Nuclear Fission Lab

Choose a fissioning parent and conditions to explore evaluated product yields from IAEA LiveChart (neutron-induced fission) or NNDC ENDF/B-VIII.1 (Cf-252 spontaneous fission). Values are products per fission; independent yields sum to about two products, not 100%. The mass chart sums independent yields over charge and source state indices. Cumulative yields include decay feeding and cannot be summed into a mass distribution. Uncertainties are source uncertainties; missing values are not zero.

The relationship view connects nuclide identities using charge and mass conservation for reported decay modes. Lifetimes refer only to ground states. Excited and isomeric daughter levels are not resolved, so this is not a full decay scheme. Stable and unknown lifetimes are distinguished.

The chain view is a spatial teaching model. A collision absorbs a neutron and, with probability mean/ν, splits a nucleus; the emitted count is sampled from the adjacent integers around the illustrative ν value. Leakage, exhaustion and finite particle lifetimes reduce growth. The parameter is not an effective multiplication factor or a criticality prediction. Geometry, speed, time and ν are schematic, without cross sections, energy-dependent transport or moderation.

A random seed repeats a run with the same settings. Computation uses fixed 0.01 animation-time steps; a slow browser catches up over later frames. Tab changes and hidden browser windows pause. Inputs remain fixed during a run; Reset clears it. The particle limit ends the run instead of continuing a silently truncated population. Rotate by dragging; zoom with Ctrl/Meta and the wheel.

Yield data and ground-state relationships update directly when you change their inputs. The 3D library loads only when you start the chain model. Reset, changing sections or leaving the page cancels a pending start. Only authored input drafts are retained, including unfinished values; results, paths and camera positions are not saved.