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Generation and verification of ORIGEN and ORIGEN-S activation cross-section libraries of JENDL-5 and JENDL/AD-2017

今野 力; 河内山 真美; 林 宏一

Mechanical Engineering Journal (Internet), 11(2), p.23-00386_1 - 23-00386_11, 2024/04



Optimization in granulation conditions for adsorbent of extraction chromatography

長谷川 健太; 後藤 一郎*; 宮崎 康典; 安倍 弘; 渡部 創; 渡部 雅之; 佐野 雄一; 竹内 正行

Mechanical Engineering Journal (Internet), 11(2), p.23-00407_1 - 23-00407_8, 2024/04

JAEA has been working on development of extraction chromatography technology for recovery of trivalent minor actinides (MA(III)) from high-level radioactive waste generated in reprocessing of spent fuel. The technology utilizes porous silica particles with about 50 micrometre diameter for support of adsorbents. Pressure drop of the packed column depends on characteristics of the particle. Large pressure drop of the column is not favorable for safety assessment of the technology although a certain level of the pressure drop is indispensable for excellent separation performance. In this study, we applied a granulation technique using a spray dryer that is widely used in industry, and conducted experiments to find the optimal specifications for silica support particles and conditions for the granulation operation. A basic characterization of the adsorbent prepared from the produced particles was carried out by an adsorption test of simulated high level liquid waste.


Seismic qualification of crossover piping systems on a sodium-cooled fast reactor with a seismic isolation system

渡壁 智祥; 奥田 貴大; 岡島 智史

Mechanical Engineering Journal (Internet), 11(2), p.23-00395_1 - 23-00395_13, 2024/04



Reduction of accident occurrence frequencies by taking safety measures for defense-in-depth level 4 in a sodium-cooled fast reactor

西野 裕之; 栗坂 健一; 鳴戸 健一*; 権代 陽嗣; 山本 雅也

Mechanical Engineering Journal (Internet), 11(2), p.23-00409_1 - 23-00409_15, 2024/04



Proposal of a novel AI-based plant operator support system for the safety of nuclear power plants

高屋 茂; 関 暁之; 吉川 雅紀; 佐々木 直人*; Yan, X.

Mechanical Engineering Journal (Internet), 11(2), p.23-00408_1 - 23-00408_11, 2024/04



Performance comparison of monoamides on U recovery by temperature swing extraction using Ce

岩本 敏広; 齋藤 まどか*; 高畠 容子; 渡部 創; 渡部 雅之; 成瀬 惇喜*; 塚原 剛彦*

Mechanical Engineering Journal (Internet), 11(2), p.23-00444_1 - 23-00444_7, 2024/04

Nuclear fuel fabrication process has generated a large amount of wastes contaminated with enriched uranium, and those have been accumulated for long time in Japan. These waste hasn't treated, because there is no protocol to treat and dispose these. Procedure is proposed; 1) Leaching Uranium from the waste, 2) recovering uranium from the leaching solution, 3) treating residue and secondary waste for disposing in the near field region. Temperature swing extraction technology is one of promising methods to recover uranium efficiently. In the technology, uranium ions are extracted by extraction, and complex with ligands are separated by a polymer with reversible hydrophilic-hydrophobic properties. Monoamides can be adopted to the procedure. However suitable structure of monoamide for the technology is unclear. Therefore, for deciding appropriate structure of monoamides, these with different alkyl chain structures were synthesized, and applicability of the extractants were evaluated by solvent extraction and temperature swing extraction experiments. In experiments, Ce(IV) was used as a simulant of U(IV). Three monoamides were synthesized, and solvent extraction experiments and Temperature swing extraction experiments were carried out.


Fundamental study of perfluoro oil degradative treatment by subcritical water reaction and design of bench-scale equipment

船越 智雅; 渡部 創; 荒井 陽一; 岩本 敏広; 渡部 雅之; 西本 能弘*; 安田 誠*

Mechanical Engineering Journal (Internet), 11(2), p.23-00445_1 - 23-00445_7, 2024/04

Various types of machine oil are used for analysis and utility equipment, and these organic liquid wastes are stored in nuclear facilities and laboratories. Perfluoro oil, generally used in vacuum pumps, is difficult to decompose because of its chemical stability. In order to achieve complete mineralization of the organic liquid wastes, the application of a subcritical water reaction was examined. In this study, the effect of introducing a functional group into a perfluoro compound on its decomposition performance was experimentally evaluated. First, we carried out the transformation of perfluorohexane to perfluorohexyl iodide or perfluoroheptanoic acid based on reported procedures. Next, laboratory scale batchwise decomposition tests with subcritical water on perfluorohexyl iodide and on perfluoro heptanoic acid were carried out. The decomposition products of each fluorine compound were identified, confirming that subcritical treatment is a promising treatment method.


