Radioactive Fallout Deposition & Land Remediation

Release Conditions

Wind speed 4.0 m/s

Wind direction 45°

Source release rate 18

Decay & Time

Isotope

Time since release 0 days

Remediation

Live Readouts

Peak dose rate0.00 µSv/h

Contaminated area (>1 µSv/h)0 m²

Monitor cumulative dose0.00 µSv

Cells remediated0

low

high dose

How it works

Radioactive particles are released from the source, carried by the wind vector plus a random turbulent-diffusion walk, and settle onto a ground grid — a simplified Lagrangian stand-in for the Gaussian plume model used in real fallout dispersion. Each landed particle adds its activity to the surface contamination density C(x,y) of the cell it lands in.

Surface dose rate:  Ḋ(x,y,t) ≈ k · C(x,y) · A(t)/A₀
Radioactive decay:  A(t) = A₀ · (1/2)^(t / T½)
Cumulative dose:    D = ∫ Ḋ dt   (integrated at the fixed monitor point ●)

Wind speed / direction — sets the advection vector; a stronger wind stretches the plume further downwind before particles settle.
Source release rate — how many contamination-carrying particles leave the source per second.
Isotope — Iodine-131's 8-day half-life visibly decays within the slider's range; Caesium-137's 30-year half-life barely moves over the same window, illustrating why long-lived isotopes dominate long-term land contamination.
Time since release — applies the decay law above uniformly to everything already deposited.
Remediate hotspot — finds the worst-contaminated cell and simulates topsoil removal: it and its immediate neighbours are zeroed, the standard emergency-response technique for cutting local dose rate quickly.

Real-world relevance: this is the same logic environmental-monitoring teams use after an accident — deposition mapping to find hotspots, decay-corrected dose projections, and targeted remediation of the worst cells rather than the whole territory.

Source Monitor point

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