Safety in this design comes from physics. Decay heat leaves by natural air flow with no pumps. Thick shielding lets workers approach the building. Sensors report on the core in real time, and the control system acts on them.
After shutdown the fuel still produces a few percent of full power. Air ducts around the guard vessel let natural convection carry that heat to a chimney with no pumps and no power.
| Type | Reactor vessel auxiliary cooling (RVACS) |
|---|---|
| Capacity | ≈ 1 MWt |
| Driving force | Natural draft |
| Availability | Always on, passive |
Thick concrete and steel around the vessel absorb neutrons and gamma rays. Workers can approach the building while the reactor operates.
| Material | Reinforced concrete and borated steel |
|---|---|
| Radial thickness | ≈ 1.4 m |
| Top shield | Rotating shield plug |
| Design goal | Public dose limits met at site boundary |
Neutron detectors, thermocouples, and sodium level sensors report on the core in real time. The control system uses these readings to adjust the drums automatically.
| Neutron detectors | 4 ex-core fission chambers |
|---|---|
| Temperature | ≈ 200 thermocouples |
| Leak detection | Guard-vessel gap sensors |
| Operation | Autonomous with remote monitoring |