Effectiveness of Ni-based diffusion barriers in preventing hard zone formation in ferritic steel joints

Anand, Ravi Shankar; Sudha, C.; Karthikeyan, T.; Terrance, A. L. E.; Saroja, S.; Vijayalakshmi, M.

doi:10.1007/s10853-008-3052-9

Cited by 30 publications

(17 citation statements)

References 13 publications

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“…Therefore, Ni-based transition weldments, i.e. the dissimilar welds with Ni-based weld metal (Ni WM) serving as diffusion barrier are frequently used for suppression of interstitial elements migration [27].…”

Section: Introductionmentioning

confidence: 99%

Hydrogen pre-charging effects on the notch tensile properties and fracture behaviour of heat-affected zones of thermally aged welds between T24 and T92 creep-resistant steels

Falat¹,

Čiripová²,

Homolová³

et al. 2016

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The effects of thermal exposure at 600• C and subsequent electrolytic hydrogen charging at ambient temperature were studied in terms of their influence on notch-tensile properties and fracture behaviour of individual heat-affected zones (HAZ) of Ni-based transition weldments between T24 and T92 creep-resistant steels. The experimental welded joints were prepared by gas tungsten arc welding using "Inconel-type" filler metal Nirod 600. Post-weld heat treatment (PWHT) was carried out at 720• C for 2 h, followed by passive cooling within tempering furnace. Subsequent long-term ageing of two series of prepared T24/T92 dissimilar welds at 600• C for 1000 and 5000 h, respectively, led to gradual changes in both T24 and T92 HAZ microstructures, which were mainly related to their additional tempering accompanied by the coarsening of original precipitates as well as newly-formed secondary phases. The observed thermally-induced microstructural changes together with subsequently applied hydrogen charging effects resulted in complex variations in tensile properties and fracture behaviour of individual HAZ regions related to the pre-existing differences in their initial tempering grade due to the used PWHT procedure. K e y w o r d s : creep-resistant steels, dissimilar welding, isothermal ageing, hydrogen embrittlement, mechanical properties, fracture mechanisms

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Section: Introductionmentioning

confidence: 99%

Hydrogen pre-charging effects on the notch tensile properties and fracture behaviour of heat-affected zones of thermally aged welds between T24 and T92 creep-resistant steels

Falat¹,

Čiripová²,

Homolová³

et al. 2016

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“…A number of modelling methods such as the Monte Carlo method, percolation model and fractal analysis have been carried out with the support of results from electron back-scattered diffraction (Karthikeyan et al, 2009). Size reduction of grains by 50% and DBTT reduction by 20°C could be achieved.…”

Section: Role Of Modelling In Development Of Nuclear Materialsmentioning

confidence: 99%

“…The finite difference method, Thermo-Calc, and DICTRA have been used (Anand et al, 2009) to study the mass transfer across dissimilar materials. The basic understanding of the process was based on molecular dynamics calculations which showed that sluggish diffusion of carbon in nickel compared to iron is responsible for prevention of formation of hard zone.…”

Section: Role Of Modelling In Development Of Nuclear Materialsmentioning

confidence: 99%

Materials Science & Technology: Research and Challenges in Nuclear Fission Power

Raja¹

2015

Proceedings of the Indian National Science Academy

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The performance and integrity of structural and functional materials are key issues in the safety and competitiveness of current and future nuclear fission reactors being developed for sustainable nuclear energy applications. The challenges towards development of nuclear structural materials arise due to the demanding hostile environments with respect to radiation, temperature, stress, etc., and requirements of total reliability and high performance over the long service life (say 60 years). A successful materials science research programme in nuclear industry has to take into account these challenges to improve the performance of materials and components in the emerging scenario of extending life of existing plants and realizing advanced reactors. In this study, material challenges associated with water reactors and fast breeder reactors (FBR) with focus on short-term and long-term strategies for materials development are considered. The materials in the existing and proposed future nuclear fission reactors are summarized along with a description of major material degradation mechanisms in different environments. The priority in the nuclear industry is to extend the life of reactors with robust safety features and sufficient cost-effectiveness, beyond forty to sixty years and from sixty to even one hundred years. The importance of modelling and developing predictive tools to estimate materials behaviour for effective computing of lifetime of nuclear reactor components is fast developing to cut down cost and time and also to enhance safety and confidence in existing and new systems. The future FBR technology relies heavily on advanced waste management and effective proliferation resistance. We review advanced reactor concepts of Generation IV forum and the new materials and technologies. Nuclear energy is not the right option for every country. Careful examination of the energy basket and commitment over a long period with effective mechanisms of safety governance is the key to make a decision to harness large amounts of nuclear energy. China, France, India, Russia, USA,UK, etc. are extremely committed to use large amounts of nuclear energy. Japan after the Fukushima accident, faces a challenge of public acceptance though the country has deep and rich expertise in nuclear technology and it is advantageous to produce low carbon power, on a sustained competitive basis from nuclear energy.

