High temperature gas-cooled reactors

Takeda, Tetsuaki*; Inagaki, Yoshiyuki; Aihara, Jun; Aoki, Takeshi; Fujiwara, Yusuke; Fukaya, Yuji; Goto, Minoru; Ho, H. Q.; Iigaki, Kazuhiko; Imai, Yoshiyuki; et al.

High Temperature Gas-Cooled Reactors; JSME Series in Thermal and Nuclear Power Generation, Vol.5, 464 Pages, 2021/02

https://doi.org/10.1016/C2018-0-05383-9

As a general overview of the research and development of a High Temperature Gas-cooled Reactor (HTGR) in JAEA, this book describes the achievements by the High Temperature Engineering Test Reactor (HTTR) on the designs, key component technologies such as fuel, reactor internals, high temperature components, etc., and operational experience such as rise-to-power tests, high temperature operation at 950C, safety demonstration tests, etc. In addition, based on the knowledge of the HTTR, the development of designs and component technologies such as high performance fuel, helium gas turbine and hydrogen production by IS process for commercial HTGRs are described. These results are very useful for the future development of HTGRs. This book is published as one of a series of technical books on fossil fuel and nuclear energy systems by the Power Energy Systems Division of the Japan Society of Mechanical Engineers.

In situ electrochemical, electrochemical quartz crystal microbalance, scanning tunneling microscopy, and surface X-ray scattering studies on Ag/AgCl reaction at the underpotentially deposited Ag bilayer on the Au(111) electrode surface

Uosaki, Kohei*; Morita, Jun*; Katsuzaki, Tomoko*; Takakusagi, Satoru*; Tamura, Kazuhisa; Takahashi, Masamitsu; Mizuki, Junichiro; Kondo, Toshihiro*

Journal of Physical Chemistry C, 115(25), p.12471 - 12482, 2011/06

https://doi.org/10.1021/jp2010502

Ag/AgCl reaction at the Ag bilayer, which was underpotentially prepared on a Au(111) surface, was investigated using electrochemical quartz crystal microbalance (EQCM), scanning tunneling microscopy (STM), surface X-ray scattering (SXS), and electrochemical techniques. When the potential was scanned positively from -200 mV, the Cl ion was adsorbed on the Au(111) electrode surface around 0 mV, and then the phase transition of the adsorbed Cl ion layer from random orientation to ( ) structure took place at around +130 mV. The Ag bilayer and Cl ions were oxidatively reacted to form the AgCl monolayer with ( ) 13.9 structure around +200 mV, accompanied with the formation of AgCl monocrystalline clusters on the AgCl monolayer surface. The structure of the AgCl monolayer on the Au(111) surface was changed from ( )R13.9 structure to (44) structure around +500 mV.

Structure of Au(111) and Au(100) single-crystal electrode surfaces at various potentials in sulfuric acid solution determined by in situ surface X-ray scattering

Kondo, Toshihiro*; Morita, Jun*; Hanaoka, Kazuya*; Takakusagi, Satoru*; Tamura, Kazuhisa; Takahashi, Masamitsu; Mizuki, Junichiro; Uosaki, Kohei*

Journal of Physical Chemistry C, 111(35), p.13197 - 13204, 2007/09

https://doi.org/10.1021/jp072601j

Potential-dependent surface structures of Au(111) and Au(100) single-crystal electrodes in a 50 mM HSO solution were investigated at an atomic level using in situ surface X-ray scattering (SXS) techniques. It was confirmed that both the Au(111) and Au(100) surfaces were reconstructed with an attached submonolayer of an oxygen species, most probably water, at 0 V (vs Ag/AgCl). Results at +0.95 V supported a previously suggested model for both the Au(111) and the Au(100) electrodes that, based on infrared and scanning tunneling microscopy measurements, the surfaces were a (11) structure with the coadsorbed sulfate anion and hydronium cation (HO). At +1.05 V, where a small amount of an anodic current flowed, adsorption of a monolayer of oxygen species was observed on both surfaces.

The Development of SIMMER-III, an advanced computer program for LMFR safety analysis, and its application to sodium experiments

Tobita, Yoshiharu; Kondo, Satoru; Yamano, Hidemasa; Morita, Koji*; Maschek, W.*; Coste, P.*; Cadiou, T.*

Nuclear Technology, 153(3), p.245 - 255, 2006/03

https://doi.org/10.13182/NT06-2

SIMMER-III is a general two-dimensional, three-velocity-field, multiphase, multicomponent, Eulerian, fluid-dynamics code coupled with a space-time and energy-dependent neutron transport kinetics model. The philosophy behind the SIMMER development was to generate a versatile and flexible tool, applicable for the safety analysis of various reactor types with different neutron spectra and coolants, up the new accelerator driven systems (ADS) for waste transmutation. SIMMER-III has proven especially well suited for fast spectrum systems as the LMFR, where it is one of the key codes for safety analysis, including its application within licensing procedures. To serve especially the last purpose, the code must be made sufficiently robust and reliable, and be tested and validated extensively. A comprehensive and systematic assessment program of the code has been conducted. This paper gives the major achievement of this assessment program. The code assessment program is an ongoing effort. Two major milestones have been achieved in the past by completing two assessment campaigns, Phase 1 and Phase 2. Phase 1 for fundamental code assessment of individual models; and Phase 2 for integral code assessment for key phenomena relevant to LMFR safety. Through this systematic code assessment program, comprehensive validation of the physical models has been conducted step-by-step. The assessment program has demonstrated that SIMMER-III is a state-of-the-art code with advanced models sufficiently flexible for simulating transient multiphase phenomena occurring during CDAs. In this paper we will concentrate on the specifics of the code, mainly reflected at its application to sodium experiments related to the safety of LMFR.

