DEEP FISSION, INC. — Form 8-K

Deep Fission announced a collaboration with Youngquist Brothers, LLC to jointly evaluate and test drilling and borehole-construction methods for underground nuclear reactor deployment. On September 3, 2026, the companies completed a demonstration in Fort Myers where Deep Fission lowered its 30-inch prototype reactor canister into a 34-inch borehole to 100 feet depth using Youngquist's proprietary equipment. No financial terms, equity stake, or specific dollar commitments are disclosed; the agreement is described as ongoing technical collaboration with intent to continue working together as Deep Fission targets commercial deployment as early as 2027.