Solid Radioactive Waste Strategy Report.pdf - UK EPR

EPR UK
N° NESH-G/2008/en/0123
REV. A PAGE 58 / 257
7.3.1 Liquid Effluent Treatment By Evaporation
Evaporation is the most effective method for chemical and radiological purification of liquid
effluent from a Nuclear Power Station [Ref. 36]. The evaporator separates the dissolved and
suspended liquid effluent constituents, concentrating the radioactivity in the resulting residue
(see Figure 11).
Clean water leaving the evaporator can be discharged or recycled directly following monitoring
to confirm compliance with discharge authorisations. The evaporator concentrate will be subject
to further conditioning prior to disposal.
Application
Evaporation can be used for:
· Equipment drains and sump water;
· Decantation water;
· Liquid chemical waste (from decontamination operations, laboratory);
· Laundry water (detergents);
· Regenerants (chemicals).
Design Data
· System throughput 4m 3 /h (typical);
· Decontamination factor (bottoms, distillate): up to 10 7 .
Advantages
· Reduces radioactive discharges by concentrating particulate in the evaporate;
· Minimises discharges of chemical and solid impurities;
· High decontamination factor;
· Proven system design/technology;
· Well documented operational experience;
· Customised application;
· Continuous and automatic operation.
· Disadvantages
· Unsuitable for liquids containing a high foam component;
· Evaporators can have higher operational costs than non-thermal separation
technologies.