Use of bimetallic welds in nuclear reactors: Associated problems and structural integrity assessment issues

Abstract

The bimetallic welds (BMWs) play a critical and indispensable role in the primary heat transport piping system of nuclear reactors. The primary heat transport system in itself is the critical part of a nuclear reactor. Any failure of this system can lead to grave consequences, not only speaking of huge monetary losses resulting from non-utilization of the reactor setup, but also immensely valuable and irreparable loss of human life. The present paper is an effort towards identifying and understanding the problems affecting the BMWs and is as well an attempt to highlight the current issues in the structural integrity assessment of structures having these welds. The basic aim of this work is to provide a clear understanding of the current structural safety issues and their importance in underpinning the use of BMWs in modern nuclear reactors.

Keywords

bimetallic welds weld mismatch carbon migration constraint effects stress triaxility residual stresses

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References

Laukkanen

Nevasmaa

Ehrnstã©n

Rintamaa

Mapping of characteristic features of bimetallic welds from the standpoint of engineering critical analysis, Transactions SMiRT 16, paper 1566, Washington DC, August 2001.

Buckthorpe

Escaravage

Neri

Pierantozzi

Schmidt

CSC-WGCS/AG2, Study contract on bi-metallic weldments (ETNU-CT94–0133UK). Final report, document no. C9731/TR/002, Issue V02.NNC Ltd, 1997.

Busboom

Ring

P. J.

Dissimilar-weld failure analysis and development-comparative behavior of similar and dissimilar welds, EPRI report CS64666, July 1986.

Scott

Francini

Rahman

Rosenfield

Wilkoski

Fracture evaluations of fusion line cracks in nuclear pipe bimetallic welds, NUREG report/CR-6297, April 1995.

Leggatt

R. H.

Olden

E. J.

Variation of residual stresses in aged components (VORSAC), final report, TWI report 88291/15/01, August 2001.

Cattant

De Bouvier

Economou

Teissier

Yriex

Examens et atudes Mã©tallurgiques de Liaisons, Bimã©talliques de Circuit Primaire Principal, Contribution des expertises sur matã©riaux ã la rã©solution des problãmesrencontrã©s dans les rã©acteurs ã eau pressurisã©e. Colloque International Fontevraud III, Fontevraud, France, September 1994.

Heys

G. B.

Evaluation of techniques for assessing corrosion cracking in dissimilar metal welds (DISWEC), final report, AEAT-4313, October 2000.

Defects-solidification cracking, TWI Job knowledge for welders 44, November 1999, TWI connect No. 103.

Assessment and management of ageing of major nuclear power plant components important to safety in primary piping in PWRs, IAEA report, TECDOC-1361, July 2003, Engineering Safety Section, IAEA Vienna, ISBN 92–0-1080003–4.

10.

Schwalbe

K. H.

Cornec

Lidbury

Fracture mechanics analysis of the BIMET welded pipe tests. Int. J. Pres. Ves. Pip., 2004, 81, 251–277.

11.

Dawes

M. G.

Squirrell

S. J.

Pisarski

H. G.

KIC, CTOD and J-tests on weldments. In Nonlinear fracture mechanics-elastic-plastic fracture, 1979, pp. 486–497, (ASTM STP995 American Society for Testing and Materials, Philadelphia).

12.

Cray

M. J.

Luxmore

A. R.

Sumpter

J. D. G.

The effect of weld metal mismatch on J and CTOD. Proceedings of the European Symposium on Elastic-plastic fracture mechanics: Elements of defect assessment, Freiburg, FRG, 1989.

13.

Zhang

J. X.

Studies on the fracture mechanics parameters of weldment with mechanical heterogeneity. Eng. Fract. Mech., 1990, 34, 1041–1050.

14.

Kocak

Knaack

Schwalbe

K. H.

Fracture behavior of undermatched weld joints. In Proceedings of International Conference on Offshore mechanics and arctic engineering, Houston, USA, 1990, pp. 453–459.

15.

Dong

Gordon

J. R.

An investigation to determine the effect of under/overmatching on the accuracy of fracture prediction models. In Proceedings of Sixth Annual North American Welding Research Conference on Design and fitness for service of welded structures, on Columbus, Ohio, USA, 8–10 October 1990, pp. 41–65.

16.

Dong

Gordon

J. R.

The effect of weld metal mismatch on the fracture behavior of center-cracked panels. In Proceedings of ASME Pressure Vessels and Piping Conference on Fatigue, fracture and risk, New Orleans, Louisiana, USA, 21–25 June, 1992, ASME PVP, vol. 241, pp. 59–67.

