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Journal Articles

Study on loss-of-cooling and loss-of-coolant accidents in spent fuel pool, 2; Fuel cladding oxidation

Nemoto, Yoshiyuki; Kaji, Yoshiyuki; Kanazawa, Toru*; Nakashima, Kazuo*; Tojo, Masayuki*

Proceedings of 27th International Conference on Nuclear Engineering (ICONE-27) (Internet), 8 Pages, 2019/05

Oxidation behaviour of Zr cladding in SFP accident condition was evaluated by using a thermobalance in this work, and the obtained data were applied to construct oxidation model for SFP accident condition. For the validation of the constructed oxidation model, oxidation tests using a long cladding tube 500mm in length were conducted in conditions simulating SFP accidents, such as flow rate of the atmosphere in spent fuel rack, temperature gradient along the axis of cladding, and heating-up history. Thickness of oxide layer formed on the surface of cladding samples was evaluated by cross sectional observation, and compared with calculation results obtained by using the oxidation model. The detail of experimental results and validation of the oxidation model will be discussed.

Journal Articles

Study on loss-of-cooling and loss-of-coolant accidents in spent fuel pool, 4; Investigation of fuel loading effects in BWR spent fuel rack

Tojo, Masayuki*; Kanazawa, Toru*; Nakashima, Kazuo*; Iwamoto, Tatsuya*; Kobayashi, Kensuke*; Goto, Daisuke*; Nemoto, Yoshiyuki; Kaji, Yoshiyuki

Proceedings of 27th International Conference on Nuclear Engineering (ICONE-27) (Internet), 13 Pages, 2019/05

In this study, fuel loading effects in BWR spent fuel rack accidents are widely investigated using three-dimensional analysis methods from both nuclear and thermal hydraulics viewpoints, including: (a) Decay heat of spent fuel after discharge, (b) The maximum temperature of spent fuel cladding in the spent fuel rack depending on heat transfer phenomena, and (c) Criticality of the spent fuel rack after collapsing of the fuel due to a severe accidents in the BWR spent fuel pool (SFP).

Journal Articles

Published electronic media are becoming Grey

Kumazaki, Yui; Suzuki, Satoru; Kanazawa, Masashi*; Kunii, Katsuhiko; Yonezawa, Minoru; Itabashi, Keizo*

The Grey Journal; An International Journal on Grey Literature, 15(1), p.45 - 50, 2019/04

JAEA Library focuses on collecting conference proceedings and technical reports which are very important and referred materials for our users in the field of nuclear science and technology. There are an increasing number of cases that they are published in electronic media such as CD-ROM and flash memories. There are problems as to manage such electronic media in a library. Largest problems for electronic media would be the long-term preservation and permanent access. Lifetime of electronic media are much shorter compared with paper and/or microfilm. In this regard, the JAEA library is struggling to preserve electronic media including related PCs and software for a long-term. One of the effective countermeasure should be preserving PCs and software to browse, emulation and migration to another media. However, our countermeasure is not good enough for users and preservation. The authors would like to present JAEA Library's current activities on long term preservation and use of electronic media, and it comes to the conclusion the fact that even published electronic media are becoming grey literature in certain environment.

Journal Articles

Published electronic media are becoming Grey

Kumazaki, Yui; Suzuki, Satoru; Kanazawa, Masashi*; Kunii, Katsuhiko; Yonezawa, Minoru; Itabashi, Keizo

Proceedings of 20th International Conference on Grey Literature (GL-20), p.99 - 104, 2019/02

JAEA Library focuses on collecting conference proceedings and technical reports which are very important and referred materials for our users in the field of nuclear science and technology. There are an increasing number of cases that they are published in electronic media such as CD-ROM and flash memories. There are problems as to manage such electronic media in a library. Largest problems for electronic media would be the long-term preservation and permanent access. Lifetime of electronic media are much shorter compared with paper and/or microfilm. In this regard, the JAEA library is struggling to preserve electronic media including related PCs and software for a long-term. One of the effective countermeasure should be preserving PCs and software to browse, emulation and migration to another media. However, our countermeasure is not good enough for users and preservation. The authors would like to present JAEA Library's current activities on long term preservation and use of electronic media, and it comes to the conclusion the fact that even published electronic media are becoming grey literature in certain environment.

