A Novel, Safe, and Environmentally Friendly Technology for Water Production Through Recovery of Rejected Thermal Energy From Nuclear Power Plants

Abstract

In this work, we describe a novel design that utilizes seawater and a portion of rejected heat from a nuclear plant’s steam cycle to operate a water desalination system using forward osmosis technology. Water produced from this process is of sufficient quality to be readily used to supply plant demands for continuous makeup water. The proposed process minimizes the environmental concerns associated with thermal pollution of public waters and the resulting adverse impact on marine ecology. To demonstrate the technical feasibility of this conceptual design of a water treatment process, we discuss a case study as an example to describe how the proposed design can be implemented in a nuclear power station with a once–through cooling system that discharges rejected heat to an open sound seawater as its ultimate heat sink. In this case study, the station uses a leased (vendor owned and operated) onsite water treatment system that demineralizes and polishes up to 500-gpm of city water (at 100 ppm TDS) to supply high-quality makeup water (< 0.01 ppm TDS) to the plant steam system. The objectives of implementing the new design are three fold: 1) forego current practice of using city water as the source of plant makeup water, thereby reducing the nuclear station’s impact on the region’s potable water supply by roughly 100 million gallons/year, 2) minimize the adverse impact of discharging rejected heat into the open sound seawater and, hence, protect the marine ecology, and 3) eliminate the reliance on external vendor that owns and operates the onsite water treatment system, thereby saving an annual fixed cost of $600K plus 6 cents per 1,000 gallons of pure water. The design will also eliminate the need for using two double-path reverse osmosis (RO) units that consume 425 kW/h of electric power to operate two RO pumps (480V, 281.6 HP, and 317.4 amps).