Validity of the master curve temperature dependence assumption for highly embrittled RPV materials

Results from the IAEA Coordinated Research Project (CRP-8)

Tapio Planman, K. Onizawa, W. Server

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review

Abstract

The fracture toughness temperature dependence (transition curve shape) has been discussed almost since the original empirical definition of the curve in 1991. The data sets showing anomalous fracture behaviour of highly irradiated VVER-1000 pressure vessel steels presented in 2000’s have further enhanced this discussion and even a special model has been proposed for highly irradiated steels, including a mathematical definition of the curve shape change. Although in most cases the standard Master Curve (MC) approach, assuming a constant transition curve shape, has proven to give a realistic description for also highly irradiated ferritic steels, there are grades which show for example abnormally weak temperature dependence. In these cases, however, an obvious reason for the behaviour may be that the material does not fail by the mechanism assumed in the MC model. The fracture toughness data collected and analysed in the CRP-8 Topic Area 3 supports the validity of the curve shape assumption of ASTM E1921 also in case of irradiated steels and gives no rise to change the present definition. The Master Curve C-parameter (the shape parameter) estimation is proposed as an appropriate analysis method when there is need to estimate also the temperature dependence, whereas the SINTAP procedure is recommended for ensuring conservative lower bound estimates when material inhomogeneity is suspected. The results show that irradiation may slightly lower the fracture toughness in the upper transition region in relation to that predicted by ASTM E1921, but the effect after moderate T0 shift values (up to about 100°C) seems to be negligible. The investigated steels exhibit no or very weak correlation between the C-parameter and T0.
Original languageEnglish
Title of host publicationASME 2009 Pressure Vessels and Piping Conference
PublisherAmerican Society of Mechanical Engineers ASME
Pages359-366
Volume3: Design and Analysis
ISBN (Print)978-0-7918-4366-6
DOIs
Publication statusPublished - 2010
MoE publication typeA4 Article in a conference publication
EventASME 2009 Pressure Vessels and Piping Conference, PVP 2009 - Prague, Czech Republic
Duration: 26 Jul 200930 Jul 2009

Publication series

Name
Volume3

Conference

ConferenceASME 2009 Pressure Vessels and Piping Conference, PVP 2009
CountryCzech Republic
CityPrague
Period26/07/0930/07/09

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steel
fracture toughness
temperature
inhomogeneity
irradiation
vessel
research project
material
parameter

Cite this

Planman, T., Onizawa, K., & Server, W. (2010). Validity of the master curve temperature dependence assumption for highly embrittled RPV materials: Results from the IAEA Coordinated Research Project (CRP-8). In ASME 2009 Pressure Vessels and Piping Conference (Vol. 3: Design and Analysis, pp. 359-366). American Society of Mechanical Engineers ASME. American Society of Mechanical Engineers. Pressure Vessels and Piping Division. Publication PVP, Vol.. 2009 https://doi.org/10.1115/PVP2009-77359
Planman, Tapio ; Onizawa, K. ; Server, W. / Validity of the master curve temperature dependence assumption for highly embrittled RPV materials : Results from the IAEA Coordinated Research Project (CRP-8). ASME 2009 Pressure Vessels and Piping Conference. Vol. 3: Design and Analysis American Society of Mechanical Engineers ASME, 2010. pp. 359-366 (American Society of Mechanical Engineers. Pressure Vessels and Piping Division. Publication PVP, Vol. 2009).
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title = "Validity of the master curve temperature dependence assumption for highly embrittled RPV materials: Results from the IAEA Coordinated Research Project (CRP-8)",
abstract = "The fracture toughness temperature dependence (transition curve shape) has been discussed almost since the original empirical definition of the curve in 1991. The data sets showing anomalous fracture behaviour of highly irradiated VVER-1000 pressure vessel steels presented in 2000’s have further enhanced this discussion and even a special model has been proposed for highly irradiated steels, including a mathematical definition of the curve shape change. Although in most cases the standard Master Curve (MC) approach, assuming a constant transition curve shape, has proven to give a realistic description for also highly irradiated ferritic steels, there are grades which show for example abnormally weak temperature dependence. In these cases, however, an obvious reason for the behaviour may be that the material does not fail by the mechanism assumed in the MC model. The fracture toughness data collected and analysed in the CRP-8 Topic Area 3 supports the validity of the curve shape assumption of ASTM E1921 also in case of irradiated steels and gives no rise to change the present definition. The Master Curve C-parameter (the shape parameter) estimation is proposed as an appropriate analysis method when there is need to estimate also the temperature dependence, whereas the SINTAP procedure is recommended for ensuring conservative lower bound estimates when material inhomogeneity is suspected. The results show that irradiation may slightly lower the fracture toughness in the upper transition region in relation to that predicted by ASTM E1921, but the effect after moderate T0 shift values (up to about 100°C) seems to be negligible. The investigated steels exhibit no or very weak correlation between the C-parameter and T0.",
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language = "English",
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Planman, T, Onizawa, K & Server, W 2010, Validity of the master curve temperature dependence assumption for highly embrittled RPV materials: Results from the IAEA Coordinated Research Project (CRP-8). in ASME 2009 Pressure Vessels and Piping Conference. vol. 3: Design and Analysis, American Society of Mechanical Engineers ASME, American Society of Mechanical Engineers. Pressure Vessels and Piping Division. Publication PVP, vol. 2009, pp. 359-366, ASME 2009 Pressure Vessels and Piping Conference, PVP 2009, Prague, Czech Republic, 26/07/09. https://doi.org/10.1115/PVP2009-77359