Overview of development program for engineering scale extraction chromatography MA(III) recovery system

渡部 創; 高畠 容子; 長谷川 健太; 後藤 一郎*; 宮崎 康典; 渡部 雅之; 佐野 雄一; 竹内 正行

Mechanical Engineering Journal (Internet), 11(2), p.23-00461_1 - 23-00461_10, 2024/04

Japan Atomic Energy Agency is developing extraction chromatography technology to recover MA(III) from spent nuclear fuel. Developments in the extraction chromatography system especially focusing on safety and stable operation are required for practical application of the technology. This paper discusses the main tasks that have to be challenged preferentially based on achievements obtained by previous studies and potential MA(III) recovery process flow.


Investigation on damage evaluation index with ductility factor based on simulation analysis for loading test of piping support structure

奥田 幸彦; 滝藤 聖崇; 西田 明美; Li, Y.

Mechanical Engineering Journal (Internet), 12 Pages, 2024/00



Development of probabilistic risk assessment methodology against strong wind for sodium-cooled fast reactors

西野 裕之; 山野 秀将; 栗坂 健一

Mechanical Engineering Journal (Internet), 10(4), p.22-00387_1 - 22-00387_20, 2023/08



Development of a numerical simulation method for air cooling of fuel debris by JUPITER

山下 晋; 上澤 伸一郎; 小野 綾子; 吉田 啓之

Mechanical Engineering Journal (Internet), 10(4), p.22-00485_1 - 22-00485_25, 2023/08



Analytical study for low ground contact ratio of buildings due to the basemat uplift using a three-dimensional finite element model

崔 炳賢; 西田 明美; 塩見 忠彦; 川田 学; Li, Y.; 太田 成*; 園部 秀明*; 猪野 晋*; 宇賀田 健*

Mechanical Engineering Journal (Internet), 10(4), p.23-00026_1 - 23-00026_11, 2023/08

原子力施設における建物の耐震評価において、地震時の転倒モーメントによって建物の基礎底面が地盤から部分的に浮上る現象は、建物自体の耐力や構造安全性に関わる問題だけではなく、建物内に設置される機器類の応答に影響を及ぼすため、非常に重要な問題である。一方、建物の基礎浮上りによる基礎底面と地盤との間の接地率が小さくなる場合の建物の地震時挙動については、実験や解析的検討が十分とはいいがたい。そこで、本研究では、建物の基礎浮上りに係る既往実験を対象とし、3次元詳細解析モデルを用いたシミュレーション解析を行い、解析手法の妥当性について確認した。解析コードによる結果の違いを確認するために、3つの解析コード(E-FrontISTR, FINAS/STAR, TDAPIII)を用いて同じ条件で解析を実施し、得られた結果を比較した。解析結果については、低接地率状態となる試験体底面の付着力の違いによる建物の応答への影響、解析手法の精度等について考察した。また、建物の応答に係る解析結果への影響が大きいと判断された解析パラメータについては、感度解析により解析結果への影響を具体的に確認した。本論文では、これらの検討を通して得られた知見について述べる。


Verification of probabilistic fracture mechanics analysis code PASCAL for reactor pressure vessel

Lu, K.; 高見澤 悠; Li, Y.; 眞崎 浩一*; 高越 大輝*; 永井 政貴*; 南日 卓*; 村上 健太*; 関東 康祐*; 八代醍 健志*; et al.

Mechanical Engineering Journal (Internet), 10(4), p.22-00484_1 - 22-00484_13, 2023/08

A probabilistic fracture mechanics (PFM) analysis code, PASCAL, has been developed by Japan Atomic Energy Agency for failure probability and failure frequency evaluation of reactor pressure vessels (RPVs) considering neutron irradiation embrittlement and thermal transients. To strengthen the applicability of PASCAL, considerable efforts on verifications of the PASCAL code have been made in the past years. As a part of the verification activities, a working group consisted of different organizations from industry, universities and institutes, was established in Japan. In the early phase, the working group focused on verifying the PFM analysis functions for RPVs in pressurized water reactors (PWRs) subjected to pressurized thermal shock (PTS) events. Recently, the PASCAL code has been improved in order to run PFM analyses for both RPVs in PWRs and boiling water reactors (BWRs) subjected to a broad range of transients. Simultaneously, the working group initiated a verification plan for the improved PASCAL through independent PFM analyses by different organizations. Concretely, verification analyses for a PWR-type RPV subjected to PTS transients and a BWR-type RPV subjected to a low-temperature over pressure transient were performed using PASCAL. This paper summarizes those verification activities, including the verification plan, analysis conditions and results. Based on the verification studies, the reliability of PASCAL for probabilistic integrity assessments of Japanese RPVs was confirmed with confidence.


