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Ito, Yasuhisa; Noda, Kimio; ; Izaki, Kenji; Ebana, Minoru*
JNC TN8410 2001-007, 81 Pages, 2001/03
JNC-TN8410-2001-007.pdf:3.42MB
Dust Monitor is one of the equipments that measure the concentration of air-borne radioactive materials. This monitor generally collects the dusts in the air by the air pumps, but this system has several problems. Therefore we made the prototypes of Dust Monitor and Dust Sampler that adopted static electrical collecting system, and examined these prototypes. As the result of examination, we confirmed that the static electrical collecting system has the same collection efficiency with air suction system and it is possible to use these prototypes in controlled area.
Izaki, Kenji; Noda, Kimio; ; Kashimuta, Yoshio*
JNC TN8410 2001-005, 30 Pages, 2001/01
JNC-TN8410-2001-005.pdf:0.62MB
Stack monitoring is the most important work in radiation control works. Exhaust monitors used for stack monitoring have the background (which is the counts by natural radio-nuclides) on normal condition, and the values of the background vary with the facilities. Therefore, if the value of background is high, it is difficult to estimate rapidly the radioactive concentration in the exhaust. In order to estimate rapidly the radioactive concentration in exhaust, we analyzed the behavior of natural radioactivity in the facilities and examine the technique fo reducing the value of the background. As a result of the examination, we found that it is possible to estimate rapidly if we change over the monitoring point to immediately after the HEPA filters on the exhaust duct. In this reports, the analyzed results of behavior of natural radio-nuclides in the facilities and the technique for reducing the values of the background are described. To reduce the value of the background has a major effect on not only rapidly estimating the radioactive density in the exhaust but also finding the unusual things on stack monitoring.
Morinaga, Masahiko*; *; *; *
PNC TJ9603 97-001, 95 Pages, 1997/03
[PURPOSE] Nb-based and Mo-basd alloys have been investigated in order to develop the frontiers of matelials technique which will be utililized in the environment of high-temperature liquid alkali metals. In this study, both mechanical properties and corrosion resistance to liquid Li were evaluated for two designed Mo-based alloys, Mo-15Re-0.1Zr and Mo-15Re-0.1Zr-0.1Ti. In addition, a series of corrosion test was performed with provisionally designed Nb-based alloys, Nb-(1-4)Hf. [EXPERIMENTAL METHODS] (1)High-temperature tensile test : A tensile test in the Ar atmosphere was carried out at 1473K for the designed Mo-based alloys. Commercial TZM alloy was also tested as a reference. (2)High-temperature creep test : A Creep test in the Ar atmosphere was performed at 1473K under the several applied stress levels for the designed Mo-based alloys. (3)Workability test : A three-point bend test was carried out at room temperature to evaluate the workability of the designed Mo-based alloys. (4)Corrosion resistance to liquid Li : Both the provisionally desingned Nb-based alloys and the designed Mo-based alloys were immersed in the liquid Li at 1473K. The weight change was measured as an indication of the corrosion resistance. Also, the Auger electron spectroscopy analysis was performed with several specimens to examine the surface state of them after corrosion tests. [RESULTS AND DISCUSSIONS] (1)High-temperature tensile properties : The designed Mo-based alloys were superior in the tensile properties at 1473K to the commercial TZM alloy. In fact, both the tensile and yield strengths of them were about 1.5 and 2.3 times higher than the TZM alloy, respectively. (2)High-temperature creep properties : The creep rate of the designed Mo-based alloys at 1473K was lower, compared to other solid solution hardening Mo-based alloys, but higher than the precipitation hardening TZM alloy. (3)Workability : The workability of the designed Mo-based alloys was satisfactory regardless ...
Morinaga, Masahiko*; *; *; *; Inoue, Satoshi*
PNC TJ9603 96-001, 79 Pages, 1996/03
[PURPOSE] In order to develop the frontier domain of technique for the high temperature liquid alkali metal, candidate Nb-based and Mo-based alloys are needed. They are needed to have excellent compatibility with liquid Li (max. 1200
C) and super-heat-resistance. In this study, alloy design using a d-electrons alloy theory and estimation of designed alloy were performed. [EXPERIMENTAL METHODS] (1)Workability : A bend test was carried out with the provisionally designed Mo-based alloys, but by modifying the compositions by adding intergranular strengthening elements, Ti, B, C, Hf, into them to improve the ductility. (2)Corrosion resistance to liquid Li : The provisionally desingned Nb-based alloys were immersed in liquid Li at 1200C for three hundred hours, and the weight change due to the corrosion was measured. The corrosion surface was also analyzed using SEM and EPMA. In addition, a similar corrosion test was carried out with binary Nb-based and Mo-based alloys. (3)Embrittlement at 800C : A series of experiments such as the hardness test, X-ray analysis and microstructure observation was perfomed with the Nb-1Zr alloy which was creep-tested at 800C or 1200C. Also, a Nb-1Zr alloy specimen which was not creep-tested, was used as a reference specimen. [RESULTS AND DISCUSSIONS] (1)Workability : The Ti addition into the Mo-based alloys was effective in improving workability. The brittleness of Mo may be caused by the existence of oxygen in the grain boundaries, so that the formation of Ti oxides probably weakened the oxygen effect, resulting in the better workability of the alloy. However, B, C and Hf additions into Mo-based alloys never improved the workability. (2)Corrosion resistance to liquid Li : Many cracks were observed on the corroded surface of the provisionally designed Nb-based alloys despite the addition of a corrosion resistant element, Hf, into them. In paticular, such cracks were developed ...
Kobayashi, Hirohide; Kanamori, Masashi; Noda, Kimio; Izaki, Kenji; Miyabe, Kenjiro;
Nihon Genshiryoku Gakkai-Shi, ,
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