Refine your search:     
Report No.
 - 
Search Results: Records 1-20 displayed on this page of 21

Presentation/Publication Type

Initialising ...

Refine

Journal/Book Title

Initialising ...

Meeting title

Initialising ...

First Author

Initialising ...

Keyword

Initialising ...

Language

Initialising ...

Publication Year

Initialising ...

Held year of conference

Initialising ...

Save select records

Journal Articles

Study of recent sodium pool fire model improvements for MELCOR code

Aoyagi, Mitsuhiro; Louie, D. L. Y.*; Uchibori, Akihiro; Takata, Takashi; Luxat, D.*

Proceedings of 28th International Conference on Nuclear Engineering; Nuclear Energy the Future Zero Carbon Power (ICONE 28) (Internet), 10 Pages, 2021/08

Journal Articles

Study of sodium pool fire model improvement in MELCOR for SFR

Louie, D. L. Y.*; Aoyagi, Mitsuhiro

Transactions of the American Nuclear Society, 124(1), p.824 - 827, 2021/06

The Sodium Chemistry (NAC) package in MELCOR has been developed to enhance application to sodium cooled fast reactors. Based on the recommendations in the previous study through the benchmark analyses of the F7-1 pool fire experiment, this study aims to improve the MELCOR models capturing the oxide layer effect, sodium pool spreading and pool-pan heat transfer, respectively. Each of these models enable a better characterization of the all the processes of relevance to sodium pool fires as observed during the F7-1 test. The MELCOR sodium pool fire enhancement has demonstrated the importance of the improved models.

Journal Articles

Sodium fire collaborative study progress; CNWG fiscal year 2020

Louie, D. L. Y.*; Aoyagi, Mitsuhiro

SAND2021-0136 (Internet), 53 Pages, 2021/01

This report discusses the progress on the collaboration between Sandia National Laboratories (SNL) and Japan Atomic Energy Agency (JAEA) on the sodium fire research in fiscal year 2020. First, the current sodium pool fire model in MELCOR is discussed. The associated sodium fire input requirements are also presented. These input requirements are flexible enough to permit further model development via control functions to enhance the current model without modifying the source code. The theoretical pool fire model improvement developed at SNL is discussed. A control function model has been developed from this improvement. Then, the validation study of the sodium pool fire model in MELCOR is described. To validate this pool fire model with the enhancement, a JAEA F7-1 sodium pool fire experiment is used. The results of the calculation are discussed as well as suggestions for further model improvement. Finally, recommendations are made for new MELCOR simulations for next fiscal year, 2021.

Journal Articles

Sodium fire analysis using a sodium chemistry package in MELCOR

Aoyagi, Mitsuhiro; Uchibori, Akihiro; Takata, Takashi; Louie, D. L. Y.*; Clark, A. J.*

Proceedings of 2020 International Conference on Nuclear Engineering (ICONE 2020) (Internet), 6 Pages, 2020/08

The Sodium Chemistry (NAC) package in MELCOR has been developed to enhance application to sodium cooled fast reactors. The models in the NAC package have been assessed through benchmark analyses of the F7-1 pool fire experiment. This study assesses the capability of the pool fire model in MELCOR and provides recommendations for future model improvements. The MELCOR analysis yields lower values than the experimental data in pool combustion rate and pool, catch pan, and gas temperature during early time. The current heat transfer model for the catch pan is the primary cause of the difference. After sodium discharge stopping, the pool combustion rate and temperature become higher than experimental data. This is caused by absence of a model for pool fire suppression due to the oxide layer buildup on the pool surface. Based on these results, recommendations for future works are needed, such as heat transfer modification for the catch pan and consideration of the effects of the oxide layer.

