Research on development of high-purity iron-based alloys; Manufacture, analysis of small amount of element and property tests

; *; ; ; Aoto, Kazumi;

JNC TN9400 2000-059, 43 Pages, 2000/05

JNC-TN9400-2000-059.pdf:2.08MB

The purpose of this study is to understand the material properties of manufacturable high-purity iron and high-purity iron-based alloy in present technology and to get an applicable prospect for the structural and functional material of the frontier fast reactor. Then the about 10kg high-purity iron and iron-based alloy were melted using a cold-crucible induction melting furnace under the ultra-high vacuum. Subsequent to that, the compatibility between the melted material and the high-temperature sodium environment which is a special feature of the fast reactor and tensile property at room and elevated temperatures were investigated using the melted materials. Also, the creep test using the high-purity 50%Cr-Fe alloy at 550C in air in order to understand the high temperature creep property. ln addition, the material properties such as thermal expansion coefficient, specific heat and electrical resistance were measured and to evaluate the outlook for the structural material for the fast reactor. The following results were obtained based on the property test and evaluation. (1)lt was possible to melt the about 10kg high-purity ingot and high-purity 50%Cr-Fe alloy ingot using a cold-crucible induction melting furnace under the ultra-high vacuum. (2)The tensile tests of the high-purity 50%Cr-Fe alloy were performed at room and elevated temperatures in order to understand the deformation behavior. From the experimental results, it was clear that the high-purity 50%Cr-Fe alloy possesses high strength and good ductility at elevated temperatures. (3)The physical properties (the thermal expansion coefficient and specific heat etc.) were measured using the high-purity 50%Cr-Fe alloy. lt was clear that the thermal expansion coefficient of high-purity 50%Cr-Fe alloy was smaller than that of SUS304. (4)From the corrosion test in liquid sodium, the ordinary-purity iron showed the weight loss after corrosion test. However the high-purity iron showed ...

Static mechanical properties of buffer material

Takachi, Kazuhiko; Suzuki, Hideaki*

JNC TN8400 99-041, 76 Pages, 1999/11

JNC-TN8400-99-041.pdf:4.49MB

The buffer material is expected to maintain its low water permeability, self-sealing properties, radionuclides adsorption and retardation properties, thermal conductivity, chemical buffering properties, overpack supporting properties, stress buffering properties, etc. over a long period of time. Natural clay is mentioned as a material that can relatively satisfy above. Among the kinds of natural clay, bentonite when compacted is superior because (1)it has exceptionally low water permeability and properties to control the movement of water in buffer, (2)it fills void spaces in the buffer and fractures in the host rock as it swells upon water uptake, (3)it has the ability to exchange cations and to adsorb cationic radioelements. In order to confirm these functions for the purpose of safety assessment, it is necessary to evaluate buffer properties through laboratory tests and engineering-scale tests, and to make assessments based on the ranges in the data obtained. This report describes the procedures, test conditions, results and examinations on the buffer material of unconfined compression tests, one-dimensional consolidation tests, consolidated-undrained triaxial compression tests and consolidated-undrained triaxial creep tests that aim at getting hold of static mechanical properties. We can get hold of the relationship between the dry density and tensile stress etc. by Brazillian tests, between the dry density and unconfined compressive strength etc. by unconfined compression tests, between the consolidation stress and void ratio etc. by one-dimensional consolidation tests, the stress pass of each effective confining pressure etc. by consolidated-undrained triaxial compression tests and the axial strain rate with time of each axial stress etc. by consolidated-undrained triaxial creep tests.

Material test data of SUS304

; *

JNC TN9450 2000-001, 1370 Pages, 1999/10

JNC-TN9450-2000-001.pdf:117.18MB

This report summarizes the material test data of SUS304. Numbers of the data are as follows. (1)Tensile tests 738 (Post-irradiation: 250, others: 488) (2)Creep tests 434 (Post-irradiation: 89, others: 345) (3)Fatigue tests 612 (Post-irradiation: 60, others: 552) (4)Creep-fatigue tests 200 (Post-irradiation: 40, others: 160) This report consists of the printouts from "the structural material data processing system".

