Development of active control technology for impurities in coolant helium using High Temperature Engineering Test Reactor (HTTR)

Hamamoto, Shimpei; Nemoto, Takahiro; Sekita, Kenji; Saito, Kenji

JAEA-Technology 2015-048, 62 Pages, 2016/03

JAEA-Technology-2015-048.pdf:2.58MB

The decarburization may take place depending on the chemical impurity composition in helium gas used as the primary coolant in High-Temperature Gas-cooled Reactors, and will significantly reduce the strength of the alloy. The ability to remove impurities by a helium purification system was designed according to the predicted generation rate of impurities so as to make the coolant become the carburizing atmosphere. It has been confirmed that the coolant becomes the carburizing atmosphere during the operation period of the High Temperature engineering Test Reactor (HTTR). However, it is necessary to consider changes of generation rates of impurities since lifetime of commercial reactor is longer than the life of the HTTR. To avoid the influence of the change of generation rate, the control of removal efficiency of impurity in the helium purification system was considered in this study. To reform the decarburizing into the carburizing atmosphere, it is effective to increase the H and CO concentration in the coolant helium. By controlling the efficiency of the Cooper Oxide Trap (CuOT), it is possible to increase the H and CO concentrations. Therefore, an experiment was carried out by injecting the gas mixture of H and CO into the existing purification system of HTTR to investigate the dependencies of temperature and impurity concentration on the removal efficiency of CuOT. The experimental results are described as the following, (1) By adjusting the temperature of helium at the CuOT within a range from 110C to 50C, it is possible to reduce the removal efficiency of H sufficiently. (2) Temperature change of helium gas in the CuOT is sufficiently reduced by the cooler located at the downstream of the CuOT, which does not affect the primary cooling system of HTTR. As the results, the applicability of removal efficiency control of CuOT was verified to improve the decarburizing atmosphere for the actual HTGR system.

Long-term creep properties of Hastelloy XR in simulated high-temperature gas-cooled reactor helium

Kurata, Yuji; ; ; Shindo, Masami; Nakajima, Hajime;

Journal of Nuclear Science and Technology, 32(11), p.1108 - 1117, 1995/11

https://doi.org/10.3327/jnst.32.1108

no abstracts in English

Effects of carburization and aging on the tensile properties of an experimental Ni-Cr-W superalloy

Shindo, Masami; Nakajima, Hajime

Journal of Nuclear Materials, 144, p.20 - 28, 1987/00

https://doi.org/10.1016/0022-3115(87)90275-3

Carburization tests with experimental fine- and coarse-grained Ni-Cr-W alloys strengthened by -W phase were carried out at 950C in heavily carburizaing environment (90% Ar + 10% CH) to investigate the carburization behaviour and its effect on room temperature tensile properties; the aging effect was also examined.

Carburization of UO kernels in Cracked Particles and its Effect on Xenon Release

Tobita, Tsutomu; Ikawa, Katsuichi

JAERI-M 84-096, 16 Pages, 1984/05

JAERI-M-84-096.pdf:0.86MB

no abstracts in English

On the metallurgical and environmental factors affecting creep behaviour of Hastelloy-X

; Kondo, Tatsuo

Proc.of 2nd Japan-US HTGR Safety Technology Seminar,Material Properties andDesign Method Session, 12 Pages, 1978/00

no abstracts in English