Sensitivity-informed framework for enrichment distribution in MNR for thermal performance enhancement.

Area of Science:

• Nuclear Engineering
• Reactor Physics
• Materials Science

Background:

• Micro Nuclear Reactors (MNRs) are crucial for space exploration and remote power due to their compact size, longevity, and safety.
• Radial Power Peaking (RPP) is a significant challenge in MNRs, causing uneven power distribution and limiting safe operation.

Purpose of the Study:

• To analyze the impact of RPP on MNR design and operational constraints.
• To propose and evaluate a novel fuel enrichment strategy to mitigate RPP.

Main Methods:

• Analysis of RPP in an annular-fueled MNR core.
• Development of a zone-based, sensitivity-informed non-uniform fuel enrichment framework.
• Simulation of the proposed framework's effectiveness in reducing RPP and increasing operational power.

Main Results:

• The study observed a maximum power peaking factor of 1.28 in the baseline annular-fueled MNR core.
• RPP necessitates a reduction in allowable operating power from 1 MWth to 738 kWth.
• The novel fuel enrichment strategy reduced RPP by 75%, increasing safe operating power to approximately 950 kWth.

Conclusions:

• The proposed non-uniform fuel enrichment framework effectively mitigates RPP in MNRs without physical modifications.
• This strategy enhances the safe operating power and fuel utilization of MNRs, supporting advanced applications.
• The findings are critical for the long-term autonomous operation of reactors in demanding environments.