Ion Exchange Applications in Nuclear Power Plants

Ion exchange resins, both in bead and powder form, are used extensively in all types of nuclear power plants throughout the world. Ion exchange systems are the most cost-effective and, in some cases, the only way to produce water with the quality required for proper plant operation.
 
Ion exchange plays a vital role in eliminating soluble chemical components that contribute to corrosion and removing corrosion products and radioactive isotopes from coolant circuits. The objective of controlling these chemistries is to protect the nuclear-generating systems from corrosion, extend the system life, and maintain a safe working environment in and around the plant.
 
Nuclear power generation will continue to grow as a strategic option due to the increasing cost of fossil fuel-based energy and the pressure to reduce greenhouse gases. 

Applications for Nuclear-Grade Resins

Polishing requirements for makeup (MU) water

Regenerable resins such as NRW100 and NRW400 will perform the bulk of the demineralization and mixed bed polishing followed by a non-regenerable mixed bed UCW3710 for final polishing of trace ions and minimizing total organic carbon (TOC) release from the resin. This makeup water will be used in all nuclear systems.
 
Steam generator blowdown (SGBD) recovery
Specific resins have been developed for use in polishing steam generator blowdown for reuse. Our low sodium cations NRW160LS and NRW1160LS are specific for plants that do not regenerate and will operate polishing demineralizers months beyond a conductivity or amine break while controlling the release of Na. The complimenting mixed beds NRW3560LS and NRW3675LS also employ low sodium cation components supporting long-term service of the blowdown demineralizer. If resins are regenerated or operated in other configurations, there are many resins available to complement your system operation. 

Nuclear grade resin for deep bed condensate polishing (CP) 
Specialty condensate polishing resins Supergel™ SGC650H and Supergel SGA550OH or the premix mixed bed NRW1200 are designed for PWR polishers. For those preferring visual benefit and fouling tolerance of macroporous anions, NRW5050 is a proven product. Non-regenerable pressurized water reactor (PWR) and boiling water reactor (BWR) deep bed polishers will find NRW1160 and NRW8000 beneficial with these low organic sulfate and organic chloride releasing resins.
 
Chemical Volume Control (CVCS) during full power 
Resin layering technology in the CVCS, uses proven macroporous specialty resins including the orthoporous NRW5010XLC or NRW5070XLC for colloidal activity, the cation NRW160Li7 for high selective removal of metals including Cs, Co, and Ni and the specialty mixed bed NRW3560XLCLi7 for final polishing. This technology has a 20+ year record of exceptional results. The XLC version of the anions ensures no chloride issue during PWR startup with high boron and lithium concentrations. 
 
Radioactive waste cleanup 
Removal of isotopes and ionic impurities from waters planed for reuse of discharge is properly addressed with the specialty mixed bed NRW3560 or the slightly more economical mixed bed NRW3240. Use of the layered specialty macroporous anion NRW5010 or NRW5070 and the macroporous cation NRW160 during outage cleanup generally improves treatability of wastewater collected during outage. In the event there are difficult isotopes in the radwaste stream, there are many selective resins available for specific situations.

Nuclear grade resin for reactor water cleanup (RWC) 
The layered technology discussed above is applicable for BWR reactor water deep bed demineralizers with affinity for fine colloids and excellent selectivity for Co60. 
 
Outage cleanup with high ionic loads and fine colloids 
The layered technology discussed above was introduced by Purolite primarily for outage beds as this is where the greatest colloid and ionic load is generated during the oxidizing cleanup phase. The cleanup bed has affinity for fine colloids and high selectivity for Co58. With continuous use this technology is included in best practice for source term reduction by the nuclear industry. 
 
Spent fuel pool (SFP) cleanup 
Resins polishing spent fuel coolant encounter aggressive oxidative conditions resulting in sulfate accumulation after a short service period. The high crosslinked cation NRW1180 or the mixed bed NRW3860 incorporating this cation have shown extended life in this environment. Use of these resins and possible other practices such as short loading may improve demineralizer life and reduce resin waste. If difficult isotopes are present in the pool, selective resins are available such as NRW5330B with high affinity for antimony and other trace metals.