bluuebunny/crossref_metadata_2025_split huggingface dataset:
Application of Fracture Control to Mitigate Failure Consequence Under BDBE
Authors: Kasahara Naoto , Wakai Takashi , Nakamura Izumi , Sato Takuya , Ichimiya Masakazu 
Published: October 2020

Abstract
As a lesson learned from the Fukushima nuclear power plant accident, the industry recognized the imporatance of mitigating accident consequences after Beyond Design Basis Events (BDBE). We propose the concept of applying fracture control to mitigate failure consequences of nuclear components under BDBE.
Requirements are different between Design Basis Events (DBE) and BDBE. In the case of DBE, it requires preventing occurrence of failures, and thus, its structural approach is strengthening. On the other hand, BDBE requires mitigating failure consequences. The simple strengthening approach with DBE is inappropriate for this BDBE requirement.
As the structural strengthening approach for mitigating failure consequences, we propose applying the concept of fracture control. The fundamental idea is to control the sequence of failure locations and modes. Preceding failures release loadings and prevent further catastrophic consequent failures. At the end, locations and modes of failure are limited.
Absolute strength evaluation for each failure mode is not easy especially for BDBE. Fracture control, however, requires only relative strength evaluation among different locations and failure modes.
Our paper discusses two sample applications of our proposed method. One is a fast reactor vessel under severe accident conditions. Our method controls the upper part of a vessel above the liquid coolant surface weaker than the lower part. This strength control maintains enough coolant even after a high pressure and high temperature condition causes failure of the reactor vessel because structural failure in the upper part releases internal pressure to protect the lower part.
The other example is the piping under a large earthquake. Our proposal controls strength of supports weaker than the piping itself. When the supports fail first, natural frequencies of piping systems drop. When the natural frequencies of dominant modes are lower than the peak frequency of seismic loads, seismic loads hardly transfer to the piping and catastrophic failures such as collapse or break are avoided.
Investigation on Typical Failure Mode of High-Pressure Hydrogen Cylinders for Vehicles
Authors: Yuan Yiwen , Wang Jielu , Ding Ju 
Published: October 2020

Abstract
Compressed hydrogen gas cylinders with an aluminum liner and carbon fiber wound are currently used as main storage containers in hydrogen fuel cell vehicles region, such cylinders filled with hydrogen gas have the advantages of light weight, high pressure resistance etc. Owing to the fact that cylinders are generally pressurized to 35MPa-92MPa, they may have a vital impact on life and property if failure of the cylinder occurs. For risk prediction, a series of comparative experiments have been carried out and some tests results have been analyzed, where the typical failure mode of such hydrogen cylinders are summarized as irreversible failure, recoverable failure and preventable failure. Irreversible failure refers to the failure mode such as leakage, rupture and penetration, etc, which could cause the cylinder not to restore its original function. Recoverable failure includes thread damage, security attachment startup and so on. The original function of the cylinder could be repaired by repairing the thread and replacing the safety accessories. Preventable failure would be found under the condition such as load at extreme ambient temperature for a long time, filament wound layer cracking caused by surface damage, chemical corrosion and serious impact etc, which could decrease the cylinder strength. In case of existing the preventable failure, cylinders should be monitored in use and the service life would be reduced.
Mechanical and Thermal Assessment by BAM of a New Package Design for the Transport of SNF From a German Research Reactor
Authors: Komann Steffen , Ballheimer Viktor , Quercetti Thomas , Scheidemann Robert , Wille Frank 
Published: October 2020

