bluuebunny/crossref_metadata_2025_split huggingface dataset:
Study on the Off-Site Consequence Evaluation of NPP Severe Accident Based on JRODOS Platform
Authors: Wang Xuan , Guo Li , Lin Xiujing , Pu Xiang , Du Fenglei , Huang Xiaodong , Xiong Xiaowei , Wang Bo 
Published: October 2021

Abstract
JRODOS (Java Real-time On-line Decision Support) is currently being developed by the German KIT company and promoted globally. Because of its good user visual interface and efficient calculation and analysis functions, it has been widely used in nuclear power plants accident consequences assessment. In this paper, the MVK data set is used to verify the simulation accuracy of the RIMPUFF atmospheric dispersion model in the JRODOS system. The verification conclusion shows that the calculation results of RIMPUFF are significantly better than other calculation models. This paper presents a case study of CAP1400 severe accidents consequence assessment in one nuclear power plant base on the JRODOS platform, the IC severe accident (SA) was chosen to give an example for the rapid assessment of nuclear accidents. The research in this paper shows that for the CAP1400 nuclear SA, the I-132, I-135, I-133 and I-131 are the main radionuclide. Under the selected typhoon weather conditions in this paper, the maximum dose rate within 48 hours is only 1.79E−03mSv/h, the maximum individual dose is only 3.06mSv, the impact area is generally within 6km downwind. Under the selected typhoon weather conditions, the plume can basically reach the monitoring point in the downwind direction within 1h, while for other monitoring points, it will take 17h to reach the points, this is mainly affected by the wind direction. The research results of this paper can be used for rapid assessment of nuclear accidents in nuclear power plants and formation of evaluation manuals, which can better guide emergency or conventional emergency drills.
Failure Assessment of Gas Pipeline Based on Fuzzy Bayesian Network and AHP
Authors: Yu Qiaoyan , Hou Lei , Li Yanhao , Cai Chong 
Published: October 2021

Abstract
The long-distance pipeline is the crucial connection for gas producing area and demand location. It may be damaged due to the impact of various factors, resulting in the leakage of gas. Reliable failure assessment can avoid the occurrence of pipeline leakage and reduce losses effectively. Because of the lack of pipeline historical data and the impact of various uncertainties, this paper adopts the fuzzy Bayesian network (BN) and analytical hierarchy process (AHP) method with expert heuristic to analyze the probability of gas pipeline failure. In the proposed model, an AHP is developed to identify the factors affecting pipeline failure by literature, database and expert questionnaire. Their prior probabilities and conditional probabilities are analyzed with expert opinion and fuzzy theory in the absence of historical data. By using the prediction and diagnosis techniques of BN, the failure probability of gas pipeline is achieved and the critical events are identified. The model is applied to an underwater natural gas pipeline to prove the feasibility and rationality of the model. The results indicate that the proposed model can provide guidance to pipeline managers for the safety of gas pipelines and a technical guide for decision makers with pipeline failure.
Development and Implementation of an In-Situ Repair Method for ISFSI Canisters
Authors: Williams Allen , Johnson Kyle , Beard Jamie , Canfield Stephen , Stephenson Jerry 
Published: October 2021

Abstract
A remote, robotic method of mitigating damage to an Independent Spent Fuel Storage Installation (ISFSI) canister has been developed and tested. It is currently ready for implementation if required for a vertical canister system and will be ready for implementation in 2020 for a horizontal canister system. The development was in response to State of California directives to be ready and able to implement a canister repair technology if needed at San Onofre Nuclear Generating Station.
The method was developed by miniaturizing existing cold spray technology and combining it with robotics previously used on site. The Metallic Overlay method (also known as ‘Cold Spray’) has been tested and accepted for use at San Onofre.
The testing involved the miniaturization of the Metallic Overlay Equipment, testing of several metals which were considered for use, the decision process for the down-selecting of the chosen material, the combining of mitigation tooling and robotics, and the final testing and qualification of the process. This paper will also discuss the details needed to implement on site.
This paper will focus on the development, testing and implementation of the miniature robotic platform and the metallic overlay equipment/process. The background leading to the development of the overlay process will be provided, and will note the tie to (in development) Code Case N-860[1], which would indicate the conditions that would occur to direct the site towards implementation of the metallic overlay process.
The process has been developed in advance of a specific need. It is a proactive action intended to allow efficient response in the event mitigation is required at San Onofre.
Welding Tube to Tubesheet Joints for Corrosion Resisting Applications
Authors: Sippy Haresh K. 
Published: October 2021

