Study of Aging Mechanisms for Structural Materials within SAFELIFE Project
EUROATOM research programs aimed at study of aging mechanisms and remedial procedures for structural materials of nuclear reactor components have been analyzed. Within this framework, projects are carried out focusing on the development of non-destructive techniques applied to thermal aging, n...
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Інститут проблем міцності ім. Г.С. Писаренко НАН України
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irk-123456789-470612013-07-09T18:41:25Z Study of Aging Mechanisms for Structural Materials within SAFELIFE Project Sevini, F. Debarberis, L. Taylor, N. Gerard, R. Brumovsky, M. Научно-технический раздел EUROATOM research programs aimed at study of aging mechanisms and remedial procedures for structural materials of nuclear reactor components have been analyzed. Within this framework, projects are carried out focusing on the development of non-destructive techniques applied to thermal aging, neutron embrittlement monitoring, improved surveillance for WWER-440 reactors, dosimetry, and advance fracture mechanisms for NPP integrity assessment. Among major achievements are the ATHENA project activities on re-embrittlement model validation after annealing and the effect of chemical composition on embrittlement rate in RPV steels. A brief description is given of the main results of current EUROATOM projects, as well as the next research stage goals of a more expanded SAFELIFE network. Рассмотрен комплекс исследовательских программ EURATOM, направленных на изучение механизмов старения и методов устранения повреждений конструкционных материалов корпусов реакторов. Данный комплекс предусматривает разработку неразрушающих методов исследования теплового старения и мониторинга радиационного охрупчивания материалов, усовершенствование программы испытаний с использованием образцов-свидетелей для реакторов типа ВВЭР-440, дозиметрии, а также применение различных механизмов разрушения для оценки структурной целостности АЭС. В частности, проект ATHENA позволил обосновать модель повторного охрупчивания после отжига и выявить зависимость скорости охрупчивания от химического состава корпусных сталей. Кратко изложены основные достижения действующих программ EURATOM, а также задачи следующего этапа исследований в рамках проекта SAFELIFE. Розглянуто комплекс дослідних програм EURATOM, що спрямовані на вивчення механізмів старіння та методів усунення пошкоджень конструкційних матеріалів корпусів реакторів. Даний комплекс передбачає розробку неруйнівних методів дослідження теплового старіння і моніторинга радіаційного окрихчування матеріалів, удосконалення програми досліджень із використанням зразків-свідків для реакторів типу ВВЕР-440, дозиметрії, а також застосування різних механізмів руйнування для оцінки структурної цілісності АЕС. Зокрема, проект ATHENA дозволив обгрунтувати модель повторного окрихчування після відпалу та виявити залежність швидкості окрихчування від хімічного складу корпусних сталей. Коротко викладено основні досягнення діючих програм EURATOM та задачі наступного етапу досліджень у рамках проекту SAFELIFE. 2004 Article Study of Aging Mechanisms for Structural Materials within SAFELIFE Project / F. Sevini, L. Debarberis, N. Taylor, R. Gerard, M. Brumovsky // Проблемы прочности. — 2004. — № 1. — С. 54-60. — Бібліогр.: 5 назв. — англ. 0556-171X http://dspace.nbuv.gov.ua/handle/123456789/47061 539.4 en Проблемы прочности Інститут проблем міцності ім. Г.С. Писаренко НАН України |
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Научно-технический раздел Научно-технический раздел |
| spellingShingle |
Научно-технический раздел Научно-технический раздел Sevini, F. Debarberis, L. Taylor, N. Gerard, R. Brumovsky, M. Study of Aging Mechanisms for Structural Materials within SAFELIFE Project Проблемы прочности |
| description |
EUROATOM research programs aimed at study of
aging mechanisms and remedial procedures for
structural materials of nuclear reactor components
have been analyzed. Within this framework, projects
are carried out focusing on the development
of non-destructive techniques applied to thermal
aging, neutron embrittlement monitoring, improved
surveillance for WWER-440 reactors, dosimetry,
and advance fracture mechanisms for
NPP integrity assessment. Among major achievements
are the ATHENA project activities on
re-embrittlement model validation after annealing
and the effect of chemical composition on
embrittlement rate in RPV steels. A brief description is given of the main results of current