Structural analysis of a reactor vessel in a sodium-cooled fast reactor under extremely high temperature conditions

山野 秀将; 二神 敏; 安藤 勝訓

Mechanical Engineering Journal (Internet), 10(4), p.23-00043_1 - 23-00043_12, 2023/08



Application of a first-order method to estimate the failure probability of component subjected to thermal transients for optimization of design parameters

岡島 智史; 森 健郎; 菊地 紀宏; 田中 正暁; 宮崎 真之

Mechanical Engineering Journal (Internet), 10(4), p.23-00042_1 - 23-00042_12, 2023/08



Application of quasi-Monte Carlo and importance sampling to Monte Carlo-based fault tree quantification for seismic probabilistic risk assessment of nuclear power plants

久保 光太郎; 田中 洋一; 白田 勇人*; 荒毛 大輔*; 内山 智曜*; 村松 健

Mechanical Engineering Journal (Internet), 10(4), p.23-00051_1 - 23-00051_17, 2023/08

福島第一原子力発電所事故後、原子力発電所の外部事象に対する確率論的リスク評価(PRA)の重要性が再認識された。地震PRAでは、システム、コンポーネント、構造(SSC)の相関故障の扱いが非常に重要である。SSCが連関して故障した場合に、事故緩和システムの冗長性に悪影響を与える恐れがある。原子力機構では、SSCの相関故障を詳細かつ現実的に取り扱うために、Direct Quantification of Fault Tree by Monte Carlo Simulation(DQFM)法と名付けられたフォールトツリー定量化手法を開発している。この手法では、地震応答や耐力に関する相関を有する不確実さをモンテカルロ・サンプリングで考慮することにより、頂上事象の発生確率を定量化することができる。DQFMの有用性は既に実証されているが、その計算効率を向上させることで、リスク分析者は複数の分析を行うことができるようになる。そこで本研究では、簡易的な地震PRAのDQFM計算に準モンテカルロ法および重要度サンプリングを適用し、少ないサンプリングで分岐確率を定量化する効果を検証した。準モンテカルロサンプリングを適用することで、中・高地震動レベルでの結果の収束性がモンテカルロサンプリングに比べて一桁加速されることを示すと共に、重点サンプリングの適用により、低い地盤変動レベルにおいて故障確率が低いSSCに対して統計的に有意な結果を取得できることを示した。これらのサンプリング手法の応用による計算の高速化はリスク情報を活用した意志決定におけるDQFMの実用化の可能性を高めるものである。


Proposal for maintenance optimization scheme based on system based code concept

矢田 浩基; 高屋 茂; 諸星 恭一*; 横井 忍*; 宮川 高行*

Mechanical Engineering Journal (Internet), 10(4), p.23-00044_1 - 23-00044_13, 2023/08

原子力発電所の合理的な保全計画を策定するには、各プラントの特性を考慮する必要がある。ナトリウム冷却高速炉では、ナトリウムを扱う特殊性から検査上の制約が保全合理化の重要なポイントとなる。本研究では、リスク情報を活用して保全方針を策定する設計支援ツールである保全最適化スキームを提案した。保全最適化スキームは、システム化規格概念に基づくASME Boiler and Pressure Vessel Code, Code Case, N-875が基となっており、最適な保全方針を策定するための詳細な手順を提供するものである。さらに、保全最適化スキームを用いて次期高速炉の候補概念を対象に炉心支持構造物の保全方針設定に関する試評価を実施した。


Effect of the plasticity of pipe and support on the seismic response of piping systems

奥田 貴大; 高橋 英樹*; 渡壁 智祥

Mechanical Engineering Journal (Internet), 10(4), p.23-00075_1 - 23-00075_9, 2023/08



Experimental study on scabbing limit of local damage to reinforced concrete panels subjected to oblique impact by projectile with semispherical nose

奥田 幸彦; Kang, Z.; 西田 明美; 坪田 張二; Li, Y.

Mechanical Engineering Journal (Internet), 10(3), p.22-00370_1 - 22-00370_12, 2023/06



A Statistical approach for modelling the effect of hot press conditions on the mechanical strength properties of HTGR fuel elements

相原 純; 黒田 雅利*; 橘 幸男

Mechanical Engineering Journal (Internet), 9(4), p.21-00424_1 - 21-00424_13, 2022/08


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