Malins, A.; Lemoine, T.*
Journal of Open Source Software (Internet), 7(71), p.3318_1 - 3318_6, 2022/03
Meng, L.*; Wang, G.-J.*; Wang, B.*; Zhu, S.-L.*
Physical Review D, 104(5), p.L051502_1 - L051502_8, 2021/09
We investigate the kinetically allowed strong and electromagnetic decays of the recently observed . Our results show that the decay width of is the largest one, which is just the experimental observation channel. Our theoretical total strong and radiative widths are in favor of the as a dominated bound state. Our calculation is cutoff-independent and without prior isospin assignment. The absolute partial widths and ratios of the different decay channels can be used to test the structure of state when the updated experimental results are available.
Yokoyama, Kenji; Jin, Tomoyuki*
JAEA-Data/Code 2021-001, 47 Pages, 2021/03
A new burnup/depletion calculation code, CRAMO, was developed by combining an ORIGEN2 cross-section library set, ORLIB, based on Japanese evaluated nuclear data library, JENDL, and a burnup/depletion solver based on Chebyshev rational approximation method. CRAMO uses the ORIGEN2 cross-section library set ORLIBJ40 based on JENDL-4.0, and the burnup/depletion solver implemented in the versatile reactor analysis code system, MARBLE. It was confirmed that results of CRAMO agreed well with those of ORIGEN2 for burnup/depletion and radioactivity calculation cases. The development of CRAMO made it possible to use ORLIB without using ORIGEN2. It will be possible to provide an easy-to-use processed JENDL data set for burnup/depletion and radioactivity calculations in combination with a burnup/depletion based on Chebyshev rational approximation method. The present version of CRAMO is a subset of ORIGEN2 and can compute only compositions and radioactivities after irradiation. However, since various kinds of outputs of ORIGEN2 can be evaluated by using the composition, it is possible to reproduce many functions of ORIGEN2 by adding post-processing modules.
Wang, G.-J.*; Meng, L.*; Xiao, L.-Y.*; Oka, Makoto; Zhu, S.-L.*
European Physical Journal C, 81(2), p.188_1 - 188_12, 2021/02
The mass spectrum and strong decays of the S-wave states are studied in the compact tetraquark scenario with the quark model. The model consists of the Coulomb, the linear confinement, and the hyperfine interactions. We calculate their decay amplitudes into the channels using the quark interchange method. The mass and decay width of the state are MeV and MeV, respectively, which indicates that it might be a good candidate for the recently observed state. We also obtain an isospin partner state with MeV and MeV, respectively. Future experimental search for will be very helpful.
Yokoyama, Kenji; Lahaye, S.*
Proceedings of Joint International Conference on Supercomputing in Nuclear Applications + Monte Carlo 2020 (SNA + MC 2020), p.109 - 116, 2020/10
CEA/DEN/DM2S/SERMA and JAEA/NSEC are working on benchmarks for burnup, isotopic concentrations and decay heat calculations in the collaboration framework between both organisms. Both actors of this benchmark are independently developing their own simulation code systems for computing quantities of interest in nuclear fuel cycle domain: MENDEL in CEA and MARBLE in JAEA. The purpose of the benchmark is to verify each system by comparing both calculation results on specific applications. MENDEL uses a several solvers for the resolution of Bateman equation. Runge-Kutta method or Chebyshev Rational Approximation method (CRAM) are used for irradiation computations. An analytical solver can also be used for decay calculations. MARBLE can use Krylov subspace method or CRAM method. As the first phase of the benchmark, we compared the calculated results of decay heat and isotropic concentrations following by a Pu-239 fast fission pulse. We applied nuclear data from three libraries: (1) JEFF-3.1.1, (2) JENDL/DDF-2015 + JENDL/FPY-2011, and (3) ENDF/B-VII.1. Nuclear data and burnup chain were generated from these libraries independently on each system. We confirmed that the results for both systems were in very good agreement with each other. Numerical results were also compared to experimental data. As the second phase of the benchmark, we are proceeding with a burnup calculation benchmark of MENDEL and MARBLE using the nuclear data and burnup chain provided by ORLIBJ33, which is a set of cross-section data based on JENDL-3.3 for ORIGEN-2 code system. We will also compare with calculation results by the ORIGEN-2 code with ORLIBJ33. Since the series of ORLIB, that is, ORLIBJ32, ORLIBJ33, and ORLIBJ40, have been widely used especially in Japan for many years, the comparison with ORLIB is effective for confirming the performance of MENDEL and MARBLE.
Ono, Ayako; Tanaka, Masaaki; Miyake, Yasuhiro*; Hamase, Erina; Ezure, Toshiki
Mechanical Engineering Journal (Internet), 7(3), p.19-00546_1 - 19-00546_11, 2020/06
Fully natural circulation decay heat removal systems (DHRSs) are to be adopted for sodium fast reactors, which is a passive safety feature without any electrical pumps. It is required to grasp the thermal-hydraulic phenomena in the reactor vessel and evaluate the coolability of the core under the natural circulation not only for the normal operating condition but also for severe accident conditions. In this paper, the numerical results of the preliminary analysis for the sodium experimental condition with the PLANDTL-2 are discussed to establish an appropriate numerical models for the reactor core including the gap region among the subassemblies and the DHX. From these preliminary analyses, the characteristics of the thermal-hydraulics behavior in the PLANDTL-2 to be focused are extracted.
