HTGR Knowledge Base

Conference Article: Present activity of the feasibility study of HTGR-GT system

Abstract

In JAERI a feasibility study of the High Temperature Gas-cooled Reactor - Gas Turbine (HTGR-GT) system has been carried out since January, 1997 as an assigned work by the Science and Technology Agency. The study aims at obtaining a promising concept of HTGR-GT system that yields a high thermal efficiency and at the same time is economically competitive. Designs of a few candidate systems will be undertaken and their power generation costs will be evaluated In parallel with design works, some experimental works such as the fabrication of a plate-fin type heat exchanger core and material tests will be carried out. The study will be continued fill 2000 fiscal year.

In 1997 fiscal year, a preliminary design of a direct cycle plant of 600MWt was developed. A reactor inlet gas temperature of 460 deg. C, a reactor outlet gas temperature of 850 deg. C and a helium gas pressure of 6MPa were selected. Some advanced technologies were adopted such as a monolithic fuel compact and a control rod sheath made of carbon/carbon composite material. They were very effective to enhance the heat transfer of fuel and to reduce the core bypass flow. As a result, a power density of 6MW/m3 and the maximum burnup of 10 5 MWD/ton were achieved. A single-shaft horizontal turbomachine of 3600rpm was selected to ease the mechanical design of the rotor supported by magnetic bearings. The turbine, two compressors, a generator and six units of intercooler were placed in a turbine vessel. Plate-fin type recuperator and precooler are installed in a vertical heat exchanger vessel. By this design, a net thermal efficiency of 45.7% is expected to be achieved To develop a high performance plate-fin recuperator, a core model of W200mm x L200mm x H200mm with small fin size of 1.15mm height was fabricated and as a result of tests, leak tightness, component strength and bonding appearance were found to be satisfactory.

In 1998 fiscal year, a design of a direct cycle plant of 300MWt is undertaken. The new concept of an annular pebble bed core and a reactor pressure vessel provided with inner insulator were employed. By this challenging concept, a very high thermal efficiency could be expected

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Reference:

Proceedings of a Technical Committee Meeting held in Beijing, People's Republic of China, 2-4 November 1998

International Atomic Energy Agency, International Working Group on Gas-Cooled Reactors, Vienna (Austria)

IAEA-TECDOC--1210, pp:39-51