Thermal mixing characteristics of helium gas in high-temperature gas-cooled reactor, (I) thermal mixing behavior of helium gas in HTTR. Issue 3 (3rd March 2016)

• Record Type: Journal Article
• Authors: Tochio, Daisuke; Fujimoto, Nozomu
• Is Part Of: Journal of nuclear science and technology. Volume 53:Issue 3(2016)
• Page Start: 425
• Page End: 431
• Publication Date: 2016-03-03
• Subjects: HTGR -- HTTR -- helium gas -- piping system -- concentric hot gas duct -- thermal mixing behavior -- thermal-hydraulic analysis; Nuclear engineering -- Periodicals; Nuclear physics -- Periodicals; Nuclear energy -- Periodicals; 621.4805
• DOI: 10.1080/00223131.2015.1054910
• Languages: English
• ISSNs: 0022-3131

Abstract

Abstract : The future high-temperature gas-cooled reactor (HTGR) is now designed in Japan Atomic Energy Agency. The reactor has many merging points of helium gas with different temperatures. It is needed to clear the thermal mixing characteristics of helium gas at the pipe in the HTGR from the viewpoint of structure integrity and temperature control. Previously, the reactor inlet coolant temperature was controlled lower than specific one in the high-temperature engineering test reactor (HTTR) due to lack of mixing of helium gas in the primary cooling system. Now, the control system is improved to use the calculated bulk temperature of reactor inlet helium gas. In this paper, thermal–hydraulic analysis on the primary cooling system of the HTTR was conducted to clarify the thermal mixing behavior of helium gas. As a result, it was confirmed that the thermal mixing behavior is mainly affected by the aspect ratio of annular flow path, and it is needed to consider the mixing characteristics of helium gas at the piping design of the HTGR.