Conceptual design of multipurpose compact research reactor; Annual report FY2011

Watahiki, Shunsuke; Hanakawa, Hiroki; Imaizumi, Tomomi; Nagata, Hiroshi; Ide, Hiroshi; Komukai, Bunsaku; Kimura, Nobuaki; Miyauchi, Masaru; Ito, Masayasu; Nishikata, Kaori; et al.

JAEA-Technology 2013-021, 43 Pages, 2013/07

JAEA-Technology-2013-021.pdf:5.12MB

The number of research reactors in the world is decreasing because of their aging. On the other hand, the necessity of research reactor, which is used for human resources development, progress of the science and technology, industrial use and safety research is increasing for the countries which are planning to introduce the nuclear power plants. From above background, the Neutron Irradiation and Testing Reactor Center began to discuss a basic concept of Multipurpose Compact Research Reactor (MCRR) for education and training, etc., on 2010 to 2012. This activity is also expected to contribute to design tool improvement and human resource development in the center. In 2011, design study of reactor core, irradiation facilities with high versatility and practicality, and hot laboratory equipment for the production of Mo-99 was carried out. As the result of design study of reactor core, subcriticality and operation time of the reactor in consideration of an irradiation capsule, and about the transient response of the reactor to the reactivity disturbance during automatic control operation, it was possible to do automatic operation of MCRR, was confirmed. As the result of design study of irradiation facilities, it was confirmed that the implementation of an efficient mass production radioisotope Mo-99 can be expected. As the result of design study with hot laboratory facilities, Mo-99 production, RI export devised considered cell and facilities for exporting the specimens quickly was designed.

Preliminary accident analysis for a conceptual design of a 10 MW multi-purpose research reactor

Park, C.; Tanimoto, Masataka; Imaizumi, Tomomi; Miyauchi, Masaru; Ito, Masayasu; Kaminaga, Masanori

JAEA-Technology 2012-039, 87 Pages, 2013/01

JAEA-Technology-2012-039.pdf:3.55MB

Preliminary accident analysis has been carried out for a LOFA (Loss of Flow Accident) and RIAs (Reactivity Insertion Accidents) of the conceptual 10 MW MRR (multi-purpose research reactor) under design study by using the RELAP5/MOD3 code in order to provide the preliminary evaluation of safety margin as well as the intuitions to the design of the MRR. Input and modeling for the RELAP5/MOD3 simulations have also been described. The analysis results indicate that the concept of the MRR is feasible with practical safety margins. The same events have been also analyzed by using the PARET/ANL and the EUREKA-2/RR codes to compare the codes suitability, which have been widely used for the analysis of research reactors. Same geometric and modeling data used for the RELAP5/MOD3 have been used as long as they correspond to each code's input requirements. The three codes show the same or similar overall trends for the events analyzed, but show a small difference in a specific condition.

Ab initio path integral simulation of AgOH(HO)

Koizumi, Akihito*; Suzuki, Kimichi*; Shiga, Motoyuki; Tachikawa, Masanori*

International Journal of Quantum Chemistry, 112(1), p.136 - 139, 2012/01

https://doi.org/10.1002/qua.23174

Ab initio path integral molecular dynamics simulation of MOH(HO) (M= Cu, Ag, and Au) clusters has been carried out to analyze how the hydrogen-bonded proton can be affected by the counter noble metal cation. The CuOH(HO) cluster forms no hydrogen bonded structure even for the static equilibrium structures. Contrary to our previous paper of hydrated alkali metal hydroxide clusters, proton transferred distribution was not observed because of the high potential barrier heights of MOH(HO).

Results of the environmental radiation monitoring following the accident at the Fukushima Daiichi Nuclear Power Plant; Interim report (Ambient radiation dose rate, radioactivity concentration in the air and radioactivity concentration in the fallout)

Furuta, Sadaaki; Sumiya, Shuichi; Watanabe, Hitoshi; Nakano, Masanao; Imaizumi, Kenji; Takeyasu, Masanori; Nakada, Akira; Fujita, Hiroki; Mizutani, Tomoko; Morisawa, Masato; et al.

JAEA-Review 2011-035, 89 Pages, 2011/08

JAEA-Review-2011-035.pdf:2.97MB

As a correspondence to the accident at the Fukushima Daiichi Nuclear Power Plant, the environmental radiation monitoring was performed at the Nuclear Fuel Cycle Engineering Laboratories, JAEA. This report presented the measurement results of ambient radiation dose rate, radioactivity concentration in the air and radioactivity concentration in fallout and meteorological observation result until May 31, 2011. The ambient radiation dose rate increased, with the peak dose rate of several thousand nGy/h at 7 o'clock in March 15, at 5 o'clock in March 16, and at 4 o'clock in March 21. The variation on the radioactivity concentration in the air and in fallout showed the almost same tendency as that of the dose rate. The concentration ratio of I-131/Cs-137 in the air increased to about 100. The dose was estimated resulting from internal exposure due to inhalation.

