Status of FRJ-2 Refurbishment of tank pipes and essential results of aging analysis

An aging evaluation program for FRJ-2 (DIDO) of the Forschungszentrum Juelich GmbH has been developed and is currently executed in cooperation with the licensing and regulatory and TUEV experts in order to determine the overall life expectancy of the facility and to identify critical systems and components that need to be upgraded or refurbished for future safe reactor operation. In Phase A (completed) a so called master list of the FRJ-2 mechanical, electrical and structural components was compiled on a system-by system basis and the operational documentation with respect to regular inspections, maintenance, repair and unusual occurrences was carefully examined. Critical components were selected and their ageing respectively life limiting mechanisms identified. In Phase B (currently under way) special inspections, examinations and tests for critical systems/components are being elaborated, executed and evaluated. Current work is being concentrated on non replaceable components (e.g. reactor aluminium tank (RAT) and the connecting pipes to the primary cooling circuit, the reactor steel tank and pipe work inside the concrete reactor block). As a consequence of first results of the aging evaluation program and due to leaks in the weir and drain pipes of the RAT a repair/refurbishment program was set up for the Al-RAT pipes (risers, downcomers, weir and drain pipes) and the steel guide tubes. Details of the r/r program which is in far progress and first essential results of the aging evaluation will be presented. The results achieved until today are encouraging with respect to safe reactor operation on short and medium term. (J.P.N.)