Fast Reactors and Accelerator Driven Systems Knowledge Base

Conference Article: Experience of the BN-600 reactor control rods development

Abstract

During the BN-600 reactor operation (1980-1994), the control rod design was modified with a view to improve reliability and lifetime. Control rod updating was carried out in two stages. The design of control rods modified during the first stage (1981-1985), with an aim to reduce deformation of the main units and exclude their jamming in guide sleeves, and the modified design of the control sleeves, allowed a contact between control rods and sleeves in the core area to be excluded. 350 eff. lifetime days were reached as a result of the first updating of control assemblies. At the second stage (1986-1994), the structural materials of absorber pin claddings, rod wrappers and sleeves, as well as the application of em-opium oxide instead of natural boron as absorber in compensating and control rods were optimized. As a result of the second updating, control assemblies lifetime was extended to approx, 500 eff. days.

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Reference:

Technical committee meeting on absorber materials, control rods and designs of backup reactivity shutdown systems for breakeven cores and burner cores for reducing plutonium stockpiles. Obninsk (Russian Federation). 3-7 Jul 1995

International Atomic Energy Agency, Vienna (Austria)

IAEA-TECDOC--884, pp:34-46