検索対象:     
報告書番号:
※ 半角英数字
 年 ~ 
 年

Applicability study of Bayesian optimization in core neutronic design using a toy model

トイモデルを用いた炉心核設計におけるベイズ最適化の適用性検討

桑垣 一紀  ; 横山 賢治   

Kuwagaki, Kazuki; Yokoyama, Kenji

日本原子力研究開発機構(JAEA)では、先進的な原子炉を対象とした革新的な設計手法であるARKADIA (Advanced Reactor Knowledge- and AI-aided Design Integration Approach through the whole plant lifecycle)の開発を進めている。ARKADIAの開発項目の一つに、炉心核計算や熱流動計算、燃料の健全性評価、プラント動的解析などを行い、炉心・燃料仕様の最適化を自動で行うシステムの構築がある。このシステムは、燃料ピン径や炉心高さ・直径等の設計パラメータを変化させながら、炉心性能で定義される目的関数を最小化(または最大化)する最適設計を、自動で求めるように実装される。本研究では、そのシステム開発の第一段階として、炉心核設計のみに焦点をあて、自動最適化に関する検討を行った。最適化アルゴリズムには、目的関数の評価コストが大きい問題に有効とされているベイズ最適化手法(Bayesian Optimization: BO)を選定した。トイモデルを用いて、核設計最適化の単目的最適化例題、及び2目的最適化例題を設定し、BOの適用性検討を行った。解析の結果、前者については、BOは少ない試行回数で、参照解をよく再現する最適解を得ることができ、一ケース当たりの評価コストが大きい核設計において、その有用性が示された。後者については、BOによって、参照解を再現するようなパレート解セットを求めることができると示された。

In Japan Atomic Energy Agency (JAEA), an innovative design approach named ARKADIA (Advanced Reactor Knowledge- and AI-aided Design Integration Approach through the whole plant lifecycle) for the advanced nuclear reactors is currently under development. One of the tasks in ARKADIA is to build a system that automatically optimizes core and fuel designs by conducting core neutronic and thermal-hydraulic calculations, fuel integrity evaluations, and plant dynamic analyses. This system will be implemented to automatically find an optimal design that minimizes (or maximizes) objective function defined by a core performance, while varying the core and fuel design parameters such as fuel pin diameter, core height and diameter. In this study, as the first step of the system development, we focused only on core neutronic design and conducted a study of automatic optimization. As the optimization algorithm, Bayesian optimization (BO), which is an effective method for optimization problems with expensive computation cost of objective function, was selected. The applicability of BO was studied based on single- and two-objective optimization examples of core neutronic design in a toy model. As a result, in the former, it was confirmed that BO can obtain the optimal solution, which well matches the reference solution calculated by a brute force calculation, with a small number of required calculation executions. Its usability on core neutronic designs, where the computation cost per case is large, was confirmed. In the latter, it was shown that BO can obtain a pareto solutions-set that shows good agreement with the reference solution.

Access

:

- Accesses

InCites™

:

Altmetrics

:

[CLARIVATE ANALYTICS], [WEB OF SCIENCE], [HIGHLY CITED PAPER & CUP LOGO] and [HOT PAPER & FIRE LOGO] are trademarks of Clarivate Analytics, and/or its affiliated company or companies, and used herein by permission and/or license.