New Technology Helps Boost Plant Sustainability and Reliability

Dow Water & Process Solutions (DW&PS), a business unit of The Dow Chemical Company (USA), has introduced DOWEX MONOSPHERE 1400PC Cation Resin for Pressurised Water Reactor (PWR) nuclear power plants. Launched at the 2013 Electrical Power Research Institute (EPRI), this new high capacity cation resin was designed to help strengthen plant reliability by minimising anion resin kinetic degradation associated with the use of ethanolamine (ETA) which is used to minimise flow-assisted corrosion (FAC) and iron transport within the secondary water systems.

PWR plants can experience extremely small condenser leaks that are nearly impossible to locate and repair and yet introduce contamination at levels that cannot be tolerated within the steam generator guideline targets. In order to maintain full power operation in these scenarios, the plants must operate their condensate polishers. Although the use of ETA minimises FAC and iron transport, this chemistry causes degradation of anion resin kinetics in the mixed bed condensate polishers, making it difficult to meet guideline targets for sulphate in steam generators. As a result, many plants have resorted to using extra polisher maintenance procedures, such as hot water rinsing, partial exchange of the anion resin and frequent mass transfer coefficient (MTC) testing to keep acceptable polisher effluent sulphate levels.

“DOWEX MONOSPHERE 1400PC is the first resin to specifically address the problems associated with ETA in condensate polishers. It delivers high-quality water to the steam generator for uninterrupted power production,” remarks Bill Carlin, industrial/power technical service specialist for Dow Water & Process Solutions.

The performance of DOWEX MONOSPHERE 1400PC was proven in a recent trial at Diablo Canyon Nuclear Power Plant in Avila Beach, California, which was experiencing rapid kinetic impairment of the anion resin. A test bed of DOWEX MONOSPHERE 1400PC cation resin combined with AMBERJET 9000 OH anion resin, was installed at the plant. The test bed was able to maintain stable, acceptable anion resin kinetics (MTC) and sulphate effluent performance in a PWR mixed bed condensate polisher where ETA was used as the neutralising amine. This was accomplished without the need for special hot water rinsing or partial exchange of the anion resin in the test bed.

DOWEX MONOSPHERE 1400PC provides a significant new tool to help facilitate sustainable full flow condensate polisher operation. The new DOWEX MONOSPHERE 1400PC can also be paired with the DOWEX MONOSPHERE 550A anion resin for use in PWR mixed bed condensate polishers.