17.

Dong

Gordon

J. R.

The effect of under and overmatching on fracture prediction models. Welding-90: Technology, materials, fracture (Ed. Kocak

), i. i. t. t. International, Geesthaet, Germany, pp. 363–370, ISBN 2–907–669–15-x.

18.

Wang

Y. Y.

Kirk

M. T.

A structural integrity assessment procedure for welded structures with weld metal strength mismatch. In Proceedings of ASME Pressure Vessels and Piping Conference on Fatigue and fracture, Montreal, Quebec, Canada (Eds Mehta

H. S.

Bhandari

Jones

Rahman

Wilkowski

Yoon

K. K.

), July, 1996, vol. 324, pp. 133–141, ISBN 0791817709.

19.

Scott

Rudland

Francini

Rahman

Wilkowski

Fracture evaluations of fusion line cracks in bimetallic welds. In Proceedings of ASME Pressure Vessels and Piping Conference on Fatigue and fracture, Montreal, Quebec, Canada (Eds Mehta

H. S.

Bhandari

Jones

Rahman

Wilkowski

Yoon

K. K.

), July 1996, vol. 323, pp. 39–50, ISBN 0791817709.

20.

Kim

Y. J.

Lin

Cornec

Schwalbe

K.-H.

Effect of elastic and plastic mis-matching on interfacial crack tip fields in contained yielding. In Mis-matching of interfaces and welds (Eds Schwalbe

K.-H.

Koã§ak

), 1997, pp. 135–148 (GKSS Research Centre Publications, Germany).

21.

Ganti

Parks

D. M.

McClintock

F. A.

Analysis of strength mis-matched interfacial cracks in SSY. In Mis-matching of interfaces and welds (Eds Schwalbe

K.-H.

Koã§ak

), 1997, pp. 3–16 (GKSS Research Centre Publications, Germany).

22.

Lian

Denys

R. M.

Walle van de

An experimental assessment of the effect of weld metal yield strength overmatching in pipeline girth welds, 3rd International Conference on Welding and performance of pipelines, London, UK, 18–20 November 1986.

23.

Denys

R. M.

In the fracture mechanics of welds (Eds Blauel

J. G.

Schwalbe

K.-H.

), 1987, (Mechanical Engineering Publications, Bury St Edmunds and London).

24.

Wäppling

Gunnars

Stähle

Crack growth across a strength mismatched bimaterial interface. Int. J. Fracture, 1998, 89, 223–243.

25.

Burstowm

M. C.

Howard

I. C.

Ainsworth

R. A.

The influence of constraint on crack tip stress fields in strength mismatched welded joints. J. Mech. Phys. Solids, 1998, 46 (5), 845–872.

26.

Ranestad

Zhang

Z. L.

Thaulow

Quantification of geometry and material mismatch constraint in steel weldments with fusion line cracks. Int. J. Fracture, 1999, 99, 211–237.

27.

Kim

Y. J.

Kocak

Ainsworth

R. A.

Zerbst

SINTAP defect assessment procedure for strength mismatched structures. Eng. Fract. Mech., 2000, 67, 529–546.

28.

Kim

Y.-J.

Schwalbe

K.-H.

Ainsworth

R. A.

Simplified J-estimations based on the engineering treatment model for homogeneous and mismatched structures. Eng. Fract. Mech., 2000, 68, 9–28.

29.

Lee

Kim

Y. J.

Interfacial crack-tip constraints and J-integrals in plastically mismatched bi-materials. Eng. Fract. Mech., 2001, 68, 1013–1031.

30.

Schwalbe

K.-H.

Kocak

Mis-Matching of Welds, ESIS 17, 1994, (Mechanical Engineering Publications, Bury St Edmunds and London).

31.

Schwalbe

K.-H.

Kocak

Eds Mis-matching of interfaces and welds, 1997 (GKSS-Forschungszentrum, Geesthacht).

32.

R6: Assessment of the integrity of structures containing defects, British energy generation report R/H/R6, revision 4, 2001, British Energy Ltd, Gloucester, UK.

33.

Schwalbe

K.-H.

Zerbst

The engineering treatment model. Int. J. Pres. Ves. Pip., 2000, 77, 905–918.

34.

SINTAP. Structural assessment procedures for European industry, final procedure, project BE95–1426. British Steel Report, 1999.

35.

Faidy

Chas

Bhandari

Valeta

M. P.

Hurst

Youtsas

Nevasmaa

Brocks

Lidbury

Weisner

Structural integrity of Bi-metallic components BIMET, Brite-Euram final project report, 2001.

36.

