Use of Large Databases to Identify Trends in the Behavior of Ferritic Steels

EricksonKirk, Mark T.; EricksonKirk, MarjorieAnn; Rose, Charles W.; Zhang, Xian J.

doi:10.1115/pvp2009-77788

Cited by 2 publications

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“…Another determines the reference temperature of the master curve of Charpy absorbed energy. Although this method does not determine the temperature dependence of fracture toughness, the reference temperature of Charpy absorbed energy is almost of the same value as T 0 obtained from fracture toughness tests [161,162]. Further studies are needed to assess the applicability of these methods to fracture toughness evaluation of RPVs.…”

Section: Fracture Toughnessmentioning

confidence: 99%

Current understanding of radiation-induced degradation in light water reactor structural materials

Fukuya¹

2013

Journal of Nuclear Science and Technology

155

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Current phenomenological knowledge and understanding of mechanisms are reviewed for radiation embrittlement of reactor pressure vessel low alloy steels and irradiation assisted stress corrosion cracking of core internals of stainless steels. Accumulated test data of irradiated materials in light water reactors and microscopic analyses by using state-of-the-art techniques such as a three-dimensional atom probe and electron backscatter diffraction have significantly increased knowledge about microstructural features. Characteristics of solute clusters and deformation microstructures and their contributions to macroscopic material property changes have been clarified to a large extent, which provide keys to understand in the degradation mechanisms. However, there are still fundamental research issues that merit study for long-term operation of reactors that requires reliable quantitative prediction of radiation-induced degradation of component materials in low-dose rate high-dose conditions.

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Section: Fracture Toughnessmentioning

confidence: 99%

Current understanding of radiation-induced degradation in light water reactor structural materials

Fukuya¹

2013

Journal of Nuclear Science and Technology

155

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“…The above-described procedure assesses the fast (brittle) fracture of RPV. For the "upper-shelf region", where ductile failure takes place, the analogous approach called "Master Curve for upper-shelf", as described in [6], and [7], was used.…”

Section: Determination Of the Total Conditional Probability Of Fast Fmentioning

confidence: 99%

Probabilistic assessment of pressurised thermal shocks

Pistora

Pošta

Lauerová

2014

Nuclear Engineering and Design

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Rector pressure vessel (RPV) is a key component of all PWR and VVER nuclear power plants (NPPs). Assuring its integrity is therefore of high importance. Due to high neutron fluence the RPV material is embrittled during NPP operation. The embrittled RPV may undergo severe loading during potential events of the type of pressurised thermal shock (PTS), possibly occurring in the NPP. The resistance of RPV against fast fracture has to be proven by comprehensive analyses. In most countries (with exception of the USA), proving RPV integrity is based on the deterministic PTS assessment. In the USA, the "screening criteria" for maximum allowable embrittlement of RPV material, which form part of the USA regulations, are based on the probabilistic PTS assessment. In other countries, probabilistic PTS assessment is performed only at research level or as supplementary to the deterministic PTS assessment for individual RPVs. In this paper, description of complete probabilistic PTS assessment for a VVER 1000 RPV is presented, in particular, both the methodology and the results are attached. The methodology corresponds to the Unified Procedure for Lifetime Assessment of Components and Piping in WWER NPPs, "VERLIFE", Version 2008. The main parameters entering the analysis, which are treated as statistical distributions, are as follows:-initial value of material reference temperature T 0 ,-reference temperature shift ∆T 0 due to neutron fluence,-neutron fluence,-size, shape, position and density of cracks in the RPV wall,-fracture toughness of RPV material (Master Curve concept is used). The first step of the analysis consists in selection of sequences potentially leading to PTS, their grouping, establishing their frequencies, and selecting of representative scenarios within all groups. Modified PSA model is used for this purpose. The second step consists in thermal hydraulic analyses of the representative scenarios, with the goal to prepare input data for the structural analyses (pressure and temperature variations in the reactor downcomer). The third step consists in performing structural analyses, covering (deterministic) temperature and stress fields calculations for all representative scenarios, and finally, probabilistic fracture mechanics analyses. The results of the third step analyses are conditional probabilities of initiation of fast fracture for all selected representative scenarios. Combining them with frequencies of all groups, the final value of (unconditional) frequency of initiation of fast fracture of the RPV is established. In this paper, examples of both input data and the results are presented.

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Use of Large Databases to Identify Trends in the Behavior of Ferritic Steels

Cited by 2 publications

References 0 publications

Current understanding of radiation-induced degradation in light water reactor structural materials

Current understanding of radiation-induced degradation in light water reactor structural materials

Probabilistic assessment of pressurised thermal shocks

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