Please address the following:

In Parsons, Kansas, the “deep fission” project at the Great Plains Industrial Park is a pilot program by the California-based startup Deep Fission. They broke ground in December 2025 and aim to have their first 15 MWe “Gravity” reactor achieve criticality by July 4, 2026. ​Because this technology involves placing a small modular reactor (SMR) in a 30-inch borehole one mile (1.6 km) underground, the potential hazards differ from those of traditional surface-level nuclear plants.

​1. Geological and Drilling Hazards

​Since the reactor is placed at a depth of 5,280 feet, the primary risks during the 2026 construction and testing phase involve the drilling process itself:

• ​Wellbore Instability: Deep drilling in Southeast Kansas involves passing through layers of limestone, shale, and sandstone. If the borehole walls are not properly stabilized (geomechanics), it could lead to “sloughing” or collapse during the insertion of the reactor module.
• ​Abnormal Pressure & Mud Loss: Drilling can encounter unexpected fluid pressures. “Lost circulation” (where drilling mud escapes into underground fractures) can stall the project or, in rare cases, create pathways for fluids to move between geological layers.
• ​Seismic Integrity: While the surrounding rock provides “passive shielding,” any natural or induced seismic activity must be monitored to ensure the 30-inch shaft remains perfectly aligned for the gravity-based safety systems to function.

​2. Operational Safety (The “Gravity” Design)

​The “Gravity” reactor uses a pressurized water design. The hazards here relate to the experimental nature of the deep-borehole setup:

• ​Coolant Circulation: The design relies on the weight of the water column (gravity) to provide the necessary pressure. A hazard unique to this setup would be a blockage or failure in the one-mile-long coolant loop, which could theoretically lead to overheating at the bottom of the shaft.
• ​Containment Failure: While the rock itself acts as a massive containment vessel, a breach in the reactor casing could potentially release radionuclides into the deep subsurface. However, at one mile deep, the reactor is far below the freshwater aquifers used for local agriculture and drinking water.

​3. Environmental and Local Impact

• ​Radioactive Waste Management: Although the reactor is designed to stay underground, the long-term plan for the spent fuel must be addressed. If the borehole is used as a permanent “repository,” the hazard shifts to the long-term integrity of the borehole seals (over centuries).
• ​Thermal Pollution: Deep reactors generate significant heat. Engineers must ensure that this heat dissipation through the rock doesn’t adversely affect the local subsurface environment or cause thermal expansion that could damage the shaft.
• ​Surface Infrastructure: In 2026, the primary visible hazard will be typical of any heavy industrial site: increased truck traffic at the industrial park, high-voltage electrical connections, and the handling of specialized drilling equipment.

​Summary of Risk Mitigation according to Deep Fission

​Deep Fission argues that this method is inherently safer than surface plants because:

• ​It is unreachable by aircraft or most surface-level terrorist threats.
• ​The high pressure of the deep earth prevents the water from boiling away easily.
• ​The “billions of tons” of surrounding rock provide a natural barrier that surface domes cannot match.

​If you are following the project closely, the July 2026 criticality goal will be the major milestone to watch, as it will prove whether the gravity-pressurized system can maintain a stable nuclear reaction at that depth.