This log begins with the public launch. The years of development before
that aren’t listed — there is no point cataloguing changes to
something nobody could yet use.
Anonymous visitor counts
Alpha 1.6.1
AddedPage‑view analytics. The site now counts visits, using the host’s cookieless analytics — page address, referring link, and country/device/browser. It sets no cookies and cannot track you across sites, and nothing you do inside the simulator is recorded.
ChangedPrivacy page updated to match. It now states exactly what is collected, instead of saying nothing is.
1/M startup checklist, checklist highlights
Alpha 1.6.0
AddedChecklist highlights. Hovering a step in a live checklist glows the controls and readouts it uses.
ChangedRebuilt Mode 3 → Mode 1 startup checklist. Twelve steps that walk the 1/M plot approach to criticality, the source‑range → intermediate‑range handoff, and levelling off before the turbine goes on line.
ChangedProcedures list is a menu again. Each procedure shows compactly; expand a card to preview its steps.
Boron trend, 30-minute chart history
Alpha 1.5.0
AddedBoron trend. Boron (ppm) is now a plottable graph option.
Changed30 minutes of history. The trend chart records 30 minutes; the time window sets how much is shown.
ChangedWider trends when the panel is hidden. Hiding the side panel widens the trend/alarms column into the freed space.
ChangedProactive trip blocks. A blockable trip can be blocked any time it isn’t already tripping; a block you set by hand stays until you clear it.
Three-column control room
Alpha 1.4.0
ChangedThree-column layout. Plant diagram and vitals on the left, trend chart and alarms in the middle, simulator panel on the right. Larger diagram.
AddedHide the side panel. The ⛶ button hides the simulator panel and moves the time controls onto the trend/alarms column.
ChangedAuto-scaling trend chart. Each line scales to its own range; faint gridlines added.
ChangedGenerator load starts in Manual. Mode 1 free-play now begins in Manual rather than load-follow.
Open source, Legal page, contact
Alpha 1.3.0
AddedOpen source. Code under AGPL‑3.0, manuals under CC BY 4.0.
AddedLegal page. Terms of use, safety disclaimer, and licensing; linked in the footer.
Fine rod control, timed pressurizing, startup checklists
Alpha 1.2.0
ChangedFine-step control bank. 912 steps of travel; about 1.5 cents of reactivity per tap near critical. Old saves migrate.
ChangedPressurizing takes real time. A 350‑to‑600 psi setpoint step climbs over about 90 seconds.
AddedMode 5 → Mode 3 heatup checklist. Pumps, pressurization, instrument handoff, approach to criticality, dilution to Hot Standby.
ChangedStartup checklist runs to Mode 1. Carries past criticality across the 5 % boundary and puts the generator on line.
Fixed“Cold to Power” completion. The arrival check now declares Mode 1 reliably.
Xenon trend, clearer readouts
Alpha 1.1.0
AddedXenon trend. Xenon (% of equilibrium) is now plottable on the strip chart.
ChangedVital gauges match the board. Same green/amber/red readout colors as the diagram.
ChangedAuto-controlled inputs read grey. Cyan means the value is yours to set.
Hands-on TMI-2, calmer board
Alpha 1.0.0
ChangedTMI-2 Part 1 is hands-on. Secure injection and isolate the stuck relief valve yourself; the stuck valve, hot tailpipe, and maintenance tag are on the board.
ChangedCalmer gauges. Indication noise halved; boration/dilution moves power at the boron mixing rate. Gentler rods near startup.
AddedKeyboard rods and finer controls. Arrow keys drive the rods; controls highlight on hover; generator-load and boron arrows step by 1 MW / 1 ppm.
FixedNo strobing or drifting rods. Numbers and strip chart no longer strobe after a few minutes; rods stop when you release the key.
Found a bug, or want to suggest something? The
feedback page comes straight to me, and there is
a 💬 button inside the simulator that can attach your session so I can see
what actually happened.