Japan materials testing reactor

Several post irradiation material tests and in-pile creep tests on FBR grade 316 stainless steel were continued in Joyo and JMTR (Japan Material Test Reactor of JAERI) in accordance with the R D program Spica step-2. 

Japan Materials Testing Reactor (JMTR). The main design parameters of ftiel pins are as follows [7.56] ... 

WATANABE, K., et al.. Evaluation of Materials Performance of Hastelloy Alloy XR for the High Temperature Engineering Test Reactor Components - Weldability and High Temperature Strength Properties, (3rd JAERI Symp., Oarai, 1996), Proc. JAERI-Conf 96-010, Japan Atomic Energy Research Institute (1996) 368-382. 

Both in Europe and Japan low carbon stainless steel of type 316L with controlled addition of nitrogen is recommended for use even at low temperature. At doses above about 15 displacements per atom the degree of embrittlement and the level of swelling in all materials tested are probably unacceptable for use in critical fixed reactor components. 

In the development of a new correlation method, microstructural characterization of the surveillance materials of some PWR plants was also performed in order to understand the embrittlement mechanism of RPV steels with different Cu contents. At the same time, another test reactor irradiation project, the PLIM project, was also conducted by Japan Nuclear Energy Safety (JNES), where extensive microstructural characterization of base metals and weld metals with a wide range of chemical compositions in terms of Cu and Ni was performed using APT, transmission electron microscopy and positron annihilation to obtain new insights with the embrittlement mechanism at high fluences.The mechanism of embrittlement identified or confirmed in these projects was summarized as follows ... 

DS86 dose. Accurate and precise estimates of the radiation to which A-bomb survivors were exposed have been developed through the joint efforts of scientists from Japan and the United States, who measured radiation doses at weapon tests, reactor simulations, and radiation-induced changes in materials and the earth in the vicinity of the... 

The experimental fast reactor JOYO at the Japan Nuclear Cycle Development Institute s Oarai Engineering Center attained initial criticality in April 1977 and was the first liquid metal cooled fast reactor in Japan. From 1983 to 2000, JOYO operated with the MK-II core as an irradiation test bed to develop the fuels and materials for future Japanese fast reactors. Thirty-five duty cycle operations and thirteen special tests with the MK-II core were completed by June 2000 without any fuel pin failures or serious plant trouble. The reactor is currently being upgraded to the MK-III core. This paper provides a review of the operational experiences obtained through the JOYO s operation. 

ITER is the result of a 1987 agreement, a joint research enterprise for the design of an experimental fusion reactor, supported by the EU, the USA, Japan and by the Community of Independent States. Before getting to this stage, it is firstly necessary to develop and test materials which can withstand a very high neutron flux, with the principal aim not to generate an excessive decay power (DeMarco, 2001). In order to cope with these needs, it has now been decided to build a dedicated experimental facility, the International Fusion Materials Irradiation Facility (IFMIF), based on the Li(d, n) reaction. 

In Japan, the Japan Electric Association Code, JEAC 4201, Method of Surveillance Tests for Structural Materials of Nuclear Reactors (JEAC 4201, 2007), specifies the design for a surveillance program to monitor radiation-induced changes in mechanical properties of beltline materials in light-water moderated nuclear power reactor vessels testing and evaluation of the test results. The JEAC 4201 was developed based on the ASTM E 185 for nuclear power RPVs for which the predicted maximum neutron fluence at the end of the operating period (usually 32 EFPY unless otherwise identified) exceeds 1 x 10 n/cm" E > IMeV) at the inside surface of the reactor vessels. 

JEAC (2007), Method of surveillance tests for structural materials of nuclear reactors, JEAC 4201-2007, Japan Electric Association,Tokyo. 

JE AC, Method of Surveillance Tests for Structural Materials of Nuclear Reactors, JEAC4201-1991, Japan Electric Association, Chiyoda-ku, Tokyo, Japan, December 13,1991. 

In Japan, the experimental fast reactor "Joyo started operation in 1975 following the criticality test equipment called fast critical assembly (FCA). Joyo has run irradiation tests for domestic fuel material and increased the core thermal output as well. At the beginning of operation, the thermal output of the core was 100 MW. Currently, it employs a third-generation core, called the MK-in, with 140 MW thermal output. 

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