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PNC TN941 85-60, 126 Pages, 1985/03
Sodium sampling in JOYO, Experimental Fast Reactor, has been done by methods of flow through sampler and dip tube, one the former is used for purity control of the primary sodium, study was made on behavior of radionuclides in those sampling and following observations were obtained. (1)
Na and 
Ag were distributed homogeneously in longitudinal sampler sodium but a few percentage of Ag were diffused on the wall of sampling tube. (2)Most of 
Mn, 
Co, 
Co, 
Zn and 
Sb, or rarely 
Cr and 
Fe were found on the wall of sampling tube. It was concluded that substances in sodium were moved, deposited and diffused to the tube wall during flushing by sodium or cooling after flushing. (3)Co, and Co had tendency to increase deposit on the wall of sampling tube in proportion to sodium flow time. (4)Depth of penetration in to the wall of sampling tube were approximately 10
20
m for Mn, C0, Co and Ag less than a few m for Zn, Sb, Cr and Fe. From above observations, regarding Na and Ag it is possible to analyze by using present sampling method. However concerning other radioactive nuclides, amount of each nuclide in the sampler should be determined by calculation, that is summation of amount in the sodium and one in the sampler tube wall. As for flow through sampler, it is necessary to shorten the flushing time as possible in order to analyze radioactive nuclide in sodium. Suitable sampling methods are to be developed here after.
Maruyama, Akira; Nomura, Shigeo; Kawai, Masashi; Takani, Satoru; Ota, Yoshio; Atsumo, Hideo
Nihon Genshiryoku Gakkai-Shi, 26(4), p.327 - 338, 1984/04
Times Cited Count：5 Percentile：51.22(Nuclear Science & Technology)None
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PNC TN941 82-168, 64 Pages, 1982/09
It is very important to confirm time response of LMFBR subassembly outlet thermometers for core monitoring, plant control and estimation of thermal transient in various kinds of reactor components. The thermowell is used for subassembly outlet thermometers of JOYO or MONJU in order to protect a sheathed thermocouple from sodium and to keep the primary pressure boundary. This thermocouple assembly is called as well type thermocouple, and its response characteristics is considered to be influenced by shape and size of the well, materials (argon gas) filled into the gap between well and sheathed thermocouple, gap size, etc. Therefore, it is necessary to estimate its response characteristics under almost the same conditions as a reactor. The well type thermocouples (JSA and MSA), which simulated JOYO and MONJU subassembly outlet thermometers, were tested in sodium by step response method, and their time constants (1st and 2nd order time constants) were measured. The program SOFT was made for on-line data acquisition by a mini-computer and the time constants were calculated from measured transient signals. In order to generalize experimental results, the thermal transient analysis code for thermocouple, REST (one-dimension cylindrical model), was developed. From parameter survey by using REST, factors which significantly influence the time constant were investigated. Optimization of the well type thermocouple in response was also discussed in this report.
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PNC TN941 82-92, 42 Pages, 1982/04
Based on the results of basic function tests with an experimental on-line gas chromatograph, the improved on-line cover gas monitor was fabricated, and examinations were conducted to confirm actuation, performance and durability of this monitor. The results are summarised as followed; (1)It was confirmed that each functions of data typewriter, X-Y plotter and monitor panel, contained data display and alarm sending, etc., satisfied its specifications. (2)It was confirmed that the program of this monitor was correctly actuated during 2 times of continuous monitoring for 45 days period. (3)It was found that the slope factors of calibration curves obtained by the relative sensitivity method and the former absolute sensitivity method almost agreed. Using the relative sensitivity method, the required time to calibrate and to make the standard gas samples could be shorten to 1/4 and 1/6, respectively. (4)Three troubles occured during this test. However, these troubles will be able to avoid by regular inspection because these are essencially simple accidents.
Kano, Shigeki; Nakayama, Koichi; Koakutsu, Toru; ; ;
PNC TN941 81-183, 115 Pages, 1981/09
The wear mark was observed between fuel cladding tube and adjacent wrapping wire in the fuelassembly irradiated at the "JOYO" MK-I core. It is necessitated that the formation mechanism, formation condition in the core and the effect of wear mark on the integrity of fuel cladding tube are clarified. The out-of-core sodium test was conducted at the Sodium Tachnology Section, O-arai Engineering Center, PNC, to estimate the load condition in the core and grasp the growth of wear mark. The test conditions were as follows: sodium temperature of 550
C, cold trap temparatures of 120C and 150C, contact loads of 59 - 885g, sliding frequency of 1 Hz and sliding cycles of 10
, 10
and 10
. The test results obtained are as follows. (1)The wear depth linearly increases with increasing load and logarithm of sliding cycle, respectively. The growth of wear mark changes from initial wear to steady state wear. (2)The contact load between fuel cladding tube and wrapping wire in "JOYO" MK-I core is estimated as lower than 250g by the analysis using the test results, wear depth values, obtained at the present test. (3)The higher the contact load, the smoother the morphology of wear mark surface was. The increase of hardness was observed on the sliding surface, but the compositional and crystalline structure change and the crack caused by fatigue were not observed. (4)The sliding resistance between fuel cladding tube and wrapping wire incrementally increases with sliding and, there after, it is apt to be constant at ca. 5
10 sliding cycles. (5)There is not significant difference in the wear depth and the sliding reststance, respectively, between at cold trap temperatures of 120C and 150C. (6)The estimation of the growth of wear mark until the JOYO MK-I No.6 cycle by the present test results shows that the growth of wear depth is slight even after No.6 cycle.