Abstract
For disposal of the research reactor of the Technical University Munich FRM II a new transport and storage cask design was under approval assessment by the German authorities on the basis of International Atomic Energy Agency (IAEA) requirements. The cask body is made of ductile cast iron and closed by two bolted lid systems with metal seals. The material of the lids is stainless steel. On each end of the cask the wood-filled impact limiters are installed to reduce impact loads to the cask under drop test conditions. In the cavity of the cask a basket for five spent fuel elements is arranged.
This design has been assessed by the Bundesanstalt für Materialforschung und -prüfung (BAM) in view to the mechanical and thermal safety analyses, the activity release approaches, and subjects of quality assurance and surveillance for manufacturing and operation of the package.
For the mechanical safety analyses of the package a combination of experimental testing and analytical/numerical calculations were applied. In total, four drop tests were carried out at the BAM large drop test facility. Two tests were carried out as a full IAEA drop test sequence consisting of a 9m drop test onto an unyielding target and a 1m puncture bar drop test. The other two drop tests were performed as single 9m drop tests and completed by additional analyses for considering the effects of an IAEA drop test sequence.
The main objectives of the drop tests were the investigation of the integrity of the package and its safety against release of radioactive material as well as the test of the fastening system of the impact limiters. Furthermore, the acceleration and strain signals measured during the tests were used for the verification of finite-element (FE) models applied in the safety analysis of the package design.
The FE models include the cask body, the lid system, the inventory and the impact limiters with the fastening system. In this context special attention was paid to the modeling of the encapsulated wood-filled impact limiters.
Additional calculations by using the verified numerical model were done to investigate e.g. the brittle fracture of the cask body made of ductile cask iron within the package design approval procedure.
The thermal safety assessment was based on analytical energy balance calculations and FE analyses. As an additional point of evaluation in frame of approval procedure, the effect of possible impact limiter burning under accident conditions of transport was considered by the applicant and assessed by BAM.
This paper describes the package design assessment from the point of view of the competent authority BAM including the applied assessment strategy, the conducted drop tests and the additional calculations by using numerical and analytical methods.
Evaluation of Pressure-Temperature Limit Curve Considering Revised Stress Intensity Factor Method
Authors: Lee Yunjoo , Yoon Hyosub , Kim Kyuwan , Kim Jongmin , Kim Hyunmin 
Published: October 2020

Abstract
Pressure-Temperature limit methodology is based on the rules of Appendix G in Section XI of the ASME Code in accordance with the requirements of 10 CFR 50, Appendix G, and the Appendix G in Section XI method refers to Welding Research Council (WRC) Bulletin 175 (WRC175). Flaw size is an important factor to protect the reactor pressure vessel from brittle failure but is not explicitly documented in WRC175. However, according to the recent change of Appendix G, the ¼ thickness (¼T) flaw size is postulated in the surface of the nozzle inner corner for the evaluation of Pressure-Temperature limit.
In this paper, stress intensity factor is computed by using 3D finite element analysis (FEA) considering ¼T corner cracks of inlet nozzle and outlet nozzle in reactor pressure vessel. The result is compared with the stress intensity factor using influence function in the ASME Code. The results of stress intensity factor in accordance with the ASME Code are more conservative than those of the 3-D FEA with a crack. The allowable pressure and operation region in Pressure-Temperature limit curve are affected by the calculation methods of stress intensity factor.
Ground Motion Model for Seismic Vulnerability Assessment of Prototype Industrial Plants
Authors: Nardin Chiara , Lanese Igor , di Filippo Rocco , Endrizzi Roberto , Bursi Oreste S. , Paolacci Fabrizio 
Published: October 2020

Abstract
Relationships between seismic action, system response and relevant damage levels in industrial plants require a solid background both in experimental data, due to the high level of non-linearity and seismic input. Besides, risk and fragility analyses depend on the adoption of a huge number of seismic records usually not available in a site-specific analysis. In order to manage these issues and to gain knowledge on the definition of damage levels, limit states and performance for major-hazard industrial plant components, we present a possible approach for an experimental campaign based on a real prototype industrial steel structure. The investigation of the seismic behaviour of the reference structure will be carried out through shaking table tests. In particular, tests are focused on structural or process-related interactions that can lead to serious secondary damages as leakage in piping systems or connections with tanks and cabinets. The aforementioned test program has been possible thanks to the adoption of: i) a number of artificial spectrum-compatible accelerograms; ii) a ground motion model (GMM) able to generate a suite of synthetic time-histories records for specified site characteristic and earthquake scenarios. More precisely, GMM model parameters can be identified by matching the statistics of a target-recorded accelerogram to the ones of the model in terms of faulting mechanism, earthquake magnitude, source-to-site distance and site shear-wave velocity. As a result, the stochastic model, based both on these matched parameters and on filtered white-noise process, can generate the ensemble of synthetic ground motions capable of capturing the main features of real earthquake ground motions, including intensity, duration, spectral content and peak values. Moreover, the synthetic records are selected to target specific damages and limit states in industrial components. Finally, by means of the combination of artificial and synthetic accelerograms, a seismic vulnerability assessment of both the whole structure and relevant industrial components can be carried out.
Experimental Study on the Characteristics of Bolted Pipe Flange Connection Under Bending Moment and Internal Pressure
Authors: Zheng Xing , Sawa Toshiyuki , Feng Mei , Ding Honggui 
Published: October 2020