Simulation of creep test on 316FR stainless steel in sodium environment at 550

Satmoko, A.*;

JNC TN9400 99-035, 37 Pages, 1999/04

JNC-TN9400-99-035.pdf:1.54MB

In sodium environment, materia1 316FR stainless steel risks to suffer from carburization. In this study, an analysis using a Fortran program is conducted to evaluate the carbon influence on the creep behavior of 316FR based on experimental results from uni-axial creep test that had been performed at temperature 550C in sodium environment simulating Fast Breeder Reactor condition. As performed in experiments, two parts are distinguished. At first, elastic-plastic behavior is used to simulate the fact that just before the beginning of creep test, specimen suffers from load or stress much higher than initial yield stress. In second part, creep condition occurs in which the applied load is kept constant. The plastic component should be included, since stresses increase due to section area reduction. For this reason, elastic-plastic-creep behavior is considered. Through time carbon penetration occurs and its concentration is evaluated empirically. This carburization phenomena are assumed to affect in increasing yield stress, decreasing creep strain rate, and increasing creep rupture strength of material. The model is capable of simulating creep test in sodium environment. Material near from surface risks to be carburized. Its material properties change leading to non-uniform distribution of stresses. Those layers of material suffer from stress concentration, and are subject to damage. By introducing a damage criteria, crack initialization can thus be predicted. And even, crack growth can be evaluated. For high stress levels, tensile strength criterion is more important than creep damage criterion. But in low stress levels, the latter gives more influence in fracture. Under high stress, time to rupture of a specimen in sodium environment is shorter than in air. But for stresses lower than 26 kgfmm, the time to rupture of creep in sodium environment is the same or little longer than in air. Quantitatively, the carburization effect at ...

Experimental evaluation of the characteristics of super-heat-resisting Nb-based and Mo-based alloys

Morinaga, Masahiko*; *; *

PNC TJ9603 98-002, 48 Pages, 1998/03

PNC-TJ9603-98-002.pdf:2.14MB

[PURPOSE]Both the Nb-based and Mo-based alloys have been designed and developed in order to establish the frontier technique for super-heat-resisting materials used in the liquid alkali metal environment at high temperatures. In this study, mechanical properties of the designed Nb-1Hf alloy were experimentally evaluated. In addition, the brittleness of Nb-based alloys observed at 1073K were discussed. Moreover, characteristics of both the designed Nb-based and the Mo-based alloys were summarized in a consistent way. [EXPERIMENTAL METHODS] (1)Tensile test : The tensile test was performed at room temperature and 1473K in an Ar gas atmosphere for the designed Nb-1Hf alloy and also for commercial Nb-1Zr alloy. (2)High temperature creep test:The creep test of the designed Nb-1Hf alloy was carried out at 1473K in an Ar gas atmosphere under several applied stress levels. (3)TEM observation : The TEM observation was performed with the creep specimens tested at both 1073K and 1273K in order to get information for the 1073K brittleness of the Nb-1Zr alloy. [RESULTS AND DISCUSSIONS] (1)Tensile test : The tensile stress and the proof stress of the designed Nb-1Hf alloy were slightly lower than those of commercial Nb-1Zr alloy at room tempetarure. But the alloy was superior in the elongation to the Nb-1Zr alloy. High temperature tensile properties were not able to be evaluated properly because of the large grain size of the specimens. (2)High temperature creep test : The Nb-1Hf alloy was superior in the ereep resistance to other solid solution hardened Nb-based alloys. (3)TEM observation : A modulated structure with about 1nm preiod was observed in the specimen which was brittle at 1073K. This was supposed to cause the 1073K brittleness of the Nb-1Zr alloy. [CONCLUSION] The tensile strength of the designed Nb-1Hf alloy was slightly lower at room temperature than that of the commercial Nb-1Zr alloy. But, the designed alloy was superior in high temperature creep properties to any

