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Kaida, Takuyo*; Ishizaki, Yoichi*; Okajima, Satoshi
Atsuryoku Gijutsu, 52(2), p.53 - 63, 2014/04
Probabilistic approach for Fitness-For-Service (FFS) assessment of pressure equipment in petroleum and petrochemical plant helps to quantify the safety margin and rationalize the assessment. As for local metal loss assessment, several studies have been made on reliability analysis of the damaged equipment by use of limit state function, denoted by deterministic FFS model in published standard. Stochastic properties of random variables are needed in the reliability analysis. Remaining thickness of the pressure equipment is one of the important variables in limit state function for metal loss assessment. The thickness readings on a prescribed grid, which characterize the remaining thickness and size of the region of metal loss, might be varied by each inspector. There has been, however, no studies on stochastic properties of thickness readings for the local metal loss assessment. In this study, the stochastic properties of thickness readings were investigated by analyzing of the results of Round-Robin test. The cause of variation of thickness readings was clarified for the purpose of either protection of failure by pressure or that of leakage. The results of investigation indicated that standard deviation of thickness readings in the region of metal loss was more than that of thickness away from metal loss. Finally, the reliability of pressure equipment with local metal loss was analyzed using stochastic properties.
Kurihara, Tomoyuki*; Kaida, Takuyo*; Okajima, Satoshi
Atsuryoku Gijutsu, 52(2), p.64 - 71, 2014/04
In Fitness-For-Service (FFS) assessment of pressure equipment, high reliability is needed in petroleum and petrochemical plant. Future Corrosion Allowance (FCA) is one of the most important factors in the metal loss assessment of FFS because it decides predicted value of the thickness during service periods. For the evaluation of FCA, the accurate corrosion rate from actual thinning data is needed and it is necessary to make a consideration of their variability of the thinning phenomena. In this study, the measured thickness data of the oil piping in the actual plant are collected and statistically analyzed as corrosion rate data which are classified by the operation condition. By the analysis, the probabilistic properties of corrosion rate are clarified in this piping system. Especially it is cleared that the corrosion rate of the air injection part is higher than that of the no air injection part. And the reliabilities of the protection of the failure by pressure and their change are quantitatively evaluated from the probabilistic properties of corrosion rate. From this case study, the procedure of FCA evaluation of FFS assessment was established and it's clear that the statistical analysis by the feature of thinning phenomena is important for accurate evaluation of corrosion data.
Nagashima, Nobuo*; Hayakawa, Masao*; Tsukada, Takashi; Kaji, Yoshiyuki; Miwa, Yukio*; Ando, Masami*; Nakata, Kiyotomo*
Atsuryoku Gijutsu, 47(4), p.236 - 244, 2009/07
In this study, micro-hardness tests and AFM observations were performed on SUS316L low-carbon austenitic stainless steel pre-strained by cold rolling to investigate its deformation behavior. The following results were obtained. Despite the fact that the same plastic strain was applied, post-tensile test AFM showed narrower slip-band spacing in a reduction in area of 30% cold-rolled specimen than the unrolled specimen. Concentrated slip bands were observed near grain boundaries. Micro-hardness exceeding 300 was found to occur frequently in after tensile test specimens with a reduction in area of 30% or more, particularly at grain boundaries. It is suggested that the nonuniformity of deformation at grain boundaries plays an important role of IGSCC crack propagation mechanism of low-carbon austenitic stainless steel.
Ishijima, Yasuhiro; Ioka, Ikuo; Kiuchi, Kiyoshi; Kaneko, Tetsuji*; Okubo, Tsutomu; Yamamoto, Masahiro
Atsuryoku Gijutsu, 47(1), p.12 - 17, 2009/01
We investigate one of these innovative water reactors; Fast Spectrum Light Water Reactor (FLWR). It has unique construction for the reactor core but the fuel cladding material will be exposed in high internal pressure and axial load and complex temperature distribution. Therefore, we conducted a specially designed fatigue-creep test that were simulated several parameters (thermal distribution, temperature variation, internal pressure variation and binding stress) to evaluate an applicability of fuel cladding material for FLWR. Zircalloy-2, which is common cladding material, was used for the test. Test result was confirmed to compare the deformation value between tested and calculated. The result showed the evaluation method could be controlled several parameters simultaneously and the deformation value after the test coincided to the calculated value. This method is sufficient to evaluate thermal deformation characteristics for FLWR.
Kurihara, Ryoichi; Tachibana, Yukio; Nishihara, Tetsuo; Maruyama, So; Shiozawa, Shusaku; *
Atsuryoku Gijutsu, 32(3), p.154 - 165, 1994/00
no abstracts in English
Atsuryoku Gijutsu, 29(3), p.177 - 181, 1991/00
no abstracts in English
; Ueda, Shuzo
Atsuryoku Gijutsu, 24(5), p.254 - 263, 1986/00
no abstracts in English
; *; *; ; ;
Atsuryoku Gijutsu, 24(5), p.236 - 244, 1986/00
no abstracts in English
;
Atsuryoku Gijutsu, 23(5), p.255 - 267, 1985/00
no abstracts in English
Ueda, Shuzo; ; *;
Atsuryoku Gijutsu, 22(6), p.281 - 290, 1984/00
no abstracts in English
; *;
Atsuryoku Gijutsu, 17(6), p.287 - 295, 1979/00
no abstracts in English
;
Atsuryoku Gijutsu, 14(4), p.169 - 176, 1976/04
no abstracts in English
;
Atsuryoku Gijutsu, 14(3), p.127 - 134, 1976/03
no abstracts in English
Atsuryoku Gijutsu, 13(5), p.264 - 271, 1975/05
no abstracts in English
Ozawa, K.; *
Atsuryoku Gijutsu, 11(5), p.256 - 274, 1973/05
no abstracts in English
