bluuebunny/crossref_metadata_2025_split huggingface dataset:
State-of-the-Art of WPS in RPV PTS Analysis
Authors: Zarazovskii Maksym , Pištora Vladislav , Lauerova Dana , Obermeier Florian , Mora Mendez Diego Fernando , Dubyk Yaroslav , Bolinder Tobias , Cueto-Felgueroso Garcia Carlos , Szávai Szabolcs , Dudra Judit , Costa Garrido Oriol , Blain Christophe , Puustinen Markku , Katsuyama Jinya , Bass B. Richard , Williams Paul T. , Shugailo Oleksii 
Published: November 2022

Abstract
The APAL (Advanced Pressurized Thermal Shock (PTS) Analysis for Long-Term Operation (LTO)) project was launched in October 2020 for four years with funding from the European Union’s HORIZON 2020 program.
Within APAL, an extensive literature review was performed and experience with defining the state-of-the-art of the Warm Pre-Stress (WPS) effect, which has an impact on the reactor pressure vessel (RPV) brittle fracture margin in both deterministic and probabilistic terms, was collected. To gather the worldwide experience of the WPS approaches and models, a comprehensive questionnaire was developed followed by each APAL partner response. It mainly focused on the following aspects: collection of existing WPS approaches and models implemented in standards and rules for RPV brittle fracture assessment; identification of the WPS issues; collection and analysis of the existing experimental data.
The work presents a short description of the existing WPS national approaches and models along with standards or rules for RPV brittle fracture assessment under PTS events. Attention is focused on the applicability of WPS and its restrictions for constraint effect and crack arrest.
The second part of this work is devoted to the identification of the open issues connected to the practical WPS application in RPV integrity assessment together with the APAL partners’ views on this topic. The following problems are discussed:
- Overall view regarding including WPS in the RPV PTS assessment (applicability, benefit in practical applications);
- thermal-hydraulic aspects of a WPS approach (WPS benefits depending on the transient history);
- WPS and probabilistic RPV brittle fracture assessment (applicability);
- WPS and ductile fracture (applicability);
- WPS and residual stress (RS), (treatment of RS in regard to WPS effect).
The last part is dedicated to the analysis of experimental data for defining the WPS benefit. For this purpose, the Czech and Ukrainian experimental data (WWER materials), and the SMILE’s project data (heat-treated 17MoV8-4mod steel and 18MND5 steel) were analysed. The WPS effect on fracture toughness (FT) was evaluated using the ratio of enhanced FT KFrac (at re-load, after WPS) to FT of virgin material KIC (without pre-load), as obtained from the experimental data. It was shown, that relatively to the KIC,50% and KIC,95%, the WPS effect led to an increase of FT in 97.6% and 80.9% of cases respectively, which quantifies and confirms the benefit of WPS.
This work describes worldwide experience and best practice of the WPS and its application for the RPV integrity assessment. The paper’s conclusions are also focused on the recommendations for dealing with WPS issues.
Thermal Modeling of Hanford Lead Canister’s Heater Bench Tests
Authors: Suffield Sarah R. , Grant Christopher L. , Klymyshyn Nicholas A. 
Published: November 2022