Journal Articles

Study on oxidation model for Zircalloy-2 cladding in SFP accident condition

Nemoto, Yoshiyuki; Kaji, Yoshiyuki; Onizawa, Takashi*; Kanazawa, Toru*; Nakashima, Kazuo*; Tojo, Masayuki*

Proceedings of Annual Congress of the European Federation of corrosion (EUROCORR 2018) (USB Flash Drive), 8 Pages, 2018/09

The authors proposed oxidation models based on oxidation data which previously obtained in high temperature oxidation tests on small sample of Zircalloy-2 (Zry2) cladding in dry air and in air/steam mixture environment. The oxidation models were implemented in computational fluid dynamics (CFD) code to analyse oxidation behavior of long cladding sample in hypothetical spent fuel pool (SFP) accident conditions. The oxidation tests were conducted using Zry2 cladding sample 500 mm in length. The oxide layer growth in dry air was well reproduced in the calculation using the oxidation model, meanwhile which in air/steam mixture was overestimated atmosphere composition change anticipated in the spent fuel rack during the accident, and its influence on the oxidation behaviour of the cladding were discussed in consideration of the oxidation model improvement.

Journal Articles

Investigation of Zircaloy-2 oxidation model for SFP accident analysis

Nemoto, Yoshiyuki; Kaji, Yoshiyuki; Ogawa, Chihiro; Kondo, Keietsu; Nakashima, Kazuo*; Kanazawa, Toru*; Tojo, Masayuki*

Journal of Nuclear Materials, 488, p.22 - 32, 2017/05

AA2016-0383.pdf:0.86MB

 Times Cited Count:1 Percentile:15.39(Materials Science, Multidisciplinary)

The authors previously conducted thermogravimetric analyses on zircaloy-2 in air. By using the thermogravimetric data, an oxidation model was constructed in this study so that it can be applied for the modeling of cladding degradation in spent fuel pool (SFP) severe accident condition. For its validation, oxidation tests of long cladding tube were conducted, and computational fluid dynamics analyses using the constructed oxidation model were proceeded to simulate the experiments. In the oxidation tests, high temperature thermal gradient along the cladding axis was applied and air flow rates in testing chamber were controlled to simulate hypothetical SFP accidents. The analytical outputs successfully reproduced the growth of oxide film and porous oxide layer on the claddings in oxidation tests, and validity of the oxidation model was proved. Influence of air flow rate for the oxidation behavior was thought negligible in the conditions investigated in this study.

JAEA Reports

Method for separation of Cs from acid solution dissolving radionuclides and microanalysis of solution with ICP-AES

Kanazawa, Toru*; Hidaka, Akihide; Kudo, Tamotsu; Nakamura, Takehiko*; Fuketa, Toyoshi

JAERI-Tech 2004-050, 53 Pages, 2004/06

JAERI-Tech-2004-050.pdf:4.35MB

As a part of release evaluation in VEGA program, the mass balances of released and deposited FP onto the test apparatus are estimated from gamma ray measurement for acid solution leached from the apparatus, but short-life or radionuclides without emitting $$gamma$$ rays and very small quantity of elements cannot be quantified. Therefore, a microanalysis by ICP-AES is planed for acid solution leached from apparatuses. Since Cs have strong $$gamma$$ ray spectrum, they have to be removed from solution in advance to avoid contamination of ICP system and to decrease exposure to $$gamma$$ ray. The method for Cs separation using inorganic ion exchanger, AMP was applied to the test solutions. The results showed that more than 99.9% of Cs could be removed from test solution, and once removed Sb by AMP was recovered by using a complexing agent such as citric acid. The ICP-AES analysis showed that amount of U, Sr and Zr were successfully quantified. The release and deposition will be quantified through ICP-AES analysis for acid solutions from which Cs is separated by AMP or other precipitation method.

