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PNC TJ9009 89-001, 89 Pages, 1989/05
The second trial production of wrapper tubes was made on the carbide precipitation hardened ferritic steel, followed by the selection of the suitable chemical compositions and heat treatment obtained from the plates. The addition of B was of particular interest in the chemical compositions of 0.1C-11Cr-0.4Mo-2W-0.2V-0.05Nb-0.05N steel. The test results are summarized as follows. (1)In the system of 0.1C-11Cr-0.4Mo-2W-0.2V-0.05Nb-0.05N steel, the addition of B with 20ppm was found ineffective in terms of such mechanical properties as tensile strength and hardness, and rather resulted in degradation in charpy impact properties. (2)The suitable heat treatment condition was chosen that could meet the requirement of elevated temperature tensile strength with 
(650
C) 
40kgf/mm
and 
(650C)30kgf/mm which was thougth difficult to satisfy among others. When 1050 C was selected for normalization temperature, tempering temperature was required below 725C, while normalization temperature higher than 1100C could allow the tempering temperature up to 750C. (3)The requirement in impact properties (As normalized and tempered : DBTT20C, 650C
5 year service : DBTT150C) could be met even without tempering when normalized at 1050 and 1100C. While, normalized at 1200 and 1300C, the requirement could not be met, even when tempering was given at 750C (4)The chemical compositions (0.1C-11Cr-0.4Mo-2W-0.2V-0.05Nb-0.05N) and heat treatment condition (1050C normalized and 700C tempered), which was established on the plates, was extended to trial production of wrapper tubes and they were evaluated in terms of quality and properties. The results are as follows. (a)Dimensions and defects met the specification. (b)Microstructure was full martensitic and grain size was fine. ...
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PNC TJ9009 88-008, 80 Pages, 1988/07
Alleviation of Fuel Clad Chemical Interaction (FCCI) is urgently needed for the prolongation of fuel life. Appropriate coating material as well as coating technique, which are both practical and economical, should be developed for this purpose. In this work, the method of chemical vapor deposition (CVD) and lining were applied on 316 stainless steel 12%Cr steel. By using these techniques, such elements as Cr, V, Nb, Ti and Zr were coated or lined either individualluy or in combination. The results obtained are summarized as follows. (1)The coating of Cr and V through CVD method is not suitable for final product of 316 stainless steel, because processing temperature is required over 1000C. (2)Application of the above coating to in-processed product also seems difficult, since the carbide film formed on the outermost surface shows poor ductility and gets cracked and peeled off during hot and cold rolling operation. (3)The method of using the V and Cr coating as insert material between Ti or Zr and stainless steel or 12%Cr steel does not seem applicable, since cracking of the carbide layer takes place and the eutectic reaction occurs between Zr or Ti and steel, because of rather rich concentration of iron in the surface region (60-70% Fe-30-40%Cr or V). (4)The lining of Nb sheet on the steels seems applicable. Using of Nb sheet as insert material between Ti and stainless steel is also applicable and, in this case, the eutectic reaction is completely prevented. (5)The problem of Nb clad technique is that Nb carbide layer forms at the interface of steel and Nb during hot rolling and heat treatment and this layer shows poor ductility which leads to microcracks during hot and cold rolling. (6)The prevention of carbide formation can be possible by using Ni as insert material between Nb and steel.
PNC TJ209 72-02T, 39 Pages, 1972/04
It is purported to establish an eddy current testing technique to inspect stainless steel fuel cladding tubes. (1) The eddy current detector can find out the flows which are difficult to be detected by the ultrasonic flow detector due to its shape and location. These flows are detectable by improving the existing ultrasonic flow detection method and also by using the system in which the ultrasonic flow detector is used in combination with the ultrasonic thickness gauge. (2) The eddy current detector can precisely and accurately detect the surface caves, pits, or griding parts of surface. (3) The eddy current detector frequently indicates signals of flows or gives a larger background noise due to the localized wall thickness variations or inner diameter changes. (4) A coarse surface sometimes affect and increase the back-ground noise of the eddy current recording chart. (5) Other than the above, in some cases, the eddy current detector gives out signals of unknown causes. At present, ultrasonic flow detector is used in combination with the ultrasonic thickness gauge.
PNC TJ209 72-02, 42 Pages, 1972/04
PNC-TJ209-72-02.pdf:3.24MBPNC-TJ209-72-02T.pdf:2.23MB
It is purported to establish an eddy current testing technique to inspect stainless steel fuel cladding tubes. (1) The eddy current detector can find out the flows which are difficult to be detected by the ultrasonic flow detector due to its shape and location. These flows are detectable by improving the existing ultrasonic flow detection method and also by using the system in which the ultrasonic flow detector is used in combination with the ultrasonic thickness gauge. (2) The eddy current detector can precisely and accurately detect the surface caves, pits, or griding parts of surface. (3) The eddy current detector frequently indicates signals of flows or gives a larger background noise due to the localized wall thickness variations or inner diameter changes. (4) A coarse surface sometimes affect and increase the back-ground noise of the eddy current recording chart. (5) Other than the above, in some cases, the eddy current detector gives out signals of unknown causes. At present, ultrasonic flow detector is used in combination with the ultrasonic thickness gauge.