Study on applicability of evaluation model of manpower needs for dismantling of equipments in FUGEN, 2; Preparation and clean-up process in 3rd/4th feedwater heater room

Shibahara, Yuji; Tachibana, Mitsuo; Izumi, Masanori; Nanko, Takashi

JAEA-Technology 2011-010, 44 Pages, 2011/06

JAEA-Technology-2011-010.pdf:2.43MB

Manpower needs for the preparation and clean-up process on the dismantling of equipments in FUGEN 3rd/4th feedwater heater room conducted in 2008 was calculated with the management data evaluation system: PRODIA Code, and it was inspected whether the conventional evaluation model had the applicability for large nuclear facilities such as FUGEN or not. It was confirmed that the conventional evaluation model had no applicability for FUGEN causing by the difference in the plant scale between JPDR and FUGEN bringing the expanding of working area. The difference between the actual data and the calculated value was improved by the reviewing of the evaluation model, and this reviewing process also brought the new evaluation model.

Study on applicability of evaluation model of manpower needs for dismantling of equipments in FUGEN, 1; Dismantling process in 3rd/4th feedwater heater room

Shibahara, Yuji; Tachibana, Mitsuo; Ishigami, Tsutomu; Izumi, Masanori; Nanko, Takashi

JAEA-Technology 2010-033, 42 Pages, 2010/10

JAEA-Technology-2010-033.pdf:1.02MB

Manpower needs for the dismantling process in FUGEN 3rd/4th feedwater heater room was calculated with the evaluation system (PRODIA Code), and it was inspected whether the conventional evaluation model had applicability for FUGEN or not. It was confirmed that the conventional evaluation model for feedwater heater had no applicability. In comparison of the calculated value with the actual data, we found two difference: (1) the evaluated manpower were significantly larger than the actual data, (2) the manpower need for the dismantling of 3rd feedwater heater was twice larger than that of 4th feedwater heater, though these equipments were almost same weight. It was found that these were brought (1) by the difference in the work descriptions of dismantling between JPDR and FUGEN, and (2) by that in the cutting number between 3rd feedwater heater and 4th one. The manpower needs for the dismantling of both feedwater heaters were calculated with a new calculation equation reflecting the descriptions of dismantling, and it was found that these results showed the good agreement with the actual data.

Development of a tracking method for augmented reality applied to NPP maintenance work and its experimental evaluation

Bian, Z.*; Ishii, Hirotake*; Shimoda, Hiroshi*; Yoshikawa, Hidekazu*; Morishita, Yoshitsugu; Kanehira, Yoshiki; Izumi, Masanori

IEICE Transactions on Information and Systems, E90-D(6), p.963 - 974, 2007/06

https://doi.org/10.1093/ietisy/e90-d.6.963

This study designed linecode marker, a new type of paper-based marker and proposed recognition, tracking algorithm for it in order to resolve these problems. In comparison of the conventional paper-based markers, such as square markers, circle markers, the linecode marker is not only just easier to set up in complex industrial environment, but also makes it possible to use AR in industrial plant. In order to evaluate the tracking accuracy, trackable distance of the proposed tracking method, an evaluation experiment was conducted in a large room. The experiment results show that: comparing with traditional marker-based tracking method, tracking possible distance extends extremely; tracking accuracy improved to a level of 20cm in 10m distance.

The VRdose Software System: - User Manual, Report and Design Documentation for R5-

Iguchi, Yukihiro; Knehira, Yoshiki; Izumi, Masanori; Fujita, Toru*; Oya, Kiyomi*

JNC TN3520 2004-001, 172 Pages, 2004/03

JNC-TN3520-2004-001.pdf:11.04MB

In the VRdose R5 version the connection with the dynamic radiation evaluation system (DRES) was the main task. DRES can calculate the dose rate field of the Fugen plant in detail. By inserting special markers into the scenario, VRdose tells DRES what changes have been made to the model. The changes are about objects that are inserted, removed, cut or moved. DRES will then calculate new dose rate fields reflecting these changes. To minimize the calculation needed for DRES, VRdose can provide a volume enclosing only the area of interest for a given scenario and give the resolution of the calculation in all axes. In addition to the DRES connection, version R5 retrieves information about the objects in the model from the Fugen object database. Among the large amount of information available, are size, weight and surface contamination of co-60 used. The wizard uses the size and weight information in the calculation of the man-work required. The surface contamination is used in a new feature that colorizes the objects after the contamination value. This makes it easier for workers to become aware of the contamination of pipes and pumps etc. R5 has been internationalized on all menus, buttons, messages and other text. VRdose can therefore be translated into any desired language. A feasibility study has been made into using Japanese characters in names and properties in the scenario. Printing of the 3D view has been implemented, which is useful for documenting. The scenario can also be printed, both as a graphical representation and in a textual report format. Other functionality that can be mentioned is output from the wizard to Cosmard and the saving of viewpoints. The manikins wear different protection masks and in version R5 the efficiency of the protection can be changed for each nuclide. Several other minor changes have been made, such as the ability to switch between extern dose and nuclide intake in the dose graph panels.

Progress and achievements on the R&D activities for ITER vacuum vessel

Nakahira, Masataka; Takahashi, Hiroyuki*; Koizumi, Koichi; Onozuka, Masanori*; Ioki, Kimihiro*

Nuclear Fusion, 41(4), p.375 - 380, 2001/04

https://doi.org/10.1088/0029-5515/41/4/303

no abstracts in English

Fabrication and assembly of full-scale sector models for ITER vacuum vessel

Koizumi, Koichi; Nakahira, Masataka; Oka, Kiyoshi; *; Takahashi, Hiroyuki*; Tada, Eisuke; Ioki, Kimihiro*; Johnson, G.*; Onozuka, Masanori*; Y.Utin*; et al.

Fusion Technology, 34(3), p.586 - 590, 1998/11

no abstracts in English