Designing the Advanced High-Temperature Reactor for Low Radionuclide Releases in Beyond-Design-Basis Accidents

摘要

A technical approach is described to prevent major fuel failures and radionuclide releases in large [＞2000-MW(t)] Advanced High-Temperature Reactors (AHTRs) during beyond-design-basis accidents (BDBAs). The BDBAs include destruction of all cooling systems and major structural failures. The AHTR is a new reactor concept that combines a solid high-temperature fuel with a liquid fluoride salt coolant. The fuel is the same coated-particle fuel used in modular high-temperature gas-cooled reactors (MHTGRs) with fuel failure temperatures above 1600°C. The fluoride-salt coolant boiling points are above 1400°C, and the salts have a high affinity for actinides and fission products. The characteristics of the fuel, the high-temperature coolant, and reactor design are the enabling technologies to withstand most BDBAs. Smaller [～600 MW(t)] MHTGRs have been designed with this characteristic, but, no comparable designs exist for large reactors. The AHTR goal is to combine the potential economic advantages of large reactors with the potential inherent safety characteristics of some smaller advanced reactors.