Abstract
The work in this paper relates to an improved tube to tubesheet joint in a shell and tube type heat exchanger that have dissimilar metallurgies of tube and tubesheet. This improved tube to tubesheet joint configuration will not only impart reliability and strength to the mechanical integrity of the joint but also reduce the costs of the manufacturing without compromising the functional performance of the exchanger. In a shell and tube heat exchanger, generally the material of tubes may be similar to the tubesheet or of a higher corrosion resistant grade in comparison to that of the tubesheet. Conventionally, shell and tube heat exchangers that involve dissimilar materials of tube and tubesheet are either:
i. Tubes welded directly to the tubesheet with matching grade weld metal
or
ii. The tubesheets are clad / weld overlaid with the higher corrosion resistant material or material similar to the tube material
For purpose of this study, we have considered the material of tube as stainless steel type 304L and that of tubesheet as carbon steel.
The above case 1 wherein the SS-304L tubes are directly welded to the CS tubesheet, may have the following advantages:
i. Manufacturing time is less.
ii. Tubes are attached to the base metal and hence free from defects of weld overlay or cladding, if any.
In case 2, wherein the SS-304L tubes are welded to the SS-304L clad / weld overlaid portion of tubesheet, the advantages are:
i. Welding takes place between two austenitic stainless steel grades, hence PWHT is not required.
ii. The tube to tubesheet joint and adjacent material is of austenitic stainless steel grade, hence has better corrosion resistance.
The main objective of the work done and reported in this paper is to combine the advantages of the above two cases thereby:
i. Reducing the cost of manufacturing
ii. Increasing the mechanical reliability of the tube to tubesheet joint.
Extensive trials were carried out on sample tube to tube sheet joints, the results and conclusions of which are reported in this paper.
A Discussion of Strength Reduction Factor Development for Thermal Aging Effect on Nuclear Structural Alloys
Authors: Ren Weiju 
Published: October 2021

Abstract
In consideration of structural alloy property deterioration during long-term exposure to elevated temperatures, the yield and ultimate tensile strength reduction factors are provided in the Boiler and Pressure Vessel Code Section III for nuclear reactor component design and operation analysis. Because the Gen IV reactor requirement of 40 ∼ 60 years of service life makes it difficult to acquire such long exposure test data for developing the reduction factors, they must be derived from test data with relatively short exposure by predictive methods considered to be reasonably reliable. A novel approach with a physically-based model has recently been proposed for application to development of reduction factors for 9Cr-1Mo-V. In the model, contributors to the tensile strength are first identified and related to definite microstructural features of the alloy, then some physically-based methods are employed to simulate the microstructural evolution, and finally the model is assembled with test-data-calibrated parameters to generate the yield and ultimate tensile strength reduction factors covering elevated temperature exposure for up to 57 years. The approach is undoubtedly a trailblazing development that will, if proven reliable, lead to a paradigm shift in predicting thermal aging behavior of many other alloys. Its debut application to Section III, however, concerns nuclear safety and naturally warrants objective, impartial, and thorough technical scrutiny. In the present paper, the novel and conventional approaches are discussed. Necessary improvements to the novel approach are recommended for its application to nuclear structural component design and analysis, and for its potential expanded use to other alloys.
Vibration Transmission Characteristics of Periodic Composite Pipeline Considering Friction Coupling Effect
Authors: Zeng Qingna , Wang Donghui , Zang Fenggang , Zhang Yixiong 
Published: October 2021

Abstract
In this paper, transmission characteristic of periodic composite pipeline is investigated for axial vibration, focusing on friction coupling effect. A novel transfer matrix method is developed to calculate band gap structures (BGs) with the consideration of different forms of viscous friction. Frequency response function for finite periods is obtained and shows good consistency with BGs for infinite periods. The energy dissipation caused by viscous friction exists in the entire frequency range, as friction coupling is always distributed along the pipe element. Meanwhile, the attenuation intensity is relatively small compared with that induced by Bragg scattering mechanism. Therefore, viscous friction is not affecting the overall trend of BGs, only exhibiting certain attenuation in pass band frequency range. The effect of kinematic viscous coefficients on axial BGs are systematically examined in different friction models. Attenuation intensity goes up with increasing kinematic viscous coefficients, in addition, energy dissipation caused by frequency dependent friction model is generally higher than that of steady state friction condition. Moreover, frictional dissipation shows more sensitivity to high frequency. The research in this paper enriches fluid structure interaction theory of pipe element, which is also expected to be helpful in controlling the dynamical behaviors of pipeline system conveying fluid.
Constraint Effect on Fracture in Ductile-Brittle Transition Temperature Region
Authors: Hojo Kiminobu , Hirota Takatoshi , Nagoshi Yasuto , Fukahori Takuya , Sakima Kimihisa , Ohata Mitsuru , Minami Fumiyoshi 
Published: October 2021

