According to the past edition of “Guideline of Inspection and Evaluation for Core Internals (Core Spray Sparger & Piping Jet Pum p]” issued by Japan Nuclear Technology Institute (JANTI), fully penetrated flaw should be assumed for uninspected region, for ev aluating their integrity. This assumption was considered to be too conservative. Then, this study was performed on the better as sumption of flaw existence in the uninspected region to develop more appropriate flaw modeling by using statistical evaluati...
英字タイトル:
The Guideline of BWR Inspection Program Study on Flaw Characterization of Core Internals Piping for Uninspected Region

１．はじめに沸騰水型原子炉（BWR（Boiling Water Reactor））における主蒸気には、冷却材である水の放射線分解によって生じる水素と酸素がわずかに存在し、水蒸気の凝縮により非凝縮性気体である水素と酸素（混合ガス）が取り残され、機器の頂部で徐々にその濃度が上昇することが開発当初から知られていた。そこで、混合ガスが蓄積する可能性のある原子炉圧力容器、熱交換器等の頂部にはベント系を設置するとともに、復水器に集められた混合ガスについては、水素と酸素を結合させ水に戻すための再結合器を設置する設計......

The pipe rupture accidents due to combustion of radiolysis gas in BWR piping occurred in 2001. TENPES and JANTI got “The design guideline to prevent pipe rupture accident due to combustion of radiolysis gas in BWR piping” ready and proposed about ideal method of the piping placement design to BWR. This report is the summary of the method to evaluate the possibility of accu mulation of radiolysis gas in BWR piping which is mentioned in the guideline....
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The development of the guideline to prevent combustion of radiolysis gas inBWR piping

The JSME Committee on Power Generation Facility Codes is developing a fatigue evaluation method by flaw tolerance. The ASME B& PV Code Section XI has Non-mandatory Appendix L, which provides a flaw tolerance method for fatigue evaluation when a cumulati ve usage factor (CUF) of a component is greater than 1.0. In order to develop a flaw tolerance method for the JSME Codes, post ulated initial flaws, capability of nondestructive examination, compatibility to rules and flaw tolerance codes are discussed....
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Development of Fatigue Evaluation Using Flaw Tolerance Method

This study confirms applicability of so-called twice-slope method that is one of the limit analyses to evaluate llapse or plastic buckling, to cylindrical struc ture of core internals even when it has cracks. Three lindrical test specimens with radius to thickness ratio equivalent of core shroud were used for monotonic nding test with various condition of cracking to confirm applicability of twice-slope method. The other o specimens with duplicate condition of cracking and dif ferent range of loading were ...
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Evaluation Method of Structural Integrity for Cylindrical Internal Structure with Cracks

Weld Overlay is a typical technique which took many years and huge amount of efforts for standardization in Japan, though it had already been well-developed with many application examples abroad as one of the repair methods. There has not an application example in Japan at all in spite of many efforts. This paper keeps a record of some backgrounds on standardization process of the weld overlay in Japan so as to consider better processes in the future....
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Some Backgrounds on Standardization of Weld Overlay Technique in Japan

Electronic Journal of Advanced Maintenance (EJAM) has been issued on the website of Japan Society of Maintenology (ISM) on May 25th, 2009. “New Technology' is one of the EJAM categories, and introduces widely advanced techniques developed or modified for maintenance. 'New Technology' has been created through discussion by members of the New Technology Committee, which is in the editorial organization of EJAM. In th at discussion, it was pointed out that people concerned with maintenance technology have no...
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‘New Technology' of EJAM and Its Objective

From the engineering development to actual application of the new maintenance technique used for the maintenance activities of a nuclear reactor in operation, the JANTI Guide line, “the Guideline on the Application Process of a Maintenance Technique“ was developed to clarify activities to be checked or examined in each process. In engineering deve lopment, all activities are provided to be checked or examined at each process followed further, such as standardization process. It is important to carry out sh...
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Guideline on Application Process of Techniques Developed for Maintenance Activities

“Guidelines for Inspection and Evaluation of Reactor Internals”, published by Thermal and Nuclear Power Engineering Society (TENPES) and taken over by Japan Nuclear Technology Institute (JANTI), adopted a very conservative assumption on flaw characterization for uninspected region of cylindrical components. Fully penetrated flaw should be assumed for uninspected region, when SCC is found and flaw evaluation is performed on cylindrical core internals such as core shroud. The authors suggested a modified me...
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Technical Basis for Revision of Guidelines for Inspection and Evaluation of Reactor Internals on Flaw Characterization for Uninspected Region of Cylindrical Components

Neutron irradiation embrittlement of reactor pressure vessel (RPV) steels is one of the important material ageing issues. The Japan Electric Association Code, JEAC 4201-2007 “Method of Surveillance Tests for Structur al Materials of Nuclear Reactors,” was revised in December 2007. A new mechanism-guided embrittlement correlation method was adopted. The surveillance program was modified for the long term operation of nuclear plan ts by introducing the “long-term surveillance program”, which is to be applied...
英字タイトル:
Industry Practice for the Neutron Irradiation Embrittlement of Reactor Pressure Vessel Steels in Japan