Speaker
Description
Ion exchange resins (IEX) which are used in nuclear power plants have to be treated and dried, in order to ensure a safe storage in future. A main advantage of the hot resin compaction during mentioned treatment process, is the saving of limited storing capacities in comparison to non-compacted IEX.
Supplied and temporarily stored IEX have to be transported as IEX / water mixture by piping systems to the grinding process via mill. This process is necessary in order to avoid the spring-back effect of the IEX. The mentioned effect can cause the IEX to return into their original form which leads to deformation and expansion of compacted pellets. Afterwards, the ground IEX have to be dried. During the drying process, free water is evaporated before the IEX have to be further dried until reaching the required residual moisture content. The dried and still hot IEX are filled fully automatically into a compactable drum. Afterwards, the drum has to be transferred to the high force compactor, where it is compacted. The resulting pellets are transported to the pellet optimizing station by crane and gripper. This station is used to ensure the best possible and most compact filling of the storage drums for pellets. The optimization is done via parameter measurement like height and weight of the pellets. Afterwards they are filled into storage drums, transported via roller conveyors to the cementation unit, grouted and finally passed on to the customer.
The implementation of grinding and compaction of IEX leads to savings in limited storage capacities. The storage capacity will be reduced by meaning of the enlarged volume reduction factor (VRF) of compacted IEX.
Different test series were carried out to obtain knowledge about the behavior of the IEX during the treatment. Following tests were carried out:
- Grinding, in order to obtain a transportable IEX / water mixture and the average particle diameter to ensuring the conditions for successful compaction without spring-back effect
- Drying, in order to obtain dried resins with required residual
moisture content - Compaction tests in different scales considering various
investigation criteria: Exclusion of spring-back effect after compaction ; Properties of the compacted IEX ; Behavior during renewed moisture absorption ; Volume reduction factor during different test series from test-size scale to full-scale tests
Based on experiences and successful design, the hot resin compaction process was successfully implemented in Tianwan China by NUKEM Technologies Engineering Services.
| Speaker's title | Mr |
|---|---|
| Affiliation | NUKEM Technologies Engineering Services GmbH |
