摘要
本文建立了AP1000核电压力容器安全端结构的三维有限元分析模型,通过对假想存在于焊缝中不同尺寸的内表面周向裂纹进行有限元断裂力学分析,对安全端异种金属焊接接头区的缺陷评定方法进行了研究。初步构建了与安全端复杂结构几何、异种金属接头区复杂材料及裂纹尺寸相关的专用缺陷简化评定方法、失效评定图(FAD)高级评定方法和破前泄漏(LBB)分析评定方法。三种方法的评定精度和复杂程度依次提高。
简化评定方法按塑性失效的极限载荷准则建立,根据安全端载荷计算的应力比及检测或计算的寿期末裂纹长度,用构建的表格插值确定出允许的裂纹深度,用寿期末裂纹深度与允许的裂纹深度相比较评价缺陷的安全性。在高级失效评定图(FAD)方法中,构建了与安全端结构、材料和裂纹尺寸相关的失效评定曲线族、极限载荷和应力强度因子;依据被评定缺陷的尺寸选择合适的失效评定曲线进行准确的计算评定。在LBB分析评定方法中,初步构建了与安全端几何、外加主载荷和材料J-R裂纹扩展阻力曲线(材料韧性)相关的LBB曲线和LBB评定图;依据被评定缺陷的尺寸和载荷,可评判安全端异种金属接头区的缺陷是否以LBB的方式失效。
In this paper, three-dimensional finite element analysis models are built for the welded safe end of AP1000 nuclear pressure vessels. Through finite element analysis (FEA) of fracture mechanics for the circumferential surface cracks with different sizes in the weld metal, the defect assessment methods for the dissimilar weld joint in the safe end are studied. The simplified defect assessment method, advanced failure assessment diagram (FAD) method and leak-before-break (LBB) assessment method are constructed elementarily. And these methods are related to the complex structure of the safe end, the geometry of welding groove, the complex materials at weld joint region of the dissimilar metal and the crack sizes. The accuracy and complexity of the above-mentioned three methods are raised gradually.
The simplified defect assessment method is constructed according to fully-plastic limit load criteria. The stress ratios are calculated from the loading condition; the flaw lengths are inspected or calculated at the end of service period. Allowable flaw depths for a given final flaw length are obtained by interpolation in the table which we constructed. By comparing the flaw depth at end of service period with the maximum allowable flaw depth, the safety of the defect could be assessed. In the advanced FAD assessment method, we constructed FACs, limit loads and stress intensity factors which are related to the complex structure of the safe end, the complex materials at weld joint region of the dissimilar metal and the crack sizes. The accurate FAC related to crack sizes should be selected for defect assessment. In the LBB assessment method, the LBB curves and the LBB assessment figures are constructed, and they both are related to the complex structure of the safe end, the principal load and the J-resistance curves (material toughness) of the materials at weld joint region. Based on the defect sizes and loading condition, we can assess whether the defects in the dissimilar metal weld joint in the safe end will fail in LBB mode.
引文
[1]Spence J, Nash DH. Milestones in pressure vessel technology. International Journal of Pressure Vessels and Piping.2004,81:89-118
[2]彭俊,俞军.世界核电现状和发展趋势.核安全.2007,4:56-58
[3]伍浩松.世界核电现状.世界核电协会网站与经济合作组织核能机构年报.2008
[4]鲍云樵.我国核电在充满期盼中加速发展.中外能源.2007,12(4):19-23
[5]藏明昌.第三代核电和西屋公司AP1000评述.核科学与工程.2005,25(2):106-115
[6]中国广东核电集团有限公司.中国改进型压水堆核电站CPR1000简介.2006,23(5):36-38
[7]温鸿钧.如何加快中国核电的发展.核科学与工程.2006,26(1):1-8
[8]郑健超,杜祥琬.竞争性电力市场环境中核电发展战略研究.中国工程院咨询报告.2004:63-84
[9]OECD/IEA. Energy technology perspectives-scerarios&strategies to 2050. USA, OECD/IEA.2006:223-246
[10]景继强,栾洪卫.世界核电历程和中国核电发展之路.东北电力技术.2008,(2):48-52
[11]薛新民.2007我国核电大事记.中国能源.2008,30(2):1-9
[12]西屋电气公司.西屋公司的AP1000先进非能动型核电厂.现代电力.2006,23(5):55-65
[13]Xue H, Sato Y, Shoji T. Quantitative estimation of the growth of environmentally assisted cracks at flaws in light water reactor components. Journal of Pressure Vessel Technology.2009,131 (1)
[14]Chellapandi P, Chetal SC. Influence of mis-match of weld and base material creep properties on elevated temperature design of pressure vessels and piping. Nuclear Engineering and Design.2000,195 (2):189-196
[15]刘洪杰.核电站核承压设备用钢剖析.东方电气评论.2008,22(85):60-63
