日本原子力学会誌
Online ISSN : 2186-5256
Print ISSN : 0004-7120
ISSN-L : 0004-7120
42 巻, 6 号
選択された号の論文の6件中1~6を表示しています
  • 増田 純男, 梅木 博之, 内藤 守正
    2000 年 42 巻 6 号 p. 486-506
    発行日: 2000/06/30
    公開日: 2010/03/08
    ジャーナル フリー
    核燃料サイクル開発機構は,1997(平成9)年4月に公表された原子力委員会原子力バックエンド対策専門部会報告書「高レベル放射性廃棄物の地層処分研究開発等の今後の進め方について」に従い,関連する研究機関等の協力を得て,「わが国における高レベル放射性廃棄物地層処分の技術的信頼性一地層処分研究開発第2次取りまとめ」報告書(第2次取りまとめ)を作成し,1999(平成11)年11月26日に原子力委員会に報告した。
    第2次取りまとめは,1992(平成4)年に公表した第1次取りまとめの成果を受けて「わが国における地層処分の技術的信頼性」を示し,「処分事業を進めるうえでの処分予定地の選定,安全基準の策定の技術的拠り所」を与えるとともに,国による評価を経て2000年以降の研究開発を具体化するうえで重要なものと位置づけられている。本稿は,その内容について紹介するものである。
  • 第3回 中性子の空間的振舞い(2)
    平川 直弘, 岩崎 智彦
    2000 年 42 巻 6 号 p. 507-522
    発行日: 2000/06/30
    公開日: 2009/04/21
    ジャーナル フリー
  • 2000 年 42 巻 6 号 p. 522
    発行日: 2000年
    公開日: 2009/04/21
    ジャーナル フリー
  • 松永 健一
    2000 年 42 巻 6 号 p. 523-525
    発行日: 2000/06/30
    公開日: 2009/04/21
    ジャーナル フリー
  • 杉山 均, 秋山 光庸, 篠原 康則
    2000 年 42 巻 6 号 p. 557-566
    発行日: 2000/06/30
    公開日: 2009/04/21
    ジャーナル フリー
    A numerical analysis has been performed for turbulent flow developing in 90° bend with weakly swirling flows. The ratio of bend mean radius of curvature to diameter is 2.0 and straight duct of 25 and 35 diameters are attached to the inlet and outlet of the bend, respectively. In numerical analysis, an algebraic Reynolds stress model is adopted in order to predict precisely the swirling flow induced by anisotropic turbulence and boundary-fitted coordinate system was introduced as the method of coordinate transformation. Mean velocity in axial direction, secondary flow generated by interaction between pressure gradient and centrifugal forces, pressure distributions in bend and turbulent energy distribution are compared with the experimental data. The present method could predict well the streamwise mean-velocity, i.e. maximum mean-velocity located inner wall at bend inlet and low velocity region produced near inner wall at bend outlet. As for the comparison of secondary flow, acceleration of secondary flow near upper wall, deceleration of it near lower wall at bend inlet and a pair of asymmetrical vortices observed in bend tube could be reproduced by an algebraic Reynolds stress model. Moreover, numerical results show that characteristic phenomena of turbulent energy are reproduced by the present method although agreement between both results is certainly not perfect in all detail.
  • 佐野 雄二, 依田 正樹, 向井 成彦, 小畑 稔, 菅野 眞紀, 嶋 誠之
    2000 年 42 巻 6 号 p. 567-573
    発行日: 2000/06/30
    公開日: 2010/01/07
    ジャーナル フリー
    Residual stress improvement technology for component surface by underwater pulsed laser irradiation has been developed as a method of preventing stress corrosion cracking (SCC) of core components in nuclear reactors.
    In order to optimize the laser irradiation conditions based on a complete understanding of the mechanism, the propagation of a shock wave induced by the impulse of laser irradiation and the dynamic response of the irradiated material were analyzed through time-dependent elasto-plastic calculations with a finite element program. The calculated results are compared with the measured results obtained by experiments in which laser pulses with an energy of 200mJ are focused to a diameter of 0.8mm on a water-immersed test piece of 20% cold-worked Type 304 austenitic stainless steel to simulate neutron irradiation hardening.
    A residual compressive stress, which is nearly equivalent to the yield stress of the processed material, remains on the material surface after passage of the shock wave with enough amplitude to induce a permanent strain. Multiple irradiation of laser pulses extends the stress-improved depth to about 1mm, which would be the limit corresponding to the three-dimensional dispersion effect of the shock wave.
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