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LLNL Simulates Nuclear Fireball, Cooling Rate Alters Fallout Chemistry

6/9/2026

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Summary

Story summary

LLNL researchers simulated a nuclear fireball in plasma-tube experiments by heating uranium, cesium and cerium to about 5,000 K in a one-meter reactor.
They tested steady continuous cooling and a delayed rapid drop, finding uranium and cerium condensed early in both, while cesium condensed later and formed complex compounds in the delayed case.
The results indicate that cooling speed changes reaction pathways and supply data to improve fallout models for decision-making.

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Story summary

LLNL researchers simulated a nuclear fireball in plasma-tube experiments by heating uranium, cesium and cerium to about 5,000 K in a one-meter reactor.
They tested steady continuous cooling and a delayed rapid drop, finding uranium and cerium condensed early in both, while cesium condensed later and formed complex compounds in the delayed case.
The results indicate that cooling speed changes reaction pathways and supply data to improve fallout models for decision-making.