About Reactor Dynamics
A nuclear power plant you can run in the browser. Learn what operators do and why the plant responds the way it does — operation and dynamics together.
Nothing to install, no account. Desktop or laptop for now.
Who this is for
No nuclear background is required. If you have ever wanted to know what the people in that room are actually doing, this is built for you. The control room opens with a quick tour, the operator’s manual is on the same screen, and nothing you do to the plant is unrecoverable — reload and start again.
It is also built to hold up if you do have the background. If you are a Navy nuke, a nuclear-engineering student, a plant worker, or someone who has read more about Three Mile Island than is strictly healthy, the couplings are modelled rather than scripted: boration and dilution, xenon, the pressurizer, and the steam plant all act on one another, and the plant does not stop you making a real mistake.
What it asks of you is patience rather than knowledge. A plant startup is a slow evolution, and the interesting part is watching one thing move because another one did.
What this is
A pressurized-water plant in the browser, cold shutdown to full power on one continuous model. You operate the board. Two things to take away:
- What — plant operation: startup order, holding power, procedures, recovery from upsets.
- Why — plant dynamics: how heat, reactivity, inventory, steam, and the turbine couple so the board’s behavior makes sense.
You learn the what by running the plant. You learn the why from how it responds — and from the written model on the Physics page and in the in-sim manual if you want the equations and limits spelled out.
What you can do
- Bring a cold plant to life. Pressurize, start the reactor coolant pumps, heat to hot standby, go critical, raise power, put the generator on the grid, and take the plant to 100%.
- Keep it online. Load changes, boration and dilution, feedwater and level control, holding steady through xenon.
- Work plant casualties. Trips and recovery, stuck valves, pump trips, steam generator tube leaks, loss of heat sink — on your terms or without warning.
Optional: the Three Mile Island sequence (stuck-open relief, inventory loss, recovery). Same plant model for every session — an easier run is a gentler scenario, not a simpler plant.
Operator manuals are in the control room. Free play is always available.
Coming next
In work: a full training campaign, instructor-led scenarios, live checklists that tick off against the plant, step-by-step procedure walkthroughs, and control rooms for the BWR and RBMK plants (their physics engines already exist). See the Roadmap for short descriptions of each.
The plant
A compact pressurized water reactor: about 100 MWe, one coolant loop, one steam generator. Cold shutdown to full power is one continuous path. Other plant types are on the Roadmap.
Where it runs
A modern desktop browser. The simulation runs on your machine — this site, a local copy, or a single downloadable file for offline use.
Bugs, and “that is not what a plant does”
Bug reports and physics corrections go to GitHub Issues — they are public and tracked there, you can see what is already known before writing one, and a correction with a source attached is the most useful thing anyone sends. No GitHub account, or you would rather not file in public? Email reactordynamics@gmail.com instead; in the simulator, Contact has that address and optional session diagnostics to attach.
Prototypicality claims here are meant to be sourced to published documents rather than to memory, so “a real plant does not do that” is a report worth filing — especially with an NRC document number.
Physics
For the written why — what the model computes, how systems couple, what is pinned to published data, what is left out — see Physics behind the simulator.