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Ema, Akira; Ishimori, Yuu
JAEA-Review 2016-034, 84 Pages, 2017/03
JAEA-Review-2016-034.pdf:8.96MB
The Ningyo-toge Environmental Engineering Center of the Japan Atomic Energy Agency has managed the decommissioning projects since 2013. In 2015, Enforcement Management System (EMS) was established to enforce the project management systematically. The project management based on EMS was started in 2015. This report summarized the state of management activities in FY 2015.
Ema, Akira; Miyagawa, Hiroshi; Ishimori, Yuu
JAEA-Review 2016-006, 88 Pages, 2016/03
JAEA-Review-2016-006.pdf:10.59MB
The Ningyo-toge Environmental Engineering Center of the Japan Atomic Energy Agency had managed the decommissioning project based on the Quality Management System and the Environmental Management System, but found that these systems were unsuitable for project management from several viewpoints. In order to solve these problems, the Task Team for Enforcement Backend Project temporarily managed the decommissioning project in 2013. To enforce the project management systematically, the Research and Development Promotion Section was organized newly in the Environmental Research and Development Department in April 2014, and started the project management. On the other hand, to establish the primary and secondary documents related to the new system, until April 2015 the section has been developing the Enforcement Management System (EMS) to separate from the Quality Management System or the Environmental Management System. This report summarizes the state of these activities in the FY 2014.
treatment technology and proof of IF production methodEma, Akira; Kado, Kazumi; Suzuki, Kazuhiko*
Nihon Genshiryoku Gakkai Wabun Rombunshi, 10(3), p.194 - 204, 2011/09
This paper shows the investigation result of the reasonable IF treatment condition and the full-scale examination result by using this IF treatment condition. As a result, it could confirm 99% of the intermediate uranium fluoride in the cascade was removed for 60 days. Further, this paper shows the investigation result of the reasonable IF production condition and the full-scale examination result. As a result, it could be proved 3,355 kg-IF gas was produced.
treatment reaction product separation and refinementEma, Akira; Kado, Kazumi; Suzuki, Kazuhiko*
Nihon Genshiryoku Gakkai Wabun Rombunshi, 10(3), p.205 - 215, 2011/09
This paper shows we constructed theoretically the methodology using the 
-ray measured outside the gas centrifuge and MCNP code. Further, this paper shows the investigation result of the reasonable separation condition and the full-scale examination result. As a result, it could be proved IF
weight of 86% can separate and refine from UF
and IF mixture gas.
Hyakutake, Toru*; Muto, Akinori*; Sasakura, Mariko*; Minowa, Hirotsugu*; Suzuki, Kazuhiko*; Yokoyama, Kaoru; Takahashi, Nobuo; Tsunashima, Yasumichi; Ema, Akira; Sugitsue, Noritake
JAEA-Research 2009-047, 92 Pages, 2010/01
JAEA-Research-2009-047.pdf:5.13MB
System decontamination has been generally carried out with the aim of reducing the amount of radioactive waste generated and minimizing human exposure to radiation released from nuclear fuel facilities. At the Ningyo-Toge Environmental Engineering Center, metal surfaces that are contaminated by uranium are dry decontaminated by using iodine heptafluoride (IF) as a system decontaminator. In this dry decontamination technique, a chemical reaction occurs between the uranium compound attached to the metal surface and IF. Only a few studies have been carried out on the decontamination efficiency, mechanism, level, etc. of dry decontamination techniques that use a decontamination gas. Therefore, the generalization of dry decontamination techniques is required. In the present study, the efficiency of a dry decontamination technique was assessed by a numerical method using decontamination data obtained at the Ningyo-Toge Environmental Engineering Center.
treatment condition and uranium decontamination resultEma, Akira; Yokoyama, Kaoru; Nakatsuka, Yoshiaki; Shimaike, Masamitsu; Sugitsue, Noritake
JAEA-Technology 2008-037, 50 Pages, 2008/06
JAEA-Technology-2008-037.pdf:3.15MB
In the centrifugation method uranium enrichment plant, the UF gas was supplied for a long term. The main uranium compounds are estimated to the middle fluorides UFx(4
x=5). This middle fluoride is changed to UF and IF gas again by the reaction with IF. Using this reaction, the uranium compound in the plant was decontaminated. The IF treatment tests were executed to the plant in four treatment conditions. It is necessary to clarify the relation between IF treatment condition and decontamination results for the best treatment condition setting. Therefore, the decontamination development is evaluated using the result of the weight measurement of recovery UF and IF gas, the -ray measurement, and the ICP-MS analysis at the IF treatment tests. Then the technical knowledge to clarify the decontamination characteristic features is accumulated for analyzing the treatment trend, the treatment time, decontamination level and variation of the decontamination level.
gasEma, Akira; Sugitsue, Noritake; Zaitsu, Tomohisa
Proceedings of 2007 ANS Topical Meeting on Decommissioning, Decontamination and Reutilization & Technology Expo (DD&R 2007) (CD-ROM), 3 Pages, 2007/09
When we decommission the equipments contaminated by the uranium, the dismantling process of the equipments and the disposal process of the radioactive waste will be carried out. However, costs of these processes will be very expensive. In order to minimize these costs, we have developed new decontamination technology to decontaminate below the clearance level without dismantling.