EUROATOM projects, as well as the next research
stage goals of a more expanded SAFELIFE
network. |
| format |
Article |
| author |
Sevini, F. Debarberis, L. Taylor, N. Gerard, R. Brumovsky, M. |
| author_facet |
Sevini, F. Debarberis, L. Taylor, N. Gerard, R. Brumovsky, M. |
| author_sort |
Sevini, F. |
| title |
Study of Aging Mechanisms for Structural Materials within SAFELIFE Project |
| title_short |
Study of Aging Mechanisms for Structural Materials within SAFELIFE Project |
| title_full |
Study of Aging Mechanisms for Structural Materials within SAFELIFE Project |
| title_fullStr |
Study of Aging Mechanisms for Structural Materials within SAFELIFE Project |
| title_full_unstemmed |
Study of Aging Mechanisms for Structural Materials within SAFELIFE Project |
| title_sort |
study of aging mechanisms for structural materials within safelife project |
| publisher |
Інститут проблем міцності ім. Г.С. Писаренко НАН України |
| publishDate |
2004 |
| topic_facet |
Научно-технический раздел |
| url |
http://dspace.nbuv.gov.ua/handle/123456789/47061 |
| citation_txt |
Study of Aging Mechanisms for Structural Materials within SAFELIFE
Project / F. Sevini, L. Debarberis, N. Taylor, R. Gerard, M. Brumovsky // Проблемы прочности. — 2004. — № 1. — С. 54-60. — Бібліогр.: 5 назв. — англ. |
| series |
Проблемы прочности |
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2025-07-04T06:41:56Z |
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| fulltext |
UDC 539.4
Study of Aging Mechanisms for Structural Materials within SAFELIFE
Project
F. Sevini,a L. D ebarberis,a N. Taylor,a R. G erard ,b and M. Brum ovskyc
a Joint Research Centre of the European Commission, Institute for Energy, Petten, the
Netherlands
b Tractebel, Belgium
c NRI Rez, Czech Republic
УДК 539.4
Изучение механизмов старения конструкционных материалов в
рамках проекта SAFELIFE
Ф. Севиниа, Л. Дебарбериса, Н. Тейлора, Р. Ж ерар6, М. Брумовскив
а Объединенный исследовательский центр Европейской комиссии, Энергетический
институт, Петтен, Нидерланды
б Трактебел, Бельгия
в НРИ, Чехия
Рассмотрен комплекс исследовательских программ EURATOM, направленных на изучение
механизмов старения и методов устранения повреждений конструкционных материалов
корпусов реакторов. Данный комплекс предусматривает разработку неразрушающих мето
дов исследования теплового старения и мониторинга радиационного охрупчивания мате
риалов, усовершенствование программы испытаний с использованием образцов-свидетелей
для реакторов типа ВВЭР-440, дозиметрии, а также применение различных механизмов
разрушения для оценки структурной целостности АЭС. В частности, проект ATHENA
позволил обосновать модель повторного охрупчивания после отжига и выявить зависи
мость скорости охрупчивания от химического состава корпусных сталей. Кратко изло
жены основные достижения действующих программ EURATOM, а также задачи следу
ющего этапа исследований в рамках проекта SAFELIFE.
Ключевые слова : старение, радиационное охрупчивание, сети, контроль
старения.
1. Background of the AM ES Network. The AMES (Aging Materials
Evaluation and Studies) network was set up in 1993 to bring together the
organizations in Europe having the greatest expertise on nuclear reactor materials
assessment and research on aging management [1].
The aims of the general strategy was to understand the influence of various
embrittlement mechanisms; develop new techniques; improve the dosimetry
aspects; improve the prediction of irradiated material fracture toughness.
The information coming from the running projects is as much as possible
integrated with the results from different programs (EU-funded, national, TACIS
© F. SEVINI, L. DEBARBERIS, N. TAYLOR, R. GERARD, M. BRUMOVSKY, 2004
54 ISSN 0556-171X. Проблемы прочности, 2004, № 1
The AMES Network and SAFELIFE
PHARE), enabling the definition of a common European position on these issues.
An overview of AMES projects throughout FP4 is given in [2] and [3].
Hereby follows a short description of the status of the presently running
projects carried out by institutes’ members of the AMES network.
ATH ENA (coordinator R. Gerard, Tractebel). In order to optimize the
fulfillment of its strategy, in November 2001, the AMES Steering Committee
started ATHENA, a thematic network organized in task groups on technical
issues:
♦ Master Curve implementation for fracture toughness assessment
♦ Annealing and re-embrittlement issues
♦ Radiation embrittlement understanding
♦ Thermal aging, stress/strain aging and other aging mechanisms: influence
and synergism.