[16]Song TK, Kim YJ, Chun YB, Oh CY, Bae HY, Lee KS, Park CY. Effect of adjacent safe end to piping weld and preemptive weld overlay repair on residual stresses on nozzle to safe end weld. PVP2009, July 26-30,2009, Prague, Czech Republic. (PVP2009-77376)
[17]Joseph A, Rai SK, Jayakumar T, Murugan N. Evaluation of residual stresses in dissimilar weld joints. International Journal of Pressure Vessels and Piping.2005,82 (9):700-705
[18]Man GN, Kim JW, Lim DH, Kang YJ. Residual stress prediction of dissimilar metals welding at NPPs using support vector regression. Nuclear Engineering and Design. 2008,238 (7):1503-1510
[19]李培宁.核电及石化承压设备合乎使用评定规程技术进展.第七届全国压力容器学术 会议论文集,无锡.2009:46-56
[20]Wichman K, Tsao J, Mayfield M. LBB applications in the US operating and advanced reactors, LBB 95; Specialist meeting on Leak Before Break in Reactor Piping and Vessels; Lyon, France, October,1995; Proc US Nuclear Regulatory Commission, NUREG/CP-0155.1997
[21]R6 Assessment of the integrity of structures containing defects, Procedure R6-Revision 4. Gloucester:Nuclear Electric Ltd.2001
[22]Kayser Y, Marie S, Poussard C, Delaval C. Leak Before Break procedure:Recent modification of RCC-MR A16 appendix and proposed improvements. International Journal of Pressure Vessels and Piping.2008,85 (10):681-693
[23]Huh NS, Kim YJ, Yu YJ, Pyo CR.Effect of nozzle geometry on leak-before-break analysis of pressurized piping.Engineering Fracture Mechanics.2001,68(16):1709-1722
[24]Jang C, Lee J, Kim JS, Jin T. Mechanical property variation within Inconel 82/182 dissimilar metal weld between low alloy steel and 316 stainless steel. International Journal of Pressure Vessels and Piping.2008,85 (9):635-646
[25]Masao I, Toshiyuki S, Takahiro H, Chihiro N, Kazuo O, Masski K. Evaluation of fracture characteristics of Ni-base weld metal for BWR components. Proceedings of the ASME 2009 Pressure Vessels and Piping Division Conference. PVP2009, July 26-30, 2009, Prague, Czech Republic.(PVP2009-77720)
[26]Kim KC, Suk JI, Suk SI, Sung UH, Kim BK, Kim JT. Static and dynamic J-R tests for LBB design application of ferritic piping materials. Proceedings of the ASME 2007 Pressure Vessels and Piping Division Conference. PVP2007, July 22-26,2007, San Antonio, Texa. (PVP2007-26505)
[27]Alexandreanu B, Chopra OK, Shack WJ. The stress corrosion cracking behavior of alloys 690 and 152 weld in a PWR environment. Proceedings of the ASME 2008 Pressure Vessel and Piping Division Conference, PVP 2008, July 27-31,2008, Chicago, Illinois, USA.(PVP2008-61137)
[28]Samal MK, Balani K, Seidenfuss M, Roos E. An experimental and numerical investigation of fracture resistance behaviour of a dissimilar metal welded joint. Journal of Mechanical Engineering Science.2009,223 (7):1507-1523
[29]李培宁,雷月葆.炼油厂Cr5Mo工艺管线安全评估及剩余寿命研究报告.压力容器.1992:1-4
[30]李培宁,徐宏ASME IWB-3650压力管道缺陷评定规范介绍.压力容器.1993,(6)
[31]Tanguy B, Besson J, Piques R, Pineau A. Ductile to brittle transition of an A508 steel characterized by Charpy impact test. Engineering Fracture Mechanics.2005,72(1):49-72
[32]刘建章.核结构材料.北京:化学工业出版社.2007
[33]Blandford RK, Morton DK, Snow SD, Rabl TE.Tensile stress-strain results for 304L and 316L stainless steel plate at temperature. PVP2007, July 22-26,2007, San Antonio, Texa.(PVP2007-26096)
[34]曹金凤,石亦平ABAQUS有限元分析常见问题解答.北京:机械工业出版社.2009
[35]庄茁ABAQUS非线性有限元分析与实例.北京:科学出版社.2005
[36]章为民,陆明万,张如一.确定实际极限载荷的零曲率准则.固体力学学报.1989,(2):152-160
[37]ASME锅炉及压力容器委员会核动力分委员会ASME XI卷核电厂在役检查规则.2004:395-436
[38]李兆峰,江楠.基于失效分析图对含缺陷压力容器的安全评定.化工设备与管道.2009,46(6):5-9
[39]Chell G, Gardner B, Rhee C, Vargas P. J-based failure assessment diagrams for axially cracked pipes under pressure. PVP2009, July 26-30,2009, Prague, Czech Republic (PVP2009-77145)
[40]Wang GZ, Wang H, Xuan FZ, Tu ST, Wang ZD. Effects of void damage induced by warm prestressing (WPS) on cleavage fracture of notched steel specimens. Engineering Fracture Mechanics.2009,76 (8):1010-1023
