch rises with actual RPM, gains weight as steam flow increases, and falls smoothly during coast-down.

• Removed automatic neutron-count and rod-motion clicks from the machinery background.
• Replaced the feedwater pump's buzzy, wavering tone with soft water rush and a faint steady hum; softened the coolant pumps' upper harmonics.
• Turbine pitch continues to follow RPM, with switches, breakers and alarms retaining their event sounds.

A steadier control-room background and a turbine you can hear gathering speed.

• Smoothed the repeating background rumble and replaced the noisy pump buzz with a steadier motor hum.
• The synthesized turbine combines a deeper rumble, layered whine and softened steam rush. Pitch follows actual RPM through run-up and coast-down; steam flow adds weight as load rises.
• Softened the steam-dump hiss and startup count-speaker ticks, spacing the ticks so they no longer bunch into rapid crackling.

The control room has new graphics: a sectional drawing of the whole plant, and instruments and switches that look like real hardware.

🏭 See inside the plant

• The Operate and Respond screens open on a cutaway of the plant: the reactor vessel with its fuel and control rods, both steam generators with their U-tubes, the turbine hall, the condenser, the cooling tower, and the city it supplies.
• Click any equipment, or use the system keys under the drawing, for its live readings and a short note on what it does.
• Cutaway switches between the section and the outside of the equipment; Flow turns the pipe tracers on and off.

🌀 Everything moves with the plant

• Tracers run at the speed of the flow they carry; pumps and turbine stages turn with their speed.
• Bank D slides in and out as it steps, and drops into the core on a trip. The fuel warms with power, water levels rise and fall, and the steam dump valve opens when it is relieving steam.
• The cooling-tower plume follows the heat being rejected, and the skyline lights up with the megawatts you export.
• Pausing the simulation freezes the drawing, and a reduced-motion setting turns the motion off.

🎛️ Hardware with depth

• Every gauge has a turned-metal rim, cream dial paper, red limit marks, a red needle and an engraved tag plate.
• Rotary switches show a lever that sits at STOP or swings to RUN.
• The benchboard reactor trip now sits under a hinged safety cover: lift it, then trip. The TRIP key in the header is still one click.

🌙 Day and night lighting

• The sun/moon key in the header dims the room, so lit annunciator windows, lamps and readouts stand out. Your choice is remembered.
• On a phone, swipe the drawing sideways or pick a system to bring it into view.

The control room now sounds like one. Turn sound on with the speaker key in the header.

🔊 Machinery you can hear

• Each reactor coolant pump hums up to speed on its own, and the pair beat slowly against each other.
• The turbine rumbles and whines as it runs up to 3,600 rpm, and winds down when it trips.
• The transformer hums with load, steam flow hisses, and the steam dumps roar when they open wide.

☢️ The sounds operators know

• The source-range count-rate speaker: every detected neutron is a tick, and they crowd together as the reactor approaches critical.
• Rod control ticks its step relay as the banks move during a startup, and stays quiet while the regulator trims the rods at power.

🎛️ Hardware under your hands

• Rotary switches snap through their detents and setpoints tick as you turn them.
• The generator breaker closes with a slam, a ringing cabinet and the transformer's inrush hum.
• A reactor trip slams the turbine stop valves, clatters every rod into the core and thuds them onto their dashpots, and the horn changes to its trip tone.

The guided startup is rebuilt from the ground up. It now teaches you how the plant works, and shows you exactly where to go and what to click at every moment.

🎓 Twelve steps that explain the plant

• A new first step tours the control room: the header, the workstations, the indication board you read and the benchboard you operate.
• Every step opens with what is going on in the plant: why the condenser needs vacuum, what the pressurizer does, how a chain reaction goes critical, why the reactor follows the turbine.
• Every task spells out where the control is, the exact clicks, what you will see when it worked, and why it matters.

👉 It points at the next thing to click

• If the control is not on screen, the tutorial outlines the key that brings it up (the workstation, then the benchboard section), then the control itself, with a tag saying what to do: TURN TO RUN, SET TO 100%.
• While you wait, the instrument to watch is outlined in blue, and the tutorial pages the indication board to it for you to click.
• The final dispatch step works out the governor setting from the live dispatch target.

🔧 Nothing cut off

• The coach bar now sits above the boards instead of floating over them, and never truncates its text.
• The benchboard no longer runs off the right edge on a laptop, and the market's plant offer shows its + key again.
• On a phone, the instructor's Continue button stays on screen above the tab bar.

Fission Control is live: a pressurized-water reactor control room you can sit down and run, free in your browser.

⚛️ A reactor that behaves like the real one

• Six-group point kinetics with delayed neutrons, so power keeps moving after the rods stop, and a rushed rod pull trips you on short period.
• Temperature feedback that runs the plant: Doppler and a mid-cycle moderator coefficient near −24 pcm/°C mean the reactor follows the turbine. Raise turbine load and power rises on its own.
• Steam from saturation: a hot plant sits at 7.6 MPa at zero power and falls toward 6.9 MPa at full load. Steam dumps hold no-load temperature automatically and catch a load rejection.
• Real iodine and xenon half-lives — the post-trip xenon peak arrives about nine hours out, with a restart window you can miss.
• The standard decay-heat curve — about 6.5% at a trip and 1.3% an hour later — so a trip at power leaves real heat to remove.
• Realistic protection: low-flow trips at 10% and 39% power, a low-pressure trip at 13 MPa, a turbine-trip reactor trip above 50%, and shutdown banks that drop on a trip and come out first on a restart.

🎓 A guided startup anyone can follow

• Eleven short steps from hot standby to the grid. Each has one goal, a two-line reason, and a checklist that ticks itself off as the plant responds.
• Only the control for your next action is highlighted, and Show me jumps straight to it.
• Waits come with a fast-forward that drops back to normal speed the moment the step is done.

📋 Shifts, scores and the Daily

• Scored shifts — Morning Ramp, Trip and Recovery, Xenon Restart, Evening Peak — against a live two-settlement electricity market, plus an unscored Free Operation with an instructor station.
• The Daily Shift: the same plant and faults for every operator that day, a streak, and a result card to share.
• Eleven modelled malfunctions, each with its real signature — from a stuck-open PORV (falling pressure against a rising pressurizer level) to a steam generator tube rupture.

📱 Plays on phones

• A dedicated phone layout: a slim header, a bottom tab bar for the workstations, lit-only annunciators, a split plant diagram, and one control per row with thumb-sized buttons.
• Add it to your home screen to open it like an app.