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For Researchers · Fission Chain Reaction

Fission Chain Reaction for a criticality test

Built for researchers prototyping or validating an idea. Prototype fast, reproduce exactly, and share a citable, interactive version of your model. Simulate a criticality test live below — adjust the inputs and watch it respond, right in your browser.

Fission Chain ReactionLive

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Each fission releases neutrons that can trigger more fissions. The multiplication factor k is how many of those neutrons cause a new fission on average. Below 1 the chain dies out; exactly 1 sustains steady power — a running reactor; above 1 it grows exponentially. Control rods nudge k around 1 to hold a reactor critical.

▶ Run in Python

Data Inspector

k factor1.000
Generation0
Statecritical (steady)

Governing equation

Reading this result: k is essentially 1: on average one neutron per fission triggers the next, a self-sustaining steady chain — a running reactor.

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Frequently asked questions

Is this good for researchers?
Yes — this version of "Fission Chain Reaction for a criticality test" is framed for researchers prototyping or validating an idea. Prototype fast, reproduce exactly, and share a citable, interactive version of your model.
Do I need to install anything?
No. It runs in any modern browser, free, with no account required.