Design of an HTGR for high-temperature process heat applications

The high-temperature gas-cooled reactor (HTGR) offers a unique heat source for process heat applications since its operating temperature is substantially higher than that of other types of nuclear reactors. This paper discusses a design study of an advanced 842-MW(t) very high temperature reactor (VHTR) coupled with a chemical process whose product is hydrogen (or a mixture of hydrogen and carbon monoxide) generated by steam reforming of a light hydrocarbon mixture. A key feature of the plant is the nuclear reactor core, which utilizes helium as its primary coolant, has ceramic-coated fuel particles containing uranium and thorium, and employs graphite as the moderator and structural material. As in other HTGR designs, the VHTR has its entire primary coolant system contained in a prestressed concrete reactor vessel (PCRV) which provides the necessary biological shielding and pressure containment. The high-temperature nuclear thermal energy is transported to the externally located process plant by a secondary helium transport loop. In addition to providing the thermal driving potential required for the reforming process, the nuclear heat is also used to generate high-temperature, high-pressure steam to satisfy both the process and electrical generation needs for the operation of the nuclear plant and reforming process plant