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“…Mo does not participate in the solute redistributions that take place. To better understand and mitigate the effect of hard and soft zones formation, a numerical procedure based on finite difference method has been used to simulate the zone formation during hightemperature exposure [10]. The possible different barrier materials were identified and confirmed by experiments [10].…”

Section: Hard Zone Formation In Dissimilar Weldments Of Cr-mo Steelsmentioning

confidence: 99%

“…To better understand and mitigate the effect of hard and soft zones formation, a numerical procedure based on finite difference method has been used to simulate the zone formation during hightemperature exposure [10]. The possible different barrier materials were identified and confirmed by experiments [10]. Similar calculations were extended to predict the thickness of carburised layer in an AISI 316LN exposed to sodium containing 25 ppm of carbon for 16,500 hours (Fig.…”

Section: Hard Zone Formation In Dissimilar Weldments Of Cr-mo Steelsmentioning

confidence: 99%

Development of cladding materials for sodium-cooled fast reactors in India

Raj

Divakar

Vijayalakshmi

2009

Trans Indian Inst Met

Self Cite

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Sodium-cooled fast reactors are an important component of India's move towards energy security. The Fast Breeder Test Reactor (FBTR) has been successfully operated for over 22 years, and the construction of a Prototype Fast Breeder Reactor (PFBR) has been taken up. Future development of Fast Reactor technology depends to a large extent on the economics, safety and waste management issues. The targets important for economics have been identified as reduction in capital costs, higher burn-up fuels, higher temperatures of operation, longer life and higher breeding ratios. These targets can be achieved with significant improvements in performance of materials, especially of Alloy D9 (15Cr-15Ni-0.2Ti), a titanium modified austenitic stainless steel, currently used for fuel cladding. Through research programmes implemented to improve the void swelling resistance of Alloy D9, it has been established that certain solute additions are essential in association with thermomechanical treatments for conferring swelling resistance. Research work conducted on refinement of Alloy D9 composition and thermomechanical treatments aimed at understanding irradiation effects, corrosion, mechanical properties and weldability at IGCAR Kalpakkam along with modelling studies for the prediction of weld behaviour is reported in the present paper. It is concluded that a significant rise in fuel burn-up can be achieved with the use of a new generation "InD9" alloy for fuel cladding. stages: pressurised heavy water reactors of the CANDU type; sodium-cooled fast reactors; thorium-based nuclear reactors. The vast thorium reserves in the country demand that the third stage that can make use of it be introduced as early as feasible. Design efforts on accelerator driven systems are being taken up to ensure in situ incineration of longlived fission products and production of fissile U 233 from fertile U 232 . At present, the transition from the fast test reactor stage where a 40 MW (thermal) was successfully operated for over 22 years, to a 500 MW(e) prototype reactor is being made. In India, fast reactors have a minimum power potential of 530 GW(e). This stage is crucial since it will provide the necessary experience and fuel for the third stage and beyond, with a power generation potential that is estimated to be in excess of 150 trillion watts. The chosen technology for this crucial 2 nd stage is sodium-cooled fast neutron spectrum reactors for generation of electricity.In order that the nuclear option is sustainable it is necessary that improved design targets be achieved: reduction in capital cost, high burn-up fuel, longer lifetime of the reactor, higher operating temperature and higher operating performance. Innovative approach is required to achieve these targets. Materials science, engineering and technology play a significant role when coupled with robust design, engineering development, instrumentation and control and robust safety approaches.Over the years, since the discovery of radioactivity, there has been a paradigm shift in the app...

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Effectiveness of Ni-based diffusion barriers in preventing hard zone formation in ferritic steel joints

Cited by 30 publications

References 13 publications

Hydrogen pre-charging effects on the notch tensile properties and fracture behaviour of heat-affected zones of thermally aged welds between T24 and T92 creep-resistant steels

Hydrogen pre-charging effects on the notch tensile properties and fracture behaviour of heat-affected zones of thermally aged welds between T24 and T92 creep-resistant steels

Materials Science & Technology: Research and Challenges in Nuclear Fission Power

Development of cladding materials for sodium-cooled fast reactors in India

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