Abstract
A computational fluid dynamics (CFD) model was built to simulate planned testing of heater assemblies for the Hanford Lead Canister (HLC) project. The HLC is a canister storage system that will contain heaters to simulate the decay heat of nuclear material and provide the canister storage system with environmental conditions equivalent to the operating conditions on a dry storage pad. The HLC will be equipped with long-term data collection and monitoring systems to provide an early warning of corrosion, pitting, cracking, or other signs of canister degradation that might threaten the integrity of the containment boundary over the potentially long term of dry storage. An important part of the HLC development is to confirm the function and ability of the electric heater assemblies that were specially designed to provide heating similar to the decay heat of nuclear material contained within the canister storage system. Heater bench testing is planned for early 2022 in a test configuration that does not include the canister. The goal of the bench testing is to verify that the heaters can replicate the decay heat of a canister with nuclear material and to validate the thermal models, which are critical to understanding the HLC’s thermal environment, including the local air flow within the canister storage system. Testing of the heater assemblies inside the canister system are planned in the future to validate canister level thermal models, and rigorous pre-deployment testing of the complete HLC cask and canister system is intended to be completed before the HLC is deployed in the 2025–2026 timeframe.
This study presents the pre-test temperature predictions of the bench testing. A description of the heater assemblies and planned bench testing is presented. The model was developed with the commercial CFD code STAR-CCM+. An uncertainty analysis was run with the CFD model to determine the uncertainty in the temperature predictions and provide a range over which the predicted temperatures are expected to vary. The uncertainty analysis was performed by coupling STAR-CCM+ with the software Dakota, which provides advanced parametric analyses, including quantification of margins and uncertainty with computational models. This work is expected to provide insight into SNF canister behavior1.
Determination of Johnson-Cook Fracture Strain Model for Austenitic Stainless Steel 304
Authors: Seo Jun-Min , Kim Hune-Tae , Kim Yun-Jae , Yamada Hiroyuki , Kumagai Tomohisa , Tokunaga Hayato , Miura Naoki 
Published: November 2022

Abstract
In this study, Johnson-Cook fracture strain model considering the effect of stress triaxiality and strain rate is determined for austenitic stainless steel 304. Tensile test data of four different stress triaxiality and six different strain rate conditions are used to determine the parameters in the J-C fracture strain model. To see the effect of local variation of stress triaxiality and strain rate in the specimen, the J-C fracture models are determined in two different ways. The first case uses the initial stress triaxiality and nominal strain rate, and the second case uses the average value of local stress triaxiality and strain rate obtained from finite element analysis. The use of initial stress triaxiality gives conservative estimate of fracture strain at low stress triaxiality, and non-conservative estimate at high stress triaxiality. The use of nominal strain rate gives overall conservative estimate of fracture strain.
Round Robin Analysis of Small Punch Testing on 15Kh2NMFA Reference Material
Authors: Welschen Romy , Gillemot Ferenc , Simonovski Igor , Martin Oliver , Adamech Marek , Petzova Jana , Hernandez Rebeca , Kopriva Radim , Naziris Frederiki , Molenaar Boy , Kolluri Murthy 
Published: November 2022

Abstract
Miniature / sub-sized specimen test methods for the mechanical characterization of metallic alloys like the small punch test (SPT) have the benefit that only small quantities of material are needed to perform a reasonable number of tests. This makes such tests in particular interesting if only limited quantities of material are available for mechanical characterization, like irradiated specimens from reactor pressure vessel (RPV) surveillance programs of light water reactors (LWRs). The SPT only requires small discs of 8mm diameter and 0.5mm thickness and such specimens can be manufactured from broken Charpy impact test specimens that were previously tested within RPV surveillance programs. With the publication of EN 10371 earlier in 2021 the SPT is now a standardized test that can be used in principle to determine tensile, creep, fracture toughness properties and ductile-to-brittle transition temperatures (DBTTs). However, fabrication and testing of irradiated SPT specimens remotely in hot cell environments has several practical challenges. Any deviation in specification as laid down in the standard can lead to variations in test outcome. To address this issue an SPT Round Robin exercise on VVER RPV steel 15Kh2NMFA reference material has been performed in the context of the Horizon 2020 Euratom project STRUMAT-LTO. Several research organizations, namely NRG, EK/CER, JRC, VUJE, CIEMAT and UJV, have participated in this round robin exercise to validate sample manufacturing, test procedures and test equipment and to determine tensile properties and DBTTs of the above RPV steel. In this paper results and conclusions of the STRUMAT-LTO SPT round robin exercise are presented.
Technical Background for the Update and Extension of the Time-Dependent Allowable Stresses of Type 304H and 316H Stainless Steels
Authors: Sham Ting-Leung , McMurtrey Michael 
Published: November 2022

