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Conference Article: Experience obtained from construction and preliminary test of in-core structure test section (T-2)

Kunitomi, K.; Inagaki, Y.; Ioka, I.; Kondo, Y.; Miyamoto, Y.; Shimomura, H. (Japan Atomic Energy Research Inst., Tokai, Ibaraki. Tokai Research Establishment); Akisada, T.; Yamaguchi, S

Abstract

The in-core structure test section (T2) in Helium Engineering Demonstration Loop (HENDEL) simulates a part of the core bottom structure with the same scale as that of a very high temperature reactor (VHTR) in JAERI. The main objectives of T2 are to verify the following items by testing under the same condition as that of the VHTR : (1) sealing performance through the side gaps between permanent reflector blocks, and inspection of an accuracy in fabrication, (2) insulation performance of the carbon blocks, (3) mixing characteristic of the hot plenum, (4) structural integrity of the core bottom structure. The design and construction of T2 were started in March 1983, and a preliminary test was carried out in June 1986. In the construction of T2, a fabricating technology of the graphite blocks and electric graphite pipe heater for raising up the temperature of the helium gas was developed as well as that of another metal structure. Especially, the technology of the graphite blocks is thought to be prime importance to achieve the outlet coolant temperature of 950 deg C. If the side gap between the reflector blocks around the core were wider than 0.2 mm, the outlet temperature would become lower than 950 deg C because of leaking cold coolant gas. The preliminary test revealed that the flow rate of leakage was about 30 % of the expected value, because the gap was about 1/5 of the design value of 0.2 mm. These data would be useful for licensing and design work of the VHTR.

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key words: experimental data; graphite; heat transfer; helium; htgr type reactors; hydraulics; leaks; mechanical structures; reactor cores; reactor experimental facilitie; seals; thermal insulation; thermodynamics; very high temperature; carbon; gas cooled reactors; graphite moderated reactors; numerical data; reactor components
Reference:
Specialists' meeting on graphite component structural design, JAERI Tokai (Japan), September 8-11, 1986
International Atomic Energy Agency, Vienna (Austria). International Working Group on Gas-Cooled Reactors
IWGGCR--11, pp:233-238