Journal Articles

Sodium fire collaborative study progress; CNWG fiscal year 2019

Louie, D. L. Y.*; Uchibori, Akihiro

SAND2019-15043 (Internet), 35 Pages, 2019/12

This report describes the progress on the sodium fire research in fiscal year 2019 in the Civil Nuclear Energy Research and Development Working Group (CNWG). In this study, the validation study of the sodium pool fire model incorporated into the MELCOR code, which was originally developed for accident analysis in light water reactors, was carried out through the numerical analysis on the sodium pool fire experiment named F7-1. In this preliminary analysis, pool and atmosphere temperature went up to the same level with the measured results, while the unnatural behavior appeared in the latter half of the analysis. Based on this result, recommendations for improvement were made for a new analysis in next fiscal year, 2020.

Journal Articles

Multi-dimensional numerical benchmark analysis of SNL T3 sodium spray combustion experiment with AQUA-SF code

Sonehara, Masateru; Aoyagi, Mitsuhiro; Uchibori, Akihiro; Takata, Takashi; Ohshima, Hiroyuki; Clark, A. J.*; Denman, M. R.*

Proceedings of 27th International Conference on Nuclear Engineering (ICONE-27) (Internet), 8 Pages, 2019/05

In order to investigate the effect of sodium combustion, Sandia National Laboratories (SNL) and Japan Atomic Energy Agency (JAEA) have exchanged information of sodium combustion modelling and related experimental data in the framework of Civil Nuclear Energy Research and Development Working Group (CNWG). The benchmark analysis of the SNL T3 sodium spray combustion experiment and sensitivity study have been carried out using the AQUA-SF code in this paper. The sensitivity analysis clarifies the influencing factors of the multi-dimensional analysis such as turbulence models, radiation heat transfer model from sodium droplets, and momentum exchange between gas and droplets. The result shows that the turbulence effect, radiation from droplets and gas temperature increase at spray burning area affect sodium spray burning rate significantly.

Journal Articles

Multi-dimensional numerical investigation of sodium spray combustion; Benchmark analysis of SNL T3 experiment

Sonehara, Masateru; Aoyagi, Mitsuhiro; Uchibori, Akihiro; Takata, Takashi; Ohshima, Hiroyuki; Clark, A. J.*; Denman, M. R.*

Proceedings of 11th Korea-Japan Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS-11) (Internet), 5 Pages, 2018/11

no abstracts in English

Journal Articles

SNL/JAEA collaboration on sodium fire benchmarking

Clark, A. J.*; Denman, M. R.*; Takata, Takashi; Ohshima, Hiroyuki

SAND2017-12409, 39 Pages, 2017/11

Two sodium spray fire experiments performed by Sandia National Laboratories (SNL) were used for a code-to-code comparison between CONTAIN-LMR and SPHINCS. Both computer codes are used for modeling sodium accidents in sodium fast reactors. The comparison between the two codes provides insights into the ability of both codes to model sodium spray fires. The SNL T3 and T4 experiments are 20 kg sodium spray fires with sodium spray temperatures of 200$$^{circ}$$C and 500$$^{circ}$$C, respectively. The vessel in the SNL T4 experiment experienced a rapid pressurization that caused of the instrumentation ports to fail during the sodium spray. Despite these unforeseen difficulties, both codes were shown in good agreement with the experiments. SPHINCS showed better long-term agreement with the SNL T3 experiment than CONTAIN-LMR. The unexpected port failure during the SNL T4 experiment presented modelling challenges.

Journal Articles

Information sharing framework among nuclear nonproliferation experts for enhancing nuclear transparency

Kawakubo, Yoko; Inoue, Naoko; Tomikawa, Hirofumi

Kaku Busshitsu Kanri Gakkai (INMM) Nihon Shibu Dai-34-Kai Nenji Taikai Rombunshu (Internet), 9 Pages, 2013/10

Japan Atomic Energy Agency (JAEA) is carrying out R&D to design and establish an Information-Sharing Framework (ISF) for supporting and promoting nuclear transparency in cooperation with Sandia National Laboratories (SNL), the Korean Institute for Nonproliferation and Control (KINAC), and Korea Atomic Energy Research Institute (KAERI). Partner organizations have agreed on starting by establishing ISF with a focus on nuclear nonproliferation experts in Track II as primary information providers/receivers. Thus far, requirements for ISF have been developed for providing clear steps to design and establish ISF and ensuring its sustainability. As the next step, ISF is to be established following the requirements and demonstration of information sharing will be carried out. In the long-term, ISF could be expanded to invite other interested organizations and include other information. This paper describes the effort to design and establish ISF by focusing on the requirements which has been developed under the joint R&D.

