ROSA/LSTF test on nitrogen gas behavior during reflux condensation in PWR and RELAP5 code analyses

Takeda, Takeshi; Otsu, Iwao

Mechanical Engineering Journal (Internet), 5(4), p.18-00077_1 - 18-00077_14, 2018/08

https://doi.org/10.1299/mej.18-00077

RELAP5 uncertainty evaluation using ROSA/LSTF test data on PWR 17% cold leg intermediate-break LOCA with single-failure ECCS

Takeda, Takeshi; Otsu, Iwao

Annals of Nuclear Energy, 109, p.9 - 21, 2017/11

https://doi.org/10.1016/j.anucene.2017.05.007

ROSA/LSTF test on nitrogen gas behavior during reflux cooling in PWR and RELAP5 post-test analysis

Takeda, Takeshi; Otsu, Iwao

Proceedings of 25th International Conference on Nuclear Engineering (ICONE-25) (CD-ROM), 11 Pages, 2017/07

Thermal hydraulic safety research at JAEA after the Fukushima Dai-ichi Nuclear Power Station accident

Yonomoto, Taisuke; Shibamoto, Yasuteru; Takeda, Takeshi; Satou, Akira; Ishigaki, Masahiro; Abe, Satoshi; Okagaki, Yuria; Sun, Haomin; Tochio, Daisuke

Proceedings of 16th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-16) (USB Flash Drive), p.5341 - 5352, 2015/08

RELAP5 code study of ROSA/LSTF experiments on PWR safety system using steam generator secondary-side depressurization

Takeda, Takeshi; Onuki, Akira*; Nishi, Hiroaki*

Journal of Energy and Power Engineering, 9(5), p.426 - 442, 2015/05

https://doi.org/10.17265/1934-8975/2015.05.002

RELAP5 code study of ROSA/LSTF validation tests for PWR safety system using SG secondary-side depressurization

Takeda, Takeshi; Onuki, Akira*; Nishi, Hiroaki*

Proceedings of 10th International Topical Meeting on Nuclear Thermal Hydraulics, Operation and Safety (NUTHOS-10) (USB Flash Drive), 13 Pages, 2014/12

Analysis on non uniform flow in steam generator during steady state natural circulation cooling

Susyadi; Yonomoto, Taisuke

JAERI-Research 2005-011, 64 Pages, 2005/06

JAERI-Research-2005-011.pdf:2.57MB

Steady-state natural circulation (NC) in the PWR was investigated focusing on non uniform flow among steam generator (SG) U-tubes observed in the ROSA/LSTF experiments. In the analysis using the RELAP5/MOD3 code, the SG behavior was analyzed using the partial SG model with one, five, or nine parallel flow paths in the primary side and boundary conditions based on the experiments. The results showed that simulations using the model with five or nine tubes were capable to capture important non uniform phenomena such as reverse flow, fill and dump and stagnant vertical stratification, and the stable SG outlet flow as observed in the experiments. Heat transfer rates to the secondary side were, however, underpredicted by up to 15%. Furthermore, difficulties were found in establishing the steady state condition especially for the low pressure analysis: only when the inlet flow rate was carefully imposed, stable NC behavior was obtained.

ROSA/LSTF test on PWR station blackout transient and RELAP5 analyses

Takeda, Takeshi; Otsu, Iwao

no journal, , 

An experiment on accident management (AM) measures during a PWR station blackout transient with leakage from primary coolant pump seals was conducted using the ROSA/large scale test facility (LSTF) based on the Fukushima accident. Through RELAP5/MOD3.2 code, we investigate core void fraction and surface heat transfer coefficient of the cladding. In addition, sensitivity analyses were performed with the RELAP5 code. The onset timing of SG secondary depressurization as well as the SG coolant injection flow rate were found to significantly affect the peak cladding temperature.

ROSA/LSTF test on PWR station blackout transient with loss of primary coolant and RELAP5 analysis

Takeda, Takeshi; Otsu, Iwao

no journal, , 

The effectiveness of accident management measure should be confirmed in case of PWR station blackout transient with loss of primary coolant. A simulation experiment with the ROSA/LSTF was thus conducted under an assumption of nitrogen gas inflow into the primary system. After the nitrogen gas inflow, the primary depressurization rate became smaller and non-uniform flow behavior was observed among steam generator (SG) U-tubes. In addition, RELAP5/MOD3.2 code indicated remaining problems in the predictions of the primary pressure and SG U-tube liquid level after the nitrogen gas inflow through the post-test analysis.