Activity median aerodynamic diameter relating to contamination at Plutonium Fuel Research Facility in Oarai Research and Development Center; Particle size analysis for plutonium particles using imaging plate

Takasaki, Koji; Yasumune, Takashi; Hashimoto, Makoto; Maeda, Koji; Kato, Masato; Yoshizawa, Michio; Momose, Takumaro

JAEA-Review 2019-003, 48 Pages, 2019/03

JAEA-Review-2019-003.pdf:3.81MB

June 6, 2017, at Plutonium Fuel Research Facility in Oarai Research and Development Center of JAEA, when five workers were inspecting storage containers containing plutonium and uranium, resin bags in a storage container ruptured, and radioactive dust spread. Though they were wearing a half face mask respirator, they inhaled radioactive materials. In the evaluation of the internal exposure dose, the aerodynamic radioactive median diameter (AMAD) is an important parameter. We measured 14 smear samples and a dust filter paper with imaging plates, and estimated the AMAD by image analysis. As a result of estimating the AMAD, from the 14 smear samples, the AMADs are 4.3 to 11 m or more in the case of nitrate plutonium, and the AMADs are 5.6 to 14 m or more in the case of the oxidized plutonium. Also, from the dust filter paper, the AMAD is 3.0 m or more in the case of nitrate plutonium, and the AMAD is 3.9 m or more in the case of the oxidized plutonium.

Development of a radiological characterization submersible ROV for use at Fukushima Daiichi

Nancekievill, M.*; Jones, A. R.*; Joyce, M. J.*; Lennox, B.*; Watson, S.*; Katakura, Junichi*; Okumura, Keisuke; Kamada, So*; Kato, Michio*; Nishimura, Kazuya*

IEEE Transactions on Nuclear Science, 65(9), p.2565 - 2572, 2018/09

https://doi.org/10.1109/TNS.2018.2858563

In order to contribute to the development of technology to search fuel debris submerged in water inside the primary containment vessel of the Fukushima Daiichi Nuclear Power Station, we are developing a remotely operated vehicle (ROV) system equipped with a compact radiation detector and sonar. A cerium bromide (CeBr) scintillator detector for dose rate monitoring and ray spectroscopy was integrated into ROV and experimentally validated with a Cs source, both in the conditions of laboratory and submerged. In addition, the ROV combined with the IMAGENEX 831L sonar could characterize the shape and size of a simulated fuel debris at the bottom of the water pool facility.

A Remote-operated system to map radiation dose in the Fukushima Daiichi primary containment vessel

Nancekievill, M.*; Jones, A. R.*; Joyce, M. J.*; Lennox, B.*; Watson, S.*; Katakura, Junichi*; Okumura, Keisuke; Kamada, So*; Kato, Michio*; Nishimura, Kazuya*

Proceedings of 5th International Conference on Advancements in Nuclear Instrumentation Measurement Methods and their Applications (ANIMMA 2017) (USB Flash Drive), 6 Pages, 2017/06

We are developping a submersible ROV system, coupled with radiation detectors aimed at mapping the interior of the reactors at the Fukushima Daiichi Nuclear Power Station. To map the -ray intensity environment a cerium bromide (CeBr) inorganic scintillator detector sensitive to -rays has been incorporated into the ROV to measure -ray intensity and identify radioactive isotopes. The ROV is a cylindrical shape with a diameter of about 150 mm, and it have two end caps of five pumps each allowing control of the ROV in 5 degree of freedom. It is possible to directly replace the CeBr detector with a single crystal chemical vapour deposition (CVD) neutron detector with a Li convertor foil that is capable of mapping the thermal neutron flux.

HTTR hydrogen production system structure and main specifications of mock-up test facility (Contract research)

Kato, Michio; Hayashi, Koji; Aita, Hideki; Ohashi, Hirofumi; Sato, Hiroyuki; Inaba, Yoshitomo; Iwatsuki, Jin; Takada, Shoji; Inagaki, Yoshiyuki

JAEA-Technology 2007-022, 209 Pages, 2007/03

JAEA-Technology-2007-022.pdf:14.46MB

The mock-up test facility was fabricated to investigate performance of the steam generator for mitigation of the temperature fluctuation of helium gas and transient behavior of the hydrogen production system for HTTR and to obtain experimental data for verification of a dynamic analysis code. The test facility has an approximate hydrogen production capacity of 120Nm/h and the steam reforming process of methane; CH+HO=3H+CO, was used for hydrogen production of the test facility. An electric heater was used as a heat source instead of the reactor in order to heat helium gas up to 880 C (4MPa) at the chemical reactor inlet which is the same temperature as the HTTR hydrogen production system. Fabrication of the test facility was completed in February in 2002, and seven cycle operations were carried out from March in 2002 to December in 2004. This report describes the structure and main specifications of the test facility.