Abstract
Type 304H and 316H stainless steels are codified in the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code for Section III, Division 5, Class A construction for up to 1500°F (816°C) and 300,000 hours. The extension of design lifetimes to 500,000 hours has been undertaken by various research projects and by the ASME Section III, Division 5 Code Committees. Due to a long-standing issue related to non-classical creep behavior on the use of the time to the onset of tertiary creep as one of the time-dependent allowable stress criteria, little progress was made in the extension of the time-dependent allowable stresses for Type 304H and 316H stainless steels. A recent effort by Dabrow and Nestell (Impact of Tertiary Creep on Time Dependent Allowable Stresses for Type 304H and 316H Stainless Steels, Report 0300-0003-RPT-001, MPR Associates, Alexandria, VA, 2020) has provided a rational method for the treatment of the highly variable data for the time to onset of tertiary creep. This paper presents the background formulas for determining the time-dependent allowable stress values of Type 304H and 316H stainless steels, as assembled from relevant project work. These updates and extensions are being recommended to the ASME Section III Code committees for approval and are subject to change upon feedback from those committees.
Electric-Field-Assisted Diffusion Welding to Fabricate Alloy 617 Compact Heat Exchangers
Authors: Zhang Xinchang , Rupp Ryann E. , Rufner Jorgen F. , McMurtrey Michael D. 
Published: November 2022

Abstract
Compact heat exchangers are of interest for a number of applications including advanced reactors. Alloy 617 is one of the top candidate materials for the gas-cooled reactor intermediate heat exchanger. Previous endeavors to diffusion weld Alloy 617 utilized hot pressing (HP). It was reported that grain boundary migration across the interface was hindered by extensive precipitation. Bonds of this nature have been observed to reduce the elevated-temperature mechanical properties compared to the wrought-product form. It was hypothesized that the electric current applied during electric-field-assisted sintering (EFAS) can overcome these challenges, resulting in improved diffusion welding (DW). This study investigated DW of Alloy 617 via EFAS. Stacks composed of three sheets that were 20 mm in diameter were welded using EFAS. Specimens were welded with an applied electric current, a pressure of 30 MPa, hold time of 30 min, and temperatures of 1050°C, 1100°C, and 1150°C. DW using HP as the zero-current analog of EFAS was also performed at the most promising EFAS conditions. Results revealed that both the applied electric current and temperature played a key role in precipitation and grain boundary migration in diffusion-welded Alloy 617. Precipitates were observed at the interface of the hot-pressed samples which limited grain boundary migration. Electric current was found to prevent precipitate formation along the interface at 1150°C. The electric current coupled with a temperature of 1150°C during EFAS resulted in significant grain boundary migration across the interface.
On the Use of Artificial Neural Network Technique for Seismic Fragility Analysis of a Three-Dimensional Industrial Frame
Authors: Quinci Gianluca , Phan Nam Hoang , Paolacci Fabrizio 
Published: November 2022

Abstract
Fragility function that defines the probability of exceedance of a damage state given a ground motion intensity (IM) is an essential ingredient of modern approaches to seismic engineering as the performance-based earthquake engineering methodology. Epistemic as well as aleatory uncertainties associated with seismic loads and structural behavior are usually taken into account to analytically develop such curves. However, structural analyses are time-consuming, requiring generally a high computational effort. Moreover, the conditional probability of failure is usually computed by regression analysis assuming predefined probability functions, like the log-normal distribution, without prior information on the real probability distribution. To overcome these problems, the artificial neural network (ANN) technique is used for the development of structural seismic fragility curves considering record-to-record variability and structural parameter uncertainties. In this respect, the following aspects are addressed in this paper: (a) implementation of an efficient algorithm to select IMs as inputs for ANN, selecting the most relevant ones; (b) derivation of surrogate models by using the ANN technique, c) computation of fragility curves with Monte Carlo Simulations method and verification of the validity. These methods enable the implicit treatment of uncertainty in either or both of ground motion intensity and structural properties without making any prior assumption about the probability function. This methodology is then applied to estimate the probability of failure of a non-structural component (NSC), i.e., vertical tank, located on a typical three-dimensional industrial frame. First, an extensive sensitivity analysis on the ANN input parameters is performed (feature selection), identifying the type and number of seismic intensity measures (amplitude-based, frequency-based, and time-based IM). Then different surrogate models are derived investigating the number of hidden layers and parameters. A multiple stripe analysis is then performed on a nonlinear model of the structure, deriving the set of data for the ANN. Different training and test subsets are used to derive the surrogate model. Finally, a Monte Carlo simulation is performed to derive the fragility curves for the limit state considered. Finally, the risk assessment is obtained, evaluating the mean annual rate of failure of the NSC.
Research on X-Ray Digital Imaging Inspection Method of Carbon Fiber Wrapped Cylinder With Aluminum Liner for Vehicle
Authors: Gao Zhaojiang , Chai Sen , Wang Qian , Huang Liang , Li Xiang , Deng Guide 
Published: November 2022

