At a meeting getting underway today in Vienna, a technical arm of the International Atomic Energy Agency is expected to approve a German proposal to weaken a new standard for air transport of plutonium-based nuclear fuel, despite opposition by the U.S. Government and international civil aviation associations. In an air crash, they insist, existing casks are likely to remain sufficiently intact to limit releases of plutonium to an acceptable level. A technical analysis by Nuclear Control Institute finds a number of mechanisms that could result in a dispersal of plutonium in the event of a severe accident. A high-velocity impact that breached the fuel cladding, followed by a fire of moderate temperature that burned for several hours, could cause substantial releases, according to Dr. Edwin Lyman, scientific director.
Plutonium is a highly toxic carcinogen, if inhaled.
In 1993, a plan to send MOX fuel rods by air from Germany to Scotland was blocked by Hesse state officials on safety grounds. Currently, MOX fuel fabricated in the U.K. is flown to Switzerland. The authors of the German working paper are officials from the Environment and Reactor Safety Ministry and the Bureau of Radiation Protection. Beyond the issue of exempting MOX fuel shipments from Type C casks, the adequacy of the IAEA Type C cask itself has been challenged by U.S. and international civil aviation officials. The ICAO called for sequential impact and fire tests on the same cask rather than the separate impact and fire tests on different casks that are to be required to prove a Type C cask.