Development of numerical estimation method using spatial connection methodology for thermal striping in upper plenum of reactor vessel of an advanced loop-type sodium-cooled fast reactor in Japan

Tanaka, Masaaki; Murakami, Satoshi*

Proceedings of 25th International Conference on Nuclear Engineering (ICONE-25) (CD-ROM), 10 Pages, 2017/07

Thermal striping on the core instrumentation plate (CIP) around the primary control rod (PCR) and backup control rod (BCR) channels and the radial blanket fuel assemblies (RBAs) may be caused. Since the interaction between neighbor areas exists in the UIS and the cold sodium flowing from the RBA is affected by the external flow around the UIS, a spatial connection method consisting of the numerical model for the whole upper plenum and the local target area has been developed. The numerical results were compared with the experimental results to confirm applicability of the method to the practical problem. And, sensitivity of mesh arrangement to the numerical results was discussed by using wide and narrow area models with two different spatial resolutions in each model. Through the examinations, appropriate local model for the spatial connection mothed could be proposed.

Development of V2UP (V&V plus uncertainty quantification and prediction) procedure for high cycle thermal fatigue in fast reactor; Framework for V&V and numerical prediction

Tanaka, Masaaki; Ohno, Shuji; Ohshima, Hiroyuki

Nuclear Engineering and Design, 299, p.174 - 183, 2016/04

https://doi.org/10.1016/j.nucengdes.2015.07.010

A procedure called as V2UP (Verification and Validation plus Uncertainty quantification and Prediction) was made by referring to the existing guidelines on V&V and the methodologies of the safety assessment (CSAU, ISTIR, EMDAP). The V2UP consisted of five components as follows: (1) phenomena analysis with the Phenomena Identification and Ranking Table (PIRT) method, (2) implementation of the V&V, (3) design and rearrangement of experiments for the V&V, (4) uncertainty quantification in each problem and integration of uncertainties and (5) numerical prediction (estimation) for the target issue. Although the complete application of the procedure has not been performed at this moment, a flow chart of the V2UP procedure was described in this paper with recent results of the examinations.

Establishment of numerical estimation method for high cycle thermal fatigue estimation in sodium-cooled fast reactor, 1; Conceptual model development for numerical estimation by using PIRT method

Tanaka, Masaaki

Dai-20-Kai Doryoku, Enerugi Gijutsu Shimpojiumu Koen Rombunshu, p.55 - 58, 2015/06

Numerical estimation method for high cycle thermal fatigue on a structure has been developed in JAEA. In development of numerical simulation codes and application of the codes to plant design, implementation of verification and validation (V&V) is indispensable. A procedure called as V2UP (Verification and Validation plus Uncertainty quantification and Prediction) has been made by referring to the existing guidelines on V&V. The PIRT (Phenomena Identification and Ranking Table) method based on the nine-step process used by the USNRC for the next generation nuclear plant development was employed at the first step of the V2UP. Through the first step of the V2UP with PIRT method, the conceptual model for the numerical estimation of high cycle thermal fatigue was successfully constructed.

Numerical investigation on thermal striping phenomena in a T-junction piping system

Tanaka, Masaaki; Miyake, Yasuhiro*

Proceedings of 22nd International Conference on Nuclear Engineering (ICONE-22) (DVD-ROM), 13 Pages, 2014/07

https://doi.org/10.1115/ICONE22-30683

In this study, numerical simulation for the WATLON experiment which was the water experiment of a T-junction piping system (T-pipe) was carried out to validate the MUGTHES and to investigate the relation between the mechanism of temperature fluctuation generation and the unsteady motion of large eddy structures. In the numerical simulation, the large eddy simulation (LES) approach with standard Smagorinsky model was employed as eddy viscosity model to simulate large scale eddy motion in the T-pipe. As for uncertainty quantification in the validation process, the modified method of the Grid Convergence Index (GCI) estimation based on the least squire version could successfully quantify uncertainty. Through the numerical simulations, it was indicated that the fine mesh arrangement could improve the temperature distribution in the wake. It could be found that the thermal mixing phenomena in the T-pipe were caused by the mutual interaction of the necklace-shaped vortex around the wake from the front of the branch jet, the horseshoe-shaped vortex and the Karman's vortex motions in the wake.

