Burnup measurement using bent crystal diffraction spectrometers for pebble bed reactors

IF 2.3 3区工程技术 Q1 NUCLEAR SCIENCE & TECHNOLOGY

Annals of Nuclear Energy Pub Date : 2026-08-01 Epub Date: 2026-03-05 DOI:10.1016/j.anucene.2026.112263

Ian T. Kolaja , Lee A. Bernstein , Ludovic Jantzen , Eleanor Tubman , Tatiana Siaraferas , Massimiliano Fratoni

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引用次数: 0

Abstract

Burnup measurement is essential for monitoring and operating pebble-bed reactors (PBRs), where fuel pebbles circulate rapidly through the core. However, conventional gamma spectroscopy using high-purity germanium (HPGe) detectors is challenging due to high activity levels in discharge pebbles, leading to excessive dead time and Compton scattering. This study explores the use of bent crystal diffraction (BCD) spectrometers to filter the emitted gamma spectrum and isolate key peaks for improved measurement accuracy and speed. Pebble-wise depletion calculations were performed and the resulting spectra were analyzed using ray tracing (SHADOW3) and gamma response modeling (GADRAS). Key isotopes,

^{137 m}

Ba/¹³⁷Cs, ²³⁹Np, ¹⁴⁴Ce,

^{148 m}

Pm, and ¹⁴⁰La, were found to strongly correlate with burnup, residence time, core passes, plutonium production, and fluence. Machine learning regression models that were given synthetic spectra achieved a coefficient of determination (

R^{2}

) as high as 0.995 for burnup prediction. Among various BCD configurations, mosaic silicon crystals in the (440) orientation combined with an HPGe detector provided optimal performance for measuring ¹³⁷Cs decay (via

^{137 m}

Ba), while silicon (220) and (440) paired with scintillators were effective for the shorter-lived isotopes.

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用弯晶衍射光谱仪测量球床反应器燃耗

燃耗测量对于监测和操作球床反应堆（PBRs）是必不可少的，其中燃料卵石在堆芯中快速循环。然而，使用高纯度锗（HPGe）探测器的传统伽马能谱具有挑战性，因为放电卵石中的活度高，会导致过长的死区时间和康普顿散射。本研究探索了弯曲晶体衍射（BCD）光谱仪的使用，以过滤发射的伽马光谱并分离关键峰，以提高测量精度和速度。采用射线追踪（SHADOW3）和伽马响应建模（GADRAS）对所得光谱进行分析。关键同位素137mBa/137Cs、239Np、144Ce、148mPm和140La与燃燃量、停留时间、堆芯通过次数、钚产量和通量密切相关。给定合成光谱的机器学习回归模型对燃耗预测的决定系数（R2）高达0.995。在不同的BCD结构中，（440）取向的镶嵌硅晶体结合HPGe探测器对137Cs衰变的测量效果最佳（通过137mBa），而（220）和（440）与闪烁体配对的硅晶体对寿命较短的同位素的测量效果最好。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Annals of Nuclear Energy 工程技术-核科学技术

CiteScore

4.30

自引率

21.10%

发文量

632

审稿时长

7.3 months

期刊介绍： Annals of Nuclear Energy provides an international medium for the communication of original research, ideas and developments in all areas of the field of nuclear energy science and technology. Its scope embraces nuclear fuel reserves, fuel cycles and cost, materials, processing, system and component technology (fission only), design and optimization, direct conversion of nuclear energy sources, environmental control, reactor physics, heat transfer and fluid dynamics, structural analysis, fuel management, future developments, nuclear fuel and safety, nuclear aerosol, neutron physics, computer technology (both software and hardware), risk assessment, radioactive waste disposal and reactor thermal hydraulics. Papers submitted to Annals need to demonstrate a clear link to nuclear power generation/nuclear engineering. Papers which deal with pure nuclear physics, pure health physics, imaging, or attenuation and shielding properties of concretes and various geological materials are not within the scope of the journal. Also, papers that deal with policy or economics are not within the scope of the journal.