SIMMER-III: A Computer Program for LMFR Core Disruptive Accident Analysis; Version 3.A Model Summary and Program Description

Yamano, Hidemasa; Fujita, Satoshi; Tobita, Yoshiharu; Kamiyama, Kenji; Kondo, Satoru; Morita, Koji*; Fischer, E. A.; Brear, D. J.; Shirakawa, Noriyuki*; Cao, X.; et al.

JNC TN9400 2003-071, 340 Pages, 2003/08

JNC-TN9400-2003-071.pdf:1.54MB

An advanced safety analysis computer code, SIMMER-III, has been developed to investigate postulated core disruptive accidents in liquid-metal fast reactors (LMFRs). SIMMER-III is a two-dimensional, three-velocity-field, multiphase, multicomponent, Eulerian, fluid-dynamics code coupled with a space-dependent neutron kinetics model. By completing and integrating all the physical models originally intended at the beginning of this code development project, SIMMER-III is now applicable to integral reactor calculations and other complex multiphase flow problems. A systematic code assessment program, conducted in collaboration with European research organizations, has shown that the advanced features of the code have resolved many of the limitations and problem areas in the previous SIMMER-II code. In this report, the models, numerical algorithms and code features of SIMMER-III Version 3.A are described along with detailed program description. Areas which require future model refinement are also discussed. SIMMER-III Version 3.A, a coupled fluid-dynamics and neutronics code system, is expected to significantly improve the flexibility and reliability of LMFR safety analyses.

SIMMER-III/IV Heat-and Mass-Transfer Model; Model and Method Description

Morita, Koji*; Yamano, Hidemasa; Tobita, Yoshiharu; Kondo, Satoru

JNC TN9400 2003-047, 116 Pages, 2003/07

JNC-TN9400-2003-047.pdf:0.62MB

The present report gives the SIMMER-III/IV heat- and mass-transfer model describing melting/freezing (M/F) and vaporization/condensation (V/C) processes in multiphase, multicomponent systems. The heat- and mass-transfer processes are modeled in consideration of their importance in and effects on the behavior of reactor-core materials in the fast reactor safety analysis. Applying equilibrium and non-equilibrium transfers generalizes the phase-transition processes except for the structure breakup transfer. The non-equilibrium phase-transition processes occurring at interfaces are described by the heat-transfer limited model, while the mass-diffusion limited model is employed to represent effects of noncondensable gases and multicomponent mixture on the V/C processes. The implicit solution algorithm of V/C calculation is tightly coupled with the analytic equation-of-state (EOS) model. The use of this approach successfully solves numerical problems, which were mainly introduced by thermody

SIMMER-3 Heat-and Mass-Transfer Model -Model and Method Description-

Morita, Koji*; Tobita, Yoshiharu; Yamano, Hidemasa; kondo, Satoru

JNC TN9400 2001-074, 108 Pages, 2001/08

JNC-TN9400-2001-074.pdf:2.5MB

The present report gives the SIMMER-IIl heat- and mass-transfer model describing melting/freezing and vaporization/condensation processes in multiphase, multicomponent systems, The heat- and mass-transfer processes are modeled in consideration of their importance in and effects on the behavior of reactor-core materials in the fast reactor safety analysis. Applying equilibrium and non-equilibrium transfers generalizes the phase-transition processes except for the structure breakup transfer. The non-equilibrium transfers occurring at interfases were formulated on the basis of the heat-transfer-limited model. The implicit solution algorithm for basic vaporization/condensation equations is tightly coupled with the analytic equation-of-state (EOS) model. The use of this approach successfully solves numerical problems encountered in the previous codes, which were mainly introduced by thermodynamic inconsistencies in EOS.

None

Morita, Koji*; *; Fukuda, Kenji*; Tobita, Yoshiharu; Yamano, Hidemasa; Suzuki, Toru; kondo, Satoru

JNC TY9400 2000-013, 60 Pages, 2000/04

JNC-TY9400-2000-013.pdf:1.58MB

no abstracts in English

SIMMER-III Analytic Thermophysical Property Model

Morita, Koji; Tobita, Yoshiharu; kondo, Satoru; E.A.Fischer*

JNC TN9400 2000-004, 38 Pages, 1999/05

JNC-TN9400-2000-004.pdf:1.11MB

An analytic thermophysical property model using general function forms is developed for a reactor safety analysis code, SIMMER-III. The function forms arc designed to represent correct behavior of properties of reactor-core materials over wide temperature ranges, especially for the thermal conductivity and the viscosity near the critical point. The most up-to-date and reliable sources for uranium dioxide, mixed-oxide fuel, stainless stee1, and sodium available at present are used to determine parameters in the proposed functions. This model is also designed to be consistent with a SIMMER-III model on thermodynamic properties and equations of state for reactor-corc materials.

Preparation method of ORIGEN2 library for high temperature gas-cooled reactors

Simanullang, I. L.*; Fukuhara, Katsuki*; Morita, Keisuke; Fukaya, Yuji; Ho, H. Q.; Nagasumi, Satoru; Iigaki, Kazuhiko; Ishitsuka, Etsuo; Fujimoto, Nozomu*

no journal, ,