The FuTure oF nuclear Fuel cycle - MIT Energy Initiative

Appendix C — High-Temperature Reactors
with Coated-Particle Fuel
As in the 2003 Future of Nuclear Power Study, we recommend a public-private program to determine
the commercial viability of high-temperature reactors (HTRs) using coated-particle
fuel. This recommendation is based on five anticipated desirable characteristics of these reactors:
production of high-temperature heat that enables more efficient production of electricity,
may simplify siting due to reduced water requirements for power plant cooling, and supports
liquid fuels production; high levels of safety with less dependence on reactor operations
relative to other types of power reactors; spent nuclear fuel (SNF) with reduced concerns
relative to safeguards and nonproliferation; the capability to burn a high-fraction of the fissile
fuel; and excellent performance of the spent nuclear fuel as a waste form.
HTRs are not new. Test and demonstration reactors were built in the United States and
Germany in the 1970s. More recently, Japan and China have built test reactors and China
is in the process of building a demonstration plant. The U.S. Department of Energy Next
Generation Nuclear Plant (NGNP) program recently announced awards to two industrial
teams led by Westinghouse and General Atomics to undertake preliminary design of a
commercial prototype HTR. The commercial interest in HTRs is a result of several factors:
(1) growing markets for high-temperature heat; (2) improvements in fuel reliability and
reactor designs that may significantly improve economic viability; and (3) the potential for
economic smaller-scale nuclear power plants.
potential marKetS
LWRs have peak coolant temperatures of ~300°C and are primarily used for the production
of electricity. HTRs today have peak coolant temperatures between 700 and 850°C with
the long-term potential of higher temperatures. Higher exit coolant temperatures enable
the more efficient production of electricity (40 to 50% versus efficiencies in the mid 30s for
LWRs), and reduced demand for power plant cooling water.
There is the potential for HTRs to simplify plant siting by eliminating the need for powerplant
cooling water. Conventional thermal power stations (nuclear, fossil, geothermal, solar
thermal, etc.) require large quantities of cooling water. The siting of nuclear plants is made
more difficult because people and cities are usually near water (rivers, lakes, and oceans).
If the requirement for cooling water is eliminated, the reactor siting options are greatly expanded.
There are existing, but expensive, industrial dry cooling technologies. The dry-cooling
is more favorable for HTRs relative to LWRs because more efficient plants require less
cooling per unit of electricity output. HTRs have a second option—direct air-cooled Brayton
power cycles with no water requirements. Only limited work has been done on such options.
appendix c: high Temperature reactors with coated-Particle Fuel 207