Skip to main content

IMMOBILIZATION IN CEMENT OF ION EXCHANGE RESINS ARISING FROM THE PURIFICATION OF REAGENTS USED FOR DECONTAMINATION OF REACTOR CIRCUITS.

Objective

THE OVERALL OBJECTIVE OF THE PROGRAMME IS TO IDENTIFY A SUITABLE CEMENT MATRIX TO DISPOSE OF ORGANIC ION EXCHANGE RESINS CONTAMINATED WITH DECONTAMINATING AGENTS.

FOR THE LAST FIVE YEARS, LOW OXIDATION STATE METAL ION REAGENTS (LOMI) HAVE BEEN USED TO DECONTAMINATE THE 100 MW(E) STEAM GENERATING HEAVY WATER REACTOR AT WINFRITH. THE USE OF THESE REAGENTS HAS RESULTED IN A DILUTE IONIC SOLUTION CONTAINING ACTIVATION PRODUCTS WHICH ARE PRODUCED BY CORROSION OF METALLIC COMPONENTS IN THE REACTOR. IT HAS ALREADY BEEN DEMONSTRATED THAT THE AMOUNT OF ACTIVITY IN SOLUTION CAN BE REDUCED USING ORGANIC ION EXCHANGERS, FOR EXAMPLE DUOLITE C225, A CROSSLINKED POLYSTYRENE WITH SULPHONIC ACID FUNCTIONAL GROUPS.

THE AIM OF THE PROGRAMME AT PRESENT IS TO SHOW THAT ION EXCHANGE RESINS USED TO REMOVE ACTIVITY FROM DECONTAMINATING AGENTS CAN BE SUCCESSFULLY IMMOBILIZED IN CEMENT. TO ACHIEVE THIS, BLENDS OF ORDINARY PORTLAND CEMENT (OPC) AND GROUND GRANULATED BLAST FURNACE SLAG (BFS) WILL INITIALLY BE USED.
The removal of activity from spent decontaminating solutions can be achieved using organic ion exchange resins. These resins can be successfully immobilised in a cement based matrix. The optimum cement system contained 10% ordinary Portland cement, 84% blast furnace slag, 6% microsilica with a water cement ratio of 0.5 and a dry resin loading of 36% with respect to total weight. This formulation was sucessfully scaled up to 200 litres giving a product with acceptable compressive strength, dimensional stability and elastic modulus. Storage of samples under water appears to have no detrimental effects on the product's properties.
1. IDENTIFY SUITABLE SIMULANT ION EXCHANGE RESIN WASTE.
2. DEVELOPMENT OF FORMULATION USING A RANGE OF WASTE SIMULANT TO CEMENT RATIOS AT LABORATORY SCALE.
3. DEMONSTRATE FORMULATION IS STILL ACCEPTABLE AFTER SCALING UP TO 200 LITERS. IF NECESSARY THE FORMULATION WILL BE ADJUSTED.
4. INVESTIGATE THE EFFECTS OF DECONTAMINATION REAGENT'S COMPONENTS ON CEMENT HYDRATION.
5. INVESTIGATE THE EFFECT OF ADDITIVES TO IMPROVE THE PROPERTIES OF THE CEMENTED PRODUCT.
6. EXAMINE THE PROPERTIES OF ACTIVE CEMENTED ION EXCHANGE RESIN USING THE ISO LEACH TEST.
7. ESTABLISH WASTE VOLUME REDUCTION FACTORS.
8. COMPARE AND CONTRAST METHODS USED BY OTHER LWR OPERATORS IN EUROPE FOR DECONTAMINATION OF THEIR REACTOR CIRCUITS AND DISPOSAL OF THE SOLUTIONS.
9. ESTABLISH A SATISFACTORY PROCESS FLOW SHEET FOR ENCAPSULATING ION EXCHANGE RESINS IN CEMENT.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

United Kingdom Atomic Energy Authority (UKAEA)
Address
Winfrith Technology Centre
DT2 8DH Dorchester
United Kingdom