In 1967 the
Michigan Technological University Physics Department obtained 10
Uranium fuel plates. The plates had a triangular shaped tip on the end that measured about 1 inch at the base, 1 inch high and was 0.1 inch thick. On one of the fuel plates, the tip broke off and the Department's
RSO maintained the piece in an envelope in the same locked container where he kept the fuel plates. In 1977 during the course of routine laboratory nuclear training work with the fuel plates, one of the students wanted to look at the structure of the piece microscopically for a course in Metallurgy. The
RSO gave the student the tip in an envelope sandwiched between 2
copper sheets. The student returned the piece in the envelope, and the envelope was returned to the safe unopened.
On March 16, 2006, the envelope was opened to obtain data on the piece for return to Federal control, and the piece was not in the envelope.
Further investigation determined that the tip was too large to be used in the Scanning Electron Microscope (SEM), and a small piece of the tip was removed. It appears that only this small piece was returned to the RSO. Personnel from the Metallurgy laboratory were questioned and it appears that the tip remained in the Metallurgy facility until after 1991 when it is thought that it was disposed of in the regular trash.
The uranium fuel plates were 20 weight percent enriched Uranium. The tip contained approximately 1.1 grams enriched uranium or 0.21 gm U-235. It had an activity of 0.3 micro curies U-238 and 0.4 micro curies U-235. On contact measurements for the tip are expected to be less than 1 milli rem per hour on contact.
On March 30, 2006, the Director, Occupational Health and Safety conducted a thorough search and survey of the Metallurgy laboratory and could not find the tip.
THIS MATERIAL EVENT CONTAINS A "LESS THAN CAT 3" LEVEL OF RADIOACTIVE MATERIAL
Sources that are "Less than
IAEA Category 3 sources," are either sources that are very unlikely to cause permanent injury to individuals or contain a very small amount of radioactive material that would not cause any permanent injury. Some of these sources, such as
moisture density gauges or thickness
gauges that are Category 4, the amount of unshielded radioactive material, if not safely managed or securely protected, could possibly - although it is unlikely - temporarily injure someone who handled it or were otherwise in contact with it, or who were close to it for a period of many weeks.