On this day 30 years ago (May 5, 1995), both units at Comanche Peak Nuclear Power Plant tripped after an electrical fault in the 345kV switchyard. The unexpected culprit? A charred Great Blue Heron found at the scene. At the time, both units were operating at full power. A fault occurred ~4 miles from the plant on one of five 345kV transmission lines. Neither the primary nor backup relays cleared the fault. As a result, the other 4 lines & both units fed the fault—until everything tripped. What happened next: ✔️ Both reactors safely shut down ✔️ No loss of offsite power to safety buses ✔️ EDGs didn’t need to start ✔️ 138kV remained energized There was no weather involved. Just one bird… with a very bad day 💥 Why it matters: This RARE dual-unit trip became a reference case in PRA. It highlights how wildlife can impact critical infrastructure—& why even the best systems must account for unpredictable environmental factors. 🌿 Happy 30th to one of the weirdest, most instructive nuclear trips in U.S. history. Cheers to redundant safety systems, & vigilant ops teams!