Momentum exchange functions model for SIMMER-III and SIMMER-IV

Tobita, Yoshiharu*; Kondo, Satoru; Suzuki, Toru*

JAEA-Research 2024-011, 39 Pages, 2024/10

JAEA-Research-2024-011.pdf:1.67MB

The SIMMER-III and SIMMER-IV computer code, developed at the Japan Atomic Energy Agency (JAEA), is a two- and three-dimensional, multi-velocity-field, multi-component fluid-dynamics model, coupled with a space- and time-dependent neutron kinetics model. The codes have been used widely for simulating complex phenomena during core-disruptive accidents in liquid-metal fast reactors. In the multi-velocity-field fluid dynamics, momentum exchange functions (MXFs) are required for treating inter-field drag and fluid-structure friction effects and thereby for accurately simulating reactivity effects of relative motion of core materials. Up to 8 velocity fields can be used in SIMMER-III and SIMMER-IV, with each field exchanging momentum with other fields and structure surfaces. Since both theoretical and experimental knowledge of the momentum exchange processes for a multi-component, multi-velocity flows is limited, the developed MXF formulations are based on engineering correlations of steady-state two-phase flows. Multi-phase flow regimes for both the pool and channel flows are modeled with using an appropriate averaging procedure such as to avoid abrupt changes in MXFs at flow regime transition. The MXF model, together with the multi-phase flow topology and interfacial area model, has been extensively tested through the code assessment (verification and validation) program, which has demonstrated that many of the problems associated with limitation of two velocity fields and simplistic modeling in the previous codes were resolved.

Experimental study on debris bed characteristics for the sedimentation behavior of solid particles used as simulant debris

Shamsuzzaman, M.*; Horie, Tatsuro*; Fuke, Fusata*; Kamiyama, Motoki*; Morioka, Toru*; Matsumoto, Tatsuya*; Morita, Koji*; Tagami, Hirotaka; Suzuki, Toru*; Tobita, Yoshiharu

Annals of Nuclear Energy, 111, p.474 - 486, 2018/01

https://doi.org/10.1016/j.anucene.2017.09.011

Study on In-Vessel Retention (IVR) of unprotected accident for fast reactor, 2; Assessment of PAMR/PAHR phase in ULOF

Sogabe, Joji; Suzuki, Toru; Wada, Yusaku; Tobita, Yoshiharu

Nihon Kikai Gakkai Rombunshu (Internet), 83(848), p.16-00393_1 - 16-00393_10, 2017/04

https://doi.org/10.1299/transjsme.16-00393

The achievement of In-Vessel Retention (IVR) of the accident consequences in an unprotected loss of flow (ULOF), which is one of the technically inconceivable events postulated beyond design basis, is effective and rational approach in enhancing the safety characteristics of sodium-cooled fast reactor. The objective of the present study is to show that the decay heat generated from the relocated fuels would be stably removed in post-accident-material-relocation/post-accident-heat-removal (PAMR/PAHR) phase, where the relocated fuels mean fuel discharged from the core into the low-pressure plenum through control-rod guide tubes, and fuel remnant in the disrupted core region (non-discharged fuel). As a result of the present assessments, it should be concluded that the stable cooling of the relocated fuels was confirmed and the prospect of IVR was obtained.

Irradiation test of semiconductor components on the shelf for nuclear robots based on Fukushima Accidents

Kawatsuma, Shinji; Nakai, Koji; Suzuki, Yoshiharu; Kase, Takeshi

QST-M-2; QST Takasaki Annual Report 2015, P. 81, 2017/03

https://repo.qst.go.jp/records/73804

Radiation Tolerance of semiconductor components on the shelf, utilized on the robots for emergency response or decommissioning in nuclear facilities, should be estimated. Just after the Fukushima Daiichi NPPs accidents occurred, a guideline, of irradiation tolerance estimation and management method of semiconductor components on the shelf, was tried to be made based on the old database developed in the course of Bilateral Servo Manipulator under the high radiation and high contamination environments. The estimation was conservative, because the data in the database were old and mainly based on the test results of silicon semiconductors. Ga-As Semiconductors are coming major recently, and expected to be higher radiation tolerance. For those reason, present semiconductor devices have irradiated and the irradiation tolerance have estimated.

Improvements to the simmer code model for steel wall failure based on EAGLE-1 test results

Toyooka, Junichi; Kamiyama, Kenji; Tobita, Yoshiharu; Suzuki, Toru

Proceedings of 10th Japan-Korea Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS-10) (USB Flash Drive), 7 Pages, 2016/11

Study on In-Vessel Retention (IVR) of unprotected accident for fast reactor, 2; Assessment of PAMR/PAHR phase in ULOF

Sogabe, Joji; Suzuki, Toru; Wada, Yusaku; Tobita, Yoshiharu

Dai-21-Kai Doryoku, Enerugi Gijutsu Shimpojiumu Koen Rombunshu (USB Flash Drive), 3 Pages, 2016/06

no abstracts in English

Preliminary analysis of the post-disassembly expansion phase and structural response under unprotected loss of flow accident in prototype sodium cooled fast reactor

Onoda, Yuichi; Matsuba, Kenichi; Tobita, Yoshiharu; Suzuki, Toru

Proceedings of 24th International Conference on Nuclear Engineering (ICONE-24) (DVD-ROM), 10 Pages, 2016/06

Lithium intercalation and structural changes at the LiCoO surface under high voltage battery operation

Taminato, So*; Hirayama, Masaaki*; Suzuki, Kota*; Tamura, Kazuhisa; Minato, Taketoshi*; Arai, Hajime*; Uchimoto, Yoshiharu*; Ogumi, Zempachi*; Kanno, Ryoji*

Journal of Power Sources, 307, p.599 - 603, 2016/03

https://doi.org/10.1016/j.jpowsour.2015.12.133

An epitaxial-film model electrode of LiCoO(104) was fabricated on SrRuO(100)/Nb:SrTiO(100) using pulsed laser deposition. The 50 nm thick LiCoO(104) film exhibited lithium (de-)intercalation activity with a first discharge capacity of 119 mAh g between 3.0 and 4.4 V, followed by a gradual capacity fading with subsequent charge-discharge cycles. In contrast, a 3.2 nm thick LiPO-coated film exhibited a higher intercalation capacity of 148 mAh g with superior cycle retention than the uncoated film. In situ surface X-ray diffraction measurements revealed a small lattice change at the coated surface during the (de-)intercalation processes compared to the uncoated surface. The surface modification of LiCoO by the LiPO coating could lead to improvement of the structural stability at the surface region during lithium (de-)intercalation at high voltage.

A Numerical study on local fuel-coolant interactions in a simulated molten fuel pool using the SIMMER-III code

Cheng, S.; Matsuba, Kenichi; Isozaki, Mikio; Kamiyama, Kenji; Suzuki, Toru; Tobita, Yoshiharu

Annals of Nuclear Energy, 85, p.740 - 752, 2015/11

https://doi.org/10.1016/j.anucene.2015.06.030

First analysis of local fuel-coolant interactions in a molten pool by SIMMER-III using reactor materials

Cheng, S.; Matsuba, Kenichi; Isozaki, Mikio; Kamiyama, Kenji; Suzuki, Toru; Tobita, Yoshiharu

Proceedings of 23rd International Conference on Nuclear Engineering (ICONE-23) (DVD-ROM), 9 Pages, 2015/05