These task groups have the aim of improving the co-ordination and
synergism on well-identified R&D topics concerning material degradation.
The objectives of ATHENA (AMES Thematic Network) are:
♦ To entrust the evaluation of specialized problems to a critical mass of
experts, that cannot be present in the Steering Committee;
♦ To create links with nationally-funded projects on the same or on
complementary topics and valorize as such these in-kind contributions;
♦ To coordinate with projects on similar issues that are carried out in the
framework of the Tacis and PHARE programs. The task groups provide an
opportunity to share this information. In this way, some of the tasks
carried out in the framework of the R&D projects can be re-oriented in
order to obtain additional and/or complementary information on the same
materials. It enhances the scientific and industrial co-operation with the
partners of Eastern and Central Europe, Russia and Ukraine;
♦ To introduce links with American and/or Asian institutions that work on
similar issues and can participate on an in-kind basis. This raises the stake
of European contributions on a global level.
This cross-fertilization between projects represents the greatest added value
of ATHENA. The thematic network will greatly enhance the return of different
programs (European R&D projects, national projects, Tacis-PHARE, bilateral
co-operation projects). Besides the key participants identified in the ATHENA
contract, the “work packages” are open to a wide participation on an in-kind
basis, which should ensure an improved feedback on the real needs of the
European industry.
RED OS (coordinator A. Ballesteros, Tecnatom). Follow-up to FP4 MADAM,
the scope of this project is the accurate determination and benchmarking of
radiation field parameters, relevant to the reactor pressure vessel monitoring.
Neutron exposure of the reactor pressure vessel (RPV) and reactor internals is one
of the key factors that should be quantified reliably when assessing their lifetime.
Irradiation embrittlement is the most important damaging in the RPV lifetime
evaluation.
Despite improvements in the calculation of the neutron field parameters with
the corrected cross section values, remarkable discrepancies exist between the
calculated and measured values, especially in ex-vessel position. To resolve these
ISSN 0556-171X. npoôëeubi npounocmu, 2004, № 1 55
F. Sevini, L. Debarberis, N. Taylor, et al.
difficulties and discrepancies, the experimental and computational techniques
should be combined.
PISA (coordinator C. English, AEA Technology). This project (Phosphorus
Influence on Steel Aging) has the objective of improving the understanding of
irradiation embrittlement by segregation of phosphorus to internal grain
boundaries and reducing the impact of brittle intergranular failure mechanism on
the properties of the reactor pressure vessel.
The range of the RPV steels considered includes the M n-M o-Ni steels
employed in European PWRs, the mild steels used in UK Magnox RPVs, and the
steels employed in WWER-440.
The approach employed to achieve this objective is to improve predictability
through developing improved physical understanding of both the segregation
process and any resultant change in the mechanical properties. The necessary
understanding will be developed through focused experimental investigations of
irradiated steels and model alloys, with associated modeling studies.
The project foresees three irradiations, respectfully, at the temperature 200oC
and fluence 5 • 1018 n/cm2; 290OC and 5 • 1018; 290OC and 18 • 1018. Two irradiations
have already been completed. Post-irradiation examination is in progress, and will
have to determine the microstructural and mechanical property changes in steels
and model alloys. Finally, the development of improved mechanistic
understanding will be primarily achieved through modeling of the segregation
process and the effect of such segregation on the mechanical properties.
COBRA (coordinator A. Ballesteros, Tecnatom). This project tackles the
open issue of the uncertainty in the measurement of the correct irradiation
temperature to which WWER-440 reactor surveillance capsules are subjected [4].
Non-homogeneous neutron and gamma flux distribution determines the
temperature gradient along the capsule and possible overheating as compared to
the real conditions of the reactor pressure vessel. The latter phenomenon would
produce nonconservative surveillance data.
Melting temperature monitors have shown uncertainties in assessing the
temperature in the interval from 272 to 292OC.
Hence a special direct temperature measurement system by thermocouples
has been implemented in Kola NPP in order to prove the feasibility of the solution
to the problem. The consortium includes Russian, Armenian, and European
institutions.
The obtained results show that the irradiation temperature of the surveillance
specimens is about 272OC, hence it is possible to get conservative RPV
surveillance results.
FRA M E (coordinator M. Valo, VTT). This project is concerned with
fracture mechanics based trend curves for PWR and WWER RPV materials. The
scope is to validate the use of the Master Curve approach, as compared to the
conventional one involving the increase of the ductile-to-brittle transition
temperature assessed by Charpy impact testing.