Journal Articles

Charge enhancement effects in 6H-SiC MOSFETs induced by heavy ion strike

Onoda, Shinobu; Makino, Takahiro; Iwamoto, Naoya*; Vizkelethy, G.*; Kojima, Kazutoshi*; Nozaki, Shinji*; Oshima, Takeshi

IEEE Transactions on Nuclear Science, 57(6), p.3373 - 3379, 2010/12

no abstracts in English

Journal Articles

Enhanced charge collection in drain contact of 6H-SiC MOSFETs induced by heavy ion microbeam

Onoda, Shinobu; Vizkelethy, G.*; Makino, Takahiro; Iwamoto, Naoya; Kojima, Kazutoshi*; Nozaki, Shinji*; Oshima, Takeshi

Proceedings of 9th International Workshop on Radiation Effects on Semiconductor Devices for Space Applications (RASEDA-9), p.230 - 233, 2010/10

Journal Articles

Change in ion beam induced current from Si metal-oxide-semiconductor capacitors after $$gamma$$-ray irradiation

Oshima, Takeshi; Onoda, Shinobu; Hirao, Toshio; Takahashi, Yoshihiro*; Vizkelethy, G.*; Doyle, B. L.*

AIP Conference Proceedings 1099, p.1014 - 1017, 2009/03

Metal-Oxide-Semiconductor (MOS) capacitors were made on both n- and p-type Si substrates (n-MOS, and p-MOS). These MOS capacitors were irradiated with $$gamma$$-rays at a dose of 6.3 kGy (SiO$$_{2}$$) at room temperature. The capacitance-voltage characteristics for MOS capacitors were measured before and after irradiation. The flat band shift for n-MOS and p-MOS capacitors due to $$gamma$$-ray irradiation was -12.3 V and -15.2 V, respectively. As for the generation of interface traps, the values for n-MOS and p-MOS capacitors were estimated to be 0.5$$times$$10$$^{11}$$ and 1.7$$times$$10$$^{11}$$/cm$$^{2}$$, respectively. Transient Ion Beam Induced Current (TIBIC) obtained from these MOS capacitors were compared before and after $$gamma$$-ray irradiation. For n-MOS capacitors, the peak height of TIBIC signals decreased after $$gamma$$-ray irradiation. On the other hand, the peak height of TIBIC signals for p-MOS capacitors increased after $$gamma$$-ray irradiation. The applied bias dependence of the peak height of TIBIC signals for MOS capacitors irradiated with $$gamma$$-rays can be matched to that for ones before $$gamma$$-rays irradiation by shifting the voltage by -13 V for n-MOS capacitors and by -15 V for p-MOS capacitors. These voltage values are in good agreement with the flat band voltage shifts due to $$gamma$$-ray irradiation. Since flat band shift occurs due to the generation of positive charge trapped in gate oxide, the change in TIBIC signals observed for MOS capacitors due to $$gamma$$-ray irradiation can be interpreted in terms of positive charge generated in oxide.

