Incorporating a fission-based power source in a multi-output system (electricity and process heat) can offer significant advantages over carbon-based production sources, such as coal or natural gas, including reduced atmospheric waste streams (e. g. carbon or other gaseous emissions) and reduced impact on environmental resources (land usage or modification, permanent withdrawals of fresh water, thermal emissions, etc.). In an integrated multi-output system, thermal energy from the nuclear subsystem can be diverted to industrial applications in times of low electricity demand from the grid or during times of high renewable energy input to electricity generation. High-temperature, high-quality heat from advanced reactor concepts might be used for high-temperature industrial processes, such as hydrogen production or synthetic fuels production. Low-temperature heat from either advanced or light-water reactor systems could be applied to district heating, desalination processes, or low-temperature biomass pretreatment and ethanol production. Subcritical steam can also be superheated through process heat recuperation, chemical heat pumps, or topping heat prior to being directed toward a given high-temperature heat application.

For the current discussion, a dynamic NHES describes an integrated energy complex composed of one or more nuclear reactors coupled to renewable power generation sources (wind, solar, geothermal, etc.), and possibly linked to the production of one or more chemicals, fuels, or commodity manufacturing plants. Various exchanges between thermal, electrical, mechanical, and chemical energy could make it possible to produce, store, and deliver the highest value products to the market at the right time. Hydrogen, for example, can be generated by intermittent thermal/electrical output of a power plant instead of reducing boiler output during periods of reduced power demand on the grid. This hydrogen could supply either a captive or merchant market, depending on geographic location and market factors. Alternatively, hydrogen could be stored and dispensed to an emerging fleet of hydrogen fuel-cell vehicles, to generate power for a micro grid using a set of solid oxide fuel cells, or to firm up the variable power output from the wind or solar power plant. Other process-oriented heat applications for synthetic fuels and chemical production have been developed and evaluated by the Idaho National Laboratory (INL) in support of the Industrial Alliance for the Next Generation Nuclear Plant (NGNP) [3, 4].

A multi-input, multi-output system is the ultimate goal for a nuclear hybrid energy park architecture. These systems would be composed of two or more energy conversion subsystems that are traditionally separate, but would be physically coupled in a hybrid system to produce outputs by dynamically integrating energy and material flows among energy production and delivery systems. These couplings would occur behind the electrical transmission bus, such that all subsystems share interconnections, and the system would be operated via a unified control system resulting in a single, highly dynamic and responsive system that interacts with the electrical grid.