Cleavage-initiation fracture toughness is the property needed in structural
safety analyses of the reactor pressure vessel. However, this property is not
measured directly for the irradiated (neither for the annealed or re-irradiated)
material condition, instead a correlative embrittlement estimation based on the
56 ISSN 0556-171X. npo6n.eubi npounocmu, 2004, № 1
The AMES Network and SAFELIFE
Charpy-V test is used. It is difficult to quantify the uncertainties inherent in the
current estimation, and hence, the assumed uncertainties are addressed by the use
of a conservative fracture toughness reference curve and by added margins.
Charpy-V impact toughness is in many respects a clearly different material
property than fracture toughness. Hence, the current understanding of
embrittlement may be a biased one.
In the FRAME project, fracture toughness-based embrittlement models will
be created and they will be critically compared with the published Charpy-V
based models.
Fracture toughness-based trend curves do not exist nowadays, because the
required databases are non-existing or are insufficient in size. Trend curve
development is in essence mathematical fitting of candidate functions to
measured irradiation shift data. Approximately twelve different materials are
included in the test matrix. The irradiation in HFR LYRA rig is successfully
carried out and the post-irradiation testing campaign is about to start.
GRETE (coordinator EdF). The project is the follow-up to AMES-NDT,
which was dedicated to aging monitoring of non-irradiated materials. The object
of GRETE is a round robin exercise on nondestructive techniques to assess and
monitor the degradation of reactor pressure vessel steels due to neutron irradiation
and thermal fatigue of piping. The techniques studied are based on
thermo-electric and magnetic effects. The results will be of interest for RPV
surveillance programs, because a validated non-destructive measurement of
surveillance specimens could provide an alternative to destructive testing and
therefore allow sparing of surveillance samples.
Nondestructive Techniques for the characterization of neutron irradiation
damage are: Automated ball indenter; Magnetic Barkhausen Noise;
Micromagnetic measurements; Nonlinear Harmonic Analysis of Eddy Current
signals; Thermo-electric power measurements.
For the characterization of fatigue damage: Magnetic Barkhausen Noise;
Micromagnetic measurements; Nonlinear Harmonic Analysis of Eddy Current
signals; Fluxgate, Giant Magnetic Resistor, Superconducting Quantum Interference
Device; Ultrasonic Scattering or Backscattering. Analyses of the results and
elaboration of conclusions are in progress.
2. AM ES in the 6th FWP. In the context of the European Research Area,
there is a need for integrating the activities on NPP Plant Life Management into a
common structure dedicated to the evaluation of open issues, elaboration of new
activities, and efficient utilization of available resources.
JRC-IE, starting from the experience accumulated since 1993 with the
operation of NESC, ENIQ, and AMES networks is presently elaborating a
strategy to optimize common plans for FP6 in different areas, and launch the
SAFELIFE network in September 2003, which will cover the issues of NPP
PLIM so far tackled in a scattered way by individual European networks.
The invaluable expertise and differentiated background of the present
networks will be kept by reconsidering their role as Expert Groups. This will
ensure that all different issues will be considered when planning new activities,
especially in the context of the Network of Excellence dedicated to PLIM or new
proposals for Integrated Projects (Fig. 1).
ISSN 0556-171X. npoôëeubi npounocmu, 2004, № 1 57
F. Sevini, L. Debarberis, N. Taylor, et al.
Fig. 1. Evolution towards an integrated approach to NPP PLIM in the EU.
The Expert Groups will act as review bodies advising on the contents of new
project proposals.
3. SAFELIFE and P lant Life M anagem ent of Aging NPPs in Europe. An
integrated approach to R&D activities on generic issues for plant life management
of aging nuclear power plants is required to support European needs for
sustainability and for Safe & Secure Supply (3S) of electrical power. To meet this
challenge, the European Commission’s Joint Research Centre proposes to form a
Network focused on structural integrity for plant life management of key
components, covering the main R&D disciplines involved and considering all
nuclear power plant designs, both western and eastern. This is intended to provide
a long-term structure capable of addressing generic issues related to accident
prevention, plant performance and risk informed methods, and to harness the
efforts of the leading European R&D. In addition, it can provide support for a
rationalized EU approach to plant decommissioning and related waste
management issues.
The initiative will be based on the successful established European
Networks: AMES, NESC (network for the evaluation of structural components),
ENIQ (European network for inspection qualification) and on new ones such as
NET (neutron evaluation techniques) and AMALIA (Assessment of Materials
Aging under the effect of Load and IASCC) operated by the JRC Institute for
Energy.