Journal Articles

Extrinsic sensors and external signal generator for advanced transparency framework

Katsumura, Soichiro; Kitabata, Takuya; Irie, Tsutomu; Suzuki, Mitsutoshi; Hashimoto, Yu; Kato, Keiji*

Transactions of the American Nuclear Society, 99(1), P. 780, 2008/11

Oral presentation

A Demonstration of advanced nuclear fuel cycle transparency concepts

Inoue, Naoko; Irie, Tsutomu; Kitabata, Takuya; Rochau, G.*; York, D.*; Mendez, C.*

no journal, , 

Japan Atomic Energy Agency (JAEA) and Sandia National Laboratories (SNL) have entered cooperative program, in 2005, to demonstrate a methodology capable assessing proliferation risk in support of overall plant transparency. Earlier, both organizations have preliminary discussion to develop the methodology. The Advanced Fuel Cycle Transparency Framework Concept is being implemented at the Fuel Handling Training Model designed for "Monju", prototype Fast Reactor at the International Nuclear Information and Training Center (ITC) of Tsuruga Head Office, the Japan Atomic Energy Agency (JAEA). "Monju" is fully automated facility and the training model reproducts the entire Monju fuel handling process. The training model is used to generate and transmit information to a secure database at ITC located by Monju site. A computer syncronized to the visible movements in the model mimicking process data supply data. The database is accessible to analyst at SNL via encryption and virtual private network (VPN). The data stream is fed into the "Transparency Software" for real time analysis when the model is being exeicised. "Transparency Software" is expected to monitor the information from the model and to calcurate the prolifearation risk by compared with expected values. This concept will be able to expamd the ability to enable effective transparency system in the aspect of safety and lagitmate use of nuclear material and technology, to contribute the transparency concept among international communities or between a state and IAEA, for the future nuclear fuel cycles. This paper will describe the concept, implememtation plan and status of the demonstration project, and progress toward the first demonstration of the system.

Oral presentation

Regional remote monitoring cooperation for nuclear non-proliferation and transparency; A Project summary to date and a look to the future

Betsill, D.; Hashimoto, Yu

no journal, , 

Remote monitoring and secure communications technologies can help nuclear industries demonstrate non-proliferation compliance. At the same time, web-based remote monitoring can improve non-proliferation cooperation between neighboring countries and international partners in the nuclear fuel cycle. Building upon past individual project successes toward transparency cooperation, the Japan Atomic Energy Agency (JAEA), Korea Institute of Nuclear Non-Proliferation and Control (KINAC), and Sandia National Laboratories (SNL) are exploring the possibility of a regional transparency network. Observation of the project is provided by the International Atomic Energy Agency (IAEA). This presentation describes the past project activities and expectations for future cooperation and technology development.

Oral presentation

Remote monitoring and secure communication for regional cooperation and transparency in nuclear nonproliferation

Betsill, D.; Hashimoto, Yu; Suzuki, Mitsutoshi; Hori, Masato; Inoue, Naoko; Olsen, J.*; Caskey, S. A.*; Lucero, R. L.*

no journal, , 

Remote monitoring and secure communication technologies assist organizations developing nuclear energy by demonstrating compliance with international nonproliferation agreements and IAEA safeguards. A collaboration between JAEA and Sandia on remote monitoring transparency technology at the Joyo test site is described. The history and development of the project, technology, and recent upgrades to the hardware and an internal website are described. Technical applications, and the cooperative process for development of a potential regional transparency network, are discussed.

Oral presentation

Development of transparency framework using Monju; Demo study using fuel handling training model

Kitabata, Takuya; Inoue, Naoko; Irie, Tsutomu; Rochau, G.*; Cleary, V.*; York, D.*

no journal, , 

An experimental system of "Transparency Framework" was completed connecting the output signal of the fuel handling training model of the Prototype Fast Breeder Reactor, "Monju" and server computers in the Sandia National Laboratory. The system determines a proliferation risk of the model on a real-time basis using a risk evaluation method. A prospect for application of the "Transparency Framework" to future nuclear systems is discussed.

