May 07, 2010 13:20
Traces of gunpowder found in the wreckage of the Navy corvette Cheonan, which sank in an explosion in the West Sea on March 26, came from a torpedo, a government official said Friday.
"Explosive traces found in the Cheonan's chimney and the seabed on which the stern's broken-off side had been lying were all confirmed as those of the high explosive RDX, which is more powerful than TNT," the official told the Yonhap news agency. "This explosive is used in torpedoes, not sea mines." The tiny amount of gunpowder ingredient was detected in the Cheonan's funnel.
RDX stands for "research department explosive." Water is much denser than air and is capable of transferring energy more quickly, but also dissipates faster, with the power of a blast being limited to just between 5 to 6 m, so gunpowder in torpedoes and mines is produced to maximize the power of the blast.
The gunpowder was discovered in the funnel of the vessel, which is unusual given that the Cheonan was split in half in a blast from underneath. Investigators believe traces of gunpowder on the stern and bow of the vessel may have been washed off when the sections shifted position due to the strong currents. But the funnel remained stationary, thereby allowing traces of gunpowder left inside to remain intact.
Investigators have also identified four pieces of aluminum alloy found at the scene as part of a torpedo. The official told Yonhap the material is an alloy of aluminum and magnesium commonly used in a torpedo's casing.
The pieces were discovered both inside and near the split section of the ship. X-ray and neutron diffraction techniques could determine the manufacturer of the aluminum alloy, making it possible to identify the source of the weapon.
The ministry says another two weeks will be needed to complete the analysis and that an announcement could be made around May 20. The team, which consists of South Korean and U.S. investigators, has been working aboard the South Korean ship Dokdo isolated from contact with the outside. But starting on Friday, investigators are moving to a Navy base in Pyeongtaek, and a number of personnel are expected to leave.
There are rumors that U.S. experts have already reported their findings to American military commanders and government officials and that the probe will be wrapped up soon.
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