[41]Xu J, Zhang ZL, Stby E, Nyhus B, Sun DB. Constraint effect on the ductile crack growth resistance of circumferentially cracked pipes. Engineering Fracture Mechanics.2010,77 (4):671-684
[42]Masayuki K, Hideo M. Reference stress method for evaluation of failure assessment curve of cracked pipes in nuclear power plants. International Journal of Pressure Vessels and Piping.2010,87 (1):66-73
[43]郑津洋,董其伍,桑芝富.过程设备设计.北京:化学工业出版社,2001
[44]Rudland D, Shim DJ, Csontos A. Natural flaw shape development due to stress corrosion cracking. PVP2008, July 27-31,2008, Chicago, Illinois, USA.(PVP2008-61205)
[45]林玉娟,董秋霞,贾晶晶.厚壁管的自增强损伤残余应力计算模型.科学技术与工程.2009,24:7306-7309
[46]刘梅琴,林玉霞,张扬任.关于自增强残余应力松弛规律的研究.化学工程与装备.2007,1:15-19
[47]段权,唐欣.LBB(破前漏)技术研究文献综述.第十届全国高等学校过程装备与控制工程专业教学改革与学科建设成果校际交流会.2006
[48]周剑秋,沈士明.压力管道先漏后爆(LBB)理论得进展与需解决的问题.管道技术与设备.1996(3):26-28
[49]沈士明.压力容器与管道缺陷评定的先漏后爆(LBB)准则.南京化工学院学报.1995,17(2):52-57
[50]Sharples JK, Clayton AM. A Leak-before-break method for pressure vessles and some current unresolved issues. International Journal of Pressure Vessels and Piping.1990,43: 317-327
[51]冯西桥,何树延,董铎.核反应堆管道和压力容器的LBB分析.力学进展.1998,28(2):198-217
[52]邓彩艳.压力管道“先漏后断”评定理论及应用研究.[博士学位论文].天津大学.2006
[53]张立殷,陆道纲.LBB在蠕变温度以上核级管道设计中的应用.原子能科学技术.2009,43(12):1100-1105
[54]Stadtmuller W, Sturm D. Leak-before-break behaviour of austenitic and ferritic pipes containing circumferential defects.Nuclear Engineering and Design.1997,174(3): 335-342
[55]Varfolomeev I, Ivanov D, Nagel G. Probabilistic leak-before-break assessment of a main coolant line. PVP2010, July 18-22,2010, Bellevue, Washington, USA.(PVP2010-25676)
[56]Hood JE.Fracture of steel pipelines. International Journal of Pressure Vessels and Piping.1974,2 (3):165-178
[57]Rana MD. Experimental verification of fracture toughness requirement for Leak-before-break performance for 155-175ksi strength level gas cylinder. Journal of Pressure Vessels Technology.1987,109 (4):435-439
[58]Pascal O, Pierre J, Sylvain P. Tearing resistance properties of stainless steel orbital TIG narrow gap welds of primary piping in PWR plants. PVP2009, July 26-30,2009, Prague, Czech Republic.(PVP2009-78077)
[59]董亚民,孙学伟,柳占立.用于压力容器破前漏(LBB)断裂分析的各种评估理论及计算精度研究.固体力学学报.2006,4(27):330-334
[60]Kumar V, German MD, Shih CF.An engineering approach for elastic plastic fracture. EPRI Report NP1931.Palo Alto, California, Electric Power Research Institute.1981
[61]Milne I, Ainsworth RA, Dowling AR, Stewart AT. Assessment of the integrity of structures containing defects.CEGB Report R//R6-Revision 3.1986
[62]Billy BA, Howard IC, Li ZH. Failure assessment diagrams.I.The tangency condition for ductile tearing instability.Proc R Soc Lond.1994,444:461-482
[63]Dong YM, Yang W, Hwang KC. A new approach to structural integrity assessment for ductile fracture.Fatigue & Fracture Engineering Materials & Structure.1990,13 (4): 399-410
[64]Hutchinson JW, Pairs PG. Stability analysis of J-controlled crack growth in elastic-plastic fracture.ASTM STP668.1979:37-64
[65]郑炜,董亚民,孙学伟.LBB稳定性研究的可靠性分析及临界裂纹长度计算.工程力学.2004,21(1):72-76
[66]Gudiance on methods for assessing the acceptability of flaws in fusion welded structures. PD6493.1991
[67]Kumar V, German MD, Shih CF. An engineering approach for elastic-plastic fracture analysis. EPRI-NP-1931, RP1237-1, Topical Report.1981
[68]Moore SE, Rodabaugh EC. Pressure Vessel and Piping Codes. Journal of Pressure Vessel Technonlogy.1986,108:352-336.Transaction of the ASME
[69]陈卓如,金朝铭.工程流体力学.哈尔滨:哈尔滨工业大学出版社.1987
[70]李诗久.工程流体力学.北京:机械工业出版社.1990
[71]江宏俊.流体力学.西安:西安交通大学出版社.1987
[72]彭常宏,郭贇等.管道穿透裂纹泄漏率计算程序.核动力工程.2003,6(24):505-507
[73]王双成,成弘骆.水的饱和蒸汽压的计算.河南化工.1999,11:29-31
[74]陈敏恒,丛德滋,方图南,齐鸣斋.化工原理.北京:化学工业出版社.2006:234-262