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Journal Articles

Transport model comparison studies of intermediate-energy heavy-ion collisions

Walter, H.*; Colonna, M.*; Cozma, D.*; Danielewicz, P.*; Ko, C. M.*; Kumar, R.*; Ono, Akira*; Tsang, M. Y. B*; Xu, J.*; Zhang, Y.-X.*; et al.

Progress in Particle and Nuclear Physics, 125, p.103962_1 - 103962_90, 2022/07

Transport models are the main method to obtain physics information on the nuclear equation of state and in-medium properties of particles from low to relativistic-energy heavy-ion collisions. The Transport Model Evaluation Project (TMEP) has been pursued to test the robustness of transport model predictions to reach consistent conclusions from the same type of physical model. To this end, calculations under controlled conditions of physical input and set-up were performed by the various participating codes. These included both calculations of nuclear matter in a periodic box, which test individual ingredients of a transport code, and calculations of complete collisions of heavy ions. Over the years, five studies were performed within this project. They show, on one hand, that in box calculations the differences between the codes can be well understood and a convergence of the results can be reached. These studies also highlight the systematic differences between the two families of transport codes, known under the names of Boltzmann-Uehling-Uhlenbeck (BUU) and Quantum Molecular Dynamics (QMD) type codes. On the other hand, there still exist substantial differences when these codes are applied to real heavy-ion collisions. The results of transport simulations of heavy-ion collisions will have more significance if codes demonstrate that they can verify benchmark calculations such as the ones studied in these evaluations.

Journal Articles

Revolatilization of iodine by bubbly flow in the suppression pool during an accident

Nanjo, Kotaro; Ishikawa, Jun; Sugiyama, Tomoyuki; Pellegrini, M.*; Okamoto, Koji*

Journal of Nuclear Science and Technology, 10 Pages, 2022/04

Journal Articles

Developing accelerator mass spectrometry capabilities for anthropogenic radionuclide analysis to extend the set of oceanographic tracers

Hain, K.*; Martschini, M.*; G$"u$lce, F.*; Honda, Maki; Lachner, J.*; Kern, M.*; Pitters, J.*; Quinto, F.*; Sakaguchi, Aya*; Steier, P.*; et al.

Frontiers in Marine Science (Internet), 9, p.837515_1 - 837515_17, 2022/03

Recent major advances in accelerator mass spectrometry (AMS) at the Vienna Environmental Research Accelerator (VERA) regarding detection efficiency and isobar suppression have opened possibilities for the analysis of additional long-lived radionuclides at ultra-low environmental concentrations. These radionuclides, including $$^{233}$$U, $$^{135}$$Cs, $$^{99}$$Tc and $$^{90}$$Sr, will become important for oceanographic tracer application due to their generally conservative behavior in ocean water. In particular, the isotope ratios $$^{233}$$U/$$^{236}$$U and $$^{137}$$Cs/$$^{135}$$Cs have proven to be powerful fingerprints for emission source identification as they are not affected by elemental fractionation. Improved detection efficiencies allowed us to analyze all major long-lived actinides, i.e. $$^{236}$$U, $$^{237}$$Np, $$^{239, 240}$$Pu, $$^{241}$$Am as well as the very rare $$^{233}$$U, in the same 10 L water samples of an exemplary depth profile from the northwest Pacific Ocean. Especially for $$^{90}$$Sr analysis, our new approach has already been validated for selected reference materials (e.g. IAEA-A-12) and is ready for application in oceanographic studies. We estimate that a sample volume of only (1-3) L ocean water is sufficient for $$^{90}$$Sr as well as $$^{135}$$Cs analysis, respectively.

Journal Articles

Interaction between surface acoustic waves and spin waves in a ferromagnetic thin film

Yamamoto, Kei; Xu, M.*; Puebla, J.*; Otani, Yoshichika*; Maekawa, Sadamichi*

Journal of Magnetism and Magnetic Materials, 545, p.168672_1 - 168672_10, 2022/03

Journal Articles

A Comparative CFD exercise on bubble hydrodynamics using Euler-Euler and interface tracking approaches

Dehbi, A.*; Cheng, X.*; Liao, Y.*; Okagaki, Yuria; Pellegrini, M.*

Proceedings of 19th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-19) (Internet), 15 Pages, 2022/03

Journal Articles

Overview and main outcomes of the pool scrubbing lumped-parameter code benchmark on hydrodynamic aspects in IPRESCA project

