This paper evaluates the integration of a high-temperature gas-cooled reactor (HTGR) to an in situ oil shale retort operation producing 7950 m3/D (50,000 bbl/day). The large amount of heat required to pyrolyze the oil shale and produce oil would typically be provided by combustion of fossil fuels, but can also be delivered by an HTGR. Two cases were considered: a base case which includes no nuclear integration, and an HTGR-integrated case.

The HTGR was assumed to be physically located near the oil shale operation such that heat losses during surface transport of the heating fluid were negligible. Transferring the required retort heat for all three cases to the underground oil shale was modeled by a series of closed-loop pipes. The pipes ran from the surface to the desired subsurface zone where the majority of the heat was transferred to the oil shale; the cooled fluid was then returned to the heat source at the surface for reheating. The heat source was a natural gas fired boiler for the base case and was an HTGR for the HTGR-integrated case. The fluid and heat flows through the circulation systems were modeled using Hyprotech's HYSYS.PlantTM process modeling software.

A mass and energy balance model was developed to evaluate oil production, gas production and usage, electricity generation and usage, heat requirements, and CO2 emissions for each case. Integrating an HTGR to an in situ oil shale retort operation appeared quite feasible and had some notable advantages over the base case. The HTGR-integrated case produced the same amount of refinery-ready oil, four times the amount of gas, 8% of the amount of CO2, and 70% of amount of electricity as the base case evaluated with retort heat coming from combustion of fossil fuels.