Abstract
The fully-wrapped carbon fiber reinforced cylinders with an aluminum liner are currently the most common high-pressure hydrogen storage tank for vehicles. However, it is difficult to detect it by traditional detection methods effectively. X-ray digital radiographic inspection technology is currently a feasible way to detect the typical defects of the winding layer and aluminum liner of the fully-wrapped carbon fiber reinforced cylinders with an aluminum liner for vehicles. In order to verify the detection ability of digital radiographic inspection for the main defects of carbon fiber wound gas cylinders with aluminum liner and to provide quantitative data of the detection ability, this paper aims at the fiber layer fracture, scratches, and pores that may occur during the use and manufacture of gas cylinders. In order to simulate the above-mentioned natural defects, the images of artificial defects were taken through the optimized transillumination parameters. The test results show that the digital radiographic inspection method can detect the axial notches, circumferential notches, oblique notches with a depth of 0.2 mm on the fiber layer, and axial and circumferential notches with a depth of 0.2 mm on the liner. Furthermore, it can also detect artificial defects such as 0.5mm fiber layer flat-bottom hole and 0.2mm depth /Φ1mm aluminum liner flat-bottom hole. This proves that digital radiographic inspection can be used for the early stage of a significant failure of the fully-wrapped carbon fiber reinforced cylinders with an aluminum liner and provides strong support for its safe use.
Fiber-Optic Sensing for Seating Stress Quantification in Semi-Metallic Gaskets
Authors: Cloostermans Ben , Pronk Dick , Bruckenburg Björn , Geernaert Thomas 
Published: November 2022

Abstract
Modern sealing components are essential in today’s industry. The recent global focus on environment, sustainability and safety is encouraging gasket manufacturers to innovate and think of the gasket of tomorrow. Not only are performance expectations increasing rapidly, but advancements in gasket manufacturing and material technologies are producing gaskets that — in both theory and practice — generate tighter seals and reduce harmful emissions. The major impediment to attaining these results in the field is the lack of advancement in assembly accuracy and real-time monitoring of gasket stress. Currently the user relies on industrial calculation standards that are designed to determine the required bolt load to maintain a leak free seal over the required timeframe. Such calculations often yield a proper approximation of the situation, but they inherently rely on simplifications and assumptions. Furthermore, the correct execution of installation protocols is difficult to verify. The state-of-play does not allow in-situ measurements of the seating stress in the gasket. This study addresses state-of-the-art shortcomings in bolted flange connections and proposes a solution to mitigate them by means of sensors. We successfully integrate optical fiber sensors inside semi-metallic gaskets and experimentally demonstrate the direct measurement of seating stress. Such in-situ seating stress quantification enables installation and condition monitoring serving an optimal lifecycle prediction and failure prevention. As such, this approach contributes to increased sustainability of bolted flange connections.
Investigating the Role of Ferritic Steel Microstructure and Strength in Fracture Resistance in High-Pressure Hydrogen Gas
Authors: Ronevich Joseph A. , Kagay Brian , San Marchi Chris , Wang Yiyu (Jason) , Feng Zhili , Wang Yanli , Findley Kip 
Published: November 2022

