HTGR Knowledge Base

Conference Article: A study of silver behavior in gas-turbine high temperature gas-cooled reactor

Abstract

In High Temperature Gas-cooled Reactors (HTGRs), some amounts of fission products (FPs) are released from fuel elements and are transported in the primary circuit with primary coolant during normal operation. Condensable FPs plateout on the inner surface of pipings and components in the primary circuit and the gamma-ray emitted from the plateout FPs becomes main source during maintenance works. In the design of a Gas-turbine High Temperature Gas-cooled Reactor (GT-HTGR), behaviour of FPs, especially of silver, is considered important from the view point of maintenance works of the gas-turbine. However, the behaviour of silver is not well known comparing with that of noble gases, iodine and cesium. Then a study of silver behaviour of the GT-HTGR was carried out based on experiences of High Temperature engineering Test Reactor (HTTR) design. The purposes of this study were (1) to determine how important the silver in the GT-HTGR. (2) to find out countermeasures to prevent silver release from fuel elements. And (3) to determine the items of future research and development which will be needed. In this study, evaluations of (1) inventory. (2) fractional release from fuel elements. (3) plateout distribution in the primary circuit. And (4) radiation dose at the gas-turbine were carried out. Based on this study, it was predicted that the gamma-ray from plateout silver contributes about a half of total radiation dose during maintenance work of the gas turbine. In future, it is expected that more detail data of silver release from fuel, plateout behaviour, etc. will be accumulated through the HTTR operation.

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Reference:

Technical committee meeting on design and development of gas cooled reactors with closed cycle gas turbines. Beijing (China). 30 Oct - 2 Nov 1995.

International Atomic Energy Agency, Vienna (Austria)

IAEA-TECDOC--899, pp:131-143