JAEA Reports

Radionuclides release from re-irradiated fuel under high temperature and pressure conditions; $$gamma$$-ray measurements of VEGA-5 test

Hidaka, Akihide; Kudo, Tamotsu; Nakamura, Takehiko; Kanazawa, Toru; Kiuchi, Toshio; Uetsuka, Hiroshi

JAERI-Tech 2003-009, 30 Pages, 2003/03

JAERI-Tech-2003-009.pdf:1.73MB

The VEGA (Verification Experiments of radionuclides Gas/Aerosol release) program is being performed at JAERI to clarify mechanisms of radionuclides release from irradiated fuel during severe accidents and to improve source term predictability. The fifth VEGA-5 test was conducted in January 2002 to confirm the reproducibility of decrease in cesium release under elevated pressure that was observed in the VEGA-2 test and to investigate the release behavior of short-life radionuclides. The PWR fuel of 47GWd/tU after 8.2 years of cooling was re-irradiated at Nuclear Safety Research Reactor (NSRR) for 8 hours before the heat-up test. After that, the two pellets of 10.9g without cladding were heated up to about 2,900K at 1.0MPa under the inert He condition. The experiment reconfirmed the decrease in cesium release under elevated pressure. The release data on short-life radionuclides such as Ru-103 and Ba-140 that has never been observed in the previous VEGA tests without re-irradiation was obtained using the gamma ray measurement.

JAEA Reports

Influence of plutonium contents in MOX fuel on destructive forces at fuel failure in the NSRR experiment

Nakamura, Jinichi; Sugiyama, Tomoyuki; Nakamura, Takehiko; Kanazawa, Toru; Sasajima, Hideo

JAERI-Tech 2003-008, 32 Pages, 2003/03

JAERI-Tech-2003-008.pdf:1.49MB

no abstracts in English

Journal Articles

High energy laser wakefield acceleration

Kotaki, Hideyuki; Kando, Masaki; Hosokai, Tomonao; Kondo, Shuji; Masuda, Shinichi; Kanazawa, Shuhei; Yokoyama, Takashi*; Matoba, Toru; Nakajima, Kazuhisa

International Journal of Applied Electromagnetics and Mechanics, 14(1-4), p.255 - 262, 2003/03

no abstracts in English

Journal Articles

Direct measurement of coherent ultrahigh wakefields excited by intense ultrashort laser pulses in a gas-jet plasma

Kotaki, Hideyuki; Kando, Masaki; Oketa, Takatsugu; Masuda, Shinichi; Koga, J. K.; Kondo, Shuji; Kanazawa, Shuhei; Yokoyama, Takashi*; Matoba, Toru; Nakajima, Kazuhisa

Physics of Plasmas, 9(4), p.1392 - 1400, 2002/04

 Times Cited Count:44 Percentile:80.06(Physics, Fluids & Plasmas)

no abstracts in English

Journal Articles

Present status of the JAERI photocathode microtron

Kando, Masaki; Kotaki, Hideyuki; Kondo, Shuji; Kanazawa, Shuhei; Masuda, Shinichi; Yokoyama, Takashi*; Matoba, Toru; Nakajima, Kazuhisa

Proceedings of 26th Linear Accelerator Meeting in Japan, p.132 - 134, 2001/08

no abstracts in English

Journal Articles

Development of plasma waveguide using fast z-pinch capillary discharge

Masuda, Shinichi; Kando, Masaki; Kotaki, Hideyuki; Hosokai, Tomonao*; Kondo, Shuji; Kanazawa, Shuhei; Yokoyama, Takashi*; Matoba, Toru; Nakajima, Kazuhisa

Proceedings of 13th Symposium on Accelerator Science and Technology, 3 Pages, 2001/00

no abstracts in English

Journal Articles

High energy electron acceleration by high peak power laser

Kotaki, Hideyuki; Kando, Masaki; Kondo, Shuji; Masuda, Shinichi; Kanazawa, Shuhei; Yokoyama, Takashi*; Matoba, Toru; Nakajima, Kazuhisa