Validity of the master curve temperature dependence assumption for highly embrittled RPV materials : Results from the IAEA Coordinated Research Project (CRP-8). / Planman, Tapio; Onizawa, K.; Server, W.

ASME 2009 Pressure Vessels and Piping Conference. Vol. 3: Design and Analysis American Society of Mechanical Engineers ASME, 2010. p. 359-366 (American Society of Mechanical Engineers. Pressure Vessels and Piping Division. Publication PVP, Vol. 2009).

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review

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T1 - Validity of the master curve temperature dependence assumption for highly embrittled RPV materials

T2 - Results from the IAEA Coordinated Research Project (CRP-8)

AU - Planman, Tapio

AU - Onizawa, K.

AU - Server, W.

PY - 2010

Y1 - 2010

N2 - The fracture toughness temperature dependence (transition curve shape) has been discussed almost since the original empirical definition of the curve in 1991. The data sets showing anomalous fracture behaviour of highly irradiated VVER-1000 pressure vessel steels presented in 2000’s have further enhanced this discussion and even a special model has been proposed for highly irradiated steels, including a mathematical definition of the curve shape change. Although in most cases the standard Master Curve (MC) approach, assuming a constant transition curve shape, has proven to give a realistic description for also highly irradiated ferritic steels, there are grades which show for example abnormally weak temperature dependence. In these cases, however, an obvious reason for the behaviour may be that the material does not fail by the mechanism assumed in the MC model. The fracture toughness data collected and analysed in the CRP-8 Topic Area 3 supports the validity of the curve shape assumption of ASTM E1921 also in case of irradiated steels and gives no rise to change the present definition. The Master Curve C-parameter (the shape parameter) estimation is proposed as an appropriate analysis method when there is need to estimate also the temperature dependence, whereas the SINTAP procedure is recommended for ensuring conservative lower bound estimates when material inhomogeneity is suspected. The results show that irradiation may slightly lower the fracture toughness in the upper transition region in relation to that predicted by ASTM E1921, but the effect after moderate T0 shift values (up to about 100°C) seems to be negligible. The investigated steels exhibit no or very weak correlation between the C-parameter and T0.

AB - The fracture toughness temperature dependence (transition curve shape) has been discussed almost since the original empirical definition of the curve in 1991. The data sets showing anomalous fracture behaviour of highly irradiated VVER-1000 pressure vessel steels presented in 2000’s have further enhanced this discussion and even a special model has been proposed for highly irradiated steels, including a mathematical definition of the curve shape change. Although in most cases the standard Master Curve (MC) approach, assuming a constant transition curve shape, has proven to give a realistic description for also highly irradiated ferritic steels, there are grades which show for example abnormally weak temperature dependence. In these cases, however, an obvious reason for the behaviour may be that the material does not fail by the mechanism assumed in the MC model. The fracture toughness data collected and analysed in the CRP-8 Topic Area 3 supports the validity of the curve shape assumption of ASTM E1921 also in case of irradiated steels and gives no rise to change the present definition. The Master Curve C-parameter (the shape parameter) estimation is proposed as an appropriate analysis method when there is need to estimate also the temperature dependence, whereas the SINTAP procedure is recommended for ensuring conservative lower bound estimates when material inhomogeneity is suspected. The results show that irradiation may slightly lower the fracture toughness in the upper transition region in relation to that predicted by ASTM E1921, but the effect after moderate T0 shift values (up to about 100°C) seems to be negligible. The investigated steels exhibit no or very weak correlation between the C-parameter and T0.

U2 - 10.1115/PVP2009-77359

DO - 10.1115/PVP2009-77359

M3 - Conference article in proceedings

SN - 978-0-7918-4366-6

VL - 3: Design and Analysis

SP - 359

EP - 366

BT - ASME 2009 Pressure Vessels and Piping Conference

PB - American Society of Mechanical Engineers ASME

ER -

Planman T, Onizawa K, Server W. Validity of the master curve temperature dependence assumption for highly embrittled RPV materials: Results from the IAEA Coordinated Research Project (CRP-8). In ASME 2009 Pressure Vessels and Piping Conference. Vol. 3: Design and Analysis. American Society of Mechanical Engineers ASME. 2010. p. 359-366. (American Society of Mechanical Engineers. Pressure Vessels and Piping Division. Publication PVP, Vol. 2009). https://doi.org/10.1115/PVP2009-77359