Abstract
After a bolted gasketed pipe flange connection is assembled, the pipe flange connection is usually subjected to some additional loads such as bending moment, own weight, wind load and so on. These additional loads will lead to changing the axial bolt force distribution of the pipe flange connection and the distribution will become more and more scattered. As a result, the minimum residual axial bolt force will be much smaller and the minimum contact gasket stress will decrease, so a leakage is easy to occur in the connection. In special cases such as earthquakes, the bolted pipe flange connection is usually subjected to a high bending moment. Then sometimes leakage accidents occur. In order to promote the safety of the connections and to avoid them being broken under the earthquakes, in the present paper, the equivalent pressure and the assembly efficiency in the pipe flange connection of class 150 4″ are measured experimentally. The leak rates of the connection using spiral-wound gasket when a bending moment was applied or not applied were measured to elicit the equivalent pressure. Moreover, some tightening procedures such as JIS B 2251, ASME PCC-1 Legacy and GB/T 38343 were applied to tighten the pipe flange connection. The axial bolt force distribution, the assembly efficiency based on the target axial bolt force and the assembly efficiency based on tightness parameter of the connection when bending moment was applied or not applied were measured, and the results are compared. As a result, the equivalent pressure under a given bending moment is obtained, and a difference of the equivalent pressure between our results and Kellogg’s results is demonstrated. In addition, the new assembly efficiency based on the tightness parameter is also measured under a given bending moment as well as internal pressure. Using the equivalent pressure and the assembly efficiency obtained in the present paper, a new design will be possible for pipe flange connections under bending moment.
Multiaxial Ratcheting Deformation of 316LN Stainless Steel at Elevated Temperatures
Authors: Sun Xingyue , Xing Ruisi , Chen Xu 
Published: October 2020

Abstract
316LN stainless steel is the main material used in the primary pipelines of the pressurized water reactor due to its excellent characteristics. In the consideration of its serious environment, the cyclic deformation of material at high temperatures is concerned. A series of multiaxial ratcheting experiments were conducted at room, 350°C and 550°C. These experiments contained circular, rhombus and uniaxial loading paths with different mean stresses and stress amplitudes. At elevated temperature conditions, it got quick shakedown in multiaxial cases which is similar in uniaxial ones indicating that dynamic strain aging (DSA) exists. Uniaxial strain was the maximum in all the test temperature. Mean stress is seemed to be always the main influence factor. The difference of ratcheting strain under rhombus path and circular path decreased from room temperature to elevated temperature, which is inferred that DSA effect may weakened the nonproportionality at elevated temperature. The ratcheting strain evolution was simulated by Chen-Jiao-Kim model with the multiaxial parameter associated with temperature.
A Hybrid PSO-BPNN Model Approach for Crude Oil Pipeline Electrical Energy Consumption Forecasting
Authors: Xu Lei , Hou Lei , Li Yu , Zhu Zhenyu , Liu Jiaquan , Lei Ting 
Published: October 2020

Abstract
The electrical energy consumption forecasting for crude oil pipeline is critical in many aspects, such as energy consumption target setting, batch scheduling, unit commitment, etc. For actual crude oil pipelines, the nonlinearity of the sample is strong. The electrical energy consumption of crude pipeline is affected by many parameters, including oil physical property parameter, pipe parameter, station parameter, environmental parameter and operating parameter. At the same time, the whole process has the characteristics of intermittency and complex fluctuations. The above three main reasons make the energy consumption forecasting of crude oil pipeline complicated. In the past few years, several intelligence-based models have been introduced to accurately forecast energy consumption. Among them, back-propagation neural network (BPNN) seems to be more effective and can handle the nonlinear energy behavior and achieve accurate forecast results. However, due to its over-fitting problem, the accuracy of energy consumption forecasting will be reduced. To overcome this problem, the paper proposes a hybrid method for short-term energy consumption forecasting, namely PSO-BPNN. Back propagation neural network is integrated with particle swarm optimization to find optimal network weight. In this research, an effective technique called principal component analysis is applied to eliminate redundant noise and extract the primary characteristics of transportation data. The stratified sampling method is used to divide the training set and the test set to avoid large deviations caused by the randomness of sampling. Taking a crude oil pipeline in northeast china as a case study, SCADA system data are collected daily from December 31, 2016 to June 18, 2019. Comparing the evaluation indicators of PSO-BPNN with that of five state-of-the-art forecasting methods of GA-BPNN, SA-BPNN, DE-BPNN, FOA-BPNN, BPNN, the effectiveness of PSO-BPNN algorithm is evaluated. Compared with other five forecasting methods, the forecast results of PSO-BPNN are in best agreement with the actual data. The results indicate that the proposed PSO-BPNN model outperforms all five models used for comparison, which demonstrates its superior ability to generate forecasts in terms of forecasting accuracy.
Study on Hydrogen Resistance of X42 Pipeline Steel Under Electrochemical Hydrogen Charging Condition
Authors: Bai Guangqian , Wang Qiuyan , Song Yan , Deng Haiquan , Li Donglin , Li Yun 
Published: October 2020

