A Steady-State Thermodynamic Framework for Preliminary Assessment of a Nuclear–Solar–Data-Center Integrated Power-and-Cooling System

Abstract

Small modular reactors (SMRs) offer firm low-carbon heat and power, and data centers concentrate large, continuous electrical and cooling loads. Transparent tools for screening their thermal integration are scarce. To the authors’ knowledge, this paper develops the first steady-state thermodynamic framework that couples SMR steam extraction, solar thermal input, and recovered data-center liquid-cooling heat through a single mixing-tank thermal bus serving both an absorption chiller and an organic Rankine cycle (ORC). The framework’s novelty is in its focus on the structural level rather than the component level. Two consistency requirements are built into its equations. First, the data-center control volume closes exactly, so that recovered heat reduces the residual cooling demand and heat removal equals IT dissipation. Second, delivered cooling is credited identically in every configuration compared, so that apparent gains cannot arise from asymmetric accounting. The framework identifies the governing mechanism of the architecture: a small 120 °C extraction stream (1.01% of core thermal power at the activation bound) unlocks the larger 70 °C recovered stream, which cannot drive the chiller alone. At the margin-constrained design point (2.93% extraction), direct liquid recovery removes 20.9 MWth, absorption cooling serves the remaining 16.2 MWth, and net electricity is 5.8 MWe above the all-electric reference. An itemized estimate places the integration-specific parasitic loads at 0.6–1.5 MWe (central value 1.0 MWe), which reduces the increment over the liquid-cooled non-integrated reference from +0.5 MWe (gross) to approximately −0.5 MWe (net). A 20,000-sample Monte Carlo analysis across seven uncertain parameters shows the net-of-parasitics gain over the all-electric reference is positive with 92% probability (median +4.1 MWe), while the increment over the non-integrated reference is positive with only 29% probability. A compact exergy inventory attributes 7.1 MW of destruction to the recovery train (process heat exchanger 2.0, mixing 1.2, ORC 2.0, chiller 2.0). The architecture’s robust value therefore lies in thermally driven cooling and the productive use of recovered heat, not in net energy. The framework is a screening tool rather than a validated plant model; a companion study populates it with published plant, climate, and equipment data.