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Zaima, Naoki; Nakashima, Shinichi; Nakatsuka, Yoshiaki; Fujiki, Naoki*; Kado, Kazumi
JAEA-Technology 2013-050, 39 Pages, 2014/03
JAEA-Technology-2013-050.pdf:3.56MB
A uranium mass assay system NWAS, for 200-litter wastes drums applied by NDA method was developed and accumulated the data of the actual uranium bearing wastes drums. The system consists of the 16 pieces of Helium-3 proportional counters for neutron detection generated from U-234(
,n) reaction or U-238 spontaneous fissions with polyethylene moderation and a Germanium solid state detector for 
ray detection as to determine uranium enrichment. The satisfactory works had been continued and the uranium determination data of 850 drums had been accumulated approximately. On the other hand several considerable problems on the system or methodology had been revealed technically or analytically through the measurements experiences. Furthermore as the next improvement plans, the active neutrons assay for uranium bearing wastes drums are now progressing. The results of complications will lead us to the progressive next steps.
Zaima, Naoki; Nakashima, Shinichi; Nakatsuka, Yoshiaki; Kado, Kazumi
Kaku Busshitsu Kanri Gakkai (INMM) Nihon Shibu Dai-34-Kai Nenji Taikai Rombunshu (Internet), 10 Pages, 2013/10
A uranium mass assay system for 200-litter wastes drums applied by NDA method was developed and accumulated the data of the actual uranium bearing wastes drums. The system consists of the 16 pieces of Helium-3 proportional counters for neutron detection generated from 
U(,n) reaction or 
U spontaneous fissions with polyethylene moderation and a Germanium solid state detector for ray detection as to determine uranium enrichment. In previous report, some measurement experiences had been introduced briefly. After that satisfactory works had been continued and the uranium determination data of 850 drums had been accumulated approximately. On the other hand considerable problems on the system had been revealed technically or analytically. Such experiences are to be described precisely, in addition newly gained knowledge will be marshaled. Furthermore the next improvement plans are now prepared that will be capable of active neutrons assay for uranium bearing wastes drums.
Zaima, Naoki; Nakashima, Shinichi; Nakatsuka, Yoshiaki; Kado, Kazumi; Haruyama, Mitsuo; Takase, Misao; Ozu, Akira; Kureta, Masatoshi
Kaku Busshitsu Kanri Gakkai (INMM) Nihon Shibu Dai-33-Kai Nenji Taikai Rombunshu (Internet), 8 Pages, 2012/10
We developed uranium mass assay systems for 200-litter wastes drums applied passive neutron measurements by NDA method and applied for the actual wastes drums stored in URCP. The neutron measurement methodology of U(,n) reaction using 
He proportional counters delivered superior performance, however also included some problems that the neutron penetration rates are depend upon matrices or density of wastes drums, so it was difficult to determine uranium mass against "unknown objects". For the purpose of solving problems active neutron measurements appears promising, we are now challenging to improve our equipments, which are composed of neutron generator, polyethylene moderators and He proportional counters. The uranium mass are determined by counting secondary neutrons generated from nuclear fissions. Our preliminary simulations suggest good performances with higher sensitivities and accuracies. It is extremely expected to contribute in the fields of safeguards works.
Haruyama, Mitsuo; Takase, Misao; Ozu, Akira; Kureta, Masatoshi; Zaima, Naoki; Nakashima, Shinichi; Nakatsuka, Yoshiaki; Kado, Kazumi
Kaku Busshitsu Kanri Gakkai (INMM) Nihon Shibu Dai-33-Kai Nenji Taikai Rombunshu (Internet), 9 Pages, 2012/10
no abstracts in English
Zaima, Naoki; Nakashima, Shinichi; Nakatsuka, Yoshiaki; Kado, Kazumi
JAEA-Technology 2012-023, 36 Pages, 2012/08
JAEA-Technology-2012-023.pdf:1.54MB
We developed uranium mass assay systems for 200-litter wastes drums applied neutron and measurements by NDA method. In this report we will describe measurement experiences followed by the previous report. The systems are composed of the 16 pieces of helium-3 (He) proportional counters for neutron detection. The neutron measurement methodology is consist of U (,n)F reaction and spontaneous fission of U. The extensive test trials using the known amount of uranium with different enrichment and some kinds of matrices in drums were performed. By using this NWAS we tried to determine uranium mass in the actual uranium wastes drums stored in the URCP at Ningyo-toge. The actual uranium wastes drums are of great variety, in the point of matrix, bulk density, packing condition and total uranium mass. Therefore we have tried some challenging methods which eliminate problems, and established the applicability to almost all kinds of wastes drums.