CompalisonoFnlermohydraulicCharacteristicsintheuseofvariousCoolants

; ; *; Yamaguchi, Akira

JNC TN9400 2000-109, 96 Pages, 2000/11

JNC-TN9400-2000-109.pdf:9.56MB

Numerical calculations were carried out for a free surface sloshing, a thermal stratification, a thermal striping, and a natural convection as key phenomena of in-vessel thermohydraulics in future fast reactor systems with various fluids as coolants. This numerical work was initiaied based on a recognition that the fundamental characteristics of the phenomena have been unsolved quantitatively in the use of various coolants. From the analysis for the phenomena, the following results were obtained. [Free Surface Sloshing phenomena] (1)Ther is no remarkable difference betweeen liquid sodium and luquid Pb-Bi in characteristics of internal flows and free surface charatristics based on Fr number. (2)the AQUA-VOF code has a potentiall enough to evaluate gas entrainment behavior from the free surface including the internal flow characteristics. [thermal Stratification Phenomena] (1)On-set position of thermal entainment process due to dynamic vortex flows was moved to downstream direction with decreasing of Ri number. 0n the other hand, the position in the case of C0 gas was shifted to upstream side with decreasing of Ri number. (2)Destruction speed of the thermal stratyification interface was dependent on thermal diffusivity as fluid properties. therefor it was concluded that an elimination method is necessary for the interface generated in C0 gas. [thermal Striping Phenomena] (1)Large amplitudes of fluid temperature fluctuations was reached to down stream area in the use of CO gas, due to larger fluid viscosity and smaller thermal diffusivity, compared with liquid sodium and liquid Pb-Bi cases. (2)To simulate thermal striping conditions such as amplitude and frequency of the fluid temperature fluctuations, it isnecessary for coincidences of Re number for the amplitude and of velocity value for the frequency, in various coolants. [Natural Convection Phenomena] (1)Fundamental behavior of the natural convection in various coolant follows buoyant jet ....

Development of divertor high heat flux components for ITER in JAERI

; Sato, Kazuyoshi; *; ; Dairaku, Masayuki; Nakamura, Kazuyuki; Akiba, Masato

Phys. Scr., T81, p.89 - 93, 1999/00

https://doi.org/10.1238/Physica.Topical.081a00089

no abstracts in English

Thermal cycling experiments on a 1 meter long divertor mock-up with a rigid support structure

; Sato, Kazuyoshi; Araki, Masanori; Nakamura, Kazuyuki; Dairaku, Masayuki; ; Akiba, Masato

Fusion Technology, 30(3(PT.2A)), p.793 - 797, 1996/12

no abstracts in English

A Thermal cycling durability test of tungsten copper duplex structures for use as a divertor plate

Seki, Masahiro; Ogawa, Masuro; Minato, Akio; ; Tone, Tatsuzo;

Nucl.Eng.Des./Fusion, 5, p.205 - 213, 1987/00

no abstracts in English

Analysis and experiments on lifetime predictions for first wall and divertor plate structures in JAERI

Horie, Tomoyoshi; Seki, Masahiro; Minato, Akio; Tone, Tatsuzo

Fusion Technology, 10, p.753 - 758, 1986/00

Analysis and experiments on lifetime predictions of the first wall and plate of fusion reactors have been performed.

Rapid Heating Thermal Fatigue of Molybdenum in Ultra-high Vacuum

; ; *

Nihon Genshiryoku Gakkai-Shi, 24(12), p.980 - 988, 1982/00

https://doi.org/10.3327/jaesj.24.980

no abstracts in English