Marchetto, C.*; Ha, K. S*; Herranz, L. E.*; Hirose, Yoshiyasu; Jankowski, T.*; Lee, Y.*; Nowack, H.*; Pellegrini, M.*; Sun, X.*

Proceedings of 19th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-19) (Internet), 17 Pages, 2022/03

Journal Articles

Integration of pool scrubbing research to enhance source-term calculations (IPRESCA) project

Gupta, S.*; Herranz, L. E.*; Lebel, L. S.*; Sonnenkalb, M.*; Pellegrini, M.*; Marchetto, C.*; Maruyama, Yu; Dehbi, A.*; Suckow, D.*; K$"a$rkel$"a$, T.*

Proceedings of 19th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-19) (Internet), 16 Pages, 2022/03

Journal Articles

Nanosecond structural dynamics of intrinsically disordered $$beta$$-casein micelles by neutron spectroscopy

Nakagawa, Hiroshi; Appavou, M.-S.*; Wuttke, J.*; Zamponi, M.*; Holderer, O.*; Schrader, T. E.*; Richter, D.*; Doster, W.*

Biophysical Journal, 120(23), p.5408 - 5420, 2021/12

Casein proteins are characterized by its extended structural features and its dynamics, which are different from those of typical folded proteins, due to a large number of proline residues. We were able to describe the unique structural dynamics by Orenstein-Uhlenbeck Brownian oscillator model by several types of QENS experiments with wide time-scales. The characterized dynamics also allowed us to discuss the effective sequestration of calcium phosphate in terms of its unique dynamical structure. The biological role of the physical processes of the proteins on the nanosecond order on the biological functions is presented.

Journal Articles

An Approach toward evaluation of long-term fission product distributions in the Fukushima Daiichi Nuclear Power Plant after the severe accident

Uchida, Shunsuke; Karasawa, Hidetoshi; Kino, Chiaki*; Pellegrini, M.*; Naito, Masanori*; Osaka, Masahiko

Nuclear Engineering and Design, 380, p.111256_1 - 111256_19, 2021/08

 Times Cited Count:0 Percentile:0.01(Nuclear Science & Technology)

It is essential to grasp the long-term distributions of FP as well as fuel debris all over the Fukushima Daiichi Nuclear Power Plant (1F) for safe completion of its decommissioning projects. The fuel debris is going to be removed from the plant under the severe conditions of FP being scattered during major decommissioning work, and then, the decommissioning projects are going to be terminated by storing safely the removed debris as recovered fertile materials or as materials for final radioactive disposal. In order to determine the FP distribution in the plant for the long period from the accident occurrence to the termination of the plant decommissioning, procedures for analyzing multi-term FP behaviors were proposed. The proposed procedures should be improved by applying the FP data measured in the plant and validated based on the feedback data. Then, the accuracy-improved procedures should be applied to estimate FP distribution during each period of the decommissioning projects.

Journal Articles

Conversion factors bridging radioactive fission product distributions in the primary containment vessel of Fukushima Daiichi NPP and dose rates measured by the containment atmosphere monitoring system

Uchida, Shunsuke; Pellegrini, M.*; Naito, Masanori*

Nuclear Engineering and Design, 380, p.111303_1 - 111303_11, 2021/08

 Times Cited Count:1 Percentile:81.22(Nuclear Science & Technology)

Multi-term FP analysis procedures were developed to determine FP distribution all over F1 not only for analyzing accident propagation but also for planning its decommissioning projects. They should be validated based on the measured FP data. One of the useful tools for their validation was application of the dose rate data monitored by the containment atmosphere monitoring system (CAMS). However, in order to compare the data with different characteristics and dimensional units, e.g., FP distribution (kg, Bq) and dose rate (Sv/h), application of the conversion factors bridging them would be effective and useful. In order to prepare speedy, easy-to-handle and tractable procedures to calculate radiation dose rates at the CAMS detector locations, dose rate conversion factors were determined for major source locations and major radionuclides. The dose rates could be easily calculated by multiplying FP amounts obtained with the multiterm FP analysis procedures by the conversion factors.