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.
Zaima, Naoki; Nakashima, Shinichi; Kaneda, Koji; Kado, Kazumi
JAEA-Technology 2010-046, 31 Pages, 2011/02
JAEA-Technology-2010-046.pdf:2.84MBJAEA-Technology-2010-046(errata).pdf:0.05MB
The uranium mass assay systems for 200-litter wastes drums applied neutron and measurements by NDA method had been developed. The measurement systems and trial data are described in this preliminary report. The systems are composed of the 16 pieces of helium-3 proportional counters for neutron detection and a large sized NaI(Tl) scintillation detector for ray detection. The extensive testing trials using the calibrated uranium sources with different enrichment and some kinds of matrices in drums were performed. Through the one year testing the useful experiences of this system concerning neutron and ray measurements for uranium mass were obtained. Almost all instruments and software were so good performance as is designed. As the next step we are scheduled to try measurements for actual wastes that are stored in the Uranium Refining and Conversion Plant at Ningyo-toge, and put practical uses near future. Our research was accomplished with the support of LANL.
Zaima, Naoki; Morimoto, Yasuyuki; Sugitsue, Noritake; Kado, Kazumi
Proceedings of 13th International Conference on Environmental Remediation and Radioactive Waste Management (ICEM 2010) (CD-ROM), p.311 - 320, 2010/10
Zaima, Naoki; Nakashima, Shinichi; Kaneda, Koji; Kado, Kazumi
no journal, ,
We developed uranium mass assay systems for 200-litter wastes drums applied neutron and measurements by NDA method. In this intermediate report we will describe measurement systems and trial data. The systems are composed of the 16 pieces of helium-3 proportional counters for neutron detection and a large sized NaI(Tl) scintillation detector for -ray detection. The extensive testing trials using the calibrated uranium sources with different enrichment and some kinds of matrices in drums were performed. Through the one year testing the useful experiences of this system concerning neutron and -ray measurements for uranium mass were obtained. Almost all instruments and software were so good performance as is designed. As the next step we are going to schedule to try measurements for actual wastes that are stored in the Uranium Refining and Conversion Plant at Ningyo-toge, and put practical uses near future. Our research was accomplished with the support of Los Alamos National Laboratory.
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.
Zaima, Naoki; Nakashima, Shinichi; Nakatsuka, Yoshiaki; Kado, Kazumi
no journal, ,
We developed uranium mass assay systems for 200-litter wastes drums applied neutron and measurements by NDA method. In this intermediate report we will describe measurement systems and trial data. The systems are composed of the 16 pieces of helium-3 proportional counters for neutron detection and a Germanium solid state detector for ray detection. The extensive testing trials using the calibrated uranium sources with different enrichment and some kinds of matrices in drums were performed. Through the one year testing the useful experiences of this system concerning neutron and ray measurements for uranium mass were obtained. Almost all instruments and software were so good performance as is designed. As the next step we are now trying the measurements for actual wastes that are stored in the Uranium Refining and Conversion Plant at Ningyo-toge, and put practical uses near future. Our research was accomplished with the support of LANL.
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.
Zaima, Naoki; Nakashima, Shinichi; Nakatsuka, Yoshiaki; Kado, Kazumi
no journal, ,
We developed uranium mass assay systems for 200-litter wastes drums applied neutron and measurements by NDA method. The systems are composed of the 16 pieces of helium-3 proportional counters for neutron detection with 100 mm thicken polyethylene and a Ge-SSD for ray detection. The neutron measurement methodology is consist of U-234 (,n) reaction and measurement is applied by Ge-SSD. The extensive testing trials using the calibrated uranium sources with different enrichment and some kinds of matrices in drums were performed. By using this systems we tried to determine uranium mass in drums for the purpose of reduction MUF in URCP.
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.
