Deep Fission, Inc. (NASDAQ:FISN) ("Deep Fission" or the "Company"), an advanced nuclear energy company developing small modular pressurized water reactors installed one mile underground, today announced that the U.S. Department of Energy (DOE), has approved the company's Nuclear Safety Design Agreement (NSDA) for its Gravity™ Nuclear Reactor. This marks a major regulatory milestone, confirming that Deep Fission's reactor design warrants advancement under the Department of Energy’s Reactor Pilot Program.

The NSDA approval establishes the safety framework that will guide the reactor's continued development. With this milestone in place, Deep Fission moves forward to the next phase of the DOE authorization pathway, advancing toward demonstration and eventual deployment of its underground nuclear reactor technology.