Yamashita, Takuya; Sawada, Noriyoshi*
JAEA-Research 2019-010, 227 Pages, 2020/03
In order to support the decontamination activities proceeded by the national government and municipalities in terms of technology, we have developed a simulation system "RESET" which predicts the effect of decontamination. We also developed a "two-component model" for the purpose of predicting long-term changes in the air dose rate. We use these tools to perform decontamination simulation and predictive analysis of the air dose rate after decontamination, and provide information to the national government and municipalities aiming for reconstruction. In this report, the verification result of the prediction methods implemented using actual measurement data obtained in the "Decontamination model demonstration project in difficult-to-return zone" and "Survey result on transition of air dose rate after decontamination model demonstration project" conducted by Ministry of the Environment. In addition, the decontamination simulation conducted for the entire difficult-to-return area and the results of future prediction of the air dose rate after decontamination are shown.
Katano, Ryota; Yamanaka, Masao*; Pyeon, C. H.*
Journal of Nuclear Science and Technology, 57(2), p.169 - 176, 2020/02
We proposed the linear combination method as a subcriticality measurement method which estimates the prompt neutron decay constant () correlated with the subcriticality using measurement results obtained at multiple detector positions. In the previous study, we confirmed applicability of the linear combination method through the pulsed neutron experiment with DT neutron source at Kyoto University Critical Assembly (KUCA). In this study, we conduct the pulsed neutron source experiment with spallation neutrons at KUCA and confirm the robustness of the linear combination to neutron sources.
Cubiss, J. G.*; Harding, R. D.*; Andreyev, A. N.; Althubiti, N.*; Andel, B.*; Antalic, S.*; Barzakh, A. E.*; Cocolios, T. E.*; Day Goodacre, T.*; Farooq-Smith, G. J.*; et al.
Physical Review C, 101(1), p.014314_1 - 014314_4, 2020/01
The -decay branching ratio of 0.52(5)% from the ground state of Pt to the ground state of the daughter nucleus Os has been determined more precisely than before. The Pt was produced as the -decay granddaughter of Hg which was produced and separated with the CERN-ISOLDE facility. The reduced -decay width calculated with the present result has provided a new picture of the systematics for the -decay width of neutron-deficient Pt isotopes.
Sun, M. D.*; Liu, Z.*; Huang, T. H.*; Zhang, W. Q.*; Andreyev, A. N.; Ding, B.*; Wang, J. G.*; Liu, X. Y.*; Lu, H. Y.*; Hou, D. S.*; et al.
Physics Letters B, 800, p.135096_1 - 135096_5, 2020/01
Katano, Ryota; Yamanaka, Masao*; Pyeon, C. H.*
Nuclear Science and Engineering, 193(12), p.1394 - 1402, 2019/12
The author proposed the linear combination method as a subcriticality measurement method which estimates the prompt neutron decay constant (alpha) correlated with the subcriticality using measurement results obtained at multiple detector positions. In this study, we conduct the pulsed neutron experiment at Kyoto University Critical Assembly (KUCA) and measure alpha by the linear combination method using measured neutron counts. Through experiment, we experimentally show that the linear combination method can reduce the higher-mode effect compared to the conventional method. In addition, experimentally show that the linear combination has capability of the different mode extraction.
Cubiss, J. G.*; Andreyev, A. N.; Barzakh, A. E.*; Andel, B.*; Antalic, S.*; Cocolios, T. E.*; Day Goodacre, T.*; Fedorov, D. V.*; Fedosseev, V. N.*; Ferrer, R.*; et al.
Physical Review C, 99(6), p.064317_1 - 064317_6, 2019/06
An decay of At was studied at the CERN-ISOLDE facility using a laser-ionization technique. Coincidence - data were collected for the first time and a more precise half-life value of T = 1.27(6) s was measured. A new -decay scheme was deduced based on the fine-structure of the decay. The results lead to a preferred spin and parity assignment of J = (3) for the ground state of At; however, J = (2) cannot be fully excluded.
Ono, Ayako; Tanaka, Masaaki; Miyake, Yasuhiro*; Hamase, Erina; Ezure, Toshiki
Proceedings of 27th International Conference on Nuclear Engineering (ICONE-27) (Internet), 7 Pages, 2019/05
Decay heat removal system (DHRS) by using the natural circulation without depending on the pump as the mechanical equipment is recognized as one of the most effective methodologies for the sodium-cooled fast reactor from the viewpoint of the safety enhancement. In this paper, the numerical simulation results of the preliminary analysis for the sodium experiment with the apparatus of PLANDTL-2, in which the core and the upper plenum with a dipped-type direct heat exchanger (DHX) were modeled, were discussed, in order to establish appropriate numerical models for the reactor core including the gap region among the subassemblies and the DHX.