Abstract
Bend fracture tests using flat plate specimens of 50mm thickness with a surface crack, 1TC(T), and SE(B) specimens of low alloy steel were performed in the ductile-brittle transition temperature (DBTT) region. Two types of SE(B) specimen, a/W = 0.1 and 0.5, were used. The fracture tests were conducted at −120°C and −80°C aiming at fracture mode of complete cleavage fracture at lower temperature and cleavage fracture after ductile crack growth at higher temperature. At −120°C, all specimens showed complete cleavage fracture. The shape factor of the Beremin model of the C(T) specimen or SE(B) specimen with a deep crack were determined by using each type of specimen at −80°C. Also, Toughness Scaling Model (TSM) was applied for determination of the Weibull parameters using two types of SE(B) specimens at −80°C. The GTN parameters were determined from fracture data of 1TC(T) specimen at the room temperature. The prediction analyses of the flat plate specimens for −120°C and −80°C were carried out using the Beremin model and the coupled model with the GTN model. The measured KJ of the tests for the flat plates were compared with the predicted KJ of 5% lower bound curve and 95% upper bound for the flat plate specimen which were deduced by the SE(B) specimen’s test data. Transferability from the test results of laboratory test specimens to that of a large specimen with low constraint, which was similar to the actual structure, was investigated. The temperature independency of the Weibull parameter m of the Beremin model was also confirmed.
Causal Relationship Extraction of LNG Unloading System Under Abnormal Conditions Based on Bidirectional LSTM Network
Authors: Xu Kangkai , Hu Jinqiu , Dong Shaohua , Feng Lingan 
Published: October 2021

Abstract
LNG unloading system plays an important role in the transport and storage medium of the process. Once the unloading system occurs exceptions, such as pressure fluctuations, uneven pre-cooling and unexpected temperature rises, these phenomena will affect the safe operation of LNG terminals. In the process of LNG unloading, there is a coupling relationship between the changing of pressure, flow rate, temperature and other parameters. The accurate cause and development direction of abnormal working conditions are conducive to the safe operation and maintenance of the unloading system. According to the accident statistics of 38 LNG receiving stations and peak shaving stations by The LNG International Importer’s Group (GIIGNL), the accident rate of the unloading system was 27%. Therefore, the realization of the extraction and identification of the causality of abnormal working conditions of the LNG unloading system has great significance for the traceability and early warning of the accident.
As a crucial type of relationship, causality plays a key role in many fields such as relational reasoning and so on. Therefore, extracting causality is a basic task in text mining. At present, in China, the analysis of abnormal working conditions of LNG unloading system adopts the methods of HAZOP and FMEA, and a large amount of causality is contained in the text data. To solve the problem of automatically extracting the causality of the LNG unloading system text data, this paper adopts the method of sequence labeling to extract the causal relationship entity and determine its direction. Sequence to sequence (Seq2Seq) architecture and bidirectional long short memory network (Bi-LSTM) are used to train input word vectors and predict the development of causal relationship. In order to solve the problem of unclear objects and inaccurate predictions caused by redundant causal nodes, attention mechanism is applied, and the prediction accuracy reaches 95.23%. In the sensitivity analysis, the recall rate and the granularity of causal relationship information perform well, which indicates that the algorithm has generalization and applicability in the establishment of the causal knowledge base of abnormal conditions in the unloading system.
Interlaboratory Study of All-Weld-Metal Strip Tensile Testing of Narrow Groove Pipeline Girth Welds
Authors: Park Dong-Yeob , Gravel Jean-Philippe , Xu Su , Gianetto James A. , Crapps Justin M. , Lazor Robert , Quintana Marie A. 
Published: October 2021

Abstract
The informative section of AWS B4.0-Annex D offers a recommended practice for all-weld-metal tensile testing of narrow groove pipeline girth welds, sampling a higher proportion of weld metal than is possible with more traditional testing practices. An interlaboratory study (ILS) program was conducted to examine the applicability and practicability of AWS B4.0-Annex D. Program participants represented a broad range of interests across industry, government, and academia. Precision statistics of the test method were assessed according to ASTM E691 and E177. This paper includes results of the assessments. The results from the ILS demonstrate that AWS B4.0-Annex D is repeatable and reproducible for determination of tensile properties of narrow groove pipeline girth welds.
Development of Guideline on Seismic Fragility Evaluation for Aged Piping
Authors: Yamaguchi Yoshihito , Katsuyama Jinya , Masaki Koichi , Li Yinsheng 
Published: October 2021

Abstract
The seismic probabilistic risk assessment is an important methodology to evaluate the seismic safety of nuclear power plants. In this assessment, the core damage frequency is evaluated from the seismic hazard, seismic fragilities, and accident sequence. Regarding the seismic fragility evaluation, the probabilistic fracture mechanics can be applied as a useful evaluation technique for aged piping systems with crack or wall thinning due to the age-related degradation mechanisms. In this study, to advance seismic probabilistic risk assessment methodology of nuclear power plants that have been in operation for a long time, a guideline on the seismic fragility evaluation of the typical aged piping systems of nuclear power plants has been developed considering the age-related degradation mechanisms. This paper provides an outline of the guideline and several examples of seismic fragility evaluation based on the guideline and utilizing the probabilistic fracture mechanics analysis code.
Effects of a Single Overload on Fatigue Crack Growth of Type 316 Stainless Steel
Authors: Miyoshi Koji , Kamaya Masayuki 
Published: October 2021

