Validation study of sodium pool fire modeling efforts in MELCOR and SPHINCS codes

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

Proceedings of Technical Meeting on State-of-the-art Thermal Hydraulics of Fast Reactors (Internet), 6 Pages, 2022/09

Sodium fire collaborative study progress; CNWG fiscal year 2021

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

SAND2021-15469 (Internet), 45 Pages, 2021/12

https://doi.org/10.2172/1834703

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 2021. First, the current sodium pool fire model in MELCOR is discussed. The associated sodium fire input requirements are also presented. 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, JAEA F7-1 and F7-2 sodium pool fire experiments are 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.

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

https://doi.org/10.13182/T124-35045

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.

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

https://doi.org/10.1115/ICONE2020-16751

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.

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

https://doi.org/10.1299/jsmeicone.2019.27.2089

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.

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 200C and 500C, 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.

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

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

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

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

https://doi.org/10.1063/1.3119985

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 -rays at a dose of 6.3 kGy (SiO) 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 -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 0.510 and 1.710/cm, respectively. Transient Ion Beam Induced Current (TIBIC) obtained from these MOS capacitors were compared before and after -ray irradiation. For n-MOS capacitors, the peak height of TIBIC signals decreased after -ray irradiation. On the other hand, the peak height of TIBIC signals for p-MOS capacitors increased after -ray irradiation. The applied bias dependence of the peak height of TIBIC signals for MOS capacitors irradiated with -rays can be matched to that for ones before -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 -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 -ray irradiation can be interpreted in terms of positive charge generated in oxide.

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.

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.