The UnderSec project is developing a new way to identify dangerous materials hidden under water or attached to ship hulls, without opening any containers. The Concealed Material Identification Module (CMIM) is an add‑on module for Remotely Operated Vehicles (ROVs) that uses pulsed fast neutrons to “look inside” suspicious objects and analyse their elemental composition in real time.

The system can detect key elements such as carbon, oxygen, hydrogen, nitrogen, chlorine and others that characterise many explosives, narcotics and certain chemical warfare agents by measuring gamma rays emitted when neutrons interact with nuclei. The high penetration power of fast neutrons means that CMIM can still work when objects are immersed in water, corroded or partially buried.

For UnderSec, CMIM adds a powerful identification layer on top of existing tools such as cameras, sonars and magnetometers, helping security teams confirm whether an underwater anomaly is harmless or contains a real threat near critical subsea infrastructure or ship hulls.