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For Students · Reactor Kinetics

Reactor Kinetics for a nuclear decay

Built for students learning it for a class or exam. See the concept move instead of memorizing formulas — and check your homework intuition. Simulate a nuclear decay live below — adjust the inputs and watch it respond, right in your browser.

Reactor Point KineticsLive

power, reactivity & period

Controls

Presets

Reactivity ρ

Speed1×

A small step in reactivity does not blow the power up instantly, because a fraction of neutrons are released with a delay. Those delayed neutrons slow the response to a controllable timescale — the reactor period. But push reactivity past the delayed fraction β and it goes prompt-critical, growing on the neutron lifetime — millisecond-fast and uncontrollable.

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Data Inspector

Reactivity0.15 $

Regimedelayed (controllable)

Power1.00e+0

Governing equation

\frac{d n}{d t} = \frac{ρ - β}{Λ} n + i \sum λ_{i} C_{i} (ρ = 0.0010, β = 0.0065)

Reading this result: Positive but below β — delayed neutrons stretch the response onto a stable, controllable reactor period.

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Frequently asked questions

Is this good for students?: Yes — this version of "Reactor Kinetics for a nuclear decay" is framed for students learning it for a class or exam. See the concept move instead of memorizing formulas — and check your homework intuition.
Do I need to install anything?: No. It runs in any modern browser, free, with no account required.