Nuclear waste from small modular reactors

Area of Science:

• Nuclear Engineering
• Materials Science
• Environmental Science

Background:

• Small modular reactors (SMRs) are proposed as a next-generation nuclear energy solution, often cited for potential cost and safety benefits over gigawatt-scale light water reactors (LWRs).
• The back end of the nuclear fuel cycle, encompassing waste management and disposal, is a critical consideration for the long-term viability of any nuclear technology.
• Limited research has comprehensively evaluated the waste stream characteristics and disposal implications specific to SMR designs.

Purpose of the Study:

• To characterize the low-, intermediate-, and high-level waste streams produced by selected Small Modular Reactor designs.
• To compare the waste characteristics of SMRs against those of existing Light Water Reactors (LWRs).
• To assess the implications of SMR waste properties for future waste management and disposal strategies.

Main Methods:

• Analysis of waste stream composition (low-, intermediate-, and high-level) for three distinct SMR designs.
• Comparative assessment of waste volume and chemical/physical reactivity between SMRs and LWRs.
• Evaluation of neutron leakage characteristics inherent to SMR designs and their impact on radionuclide generation.

Main Results:

• Small modular reactors are projected to produce more voluminous waste streams compared to traditional LWRs.
• The waste generated by SMRs exhibits increased chemical and physical reactivity, complicating management and disposal.
• Higher neutron leakage in typical SMR designs can lead to less favorable conditions for managing key radionuclides in nuclear waste.

Conclusions:

• SMRs present distinct waste management challenges due to increased waste volume and reactivity.
• The inherent design of most SMRs, characterized by higher neutron leakage, may be less advantageous than LWRs for the long-term disposal of nuclear waste.
• Further research and development are necessary to address the unique back-end fuel cycle implications of SMR deployment.