Wednesday, November 14, 2012

Osmium: The Best Radiation Shielding Material?

As the material of choice used as the radiation shielding in the warp nacelles of the first Starship Enterprise, is osmium the best radiation shielding material out there?

By: Ringo Bones

From a nuclear engineering standpoint, when the subject of using osmium as a radiation shielding material – every competent engineer will be concerned about costs. After all, even though the metal itself is not regularly flashed during the commodities segment of the NYSE – just by belonging in the platinum group of metals only makes one safely assume that osmium could be closer in price to either platinum or palladium – its other two siblings regularly monitored on the ticker tape of the commodities markets. Cost concerns aside, is osmium truly a better radiation shielding material in comparison to ones currently used – i.e. like lead, steel or concrete?

It was in the Season 2 episode of Star Trek: Enterprise titled The Catwalk – which was originally aired back in December 18, 2002 – where osmium was mentioned as the radiation shielding used in the warp nacelles of the Starship Enterprise. The subject came about because during a deadly radioactive storm in space threatens Enterprise, the entire crew took shelter in the starship’s warp nacelles which were the most shielded part of the ship against radiation. And given that most radiation shielding currently used are known for their relatively high density – i.e. lead, steel and concrete – does this mean that the densest nonradioactive we currently know, osmium at 22.5 grams per cubic centimeter at almost twice the density of lead, is the more ideal radioactive shielding material?

Using current International Atomic Energy Agency standards in commercial nuclear fission power plants – and future nuclear fusion power plants are more than likely to comply with this figure for safety of both human personnel and electronics – adequate shielding consists in reducing radiation levels to values approximately as follows: in the gamma radiation wavelengths – 2,750 Mev per square cm/second; fast neutrons – 75 neutrons per square cm/second; and thermal neutrons – 3,600 neutrons per square cm/second. For humans – and other humanoid carbon based life-forms and the electronic systems on the Starship Enterprise to perform efficiently, not to mention stay healthy, Captain Jonathan Archer would probably stick with the IAEA’s established occupational radiation level standards.