Journal Articles

Numerical investigations on the coolability and the re-criticality of a debris bed with the density-stratified configuration

Li, C.; Uchibori, Akihiro; Takata, Takashi; Pellegrini, M.*; Erkan, N.*; Okamoto, Koji*

Dai-25-Kai Doryoku, Enerugi Gijutsu Shimpojiumu Koen Rombunshu (Internet), 4 Pages, 2021/07

The capability of stable cooling and avoiding re-criticality on the debris bed are the main issues for achieving IVR (In-Vessel Retention). In the actual situation, the debris bed is composed of mixed-density debris particles. Hence, when these mixed-density debris particles were launched to re-distribute, the debris bed would possibly form a density-stratified distribution. For the proper evaluation of this scenario, the multi-physics model of CFD-DEM-Monte-Carlo based neutronics is established to investigate the coolability and re-criticality on the heterogeneous density-stratified debris bed with considering the particle relocation. The CFD-DEM model has been verified by utilizing water injection experiments on the mixed-density particle bed in the first portion of this research. In the second portion, the coupled system of the CFD-DEM-Monte-Carlo based neutronics model is applied to reactor cases. Afterward, the debris particles' movement, debris particles' and coolant's temperature, and the k-eff eigenvalue are successfully tracked. Ultimately, the relocation and stratification effects on debris bed's coolability and re-criticality had been quantitatively confirmed.

Journal Articles

Expansion of agriculture in northern cold-climate regions; A Cross-sectoral perspective on opportunities and challenges

Unc, A.*; Altdorff, D.*; Abakumov, E.*; Adl, S.*; Baldursson, S.*; Bechtold, M.*; Cattani, D. J.*; Firbank, L. G.*; Grand, S.*; Gudjonsdottir, M.*; et al.

Frontiers in Sustainable Food Systems (Internet), 5, p.663448_1 - 663448_11, 2021/07

 Times Cited Count:0 Percentile:0(Food Science & Technology)

Agriculture in the boreal and Arctic regions is perceived as marginal, low intensity and inadequate to satisfy the needs of local communities, but another perspective is that northern agriculture has untapped potential to increase the local supply of food and even contribute to the global food system. Policies across northern jurisdictions target the expansion and intensification of agriculture, contextualized for the diverse social settings and market foci in the north. However, the rapid pace of climate change means that traditional methods of adapting cropping systems and developing infrastructure and regulations for this region cannot keep up with climate change impacts. Moreover, the anticipated conversion of northern cold-climate natural lands to agriculture risks a loss of up to 76% of the carbon stored in vegetation and soils, leading to further environmental impacts. The sustainable development of northern agriculture requires local solutions supported by locally relevant policies. There is an obvious need for the rapid development of a transdisciplinary, cross-jurisdictional, long-term knowledge development, and dissemination program to best serve food needs and an agricultural economy in the boreal and Arctic regions while minimizing the risks to global climate, northern ecosystems and communities.

Journal Articles

Overview and outcomes of the OECD/NEA benchmark study of the accident at the Fukushima Daiichi NPS (BSAF), Phase 2; Results of severe accident analyses for unit 3

Lind, T.*; Pellegrini, M.*; Herranz, L. E.*; Sonnenkalb, M.*; Nishi, Yoshihisa*; Tamaki, Hitoshi; Cousin, F.*; Fernandez Moguel, L.*; Andrews, N.*; Sevon, T.*

Nuclear Engineering and Design, 376, p.111138_1 - 111138_12, 2021/05

 Times Cited Count:3 Percentile:81.22(Nuclear Science & Technology)

This is the third part of the three part paper describing the accidents at the FDNPS as analyzed in the Phase 2 of the OECD/NEA project "Benchmark Study of the Accident at the Fukushima Daiichi Nuclear Power Plant" (BSAF). In this paper, we describe the accident progression in unit 3. In the BSAF project, eight organizations from five countries analyzed severe accident scenarios for Unit 3 at the Fukushima Daiichi site using different severe accident codes. The present paper for Unit 3 describes the findings of the comparison of the participants' results against each other and against plant data, the evaluation of the accident progression and the final status inside the reactors. Special focus is on the status of the reactor pressure vessel, melt release and fission product release and transport. Unit 3 specific aspects, e.g., the complicated accident progression following repeated containment venting actuations and attempts at coolant injection at the time of the major core degradation, are highlighted and points of consensus as well as remaining uncertainties and data needs will be summarized. FP transport is analyzed, and the calculation results are compared with dose rate measurements in the containment. The release of I-131 and Cs-137 to the environment is compared with analysis conducted by using WSPEEDI code.

Journal Articles

$$^{60}$$Fe and $$^{244}$$Pu deposited on Earth constrain the r-process yields of recent nearby supernovae

Wallner, A.*; Froehlich, M. B.*; Hotchkis, M. A. C.*; Kinoshita, N.*; Paul, M.*; Martschini, M.*; Pavetich, S.*; Tims, S. G.*; Kivel, N.*; Schumann, D.*; et al.