Abstract
With the development of renewable energy, hydrogen energy is paid more and more attention. Hydrogen is an excellent energy carrier, but it is difficult to store and transport because of its special properties. Hydrogen blended with nature gas is considered to be one of best transition solutions to solve the problem of large-scale hydrogen transportation. But hydrogen embrittlement occurs when the pipeline steel used to transport natural gas is exposed to hydrogen environment. Referencing to ASME B31.12, X42 pipeline steel is selected as the research object in this paper. And the mechanical properties of X42 were tested by electrochemical hydrogen charging, slow strain rate tensile (SSRT) test and fatigue crack growth (FCG) test combined with thermal desorption spectroscopy (TDS) and SEM. Hydrogen adsorption properties of X42 pipeline steel at room temperature was measured by TDS. SSRT test showed that the strength of X42 strengthened slightly in electrochemical hydrogen charging environment, but the plasticity decreased significantly, and the embrittlement degree of materials increased with the elevated current density. FCG test showed that the presence of hydrogen will accelerate the crack growth rate and reduce the fatigue life of materials. SEM images of tensile and fatigue specimens showed that hydrogen transforms the fracture mode from ductile fracture to cleavage fracture.
Research on the Inspection Parameters of Ultrasonic Phased Array for the Periodic Inspection of High-Pressure Hydrogen Vessel
Authors: Miao Cunjian , Guo Weican , Ling Zhangwei , Tao Yangji , Yu Ting , Tang Ping 
Published: October 2020

Abstract
Steel layered high-pressure hydrogen vessel is one of different kinds of high-pressure vessel, which is invented in China and is widely equipped in hydrogen refueling stations for its good safety and storage functions. Many of these vessels are put into application these years, and it is nearly the time for these vessels to go through periodic inspection. However, there is no such a method for the periodic inspection especially on the butt weld connecting the double-layer head and the interface forging. To conquer the difficulties about the periodic inspection, a set of periodic inspection methods was first proposed in a lasted released Chinese group standard, in which the inner ultrasonic phased array is considered to be the most complicated detecting approach. To establish effective inspection parameters, simulations and experiments were conducted on the factors, including coupling, elements and aperture, focal law, scanning approaches and ultrasound field. Standard test block and contrast test block were designed and machined and tested, then a series of feasible parameters were determined. Thus, specific probe, wedge and instrument were manufactured, and the inspection on the actual vessel product was carried out. The results showed that the proposed ultrasonic method and its inspection parameters could meet the periodic inspection well. Finally, the periodic inspection methods were established and issued as a standard.
Effects of Stud Galling on Bolted Flange Joint Assembly Performance
Authors: Dupre Ross 
Published: October 2020

Abstract
This study will focus on the galling of studs and what impact that has on the overall performance of a Bolted Flange Joint Assembly. Galling or “cold welding” occurs more so with softer metals. While tightening the nut on to the stud the contact metal will “pull” away from itself and the two surfaces will essentially become one. Once this happens the nut cannot be tightened or loosened and often cutting the stud is the only form of removal.
We’ll be studying how this affects the performance (tightness) of a bolted flange joint assembly. Does the assembly loosen over time or does it remain at the proper tightness? Data will be captured using load cells to accurately represent the amount of force being generated by test studs. There will be a standard test ran with no galling. All other tests with galled studs will be measured and compared against the standard test. One test with only one stud galled, the next with two studs galled, the next with three studs galled, and so on. It may be expected to see some load loss on the load cells with the galled studs. The integrity of the studs, once galled, becomes less than ideal.
Failure Assessment of Spring-Operated Pressure Relief Valve Proof Test Data for Extending Time-in-Service
Authors: Bukowski Julia V. , Gross Robert E. , Harris Stephen P. , Goble William M. 
Published: October 2020

Abstract
The proof test results of 1669 Spring-Operated Pressure Relief Valves (SOPRV), which were previously installed in active processes, were analyzed with respect to proof test ratio (R), time-in-service (TIS), set pressure (SP), working fluid (WF), material composition of the SOPRV and, if an SOPRV failed-to-open (FTO), the root cause of failure in the FTO failure mode if available. Many of these SOPRV had accumulated TIS in excess of the normal maximum of five years yet proof testing indicated that most would have functioned properly. This paper examines the results of the analysis and provides guidelines under which it is appropriate to consider extending TIS for individual SOPRV.