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Derecho Forces Emergency Shutdown at Iowa Nuclear Plant

12/14/2025

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Summary

Story summary

In December 2020, a derecho struck the Duane Arnold nuclear plant in Palo, Iowa.
Diana Lokenvitz, senior systems engineer, described sudden darkness enveloping the area.
The 130 mph winds severed six external power lines and triggered an automatic emergency shutdown.
Backup diesel generators activated, control rods were inserted to halt the fission reaction, and safety systems stabilized the reactor and vented excess heat for several hours.

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Story summary

In December 2020, a derecho struck the Duane Arnold nuclear plant in Palo, Iowa.
Diana Lokenvitz, senior systems engineer, described sudden darkness enveloping the area.
The 130 mph winds severed six external power lines and triggered an automatic emergency shutdown.
Backup diesel generators activated, control rods were inserted to halt the fission reaction, and safety systems stabilized the reactor and vented excess heat for several hours.