Uncertainty quantification for severe-accident reactor modelling; Results and conclusions of the MUSA reactor applications work package

Brumm, S.*; Gabrielli, F.*; Sanchez Espinoza, V.*; Stakhanova, A.*; Groudev, P.*; Petrova, P.*; Vryashkova, P.*; Ou, P.*; Zhang, W.*; Malkhasyan, A.*; et al.

Annals of Nuclear Energy, 211, p.110962_1 - 110962_16, 2025/02

https://doi.org/10.1016/j.anucene.2024.110962

PANDORA Project for the study of photonuclear reactions below

Tamii, Atsushi*; Pellegri, L.*; Sderstrm, P.-A.*; Allard, D.*; Goriely, S.*; Inakura, Tsunenori*; Khan, E.*; Kido, Eiji*; Kimura, Masaaki*; Litvinova, E.*; et al.

European Physical Journal A, 59(9), p.208_1 - 208_21, 2023/09

https://doi.org/10.1140/epja/s10050-023-01081-w

no abstracts in English

Evidence for strong correlations at finite temperatures in the dimerized magnet NaCuTeO

Shangguan, Y.*; Bao, S.*; Dong, Z.-Y.*; Cai, Z.*; Wang, W.*; Huang, Z.*; Ma, Z.*; Liao, J.*; Zhao, X.*; Kajimoto, Ryoichi; et al.

Physical Review B, 104(22), p.224430_1 - 224430_8, 2021/12

https://doi.org/10.1103/PhysRevB.104.224430

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

https://doi.org/10.1016/j.nucengdes.2021.111138

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.

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.*; Lpez, C.*; Dolganov, K.*; Cousin, F.*; Tamaki, Hitoshi; Kim, T. W.*; et al.

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

https://doi.org/10.1016/j.nucengdes.2020.110849

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.

Multiple magnetic bilayers and unconventional criticality without frustration in BaCuSiO

Allenspach, S.*; Biffin, A.*; Stuhr, U.*; Tucker, G. S.*; Kawamura, Seiko; Kofu, Maiko; Voneshen, D. J.*; Boehm, M.*; Normand, B.*; Laflorencie, N.*; et al.

Physical Review Letters, 124(17), p.177205_1 - 177205_7, 2020/05

https://doi.org/10.1103/PhysRevLett.124.177205

Numerical analytic continuation of Euclidean data

Tripolt, R.-A.*; Gubler, P.; Ulybyshev, M.*; von Smekal, L.*

Computer Physics Communications, 237, p.129 - 142, 2019/04

AA2019-0105.pdf:1.15MB

https://doi.org/10.1016/j.cpc.2018.11.012

In this work we present a direct comparison of three different numerical analytic continuation methods: the Maximum Entropy Method, the Backus-Gilbert method and the Schlessinger point or Resonances Via Pade method. First, we perform a benchmark test based on a model spectral function and study the regime of applicability of these methods depending on the number of input points and their statistical error. We then apply these methods to more realistic examples, namely to numerical data on Euclidean propagators obtained from a Functional Renormalization Group calculation, to data from a lattice Quantum Chromodynamics simulation and to data obtained from a tight-binding model for graphene in order to extract the electrical conductivity.

Development of an altitude-keeping system for underwater robots using laser beams

Takemura, Fumiaki*; Taba, Ryo*; Hirayama, Keita*; Tansuriyavong, S.*; Kawabata, Kuniaki; Sagara, Shinichi*; Ogasawara, Kei*

Artificial Life and Robotics, 22(4), p.405 - 411, 2017/12

https://doi.org/10.1007/s10015-017-0377-y

The manta method is a survey method that divers investigate the degree of coral and whitening state while being towed to a boat. The manta method makes great physical burden. Therefore, the authors think that this task can substitute an underwater robot. This underwater robot is desirable to be able to keep altitude above the seabed. Hence, the authors have been developing the altitude (its distance above the sea floor) keeping system for an underwater robot. Visual recognition of distant underwater objects is possible in the water with high transparency, for example, in the coastal sea area of Okinawa prefecture, Japan. So, the authors have been adopting the distance measuring method using the two laser beams and a monocular camera with image processing. It realize to keep altitude of an underwater robot by using such devices. The evaluation experiments of the altitude keeping system are carried out in the pool.

Single-neutron orbits near Ni; Spectroscopy of the N=49 isotope Zn

Orlandi, R.; Mcher, D.*; Raabe, R.*; Jungclaus, A.*; Pain, S. D.*; Bildstein, V.*; Chapman, R.*; De Angelis, G.*; Johansen, J. G.*; Van Duppen, P.*; et al.

Physics Letters B, 740, p.298 - 302, 2015/01

https://doi.org/10.1016/j.physletb.2014.12.006

Measurement and model analysis of cross sections for Cr, Fe, Co, and Ni from threshold energy to 150 MeV

Kunieda, Satoshi; Haight, R. C.*; Kawano, Toshihiko*; Chadwick, M. B.*; Sterbenz, S. M.*; Bateman, F. B.*; Wasson, O. A.*; Grimes, S. M.*; Maier-Komor. P.*; Vonach, H.*; et al.

Physical Review C, 85(5), p.054602_1 - 054602_10, 2012/05

https://doi.org/10.1103/PhysRevC.85.054602

Neutron reactions that produce alpha-particles have been investigated for energies from threshold to 150 MeV on elemental chromium, iron, Co and Ni. The cross sections were measured at the Los Alamos Neutron Science Center by direct observation of alpha-particles. The model calculations are made for statistical and pre-equilibrium processes. This study particularly focuses on the pre-equilibrium cluster emission, which is described by the clustering exciton model of Iwamoto and Harada. We calculate the alpha-particle formation factors numerically without any approximations that appeared in the original model. The calculated alpha-particle production cross sections agree well with the measured data, except for the Cr case. With a simple sensitivity study for the level density parameters, it is reported that relatively small changes in the level density parameters improve reproduction of experimental data significantly.