Annual report on experimental operations and maintenances of mock-up model test facility with a full-scale reaction tube for HTTR hydrogen production system in 2003 fiscal year (Contract research)

Hayashi, Koji; Morisaki, Norihiro; Ohashi, Hirofumi; Kato, Michio; Aita, Hideki; Takeda, Tetsuaki; Nishihara, Tetsuo; Inaba, Yoshitomo; Takada, Shoji; Inagaki, Yoshiyuki

JAEA-Technology 2006-012, 98 Pages, 2006/03

JAEA-Technology-2006-012.pdf:7.83MB

This is a report on the experimental operations and maintenances of the mock-up test facility with a full-scale reaction tube for the HTTR hydrogen production system in 2003 fiscal year. The fourth and fifth experimental test operations were performed, from May to July and from October to December in 2003, for the following tests; (a)start-up and shutdown operation test, (b)process change test, (c)continuous hydrogen-production test and (d)chemical reaction shutdown test. From the results, a long time-range stability of the hydrogen production system was confirmed, a behavior of the helium-gas cooling system, consists of steam generator and radiator, during chemical reaction shutdown, was understanded, and so on. Periodic inspections on boiler equipment and high-pressure gas production facilities were performed from end of July 2003. This report is summarized on outlines and results of the tests, outlines and results of the periodic inspections, and operation records of the mock-up test facility.

Annual report on experimental operation of mock-up model test facility with a full-scale reaction tube for HTTR hydrogen production system in 2001 fiscal year (Contract research)

Hayashi, Koji; Inagaki, Yoshiyuki; Kato, Michio; Fujisaki, Katsuo*; Aita, Hideki; Takeda, Tetsuaki; Nishihara, Tetsuo; Inaba, Yoshitomo; Ohashi, Hirofumi; Katanishi, Shoji; et al.

JAERI-Tech 2005-032, 46 Pages, 2005/06

JAERI-Tech-2005-032.pdf:4.79MB

This is annual report on the experimental operation of the mock-up test facility with a full-scale reaction tube for the HTTR hydrogen production system in 2001 fiscal year. The first experimental operation was performed during two weeks from March 1, 2002 to March 13, 2002 to test on the thermal hydraulic performance of the steam reformer and also to train the operators. The thermal hydraulic performance test of the steam reformer was performed to evaluate the heat transfer characteristics between helium gas and process gas in the steam reformer. This report is summarized with an overview of the test, the results and its operation records.

Improvement works report on mock-up model test facility with a full-scale reaction tube for HTTR hydrogen production system (Contract research)

Sakaki, Akihiro*; Kato, Michio; Hayashi, Koji; Fujisaki, Katsuo*; Aita, Hideki; Ohashi, Hirofumi; Takada, Shoji; Shimizu, Akira; Morisaki, Norihiro; Maeda, Yukimasa; et al.

JAERI-Tech 2005-023, 72 Pages, 2005/04

JAERI-Tech-2005-023.pdf:14.86MB

In order to establish the system integration technology to connect a hydrogen production system to a high temperature gas cooled reactor, the mock-up test facility with a full-scale reaction tube for the steam reforming HTTR hydrogen production system was constructed in fiscal year 2001 and its functional test operation was performed in the year. Seven experimental test operations were performed from fiscal year 2001 to 2004. On a period of each test operation, there happened some troubles. For each trouble, the cause was investigated and the countermeasures and the improvement works were performed to succeed the experiments. The tests were successfully achieved according to plan.This report describes the improvement works on the test facility performed from fiscal year 2001 to 2004.

Performance test results of mock-up model test facility with a full-scale reaction tube for HTTR hydrogen production system (Contract research)

Inagaki, Yoshiyuki; Hayashi, Koji; Kato, Michio; Fujisaki, Katsuo; Aita, Hideki; Takeda, Tetsuaki; Nishihara, Tetsuo; Inaba, Yoshitomo; Ohashi, Hirofumi; Katanishi, Shoji; et al.

JAERI-Tech 2003-034, 129 Pages, 2003/05

JAERI-Tech-2003-034.pdf:7.62MB

no abstracts in English

Out-of-pile demonstration test of HTTR hydrogen production system; Structure and fabrication technology of steam reformer (Contract research)

Inagaki, Yoshiyuki; Ouchi, Yoshihiro; Fujisaki, Katsuo; Kato, Michio; ; Hayashi, Koji;

JAERI-Tech 99-074, p.63 - 0, 1999/10

JAERI-Tech-99-074.pdf:3.0MB

no abstracts in English

Applicability of electronic pocket dosimeter in -beta mixed fields

Takahashi, Masa; Sekiguchi, Masato; Tachibana, Haruo; Hoshi, Shintaro; Yoshizawa, Michio; Kato, Toru*; Yamaguchi, Akihito*

no journal, , 

no abstracts in English