Proceedings of 13th Symposium on Accelerator Science and Technology, 3 Pages, 2001/00

no abstracts in English

Oral presentation

Ultimate behavior tests of seismic isolation system for FBR with a large shaking table, 6; Simulation of ultimate behavior tests

Yabana, Shuichi*; Kanazawa, Kenji*; Nagata, Seiji*; Inaba, Satoru*; Kitamura, Seiji

no journal, , 

no abstracts in English

Oral presentation

Simulation of eddy current on the turbo-molecular pump in a magnetic field

Ogiwara, Norio; Kanazawa, Kenichiro; Yanagibashi, Toru

no journal, , 

Oral presentation

The Emergency safety system of radiation control equipment at the time of all AC-power-supply loss at the Tokai reprocessing plant

Kanazawa, Nobuyuki; Nakamura, Keisuke; Miyauchi, Toru; Chikazawa, Tatsuya*; Kurosawa, Hideaki*; Shiba, Kozo

no journal, , 

no abstracts in English

Oral presentation

Study on cladding oxidation behavior on spent fuel pool severe accident, 2

Nemoto, Yoshiyuki; Kaji, Yoshiyuki; Ogawa, Chihiro; Nakashima, Kazuo*; Tojo, Masayuki*; Kanazawa, Toru*; Goto, Daisuke*

no journal, , 

In order to investigate the air oxidation behavior of cladding materials for study on improvement of safety in spent fuel pool loss of coolant accident condition, both isothermal oxidation tests by short length specimens and oxidation tests with temperature gradient by long length specimens were conducted and the knowledge on influence of temperature and air flow rate on cladding oxidation behavior was obtained in this study.

Oral presentation

Study on improvement of safety for accident conditions in spent fuel pool, 13; Investigation of cladding oxidation model

Nemoto, Yoshiyuki; Kaji, Yoshiyuki; Ogawa, Chihiro*; Nakashima, Kazuo*; Kanazawa, Toru*; Tojo, Masayuki*

no journal, , 

Concerning the severe accident analysis in spent fuel pools (SFPs), it is important to construct the high temperature oxidation model of the Zirconium claddings exposed in loss-of-coolant accident condition. In this study, an oxidation model of Zry2 in air environment was constructed by using these basic data. The constructed oxidation model was applied for simulation of oxidation tests using long cladding tubes of Zry2 in hypothetical SFP accident conditions. Reproducibility of the calculation was evaluated in comparison with the results of experiment to validate the oxidation model.

Oral presentation

Study on improvement of safety for accident conditions in spent fuel pool, 21; Investigation of cladding oxidation model

Nemoto, Yoshiyuki; Onizawa, Takashi*; Kaji, Yoshiyuki; Nakashima, Kazuo*; Kanazawa, Toru*; Tojo, Masayuki*

no journal, , 

Cladding oxidation model construction and its validation is necessary for the upgrading of severe accidentcode which will be utilized for analysis of the spent fuel pool (SFP) accident. Cladding oxidation tests and analyses using the proposed oxidation model were coducted in the simulated SFP accident condition, and their results were compared. Modification of the oxidation model will be discussed in the lecture.

Oral presentation

Study on improvement of safety for accident conditions in spent fuel pool, 23; CFD analysis for the loss of coolant accident in SFP with Zircalloy-2 cladding oxidation model

Tojo, Masayuki*; Kanazawa, Toru*; Kobayashi, Kensuke*; Goto, Daisuke*; Nemoto, Yoshiyuki; Kaji, Yoshiyuki

no journal, , 

Computational fluid dynamics (CFD) analysis for the loss of coolant accident in spent fuel pool (SFP) with Zircalloy-2 cladding was conducted. In the higher region of spent fuel rack internal, oxygen content in the atmosphere was decreased because of oxigen consumption during the oxidation reaction of cladding material. This oxygen depression is thought to surpress the oxidation of claddings.

21 (Records 1-20 displayed on this page)