Nuclear Science and Engineering, 193(4), p.431 - 439, 2019/04
We proposed "linear combination method" to reduce the higher order mode effect on the prompt neutron decay constant measured by the pulsed neutron experiment. When the spatial higher order mode effect is taken into account, the time evolution of the neutron counts after the pulsed neutron injection is given by linear combination of multiple exponential functions. However, the measurement results by the conventional method include the systematic error derived from the higher order mode effect because the conventional method fit the neutron counts with a single exponential function. The proposed method extract the single exponential function of the fundamental mode by linear combination of the neutron counts at multiple detectors, thus the proposed method reduces the higher order mode effect. As the verification, we applied the proposed method to the numerical simulation. The results indicate that the proposed method can reduce the higher order mode effect by linear combination.
Nishino, Hiroyuki; Yamano, Hidemasa; Kurisaka, Kenichi
Mechanical Engineering Journal (Internet), 5(4), p.18-00079_1 - 18-00079_17, 2018/08
Hourcade, E.*; Mihara, Takatsugu; Dauphin, A.*; Dirat, J.-F.*; Ide, Akihiro*
Proceedings of 2018 International Congress on Advances in Nuclear Power Plants (ICAPP 2018) (CD-ROM), p.556 - 561, 2018/04
In the framework of the French-Japanese agreement signed in 2014, CEA, AREVA NP, JAEA, and MHI/MFBR is jointly performing components design of ASTRID such as Decay Heat Removal Systems (DHRS). This paper is giving an update concerning ASTRID DHR strategy with description of reference architecture evolution and project objectives. In particular, new developments were made for DHR during normal shutdown and role of Ex-Vessel system. A special focus is made on design process of automatic shutter to hydraulically connect Hot Plenum and cold plenum to enhance primary vessel natural convection.
Van Duppen, P.*; Andreyev, A. N.
The Euroschool of Exotic Beams, Vol.5, p.65 - 116, 2018/04
Honda, Yuki; Inaba, Yoshitomo; Nakagawa, Shigeaki; Yamazaki, Kazunori; Kobayashi, Shoichi; Aono, Tetsuya; Shibata, Taiju; Ishitsuka, Etsuo
JAEA-Technology 2017-013, 20 Pages, 2017/06
Decay heat is one of an important factor for a safety evaluation of depressurized loss-of-forced cooling accident, a representative high consequence accident, in high temperature gas-cooled reactor (HTGR). Traditionally, a conservative decay heat curve is used for safety analysis according to the regulatory standards. On the other hand, there is growing interest in obtaining test data related to decay heat for the use of uncertainty analysis. However, such data has not been obtained for prismatic-type HTGR. Therefore, we have launched a test program to obtain the decay heat data from the HTTR. As an initial step, an applicability confirmation test of decay heat evaluation method for HTGR was conducted in February 2017 without non-nuclear heating condition. This report introduces an estimation method for the decay heat based on test data using HTTR and shows the results of validation of the reactor residual heat evaluation method which will be used to obtain the decay heat data based on test data.
Doda, Norihiro; Hiyama, Tomoyuki; Tanaka, Masaaki; Ohshima, Hiroyuki; Thomas, J.*; Vilim, R. B.*
Proceedings of International Conference on Fast Reactors and Related Fuel Cycles; Next Generation Nuclear Systems for Sustainable Development (FR-17) (USB Flash Drive), 10 Pages, 2017/06
In sodium-cooled fast reactors, a natural circulation is expected to remove the core decay heat when the plant gets into a station blackout. From a perspective of reactor safety, the core hot spot temperature arising in the natural circulation should be evaluated accurately. To this end, Japan Atomic Energy Agency is trying to couple a 1-D plant dynamics analysis code Super-COPD and a 3-D CFD code AQUA to solve the thermal-hydraulic field in the whole plant under natural circulation condition. As a validation study, the coupled code was applied to an analysis of EBR-II shutdown heat removal test. The obtained numerical results reasonably agreed with the measured data, which demonstrated the validity of the coupled code.
Ono, Ayako; Kurihara, Akikazu; Tanaka, Masaaki; Ohshima, Hiroyuki; Kamide, Hideki; Miyake, Yasuhiro*; Ito, Masami*; Nakane, Shigeru*
Proceedings of 2017 International Congress on Advances in Nuclear Power Plants (ICAPP 2017) (CD-ROM), 10 Pages, 2017/04
The water experiment apparatus simulating the thermal hydraulics in a reactor vessel under operating the decay heat removal systems (DHRSs) was fabricated. The theoretical evaluation for similarity and results of basic experiments show applicability for a scale model experiment of a sodium-cooled fast reactor. This paper, moreover, describes the results of flow visualization experiment under operating a dipped-type passive DHX, which is planned to be installed in both a loop type reactor and pool type reactor, and the calculation results using FLUENT comparing with the result of water experiment.