[en] Mean amplitudes of vibration for IOF₅ have been recalculated from known spectroscopic data using the ''Method of the Characteristic Vibrations''. The obtained values are in excellent agreement with those obtained from electron diffraction and microwave measurements and give also a correct picture of the molecular geometry. (author)

No abstract available

[en] The behaviour of iodine during a severe accident has been studied in several experimental programs, ranging from the large-scale PHEBUS FP tests and intermediate-scale ThAI tests to numerous separate effect studies. Oxidation of iodine in gas phase has been one of the greatest remaining uncertainties in iodine behaviour during a severe accident. In this study the possible formation of iodine oxide aerosol due to radiolytic oxidation of gaseous iodine is experimentally tested and the reaction products are analysed. The experimental facility applied in this study is based on the sampling system built at VTT for ISTP program project CHIP conducted IRSN. The experimental facility and the measuring technology are sophisticated and unique in the area of nuclear research as well as in the field of aerosol science. The results from the experiments show an extensive particle formation when ozone and gaseous iodine react with each other. The formed particles were collected on filters, while gaseous iodine was trapped into bubbles. The particles were iodine oxides and the size of particles was approximately 100 nm. The transport of gaseous iodine through the facility decreased when both gaseous iodine and ozone were fed together into facility. Experimental study on radiolytic oxidation of iodine was conducted in co-operation between VTT and Chalmers University of Technology as a part of the NKS-R programs. (author)

[en] This report reviews the underlying chemistry of the photochemical method for removal of radioiodines from air and evaluates the concept with respect to various applications in the nuclear industry. The method uses ultraviolet light (200-300 nm) to convert organic iodides (RI) to elemental iodine (I₂). The I₂ is then reacted with ozone to form solid iodine oxides (I₄O₉ or (I₂O₅), which deposit inside a scrubber. It is concluded that the method is applicable to large-scale systems and would have several advantages over conventional methods of radioiodine abatement

[en] Time-dependent changes in the availability of iodine in soil were investigated for 23 months. Stable iodine was added to a grassland soil collected in Rokkasho, Japan. Whether iodine was added as I^- or IO₃^-, its water extractability decreased drastically for first 4 months after addition and then slightly decreased thereafter. These results indicate that most of the I^- and IO₃^- added to the soil was rapidly converted to an insoluble form. The soil-to-grass transfer factor of the added iodine showed a double exponential decline with time, similar to the decline observed for the water-extraction yield. (author)

No abstract available

[en] This paper deals with the separation of a mixture of electrolytes into its separate constituents by using the effect of ''solventing-out''--the precipitation of a salt from an aqueous solution by the addition of miscible organic solvent (MOS). An analytic expression is found for the dependence of the precipitated fraction on the ratio of the volumes of the MOS/aqueous solution. Required conditions for separation of two electrolytes in either one stage or in a multistage process are stated. The system KX-KXO₃-KXO₄ (where X is Cl, Br, or I) is analyzed more extensively

[en] Electrolyte containing aqueous interfaces are ubiquitous in nature and an integral part of the ‘chemistry at interface’. Chemistry at aqueous interface is remarkably different from its bulk counterpart; for instance, many reactions in aqueous microdroplet and at the air/water interface are accelerated by a factor of thousand or more compared to the corresponding reactions in the bulk water. Non-uniform distribution of ions at interface and the associated electric double layer (EDL) as well as altered hydration characteristics are believed to be crucial for the thermodynamics and kinetics of such interfacial reactions. (author)

No abstract available

[en] In case of the failure of a steam generator tube, water from the primary circuit, likely to be contaminated with iodine, flows out into the secondary circuit in the form of steam jets or fine water droplets. The size of the droplets depends on 2 processes: the mechanical fragmentation of the droplets due to hydrodynamical instabilities at the level of the breach and thermal fragmentation due to the explosive growth of steam micro-bubbles contained in the droplets. A mathematical model taking into account these 2 processes combined with a chemical model describing iodine chemical forms in the primary circuit has allowed us to get a more accurate distribution of the iodine chemical forms just after the breach: IO_3"-: 43.5%, HOI: 37.5%, I"-: 12.6%, IO: 2.9%, IO_3: 2.3%, and I: 1.2%. (A.C.)