Erdogan

Shih

G. C.

On the crack extension path in the plates under loading and transverse shear. J. Basic Eng., 1963, 85, 519–527.

37.

Shih

G. C.

Minimum strain energy density. Int. J. Fracture, 1974, 10, 305–321.

38.

Dsekmann

Pawliska

Richard

H. A.

Elastic plastic crack analysis under mixed mode loading conditions. Int. J. Fracture, 1992, 57, 249–252.

39.

Smith

R. N. L.

Maximum principle stress. Eng. Fract. Mech., 1987, 26, 463–469.

40.

Waryznek

A two-dimensional crack propagation simulator. Int. J. Fracture, 1991, 6, 281–304.

41.

Finch

D. M.

Burdekin

F. M.

Effects of welding residual stresses on significance of defects in various types of welded joint. Eng. Fract. Mech., 1992, 41 (5), pp. 721–735.

42.

Finch

D. M.

Effects of welding residual stresses on significance of defects in various types of welded joint - II. Eng. Fract. Mech., 1992, 42 (3), 479–500.

43.

Brust

F. W.

Classical and emerging fracture mechanics parameters for history dependent fracture with application to weld fracture. Proceedings of ASME Pressure vessels and piping conference, Fracture Fatigue and Weld Residual Stresses (Ed. Pan

), ASME PVP-vol. 393, August 1999, ISBN 0791816273.

44.

Zhang

Dong

Brust

F. W.

Shack

Analysis of residual stresses in a girth weld of a reactor shroud. Proceedings of ASME Pressure Vessels and Piping Conference, Approximate Methods in the Design and Analysis of Pressure Vessels and Piping Components, Orlando, Florida (Ed. Rahman

), 27–31 July 1997, ASME PVP-vol. 347, pp. 141–156.

45.

Brust

F. W.

Dong

Zhang

Shack

Crack growth behavior in residual stress fields of a girth weld in reactor shroud structures. Proceedings of ASME Pressure vessels and piping conference, Fatigue and Fracture, Orlando, Florida (Ed. Rahman

), July 1997, ASME PVP-vol. 350, pp. 391–406, ISBN 0791815625.

46.

Brust

F. W.

Dong

Zhang

A constitutive model for welding process simulation using finite element methods. In Advances in Computational Engineering Science, (Eds Atluri

S. N.

Yagawa

) Proceedings of ICES Conference, San Jose, Costa Rica, 1997, pp. 51–56.

47.

Zhang

Dong

Brust

F. W.

A 3D composite shell element model for residual stress analysis of multi-pass welds in pressure vessels and pipes. In Proceedings of the 14th International Conference on Structural mechanics in reactor technology (SMiRT 14), Lyon, France (Ed. Kussmaul

), August 1997, pp. 335–344.

48.

Dong

Hong

J. K.

Roger

Analysis of residual stresses in Al-Li alloy repair welds and mitigation techniques. Welding J., 1998, 17 (11), 439s–445s.

49.

Dong

Hong

J. K.

Zhang

Roger

Bynum

Shah

Effects of repair weld residual stresses on wide-panel specimens loaded in tension. J. Pres. Ves. Technol., 1998, 120 (2), 122–128.

50.

Leggatt

R. H.

Hooton

D. G.

The treatment of residual stress in defect assessments of austenitic fast reactor structures. ASME PVP, 1988, vol. 135, 71–75.

51.

API RP-579 Recommended practices for fitness-for-service, 1st edition, 2000, American Petroleum Institute, Washington, DC, USA.

52.

PD6493: 1991, Guidance on Methods for Assessing the Acceptability of Flaws in Fusion Welded Structures, British Standards Institute, London, UK.

53.

Dong

Brust

F. W.

Welding residual stresses and effects on fracture in pressure vessel and piping components: A millennium review and beyond, the millennium issue. ASME Trans. J. Pres. Vessel Technol., 2000, 122 (3), August, 329–328.

54.

Dong

Hong

J. K.

Consistent treatment of residual stresses in fracture assessment solutions. Proceedings of 2002 ASME Pressure Vessel and Piping Conference, Computational weldmechanics, constraint, and weld fracture, Vancouver, Canada (Ed. Brust

F.W.

), August 2002, ASME PVP-vol. 434, pp. 89–100, ISBN 0791819450.

55.

Bouchard

Bradford

Validated axial residual stress profiles for fracture assessment of austenitic stainless steel pipe girth welds. Proceedings of ASME PVP Conference, Fracture and fitness Atlanta Georgia USA, July 2001, PVP vol. 422.

56.