Oral presentation

Development of transparency framework concept using Monju fuel handling model

Katsumura, Soichiro; Suzuki, Mitsutoshi; Hashimoto, Yu; Inoue, Naoko; Kitabata, Takuya; Irie, Tsutomu; Rochau, G.*; Cleary, V.*; Mcfadden, K.*; Mendez, C.*

no journal, , 

no abstracts in English

Oral presentation

Survey on experiences and needs for sharing nonproliferation-relevant information among experts within JAEA

Kawakubo, Yoko; Inoue, Naoko; Mongiello, R.*; Baldwin, G.*; Lee, N.-Y.*; Chung, J.*; Kwon, E.-H.*

no journal, , 

Japan Atomic Energy Agency (JAEA) is carrying out a project to design and establish an Information Sharing Framework (ISF) for enhancing nuclear transparency in the Asia Pacific region. This project is a cooperative effort with Sandia National Laboratories (SNL), the Korean Institute for Nuclear Nonproliferation and Control (KINAC), and Korea Atomic Energy Research Institute (KAERI). In order to design and establish the ISF as a meaningful and sustainable mechanism, it is essential to identify the needs of the potential aparticipants including their expectations and concerns. Therefore partner organizations have conducted on-line surveys and/or face-to-face interviews with the nonproliferation experts within their own organizations that were identified as primary participants of ISF. JAEA carried out several face-to-face interviews with its experts including those who are in charge of nonproliferation R&D, nuclear security implementation coordinator, and training for capacity building and infrastructure development. They were queried as to past experiences and future needs for information exchanges. The survey results indicated that there are various experiences of information sharing in each nonproliferation mission or activity, and there continues to be a need for further information sharing. Findings from the survey will be reflected to the establishment and demonstration of ISF.

Oral presentation

Development of information sharing requirements for regional nuclear transparency

Kawakubo, Yoko; Inoue, Naoko; Mongiello, R.*; Baldwin, G.*; Lee, N.-Y.*; Chung, J.*; Kwon, E.-H.*

no journal, , 

Nuclear transparency has been discussed in various contexts even within nuclear nonproliferation. Due to the wide range of the contexts, the similar discussions have been repeated. With this background, Japan Atomic Energy Agency (JAEA), US Sandia National Laboratories (SNL), Korean Institute of Nuclear Nonproliferation and Control (KINAC), and Korean Atomic Energy Research Institute (KAERI) initiated a new phase of study to develop "requirements" for information sharing framework (ISF) focusing on regional nonproliferation experts. The "requirements" in this study is defined as to implement Plan-Do-Check-Adjust (PDCA) cycle for each specific category of information to be shared. "Plan" should be made by defining seven essential elements of ISF. In "Do" stage, the participants will collect the information and initiate a sharing process. "Check" is to evaluate the effectiveness and efficiency of the ISF using the metrics and methodologies identified in "Plan". The feedback obtained from the "Check" will be reflected to the "Plan" for the second cycle, then the second cycle will be implemented. Because the nuclear transparency is a voluntary process, sustainability is a key challenge. "Requirements" were developed so that if the planning and implementation of ISF is carried out following the "requirements", ISF can automatically work in a sustainable and useful manner. This paper addresses the requirements for ISF that were developed by JAEA, SNL, KINAC, and KAERI, and demonstrates how they can work with showing the example planning.

Oral presentation

Development of the sodium fire module in integrated severe accident analysis code, SPECTRA; Code-to-code comparison with the MELCOR code through the benchmark analysis of the F7-1 pool fire test

Aoyagi, Mitsuhiro; Uchibori, Akihiro; Takata, Takashi; Louie, D. L. Y.*

no journal, , 

The SPECTRA code has been developed as an integrated simulation system for severe accident evaluation in a sodium cooled fast reactor. In this study, the sodium pool fire model of SPECTRA is accessed through the benchmark analysis of the F7-1 pool fire experiment. As well as the comparison with the experimental data, the SPECTRA result is also compared to the results of the MELCOR and SPHINCS codes. All the SPECTRA results well agree with the results of SPHINCS from which the pool fire model of SPECTRA is adapted. The comparisons with MELCOR and experiment show also reasonable agreements in the essential pool fire behavior. The principal difference is the combustion rare after sodium supply stopping especially in the comparison with the experiment. This affects smaller temperature decreasing of the pool, catch-pan, and gas in SPECTRA. Such differences should be investigated more in the future works.

21 (Records 1-20 displayed on this page)