None

Ishijima, Yoji*

PNC TJ1600 98-002, 66 Pages, 1998/02

PNC-TJ1600-98-002.pdf:7.02MB

None

Post irradiation examinations on HTTR materials

; Omi, Masao; Eto, Motokuni; Watanabe, Katsutoshi

KAERI-NEMAC/TR-32/95, 0, p.282 - 295, 1995/00

no abstracts in English

Materials properties data sheet (No.Q 01); Internal pressure creep properties data on high strength ferritic/martensitic steel in air and in sodim

; ; *; *; Yoshida, Eiichi;

PNC TN9450 92-004, 37 Pages, 1992/06

PNC-TN9450-92-004.pdf:0.78MB

High Strength Ferritic/Martensitic Steel is one of the cardidate core materials for largescale FBR because of excellent resistance to swelling. This report are presented about the internal pressure creep of High Strength Ferritic/Martensitic Steel based on the R&D results obtained through the activities of material tests. Contents of the data sheet are as follows; (1) Material: High Strength Ferritic/Martensitic Steel Fuel cladding tube (6.50.47.mm) (2) Environment: In Air and In Sodium (3) Test temperature: 600 and 650C (4) Hoop stress: 9.4832.43 kgf/㎜ (5) Number of data: 13 points

Creep fatigue behavior of SUS 304 Stainless steel tested in sodium at 550C

*

PNC TN9410 90-086, 47 Pages, 1990/05

PNC-TN9410-90-086.pdf:1.76MB

Since stainless steels like SUS 304 and SUS 316 tend to be carburized in sodiun, the grain boundary near surface may be degraded due to carbides precipitation. In order to clarify the effect of the grain boundary degradation upon creep fatigue strength, long term creep fatigue tests of SUS304 stainless steel were performed in carburized sodium, 0btained results are summarized as follows: (1)Creep fatigue life in carburized sodium was nearly equal to that in air, in spite of the fact that severe carburization and carbides precipitation on grain boundary were observed on tested specimen surface. (2)Creep fatigue life calculated using usual linear damage summation rule showed good agreement with experimental results, (3)It was revealed that crack initiation life in carburized sodium was almost the same as that in air, although crack initiated on degraded grain boundary in carburized sodium. (4)The above fact supplies an evidence to justify the concept that creep fatigue crack initiation life in sodium is longer than 1/20 of failure life obtained using small specimens in air, which is basic assumption of our creep fatigue evaluation method. It is conjectured from this study that FBR grade SUS316 stainless steel will show almost the same creep fatigue life as that in air, however, a few creep fatigue tests of FBR grade SUS316 in carburized sudium will be necessary to clarify this conjecture.

Evaluation of high temperature multiaxial fatigue behavior of 304 steel (2nd Reprot.)

*

PNC TN9410 90-093, 68 Pages, 1990/01

PNC-TN9410-90-093.pdf:1.32MB

The authors have conducted a series of axial and torsional biaxial fatigue/creep-fatigue tests with :304 stainless steel at 550 C and obtained the following conclusions, (1)A fatigue life under nonproportional loading reduces to 1/2-1/3 of that under proportional loading. (2)The life reduction under nonproportional loading can be accouted for by path-dependent Mises type equivalent strain range. In this report, the results of creep-fatigue tests under proportional and nonproportional loading are examined. The following results were obtained. (1)A creep-fatigue life under nonproportional loading reduces to 1/2-1/5 of that under proportional loading. (2)Stress relaxation occurs towards origin proportionally (to the point where axial and torsional loads are zero) even under nonproportional creep-fatigue loading. (3)A creep-fatigue life under nonproportional loading can resonably be evaluated based on the fatigue properties and the creep properties obtained under uniaxial loading conditions, using the path dependent Mises type equivalent strain range and Mises equivalent stress.