Guide tube for measuring tube reaching inside pressure vessel, and method for preventing accumulation of particles inside guide tube outside pressure vessel

摘要

The invention relates to a guide tube (2) especially for an instrumentation lance (16) extending into a reactor pressure vessel (6). Said guide tube comprises a lower tube section (12) and an upper tube section (10) which extends into the interior (8) of the reactor pressure vessel (6). In order to prevent radioactively contaminated particles (22) from reaching the lower tube section (12) disposed outside the reactor pressure vessel (6) and forming a source of radiation, a separator (20) is arranged in the upper tube section (12). Said separator (20) has a separation chamber (24) in which the particles (22) are deposited and are removed from the water.