secwatch.observer — SEC 8-K summary
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Issuer:     DEEP FISSION, INC. (FISN)
CIK:        0001918102
Form:       8-K
Filed at:   2026-09-21T15:26:05+00:00
Accession:  0001104659-26-109201
Event type: other_material
Sentiment:  positive
Materiality: 0.50
Item codes: 7.01, 9.01
LLM model:  deepseek-v4-flash:cloud@v2

Deep Fission completes borehole demo with Youngquist; targets 2027 deployment
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- Collaborated with drilling contractor Youngquist Brothers to evaluate/test deep, large-diameter borehole drilling for underground reactor deployment.
- On Sept 3, 2026, in Fort Myers FL, Deep Fission lowered and retrieved its 30-inch full-size prototype reactor canister into a 34-inch borehole to ~100 ft.
- Youngquist has drilled large-diameter boreholes to depths >8,000 ft since 1971; partnership applies that expertise to Deep Fission's Gravity™ reactor model.
- Company targets commercial deployment as early as 2027; collaboration to continue on drilling and testing.

Source:
  EDGAR index:    https://www.sec.gov/Archives/edgar/data/1918102/000110465926109201/0001104659-26-109201-index.htm
  Primary doc:    https://www.sec.gov/Archives/edgar/data/1918102/000110465926109201/tm2625786d1_8k.htm
  HTML page:      https://secwatch.observer/filing/0001104659-26-109201

License: Source filings: public domain (SEC EDGAR). Summaries (headline + bullets): CC-BY-4.0; attribute https://secwatch.observer