Science, 372(6543), p.742 - 745, 2021/05

 Times Cited Count:1 Percentile:63.46(Multidisciplinary Sciences)

Half of the chemical elements heavier than iron are produced by the rapid neutron capture process (r-process). The sites and yields of this process are disputed, with candidates including some types of supernovae (SNe) and mergers of neutron stars. We search for two isotopic signatures in a sample of Pacific Ocean crust-iron-60 ($$^{60}$$Fe) (half-life, 2.6 million years), which is predominantly produced in massive stars and ejected in supernova explosions, and $$^{244}$$Pu (half-life, 80.6 million years), which is produced solely in r-process events. We detect two distinct influxes of $$^{60}$$Fe to Earth in the last 10 million years and accompanying lower quantities of $$^{244}$$Pu. The $$^{244}$$Pu/$$^{60}$$Fe influx ratios are similar for both events. The $$^{244}$$Pu influx is lower than expected if SNe dominate r-process nucleosynthesis, which implies some contribution from other sources.

Journal Articles

Development of a reference database for beta-delayed neutron emission

Dimitriou, P.*; Dillmann, I.*; Singh, B.*; Piksaikin, V.*; Rykaczewski, K. P.*; Tain, J. L.*; Algora, A.*; Banerjee, K.*; Borzov, I. N.*; Cano-Ott, D.*; et al.

Nuclear Data Sheets, 173, p.144 - 238, 2021/03

 Times Cited Count:1 Percentile:0.03(Physics, Nuclear)

$$beta$$-delayed neutron emission has been of interest since the discovery of nuclear fission. In nuclear power reactors, delayed-neutron data play a crucial role in reactor kinetics calculations and safe operation. $$beta$$-delayed neutron data also have a significant impact in the field of nuclear structure and astrophysics especially as nuclei farther away from stability are explored at the new generation of radioactive beam facilities. Several compilations of $$beta$$-decay half-lives and delayed-neutron emission probabilities are available, however, complete documentation of measurements and evaluation procedures is often missing for these properties. Efforts to address this gap in nuclear data and create an updated compilation and evaluation of $$beta$$-delayed neutron properties were undertaken under the auspices of the International Atomic Energy Agency (IAEA) which formed a Coordinated Research Project (CRP) on "Development of a Reference Database of Beta-delayed Neutron Emission Data". In this paper we summarize the work that was performed and present the results of the CRP.

Journal Articles

Morphological reproductive characteristics of testes and fertilization capacity of cryopreserved sperm after the Fukushima accident in raccoon (${it Procyon lotor}$)

Komatsu, Kazuki*; Iwasaki, Tsugumi*; Murata, Kosuke*; Yamashiro, Hideaki*; Goh, V. S. T.*; Nakayama, Ryo*; Fujishima, Yohei*; Ono, Takumi*; Kino, Yasushi*; Shimizu, Yoshinaka*; et al.

Reproduction in Domestic Animals, 56(3), p.484 - 497, 2021/03

We have established an archive system of livestock and wild animals from the surrounding ex-evacuation zone. Wildlife within the alert zone have been exposed to low-dose-rate (LDR) radiation for a long and continuous time. In this study, we analysed the morphological characteristics of the testes and in vitro fertilization (IVF) capacity of cryopreserved sperm of raccoons from the ex-evacuation zone of the FDNPP accident. This study revealed that the chronic and LDR radiation exposure associated with the FDNPP accident had no adverse effect on the reproductive characteristics and functions of male raccoons.

Journal Articles

Discovery of a new low energy neutron resonance of $$^{89}$$Y

Katabuchi, Tatsuya*; Toh, Yosuke; Mizumoto, Motoharu*; Saito, Tatsuhiro*; Terada, Kazushi*; Kimura, Atsushi; Nakamura, Shoji; Huang, M.*; Rovira Leveroni, G.; Igashira, Masayuki*

European Physical Journal A, 57(1), p.4_1 - 4_4, 2021/01

 Times Cited Count:0 Percentile:0.03(Physics, Nuclear)

Journal Articles

Review of Fukushima Daiichi Nuclear Power Station debris endstate location in OECD/NEA preparatory study on analysis of fuel debris (PreADES) project

Nakayoshi, Akira; Rempe, J. L.*; Barrachin, M.*; Bottomley, D.; Jacquemain, D.*; Journeau, C.*; Krasnov, V.; Lind, T.*; Lee, R.*; Marksberry, D.*; et al.

