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Kitamura, Seiji; Ito, Kei; Moro, Satoshi
ASME PVP 2004, 486(2), p.61 - 67, 2004/07
The outline of the vertical seismic isolation system for component and a series of model tests with full scale coned disk spring and damper are shown in this paper.
kasahara, Naoto; Ando, Masanori; Ito, Kei; Tanaka, Yoshihiko; Shibamoto, Hiroshi; Inoue, Kazuhiko
ASME PVP-Vol.472, p.25-32, p.25 - 32, 2004/07
For the realization of safe and economical fast reactor (FR) plants, the Japan Nuclear Cycle Development Institute (JNC) and Japan Atomic Power Company (JAPC) are cooperating on a research project titled "Feasibility Study on Commercialized FR Cycle Systems. To certify the design concepts and validate their structural integrity,the research and development of the "Fast Reactor Structural Design Standard (FDS)" is recognized as begin an essential theme.
Tanaka, Yoshihiko; Shibamoto, Hiroshi; Inoue, Kazuhiko; kasahara, Naoto; Ando, Masanori; Ito, Kei
ASME PVP-Vol.472, p.53-60, p.53 - 60, 2004/07
The guideline on inelastic analysis for design, one of the key items of Fast Reactor Design Standard(FDS), is being developed.The basic policies of this guideline are as follows:(a) to emphasis conservative analysis output rather than nominal value representing actual behavior, (b) to clarify the applicable area for assurance of conservative results. With such concepts, it would be possible that the guideline provides useful explanations on the manner of analysis and estimation in the form of concrete examples of design as well as general rules (somehow vague). As the first step of the guideline development, the following five issues to be solved were extracted:1) applicable area, 2) selection of constitutive equation, 3) modeling method of the load history, 4) ratchet strain and creep fatigue damage evaluation methods by inelastic analysis and 5) example design problems to check users' analysis quality and to complement the general rules. In parallel, inelastic analyses with the promising constitutive equations were applied by way of trial to obtain rough presumption on their effects on structural design of the components. As a result,all inelastic analyses provided smaller cumulative strains and equivalent strain ranges than the existing design method based on elastic analysis,suggesting advantage of introducing them into actual design.
Tanaka, Masaaki; Muramatsu, Toshiharu
ASME/JSME 2004 Pressure Vessels and Piping Conference, p.35 - 42, 2004/07
None
Tachibana, Yukio; Nakagawa, Shigeaki; Iyoku, Tatsuo
Elevated Temperature Design and Analysis, Nonlinear Analysis, and Plastic Components, 2004 (PVP-Vol.472), p.39 - 44, 2004/07
The reactor pressure vessel (RPV) of the HTTR is 5.5m in inside diameter, 13.2m in inside height, and 122mm and 160mm in wall thickness of the body and the top head dome, respectively. Because the reactor inlet temperature of the HTTR is higher than that of LWRs, 2 1/4Cr-1Mo steel is chosen for the RPV material. Fluence of the RPV is estimated to be less than 1
10
n/cm
(E
1 MeV), and so irradiation embrittlement is presumed to be negligible, but temper embrittlement is not. For the purpose of reducing embrittlement, content of some elements is limited on 2 1/4 Cr-1 Mo steel for the RPV using embrittlement parameters, J-factor and X-bar. In this paper design, fabrication procedure, and in-service inspection technique of the RPV for the HTTR are described.
Onizawa, Kunio; Shibata, Katsuyuki; Suzuki, Masahide; Kato, Daisuke*; Li, Y.*
RPV Integrity and Fracture Mechanics (PVP-Vol.481), p.11 - 17, 2004/07
At JAERI, the prpbabilistic fracture mechanics analysis code PASCAL has been developed. Using the PASCAL, the treatment methods of an embedded crack and the fracture toughness evaluation methods were studied on the probability of crack initiation and fracture of a RPV. For calculating the stress intensity factor (SIF) of an embedded crack, the ASME and CRIEPI procedures were introduced into PASCAL. Under a severe pressurized thermal shock condition, the crack growth analysis models with different SIF calculation points and crack growth directions are compared. The results showed that the crack tip at the inner side was most important to the fracture probability. The conditional fracture probability for an embedded crack when the same crack size distribution is assumed is approximately one order of magnitude lower than that of a surface crack. Fracture toughness curves based on Weibull distribution were incorporated into PASCAL. The comparison between these new curves and the current curves showed little effect on the conditional fracture probability of a RPV.
kasahara, Naoto; Hasebe, Shinichi; Kobayashi, Sumio; Ando, Masanori; Kawasaki, Nobuchika; Morita, Hiroshi*
ASME PVP-Vol.472, P. 2986, 2004/00
Focusing on the cover layer materials (as the Radon Barrier Materials), which could have the effect to restrain the radon from scattering into the air and the effect of the radiation shielding, we produced the radon barrier materials with crude bentonite on an experimental basis, using the rotary type comprehensive unit for grinding and mixing, through which we carried out the evaluation of the characteristics thereof.
Shibata, Katsuyuki; Onizawa, Kunio; Li, Y.*; Kanto, Yasuhiro*; Yoshimura, Shinobu*
Pressure Vessel and Piping Codes and Standards (PVP-Vol.480), p.235 - 242, 2004/00
A screening standard of small flaws that have no significant influence on the structural integrity is prescribed in ASME Code Sec.XI. From the viewpoint of probabilistic methodology, there are some concerns that weather or not the failure probability is uniform for flaws with various aspect ratios and failure frequencies are small enough. Moreover, acceptable flaws may be determined more rationally based the failure probability. A study was performed on the failure probability of RPVs with a surface flaw specified in Sec.XI using the PFM code PASCAL. A PTS transient of NRC/EPRI Benchmark Study was used. Analysis results showed that the conditional failure probability of a RPV with an initial flaw of acceptable depth depended on the aspect ratio. For a circular flaw, the failure probability is high due to the increase in crack initiation at the surface point. The maximum difference in failure probability reaches one order of magnitude. A case study for determining the acceptable flaws based on failure probability was also carried out.