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PNC TN941 81-172, 30 Pages, 1981/08
The purpose of this study is to establish the analytical method for a small quantity of sodium and potassium in distillation residue of NaK-78 alloy by atomic absorption spectrophotometry. With this purpose, the examinations were carried out to confirm the measuring conditions of atomic absorption spectrophotometer, the effect of co-existing materials in sample solution and dissolving method of distillation residue. The results are as follows; (1)Optimum conditions as to respective temperature and time of atomic absorption spectrophotometer for measuring sodium and potassium in sample solution are as follows; [(Drying) Sodium : 100C, 60 sec Potassium : 150C, 60sec [(Charring) Sodium : 600C, 30 sec Potassium : 500C, 60 sec [(Atomizing) Sodium : 2500C, 15 sec Potassium : 2100C, 15 sec (2) Nitric acid is preferably used in dissolving NaK distillation residue, since it does not interfere with the absorbance measurement of sodium and potassium. For the highly sensitive and stable measurement for these elements, the acidity of nitric acid in the sample solution should be kept between 0.2 to 0.5 normal. (3) When the NaK distillation residue is dissolved with nitric acid, nickel element of the crucible also dissolves and present in the sample solution at 200 to 300 ppm. This dissolved nickel, however, does not interfere with absorbance measurement of sodium and potassium. (4) The determination limits of sodium and potassium were determined to be 1.310
ppm and 810
ppm, respectively. The accuracy of 4% was obtained at sodium and potassium concentration of 0.1 ppm and 0.02 ppm, respectively. From these results, it was confirmed that the present analytical method could measure 0.05 ppm of oxygen in NaK. This analytical method can be applied to purity control of oxygen in NaK.
Furuhashi, Ichiro*; ; ;
PNC TN941 81-128, 240 Pages, 1981/06
Thermal ratchet and mechanical ratchet analyses by Finite Element Method (FEM) were performed, and the dependence of ratchetting conditions and ratchet strains upon the following parameters were discussed. (1)Types of primary load (axial load or internal pressure load). (2)Types of cyclic secondary load (thermal load by radial temperature distribution, or strain-controlled mechanical load). (3)Types of radial temperature distribution (linear, parabolic, or real temperature distribution). (4)Types of thermal load (pulsating thermal load or alternating thermal load). (5)Material properties do not depend on temperature, and those are constant. or, material properties are variable dependent on temperature. (6)Strain hardening is zero, small, or considerable. And, thermal ratchetting conditions and thermal ratchet strains were compared between FEM Analysis and simplified analysis.
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PNC TN941 81-91, 57 Pages, 1981/04
The purpose of this study is to improve the cooling method of tag gas enrichment system and to advance the system performance. With this purpose, an improved enrichment system was fabricated, and examinations were conducted to confirm thermocontrol function of this system, adsorption characteristics of enlarged enriching tube and the separating condition of argon co-adsorbed. The results are summarised as follows ; (1)An improved enrichment system was fabricated which was compact and could control the temperature in the range from -180C to +360C using liquid nitrogen as a coolant. It was confirmed that this system was satisfactory in its cooling and thermocontrol function. (2)With the enriching tube enlarged, the treatment performance of feed gas was increased by about 50 times (2.7 m
/hr) that of Phase (I) Test, and the enrichment performance of krypton at very low concentration level was remarkably improved, thereby achieving the purpose of present study. (3)It was recognized that the measurement of isotopic ratios of krypton or xenon was interfered by the residual argon whose volume increased as the enriching tube became larger. However, it was found that such interferences could be eliminated by adding one more system of cryogenic adsorption. (4)As the result of enriching krypton and xenon in commercial argon gas with the improved enrichment system. their contents were determined to be 310
ppb and 8 10 ppb, respectively. It was found that these krypton and xenon contents were negligible for the measurement of tag gas in cover gas. The results of present work is reflected to the design of Failed Fuel Detection and Location system of "MONJU".