Abstract
The effect of a single overload on the fatigue crack growth rate was investigated for Type 316 stainless steel. Fatigue crack growth tests were conducted by controlling strain and load. Tensile and compressive overloads were applied during constant amplitude cycling. The overload ratio, which was defined as the ratio of overload size to baseline constant amplitude, was also changed. The constant amplitude tests were conducted at the strain or the stress ratio of −1.0 which was defined as the ratio of the minimum value to the maximum value. The crack opening point was obtained by the unloading elastic compliance method. The crack growth rate increased after the single compressive overload. The accelerating rate increased with the overload ratio. In contrast, not only the acceleration but also the retardation of the crack growth rate was observed for some tensile overload cases. The crack growth rate increased for relatively small tensile overload cases and decreased for relatively large tensile overload cases. The change in the crack opening level was examined. The crack growth rates after tensile and compressive single overloads correlated with the effective strain and stress intensity factor ranges both for load and strain controlling modes.
Explosive Testing of High-Pressure Vessel for Proton Imaging of Shock Physics Experiments
Authors: Spernjak Dusan , Cardon Devin , Scarafiotti Jesse , Biel Morgan , Gibson Joshem , Fehlmann Kevin , Lakey Matthew , Romero Christopher , Bustos Gerald , Marr-Lyon Mark , Llobet Anna 
Published: October 2021

Abstract
We present the results of explosive testing of an Inner Pressure Confinement Vessel (IPCV). The IPCV is explosively-loaded high-pressure vessel which is a part of the containment system to facilitate proton imaging of small-scale shock physics experiments at Los Alamos National Laboratory (LANL). The detonation of high explosive (HE) drives material to extreme loading conditions, which are imaged using a proton beam and an imaging system. The IPCV needs to satisfy the ASME Boiler and Pressure Vessel Code, Section VIII, Division 3, Code Case 2564, while allowing for maximum resolution of proton radiography.
The IPCV contains an Experimental Physics Package (EPP), fragment mitigation assembly, and radiographic windows. To achieve the optimal imaging resolution, the radiographic windows need to be very thin, located extremely close to the HE, and made of low-attenuating material such as Beryllium. While the IPCV is designed to a relatively small HE amount of 30 g TNT equivalent, the radiographic window is located only a few cm away from the HE, which is unique to this specialized high-pressure vessel. Fragment mitigation is critical to protecting radiographic windows from any fragments to allow the IPCV to maintain the pressure boundary before and after the explosive experiment. This shielding contains two layers: Boron carbide (B4C) facing the HE and Dyneema (cross plied composite layers made of ultra-high molecular weight polyethylene) facing the window. The B4C plate serves to break up and dull fragments while Dyneema catches fragments and prevents them from contacting the radiographic windows. Design development of the fragment mitigation assembly and attachment was informed by several series of explosive tests at LANL. The tests also addressed the sealing function of vessel covers, gas lines, and isolation valves before and after an explosive experiment.
Microstructure Control and Optimization of Centrifugal Casting Furnace Tube HP40 Alloys Based on Cafe Model
Authors: Xiang S. L. , Chen T. , Fan Z. C. , Lian X. M. , Chen X. D. 
Published: October 2021

Abstract
With the development of Materials Genome Initiative (MGI), Integrated Computational Materials Engineering (ICME) has emerged as an important tool in the research of materials science. For the furnace tube alloys used in ethylene pyrolysis facilities, the high-temperature mechanical properties highly depend on their microstructure, especially the grain morphology. In this work, a cellular automaton finite element (CAFE) model simulated grain structure in solidification processes is applied. In the CAFE model, the density of grains formed at any undercooling and the growth kinetics of the dendrite tip are deduced by Gaussian distributions and Kurz-Giovanola-Trivedi (KGT) theory, respectively. A method of two-stage modeling for the cylindrical furnace tube is proposed, based on the characteristics of alloy melt flow in the horizontal centrifugal casting process. By the control of different parameters in the solidification process, the various microstructure morphologies of centrifugal casting HP40 alloys are obtained and verified with the experimental observations and theoretical analysis. As a consequence, the microstructural prediction model of centrifugal casting HP40 alloys is optimized. The result shows that the desired full columnar grain morphology of HP40 alloys can be realized at the pouring temperature of 1620 °C and the revolving speed of 3100 rpm. This research reveals the potential application of the CAFE approach in microstructure control and optimization of furnace tube alloys.