BURNING RADIONUCLIDE QUESTION - WHAT HAPPENS TO IODINE, CESIUM AND CHLORINE IN BIOMASS FIRES

Fires can mobilize radionuclides from contaminated biomass through sus pension of gases and particles in the atmosphere or solubilization and enrichment of the ash. Field and laboratory burns were conducted to d etermine the fate of I, Cs and Cl in biomass fires. Straw, wood, peat, dulse (seaweed) and radish plants were combusted with temperatures va rying from 160 to 1000 degrees C, representing the normal range of fie ld fire temperatures. Loss to the atmosphere increased with fire tempe rature and during a typical field fire, 80-90% of the I and Cl, and 40 -70% of the Cs was lost to the atmosphere. The remainder was left behi nd in the ash and was soluble. Typically, the ash was enriched in I by a factor of two to three, with higher enrichments of Cs and lower enr ichments of Cl, when compared to the initial fuel concentration during field burns. Most of the I was lost to the atmosphere as a gas. If th e elements were radioactive isotopes, such as I-129, Cs-137 and Cl-36, fires could cause an increased radiological dose to people through in halation, exposure to ash, or ingestion of plants because of increased uptake of ash leachate.