SA F E LIF E composition
♦ members of the European Networks AMES, NESC, ENIQ, NET, and
AMALIA;
♦ members of running DG-RTD Thematic Networks and Shared Cost
Actions in this area;
♦ representatives as appropriate from other European and international
organizations.
58 ISSN 0556-171X. Проблемы прочности, 2004, N 1
The AMES Network and SAFELIFE
SA F E LIF E network objectives are the following:
♦ Establishment of a long-term structure to improve the focus and
effectiveness of the European R&D for plant life management for key
reactor components in aging nuclear plants.
♦ Development and funding possibilities of major “integrated” project
proposals at trans-national and EU level consistent with the European
Research Area principles.
♦ Strategic planning and management of R&D actions in this area
♦ Promote harmonization of the best practice for improved European codes
and standards.
♦ Organize training and professional development in advanced procedures
and to maintain engineering competence for safe and economic operation
of nuclear plants.
♦ Link and co-operate with all key international and national organizations.
♦ Optimize access to existing data, facilitate data exchange, and support
effective dissemination and technology transfer.
Conclusions. Evolving from the 4th and 5th EURATOM Framework
Program approach based on in-kind and co-financed initiatives promoted by its
Steering Committee, AMES has reached important results and built a wide
consensus on important issues related to neutron embrittlement of the reactor
pressure vessel [5].
With the start of the 6th Framework Program and the introduction of new
instruments like the Integrated Projects and the Network of Excellence, there is a
need for a broader and more efficient integration of activities and resources in the
spirit of the European research Area.
AMES and other European nuclear networks operated by JRC-IE will
therefore evolve into Expert Groups of a more expanded new initiative on NPP
Plant Life Management called SAFELIFE, which will be promoted by JRC and
built on the experience acquired with the operation of the present networks.
In this way, SAFELIFE could constitute the basis for the future Network of
Excellence on PLIM of nuclear power plants in the EU.
Acknowledgements. The project coordinators have provided most of the
material presented here, but along with them, all the FP5 project partners and
European Networks members made their contribution and are therefore
acknowledged.
Р е з ю м е
Розглянуто комплекс дослідних програм EURATOM, що спрямовані на
вивчення механізмів старіння та методів усунення пошкоджень конструк
ційних матеріалів корпусів реакторів. Даний комплекс передбачає розробку
неруйнівних методів дослідження теплового старіння і моніторинга радіа
ційного окрихчування матеріалів, удосконалення програми досліджень із
використанням зразків-свідків для реакторів типу ВВЕР-440, дозиметрії, а
також застосування різних механізмів руйнування для оцінки структурної
цілісності АЕС. Зокрема, проект ATHENA дозволив обгрунтувати модель
повторного окрихчування після відпалу та виявити залежність швидкості
ISSN 0556-171X. Проблеми прочности, 2004, № 1 59
F. Sevini, L. Debarberis, N. Taylor, et al.
окрихчування від хімічного складу корпусних сталей. Коротко викладено
основні досягнення діючих програм EURATOM та задачі наступного етапу
досліджень у рамках проекту SAFELIFE.
1. F. Sevini, L. Debarberis, K. Tuyrönen, and L. M. Davies, “The AMES
Netw ork strategy developments in the 5th EURATOM Framework
Program,” in: Proc. ICONE 9 Conf., Nice (2001).
2. F. Sevini, L. Debarberis, B. Acosta, et al., “Partnership projects on
embrittlement studies within the frame of the AMES European Network:
Results and prospects,” in: Proc. PLIM-PLEX’01 Conf., London (2001).
3. L. Debarberis, F. Sevini, B. Acosta, et al., “Results of embrittlement studies
on model alloys, reference steels and RPV materials at JRC-IE,” in: Proc.
PLIM-PLEX’01 Conf., London (2001).
4. L. Ballesteros, R. Andersen, L. Debarberis, et al., “Assessment of irradiation
conditions in WWER-440(213) RPV surveillance location,” in: Proc. 11th
Int. Symp. on Reactor Dosimetry, Brussels (2002).
5. F. Sevini, L. Debarberis, R. Gerard, and C. English, “The AMES network
towards the 6th Framework Program,” in: Proc. of the 7th Int. Conf. on
Material Science Problems in NPP Equipment Production and Operation,
St. Petersburg, Russia (2002).
Received 26. 05. 2003
60 ISSN 0556-171X. Проблеми прочности, 2004, № 1
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