Riou

Hooton

D. G.

Rathjen

Sperandio

Leak before break procedure for sodium boundary components, 12th SMiRT Conference, Stuttgart, paper F07/1, 1993.

57.

Naumenko

V. P.

Kolednik

Load biaxiality effects on the fracture resistance of thin steel plates. In Structural integrity, experiments-models-application, Proceedings of ECF10, (Eds Berger

Schwalbe

K. H.

) (EMAS U.K). 1994, vol. 2, pp. 911–921.

58.

O'Dowd

N. P.

Kolednik

Naumenko

V. P.

Elastic-plastic analysis of biaxially loaded centrecracked plates. Int. J. Solids Structures, 1999, 36 (36), 5639–5661.

59.

Naumenko

V. P.

, Structural integrity assessment via the unified theory of fracture in tension and/or compression. In Mechanisms and mechanics of damage and failure, Proceedings of the Eleventh European Conference on Fracture (ECF 11), (Ed. Petit

), (EMAS, U.K) 1996, vol. 3, pp. 2151–2156.

60.

Naumenko

V. P.

Kolednik

O'Dowd

N. P.

Volko

G. S.

Semenets

A. I.

Transferability of plane-stress R-curves: Effects of specimen size and crack length, Submitted to: ECF12 - Fracture from Defects: The Conference Proceedings (Eds. Brown

M. W.

Miller

K. J.

de los Rios

E. R.

) (EMAS U.K) 1998, vol. 11, pp. 631–636.

61.

Betegeon

Hancock . Two parameter characteristics of elastic-plastic crack-tip fields. J. Appl. Mech., 1991, 58, 104–110.

62.

Williams

M. L.

On the stress distribution at the base of the stationary crack, J. Appl. Mech., 1957, 24, 109–114.

63.

Brocks

Kunecke

Noack

H. D.

Veith

On the transferability of fracture mechanics to structures using FEM. Nuclear Eng. Design, 1989, 112, 1–14.

64.

Kordisch

Somme

Er.

Schemitt

The influence of triaxiality on stable crack growth. Nucl. Eng. Design, 1989, 112, 27–35.

65.

Rice

J. R.

Tracey

D. M.

On the ductile enlargement of voids in triaxial stress fields. J. Mech. Phys. Solids, 1969, 16, 201–217.

66.

McClintock

F. A.

A Criterion for Ductile Fracture by the Growth of Holes. J. Appl. Mech., 1968, 35, 363–371.

67.

O'Dowd

N. P.

Shih

C. F.

Family of crack tip fields characterized by a triaxiality parameter-I: Structure of fields. J. Mech. Phys. Solids, 1991, 39, 989–1015.

68.

O'Dowd

N. P.

Shih

C. F.

Family of crack tip fields characterized by a triaxiality parameter-II: Fracture applications. J. Mech. Phys. Solids, 1992, 40, 939–963.

69.

Chao

Y. J.

Cleavage fracture quantified by J and A 2. Constraint effects in fracture theory and applications, ASTM STP 1244, vol. II, Philadephia, 1995, pp. 3–20.

70.

Rice

J. R.

A path independent integral and the approximate analysis of strain concentration by notched and cracks. J. Appl. Mech., 1968, 35, 379.

71.

Beremin

F. M.

Cavity formation from inclusions in ductile fracture of A508 steel. Metall. Trans., 1981, 12A, 723–731.

72.

Beremin

F. M.

A local criterion for cleavage fracture of a nuclear pressure vessel steel. Metall. Trans., 1983, 14A, 2277–2287.

73.

Pineau

Global and local approaches to fracture transferability of laboratory test results to components. In Topics in fracture and fatigue (Ed. Argon

), 1992, pp. 197–234 (Springer, New York).

74.

Xia

Shih

C. F.

Hutchinson

J. W.

A computational approach to ductile crack growth under large scale yielding conditions. J. Mech. Phys. Solids, 1995, 43 (3), 389–413.

75.

Decamp

Bauvineau

Besson

Pineau

Size and geometry effects on ductile rupture of notched bars in a C-Mn steel: Experiments and modelling. Int. J. Fracture, 1998, 88 (1), 1–18.

76.

Gurson

A. L.

Continuum theory of ductile rupture by void nucleation and growth. Part I: Yield criteria and flow rules for porous ductile media. J. Eng. Mater. Technol., 1977, 99, 2–15.

77.

Tvergaard

Material failure by void growth to coalescence. Adv. Appl. Mech., 1990, 27, 83–151.

78.

Rousselier

Ductile fracture models and their potential in local approach of fracture. Nucl. Eng. Des., 1987, 105, 97–111.