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Part 1 of 5 parts
       I have often blogged about spent nuclear fuel. This nuclear waste contains radioactive materials such as plutonium-239 which has a half-life of twenty-four thousand years. Geological repositories are being developed for long term storage of such nuclear waste. When repositories are filled, they are to be sealed and made inaccessible. However, not all radioactive waste will be stored in such repositories and there will be temporary storage of spent nuclear fuel in steel and concrete casks at ground level. If anything disastrous happens to our civilization, the nature and danger of the content of these repositories and casks will probably be forgotten and they may pose a serious hazard to our descendants.
      Ionizing radiation includes higher frequencies of ultraviolet light, x-rays, gamma rays, cosmic rays, energetic neutrons, alpha and beta particles. Currently the internationally recognized symbol for ionizing radiation is called the trefoil. It was first used in 1946 at the University of California, Berkeley Radiation Laboratory. There are three blades radiating from a small circle. Each blade is one sixth of a circle. There are same sized spaces between the blades. The blades have a circular outer rim. The original color scheme was magenta symbol on a blue background.

Eventually, the background was changed to yellow in the U.S.

Internationally, the blades became black.

 

This version is also widely used in the U.S. Sometimes, the symbol is surrounded by a triangle or a circle.

      In February of 2007, the International Atomic Energy Agency (IAEA) and the International Organization for Standardization (ISO) jointly announced a new symbol that was to be used on sealed containers or repositories of radioactive materials. The symbol is intended for use by anyone anywhere regardless of language or culture. The new symbol contains three different symbols. There is the trefoil with descending lines at the top of a triangle. In the lower left corner of the triangle is a skull and cross bones and in the lower right is a human figure depicted as running away from the skull and cross bones in the direction shown by a horizontal arrow.

 

This symbol is not meant to be openly displayed but rather placed on components inside devices that employ radiation sources as well as on casks and drums of radioactive waste in repositories. It is hoped that if anyone encounters this symbol, it will show them that they should run away from whatever displays it.
      For some time, people have been considering what sort of warnings could be posted around areas where nuclear wastes are stored or which have been contaminated by radioactive materials. These warnings would have to survive for millenia and be understood by our descendant who may have lost much of the knowledge of our civilization.
      Our ancient ways of storing information such as stone and ordinary paper deteriorate over time. Stone weathers and inscriptions can disappear. Ordinary paper contains acids left over from processing wood pulp to make the paper. This results in paper that deteriorates overtime when exposed to light and heat. High tech ways of storing information on computers could be destroyed or cease functioning if our civilization collapsed.
Please read Part 2 next