Abstract
Despite their susceptibility to hydrogen-assisted fracture, ferritic steels make up a large portion of the hydrogen infrastructure. It is impractical and too costly to build large scale components such as pipelines and pressure vessels out of more hydrogen-resistant materials such as austenitic stainless steels. Therefore, it is necessary to understand the fracture behavior of ferritic steels in high-pressure hydrogen environments to manage design margins and reduce costs. Quenched and tempered (Q&T) martensite is the predominant microstructure of high-pressure hydrogen pressure vessels, and higher strength grades of this steel type are more susceptible to hydrogen degradation than lower strength grades. In this study, a single heat of 4340 alloy was heat treated to develop alternative microstructures for evaluation of fracture resistance in hydrogen gas. Fracture tests of several microstructures, such as lower bainite and upper bainite with similar strength to the baseline Q&T martensite, were tested at 21 and 105 MPa H2. Despite a higher MnS inclusion content in the tested 4340 alloy which reduced the fracture toughness in air, the fracture behavior in hydrogen gas fit a similar trend to other previously tested Q&T martensitic steels. The lower bainite microstructure performed similar to the Q&T martensite, whereas the upper bainite microstructure performed slightly worse. In this paper, we extend the range of high-strength microstructures evaluated for hydrogen-assisted fracture beyond conventional Q&T martensitic steels.
Development of Generic Unirradiated Values of T0 and RTTo for Use in ASME Code Applications
Authors: Erickson Marjorie , Kirk Mark , Long Elliot J. 
Published: November 2022

Abstract
A companion paper presented at this conference summarizes a recently published EPRI report that provides a Technical Basis for Code Case N-914, “Accounting for the Effect of Embrittlement on Fracture Toughness Properties Used in Evaluations of Pressure Boundary Materials in Class 1 Ferritic Steel Components, Section XI, Division 1.” CC N-914 is being developed by the Section XI Working Group on Operating Plant Criteria to provide a consistent and comprehensive methodology to account for embrittlement, including the effects of uncertainty, for both conventional Code applications that use RTNDT as an index temperature as well as newer methodologies that adopt the Master Curve based reference temperatures T0 or RTTo. At least in the United States it has become common practice to sometimes use “generic” values of unirradiated RTNDT that have been established as mean values for a class of materials (e.g., a weld made from a particular weld wire heat, a plate made to a certain ASTM specification, etc.) along with an associated uncertainty term in situations where a plant/material specific RTNDT value is not available. The objective of this paper is to describe a methodology that can be used to establish similar generic unirradiated values for RTTo and T0 using data published in the open literature. Such values provide a low-cost point of entry for use of Master Curve techniques such as those now in the Code itself and in various Code Cases (e.g., CC N-830-1, proposed CC N-914). Generic values may provide relief from excessively conservative RTNDT estimates while plant-specific Master Curve data is being developed.
Low Cycle Fatigue Behavior and Failure Probability of Elbow Pipes Based on High Acceleration Vibration Test
Authors: Shimazu Ryuya , Sakai Michiya , Ono Yohei 
Published: November 2022

Abstract
For the seismic fragility assessment of piping systems in a nuclear power plant, the failure probability of piping systems is calculated elastically under the assumption that ductile rupture occurs. However, some previous studies have reported that the primary failure mode of piping systems is fatigue. There exists a possibility that the result of the fragility assessment that assumed ductile rupture may have included some safety margins. In fragility assessments, it is important to accurately recognize the actual capacity and uncertainty by eliminating the safety margins considered in the design. In this study, to conduct a fragility assessment considering elastic-plastic behavior under the assumption that fatigue failure occurs, the low cycle fatigue behavior of elbow pipes was obtained via high acceleration vibration and static loading tests. The analysis model of the tests was developed for the evaluation of the fatigue failure probability of the elbow pipe. The linear cumulative damage of the specimen at the initiation of the fatigue crack was calculated. The equivalent strain amplitude was calculated, and the test results were plotted on the fatigue curve. Then, the failure probability of elbow pipes was evaluated by using the analysis model under the assumption that the vibration test results produced the median strength value. This evaluation result was compared with the case in which the value obtained from the conventional fatigue diagram was used as the median strength.