RECI

Type of Facility: Containment

  RECI

The aim of the RECI (RECombiner & Iodine) program was to quantify the iodide → iodine conversion in realistic conditions of recombiner operation, albeit under the following constraints: the experiments were to be performed with non-radioactive substances, and without hydrogen. The comprehensive tests grid allowed to investigate into the decomposition of cesium and cadmium iodides under thermal-hydraulics conditions that mimics the recombiner operation, despite the technical limitations of the RECI test bench.

Description

RECI is a 2½ year experimental programme that was brought to completion as of October 2004. The aim of the RECI (RECombiner & Iodine) program was to quantify the iodide → iodine conversion in realistic conditions of recombiner operation, albeit under the following constraints: the experiments were to be performed with non-radioactive substances, and without hydrogen. The comprehensive tests grid allowed to investigate into the decomposition of cesium and cadmium iodides under thermal-hydraulics conditions that mimics the recombiner operation, despite the technical limitations of the RECI test bench.
The aerosol generator selected limits the RECI programme to the study of water soluble substances, namely cesium and cadmium iodides: silver iodide is insoluble in water, and indium monoiodide is hydrolysed. However, the experimental results can be interpolated with reasonable confidence, since CsI and CdI2 are the two end-terms in the stability range of the relevant iodides. The instability of metal iodides, in a wet and oxidizing atmosphere, already demonstrated in chemistry laboratories, has been confirmed in more relevant physico-chemical conditions. The high conversion yields obtained do not come as a surprise since the RECI experiments provide a close analogy to the processes known as spray drying and spray (reactive-, or oxidizing-) pyrolysis, widely used in the laboratory and in the manufacturing industry. Both processes capitalize upon the high surface/volume ratio of aerosol particles to master comparatively slow chemical reactions and to produce nano-particles, the precursor material being often a finely powdered metal halide.
The experimental test bench consists of 4 units.

  • Aerosol generation: an ultrasonic aerosol generator atomises the aqueous solution of a water soluble iodide. Monodispersed droplets are then dried, yielding iodide particles, the size of which is determined by the concentration of the solution. The input power of the ultrasonic acoustic transducer sets the aerosol concentration.
  • Recombiner surrogate: a clear fused quartz or alumina tubing, which can accommodate a catalyst foil, is heated in a vertical tube furnace.
  • Aerosol characterization: particles concentration & size distribution measurements. • Gaseous iodine analysis: 3 independently calibrated methods are implemented in the flue gas.

Facility is dismanteled.


Organization: 
Type of Facility: 
Containment
Experiments available:
0