Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Kanamori, Masashi
JNC TN8440 2001-018, 50 Pages, 2001/12
JNC-TN8440-2001-018.pdf:1.31MB
On September 30 at around 10:35 AM, criticality accident occurred at the JCO's conversion building in Tokai-mura. Since criticality accident had not been anticipated, neither devices for termination of criticality accident nor neutron detectors were available. Immediately after the information of the accident, our emergency staff (Japan Nuclear cycle development institute staff) went to JCO site, to measure the intensity of neutrons and gammas. There were four main tasks, first one was to measure the radiation intensity, second one was to terminate the criticality accident, third one is to alert the residents surrounding the JCO site, fourth one is to evacuate the employees in the site. These tasks were successfully performed until October 1. This paper describes about how these operations were performed by the relevant staffs.
Ito, Yasuhisa; Noda, Kimio; ;
JNC TN8410 2001-018, 67 Pages, 2001/04
JNC-TN8410-2001-018.pdf:2.96MB
There are waste storage pits where non-radioactive wastes generated from plutonium fuel facilities were stored in JNC Tokai Works. But radioactive wastes were found in one of the pit during wastes arrangement works. Therefore we set the pit temporary controlled area and recovered wastes from it. This report describes the radiation control technique of recovery work in detail.
; Kano, Yutaka; ; Shindo, Katsutoshi
JNC TN9410 2000-001, 20 Pages, 1999/12
JNC-TN9410-2000-001.pdf:1.84MB
The 12th periodic inspection had been executed at the experimental fast reactor JOYO from February 24,1998 to June 28,1999. This inspection had been extended about three months because it was addtion to the work for the safety countermeasure. The result of collective dose equivalent was 263.92 man*mSv, whereas, the expected collective dose equivalent was about 407 man*mSv in the whole period of this inspection. It was confirmed that this inspection was carried out with the suitable radiation protection programmes. In this report, provided in 12th periodic inspection, were described with taking the results of the past periodic inspections into consideration.
Tanai, Kenji; Iwasa, Kengo; Hasegawa, Hiroshi; Goke, Mitsuo*; Horita, Masakuni*; Noda, Masaru*
JNC TN8400 99-044, 140 Pages, 1999/11
This report consists of three items: (1)Study of the repository configuration, (2)Study of the surface facilities configuration for construction, operation and buckfilling, (3)Planning schedule, In the repository configuration, the basic factors influencing the design of the repository configuration are presented, and the results of studies of various possible repository configurations are presented for both hard and soft rock systems. Here, the minimum conditions regarding geological environment required to guide design are assumed, because it is difficult to determine the repository configuration without considering specific conditions of a disposal site. In the surface facility configuration, it is illustrated based on the results of construction, operation, buckfilling studies for underground disposal facility and EIS report of CANADA. In the schedule, the overall schedule corresponding to the repository layout is outlined in link with the milestone of disposal schedule set forth in the government's basic policy. The assumptions and the basic conditions are summarized to examine the General Schedule from start of construction to closure of a repository. This summaly is based on the technologies to be used for construction, operation and closure of a repository. The basic national policies form the framework for this review of the general schedule.
Sugita, Yutaka; Fujita, Tomoo; Tanai, Kenji; Hasegawa, Hiroshi; Furuichi, Mitsuaki*; Okutsu, Kazuo*; Miura, K.*
JNC TN8400 99-039, 58 Pages, 1999/11
Regarding disposal techniques of high-level radioactive waste (HLW), the HLW is vitrified and then stored for cooling for a period of 30 to 50 years. After cooling, the HLW is isolated in the deep underground. The concept of geological disposal is based on the requirement to enclose the HLW in the deep underground for the long-term durability of the human's environmental safety. Backfilling of a repository is a unique activity on the geological disposal. If underground tunnels excavated to construct the repository are left, they may have significant influences on the barrier performance of an entire repository, such as: the mechanical stability of a tunnel may be damaged by rock stresses and a tunnel may provide a fast pathway for ground water flow. Therefore, the underground facilities are expected to be backfilled with a backfilling material after emplacement of the HLW and a buffer material. The material for the backfilling of the underground facilities is backfilling material. In this report, bentonite-aggregate mixture is considered, as one of the candidate materials for the backfilling material. Aggregate imitates the muck that is generated during construction phase of the underground facilities. The combination of backfilling, plugging and grouting is considered in some underground situations. Plug is composed of concrete material or clay-based one. Grouting material is concrete material or clay-based one, too. In this report, the concept of the backfilling, mechanical and hydrological characteristics of the bentonite-aggregate mixture, the function, work methods and a schedule of the backfilling materials, plugging and grouting are considered, and items of quality control for the bentonite-aggregate mixture, concrete material and grouting are listed.
Power Reactor and Nuclear Fuel Development Corporation
PNC TN9360 95-002, 98 Pages, 1995/11
no abstracts in English
Power Reactor and Nuclear Fuel Development Corporation
PNC TN9360 95-001, 104 Pages, 1995/11
no abstracts in English
Power Reactor and Nuclear Fuel Development Corporation
PNC TN9360 94-002, 100 Pages, 1994/02
no abstracts in English
Power Reactor and Nuclear Fuel Development Corporation
PNC TN9360 94-001, 95 Pages, 1994/02
no abstracts in English
Sawada, Shusaku*; *; *
PNC TJ9124 91-002, 331 Pages, 1991/03
"HIBEACON", which is a three dimensional core deformation analysis code for the experimental fast reactor "JOYO", had been modified in order to expand the code's functions for planning a long-term operation and managing the operation of "JOYO", and to analyse the core deformation characteristics speedily and accurately. In this study, "HITETRAS", which is a code for calculating temperatures and fast neutron fluxes on wrapper tubes, has been modified in order for it to correspond with the modification of "HIBEACON". And, the core deformation analysis on "JOYO" MK-III has been performed with those modified codes. Results of this study are as follows: (1) Improvement of core deformation analysis code. (a) Modification of function of "HITETRAS" to output temperatures and neutron fluxes. The method to output wrapper tubes' temperatures and neutron fluxes has been modified corresponding to the modification of "HIBEACON". (b) Addition of ability to alter program size of "HITETRAS". An ability to alter the program size has been added to "HITETRAS" by using INCLUDE statement and PARAMETER statement of FORTRAN language. (c) Modification of "HIBEACON". Following modifications, which are required for analysis on "JOYO" MK-III, have been perfomed. (1) alteration of calculation method for gap clearance between wrapper tubes. (2) addition of function for outputting elements of free bowing deformation (3) addition of function for selecting items to be output on list (2) Core deformation analysis on "JOYO" MK-III. "JOYO" MK-III will have different core characteristics from MK-II because of its higer neutron flux feature, two core regions, wider irradiation space, and so on. So, the core deformation behavior of "JOYO" MK-III has been analysed with the modified codes above-mentioned, and it has been clarified that there is no problem on the core integrity of MK-III from the view point of the core deformation.