Technical feasibility is, in the most basic sense, defined by system operability, measured in terms of on-line operating capacity factor and thermal efficiency (as a percent of the energy resources converted to a more usable energy currency or product). Power plants typically aim to achieve at least an 85 percent capacity factor, in consideration of grid demand cycles and seasonal plant outages for equipment maintenance. The capacity factor for the current fleet of LWRs in the United States has ranged from approximately 86 to 91 percent (over the entire US nuclear fleet) from 2006 to 2012 [5]. The chemical industry strives to establish the highest capacity factor possible, sometimes reaching 98-99 percent of nameplate capacity for annual operation of the plant. Current subsidized mandates (viz., Product Tax Credits) to build wind power has decreased the capacity factor of many baseload power plants, including some nuclear plants, to around 50 percent.

Some key technical parameters that affect the feasibility of a given combination of subsystems in a hybridized plant include (from the perspective of the reactor): reactor outlet temperature, reactor inlet temperature, heat flux, heat capacity, and peak operating temperature (and, in some cases, minimum operating temperature) of either the thermal hydraulic system materials or the heat transport fluid. These characteristics dictate materials of construction, determine the optimum power generation cycle, and dictate what process applications may best couple with reactor — produced thermal energy.

When the operating schedules of two or more subsystems are co-dependent, then plant design and operating schedules must account for startup and synchronization of all subsystems. Energy storage subsystems — on both the thermal and electrical branches of the system — may be necessary buffers to ensure smooth shutdown of one or the other facility in the event of an off-normal interruption of operations or for planned maintenance. The feasibility of cycling unit operations also needs to be considered, taking into account thermal energy production ramp rates, lag in energy delivery systems, the effects of mechanical and thermal stresses, and electrical hysteresis effects on battery storage units.

Technical feasibility is also impacted by the ability to modularize unit operations. As discussed in Section 13.1.2, SMRs are ideally suited (and designed for) modularization. Multiple modules in a single plant adds complexity to the physical integration, system operations, and control. However, modular implementations also offer the opportunity to increase capacity more easily with increasing demand, to attain higher integrated system capacity factors while allowing individual subsystems to be taken offline as needed for maintenance or refueling, and provide additional operational flexibility based on changing market trends.