Elements when bombarded with neutrons emit a gamma ray that is characteristic of the isotope that underwent a neutron induced nuclear reaction; this is known as neutron activation. The characteristic gamma energy of an isotope can then be detected and recorded. One can then analyze the gamma energies captured and determine the elemental makeup of the sample. This form of analysis can be used in an underwater environment making it potentially a valuable tool for agencies tasked with maritime security of ports and waterways, or clean-up operations. This thesis will focus on the feasibility of neutron interrogation using pulsed fast/thermal neutrons in an underwater environment for detecting various chemical substances in metal containers. A hermetically sealed, submersible container was used to test a d-T neutron generator’s and semiconductor detector’s functionality underwater in regards to detecting such chemicals as sulfur, nitrogen and chlorine rich materials.