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Yoshida, Michihiro; Suzuki, Satoshi*; Sukegawa, Yasuhiro*; Miyo, Hiroaki
JNC TN8440 2000-021, 180 Pages, 2000/10
JNC-TN8440-2000-021.pdf:42.37MB
At outside waste storage pits, containers for storage of wastes corroded and were flooded, and it was confirmed on August 26, 1997. Confirmation of contamination of the pits outskirts, installation of sheets to prevent rainwater from flowing into the pits, drawing stay water were executed, promptly. Design and authorization works of the work house and waste treatment devices to take out wastes of the pits were executed too. After construction of the work house, taking out wastes of the pits started, and finished on April 10, 1998. Investigations of the inflow point of rainwater and leak of stay water were executed next. The results were reported to Science and Thechnology Agency (STA), adjoining authorities on December 21, 1998. After decontamination of the pits inner walls to background level of the radioactivity which included general concrete, control area was removed, and the pits were closed by concrete. Measures of closing of the pits were prepared from the middle of August, 1999, and dismantlement of unnecessaly instruments started. Decontamination of the pits started fiom the beginning of September, 1999. The above works finished on June 30, 2000. After decontamination of the pits, STA, adjoining authorities confirmed the circumstances. Work pouring concrete into the pits was executed three times (three levels), and finished on August 31, 2000. In addition to above, the amount of concrete poured into the pits was about 1,200 m
. This report compiled the photographs of the works from confirmation of stay water at August, 1997 by finish of measures of closing of the pits at September, 2000.
; ; ; Miyakawa, Shunichi
PNC TN9410 98-076, 89 Pages, 1998/07
The INstrumented irradiation Test Asembly (INTA) has been used to conduct precision on-line instrumented irradiation tests in the experimental fast reactor JOYO. In INTA, direct instrumentation wiring between the irradiation test section in the core and the upper structure section in the rotating plug makes INTA structurally complex and expensive. Instead of direct wiring, if an electrical connector capable of withstanding a heated liquid sodium environment could be used between the irradiation test section and the upper structure section, the upper mechanism of INTA could be reused and testing costs would be drastically reduced. Moreover, the reactor load factor would be improved because of reduced handling time for INTA. In an attempt to gain this advantage, research and development of an electric connector in a sodium environment was carried out from 1988 to 1996 at PNC. As no previous R&D had been conducted in this area, this development activity was conducted in a boot strap manner. The first test was carried out for a small model fabrication, the second was for a water partial model, and the third was for a sodium partial model. Based on those tests, a prototype design specification of the connector was determined. In the sodium partial model test, the resiliance of the electrical connector insulation to the sodium environment was investigated. However, severe cracking in the ceramic insulator caused by the high temperature sodium environment was discovered at the junction of ceramic insulator and metallic electrode. This was recognized to be a critical problem because the boundary on the structure could not be secured. To address the problem, additional sodium partial tests were performed for various material combinations of ceramic insulators, metallic electrodes, brazing materials and metallization materials. However for insulator cracking, the results of the tests were unsatisfactory. After all although the newest technology of main ceramics ...
Watanabe, Kazuo; ;
Bunseki Kagaku, 44(1), p.19 - 23, 1995/00
no abstracts in English
PNC TN9000 94-006, 60 Pages, 1994/07
Main features were studied about an objective deep sea reactor, which will be used as an electric power source at an unmanned deep sea base. The main features determined are as follows. [Thermal power 190 kWt, Fuel Mixed nitride, Cladding material Hasteloy N, Structual material Type 316 Stainless Steel, Coolant NaK, Core height and diameter about 25cm both, Reactor vessel outlet/inlet temperature 605/ 505
C, Operation term 10 years.] Some topic subjects of a talk during deep sea reactor research were studied like follows. Availability of electric transmission from the land or a ship is as follows. (1)The electric transmission from the land is limited up to 1,000m in the depth of water and 100km in the distance from the land. (2)The electric transmission from a ship is available only in the days when the sea is calm. Therefore these transmission methods can not be used as the power source for the base. Concerning reliability, reliability analysis were performed about the part of Closed Brayton Cycle Systems of the reactor. Success probability calculated on the part was 0.999942 in the case of continuous four years operation at 20 kWe. Concerning safety, radioactivity contained in the reactor was calculated. The radioactivity was about 1/50,000 of the radioactivity thrown away in the north Atlantic Ocean from 1962 to 1982. Concerning the experience of developping a NaK cooling reactor in U.S., no anormaly was reported to be found in fuel pins and a reactor vessel after about 400 days operation under a reactor outlet temperature condition over about 527C in the test of a ground test reactor FS-3 for SNAP-10A about thirty years ago.
Matsuda, Fumio*; Wada, Ryutaro*; Fujiwara, Kazuo*
PNC TJ1058 92-001, 270 Pages, 1992/03
no abstracts in English
-
solid Waste treatment facilities Conceptual design study*; Seki, Sadao*; *
PNC TJ9409 91-001, 164 Pages, 1991/02
This report describes the result of conceptual design study concerned with "High Radioactive - Solid Waste Treatment Facilities, "which will be planed for the purpose of volume reduction and stabilization of High Radioactive - solid wastes generated and stocked in the O-arai Engineering Center of PNC. In this conceptual design study the basic process of the facilities, which are sufficient to treat each waste and develop technologies, are clarified. This report consist with: (1)Clarification of waste to be treated. (2)Study on the treatment technology and process. (3)Conceptual design of facilities and equipment. (4)Estimation of construction cost and schedule.