Nuclear Engineering and Design, 369, p.110857_1 - 110857_15, 2020/12

 Times Cited Count:0 Percentile:0.33(Nuclear Science & Technology)

Much is still not known about the end-state of core materials in each of the units at Fukushima Daiichi Nuclear Power Station (Daiichi) that were operating on March 11, 2011. The Nuclear Energy Agency of the Organization for Economic Development has launched the Preparatory Study on Analysis of Fuel Debris (PreADES) project as a first step to reduce some of these uncertainties. As part of the PreADES Task 1, relevant information was reviewed to confirm the accuracy of graphical depictions of the debris endstates at the damaged Daiichi units, which provides a basis for suggesting future debris examinations. Two activities have been completed within the PreADES Task 1. First, relevant knowledge from severe accidents at the Three Mile Island Unit 2 and the Chernobyl Nuclear Power Plant Unit 4 was reviewed, along with results from prototypic tests and hot cell examinations, to glean insights that may inform future decommissioning activities at Daiichi. Second, the current debris endstate diagrams for the damaged reactors at Daiichi were reviewed to confirm that they incorporate relevant knowledge from plant observations and from severe accident code analyses of the BSAF (Benchmark Study of the Accident at Daiichi Nuclear Power Station) 1 and 2 projects. This paper highlights Task 1 insights, which have the potential to not only inform future Decontamination and Decommissioning activities at Daiichi, but also provide important perspectives for severe accident analyses and management, particularly regarding the long term management of a damaged nuclear site following a severe accident.

Journal Articles

Overview and outcomes of the OECD/NEA benchmark study of the accident at the Fukushima Daiichi NPS (BSAF) Phase 2; Results of severe accident analyses for Unit 1

Herranz, L. E.*; Pellegrini, M.*; Lind, T.*; Sonnenkalb, M.*; Godin-Jacqmin, L.*; L$'o$pez, C.*; Dolganov, K.*; Cousin, F.*; Tamaki, Hitoshi; Kim, T. W.*; et al.

Nuclear Engineering and Design, 369, p.110849_1 - 110849_7, 2020/12

 Times Cited Count:5 Percentile:76.41(Nuclear Science & Technology)

Phase 2 of the OECD/NEA Project "Benchmark Study of the Accident at the Fukushima Daiichi Nuclear Power Plant (BSAF)" was established in mid-2015. The objectives have been similar to Phase 1 of the project but with an extended analysis period of 3 weeks, a major focus on FP behaviour and releases to the environment and the comparison to various data and results of backwards calculations of the source term. Nine organizations of six countries submitted results of their calculated severe accident scenarios for Unit 1 at the 1F site using different severe accident codes. This paper describes the findings of the comparison of the participants results for Unit1 against each other and against plant data, the evaluation of the accident progression and the final status inside the reactors. Special focus is on RPV status, melt release and FP behaviour and release. Unit specific aspects will be highlighted and points of consensus as well as remaining uncertainties and data needs will be summarised.

Journal Articles

Overview and outcomes of the OECD/NEA benchmark study of the accident at the Fukushima Daiichi NPS (BSAF), Phase 2; Results of severe accident analyses for Unit 2

Sonnenkalb, M.*; Pellegrini, M.*; Herranz, L. E.*; Lind, T.*; Morreale, A. C.*; Kanda, Kenichi*; Tamaki, Hitoshi; Kim, S. I.*; Cousin, F.*; Fernandez Moguel, L.*; et al.

Nuclear Engineering and Design, 369, p.110840_1 - 110840_10, 2020/12

 Times Cited Count:6 Percentile:84.6(Nuclear Science & Technology)

This is the second paper in a series of 3 in which results of severe accident analyses for Unit 2 of Fukushima Daiichi are presented, gained in Phase 2 of the OECD/NEA project "Benchmark Study of the Accident at the Fukushima Daiichi Nuclear Power Plant (BSAF)". Nine organizations of six countries submitted results of their calculated severe accident scenarios for Unit 2 of Fukushima Daiichi using different severe accident codes. The present paper describes the findings of the comparison of the participants' results for Unit 2 against each other and against plant data, the evaluation of the accident progression and the final status inside the reactors. Special focus is on reactor pressure vessel status, melt release and fission product behavior and release. Unit 2 specific aspects will be highlighted and points of consensus as well as remaining uncertainties and data needs will be summarized.

333 (Records 1-20 displayed on this page)