The FuTure oF nuclear Fuel cycle - MIT Energy Initiative

assembly or other component can remain in a reactor core until its physical properties
degrade. Radiation damage from radioactive decay can determine the long-term behavior
of a waste form in a repository. The historical strategy to improve materials is to develop a
new material, irradiate it, and test its properties. After several cycles of development and
testing, an improved material is developed. This strategy has almost tripled the lifetime of
nuclear fuel assemblies in today’s LWRs. However, as the technology improves the R&D
time required for the next advance increases because of the longer irradiation times needed
to support goals of developing longer lived materials. The same challenge exists for space
nuclear power systems where the decade-long missions creates major challenges to test
materials for the required times. New R&D strategies are needed.
Advances in modeling and simulation of materials and systems (with supporting experimental
work to confirm models) have begun to result in tools that may be able to dramatically
shorten development cycles (such as fewer cycles of test irradiations), enable better
understanding of options, and reduce costs 1 ,2 . This cross cutting R&D benefits all nuclear
research. Such technologies may enable the U.S. to examine a broader set of options and
understand implications before making major fuel cycle decisions. The recently launched
DOE innovation hub (Center for Advanced Simulation of Light Water Reactors) with a
focus on modeling and simulation to enhance LWR performance is a good start. Modeling
and simulation at the extreme scale can also accelerate licensing of new technologies by
developing and employing new methods for risk quantification 1 .
Modeling and simulation at the system level will underpin a new analysis regime for guiding
fuel cycle decisions addressing multiple objectives.
An R&D budget of $50 million per year is recommended.
Ultimately there is no substitute for testing to validate or disprove the conclusions of simulations.
The testing time frames are long and thus the need for long-term research programs
with appropriate irradiation facilities to create long-term fuel cycle options (see below).
Novel Applications and Innovative Concepts. This study focuses on actions that can enable
scaleup of nuclear power as a response to carbon emissions constraints. Today nuclear reactors
are used for the production of base-load electricity; however, base-load electricity is
less than a third of the total energy market. New nuclear technologies such as high-temperature
reactors, small reactors, and hybrid energy systems (nuclear-renewable systems
for electricity and liquid fuels production, nuclear-geothermal energy storage systems, etc.)
could contribute to a total low-carbon energy system. Such nontraditional uses of nuclear
energy imply modifications to the nuclear technologies and development of specialized
non-nuclear technologies.
There is a need to explore innovative concepts more robustly. We identified new potentially
attractive nuclear technology options (Appendix B)—including advanced reactor concepts
that did not exist three decades ago and innovations (primarily in materials) that may
change the viability of old technologies. A peer-reviewed competitive program should be
the centerpiece of an R&D program for novel concepts. We recommend an R&D program
of $150 million per year to address these new applications and innovative concepts.
chapter 10. recommended analysis, research, development, and demonstration Programs 137