International Topical Meeting on Nuclear Research Applications and Utilization of Accelerators
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SM/EN-06
Environmental Security of the Coastal Sea Floor V. Valkovic1, J. Obhodas2, D. Sudac2, and D. Matika3 1A.C.T.d.o.o., Zagreb, Croatia Corresponding Author: valkovic@irb.hr The coastal sea floor is littered with many of man made objects and materials including a variety of ammunition. In addition, sediments in ports, harbors and marinas have increased concentrations of chemicals used as biocides in antifouling paints. Therefore, one has to develop capabilities of measuring concentrations of chemical elements in the sediments, determining the content of different containers, establishing the presence of threat materials, identifying the material within sunken ships. In this report the activities related to the development of capabilities for the evaluation of environmenta security of the coastal sea floor are summarized. Several hundred coastal sea sediment samples have been collected and analyzed for 18 chemical elements by using EDXRF as an analytical tool. Contour maps of antifouling biocide elements (Cu, Zn, As and Pb) have been generated for the entire eastern coast of Adriatic Sea indicating the locations of “hot spots” in the distribution of chemical elements used as biocides (Cu, Zn, As, Pb). In order to be able to establish if an object on the sea floor contains some sort of threat material (explosives, chemical warfare) a system using neutron sensor installed within an unmanned underwater vessel has been developed and tested. When positioned above the object such a system can inspect the object for the presence of the threat material by using α particle tagged neutrons from the sealed tube d+t neutron generator. While the commonly used military explosives are characterized by the presence of only four chemical elements (C, H, N, O) chemical warfare agents usually have in addition one or more chemical element (P, S, Cl, F, As or Br). The results from the laboratory tests for the detection of the presence of these chemical elements are presented. It is often required to inspect ship hulls, either to detect potential anomalies attached to the hull, or to determine the nature of materials within hull, especially of sunken ships. We have performed tests with our system submerged in the test basin filled with sea water with targets being: 10 liters of diesel fuel, 5 kg of explosive and different chemicals (expected components of chemical warfare agents) placed behind 16 mm steel plate in the first measurement and behind sandwich 18 mmsteel plate – 10 cm air bag – 16 mm steel plate in the second measurement, respectively.
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