Annen, Sotonori; Ishimori, Yuu; Ema, Akira; Takanobu, Osamu; Nagayasu, Takaaki; Mita, Yutaka
JNC TN6400 2003-001, 35 Pages, 2003/10
JNC-TN6400-2003-001.pdf:2.78MB
Technology developments for the decommissioning of uranium fuel facilities and the treatments of uranium wastes are one of the current main projects in the Ningyo-toge Environmental Engineering Center of the Japan Nuclear Cycle Development Institute (JNC Ningyo-toge). In order to carry out the project reasonably and safely, all techniques from decommissioning to waste treatment should be unified systematically. Thus, the JNC Ningyo-toge is aiming at the establishment of a 'decommissioning engineering'. This booklet illustrates the decommissioning engineering, especially four engineering elements; that is, a removal technology for uranium compounds, a decommissioning technology of the centrifuges, an application of CaF2 precipitate and a decommissioning engineering system.
Ema, Akira
no journal, ,
We are developing two decontamination technologies to reduce costs of dismantling and disposal in Ningyo-Toge environmental engineering center. So, we introduce these technologies. (1) sulfuric acid immersing decontamination technology (2) system chemical decontamination technology
treatment technologyEma, Akira; Kado, Kazumi; Suzuki, Kazuhiko*
no journal, ,
When uranium enrichment plant decommissioning is carried out, a reasonable gas centrifuge decontamination technology is required. The present study proposes a dry treatment technology using Iodine Heptafluoride (IF) gas. As a result, we observe experimental decontamination performance.
Ema, Akira; Kado, Kazumi; Suzuki, Kazuhiko*
no journal, ,
In the nuclear industry, when the nuclear facilities is dismantled, the decontamination work of the radioactive substances is carried out. The selection of the decontamination method is a big problem because the enlargement of decontamination plant and increases of disposal cost is caused. In this study, we propose the new decontamination method of the uranium compounds by IF gas.
Ema, Akira; Kado, Kazumi; Suzuki, Kazuhiko*
no journal, ,
We carried out the full-scale exam of the IF production for the study of the decontamination technology using IF gas. As a result, it could be proved 3,355kg-IF gas was produced.
Ema, Akira; Kado, Kazumi; Suzuki, Kazuhiko*
no journal, ,
In the nuclear industry, when the nuclear facilities are dismantled, the decontamination work of the radioactive substances is carried out. The selection of the decontamination method is a big problem because the enlargement of decontamination plant and increases of disposal cost is caused. In this study, we propose the new decontamination method of the uranium compounds by IF gas. In this presentation, we show the full-scale exam result and so on by using the actual uranium enrichment plant.
Ema, Akira; Kado, Kazumi; Suzuki, Kazuhiko*
no journal, ,
In this study, we suggest the new technology decontaminates equipments by reacting the uranium compounds with IF gas in the uranium treatment facilities. This presentation shows the decontamination experiment result of the uranium enrichment plant, which is composed of a lot of gas centrifuges. Also, we shows the method for quantifying the uranium weight in the interior of gas centrifuge.
Ema, Akira; Kado, Kazumi; Suzuki, Kazuhiko*
no journal, ,
In this study, we propose the decontamination method of plant equipments by using the chemical reaction with IF gas as the prior study for the decommissioning of the uranium enrichment plant. This presentation shows the IF treatment examination result for the actual uranium enrichment plant. Further, we show the full-scale examination result about IF production technology and the reaction product separation refinement technology, too.
Mita, Yutaka; Sugitsue, Noritake; Ogura, Hiroaki; Daiten, Masaki; Ishimori, Yuu; Ema, Akira
no journal, ,
In enrichment engineering facilities of Ningyo-toge Environmental Engineering Center, make reports on the investment performance that was that there is no need (clearance) dealing with the centrifuge that was contaminated with uranium that was used to technological development of uranium enrichment as radioactive waste. Casings centrifuge was reused metal about 10ton by carrying the decontamination and radioactivity concentration measurement as a flower bed in the center.
