LASER EMISSION HEAD, LASER BEAM TRANSMISSION DEVICE, LASER BEAM TRANSMISSION DEVICE ADJUSTMENT METHOD AND PREVENTIVE MAINTENANCE/REPAIR DEVICE OF STRUCTURE IN NUCLEAR REACTOR

摘要

A laser emission head which applies a laser beam outputted from a laser device (624) to an operation object part, comprising an emission head main part having an in-head lightguide member (625) which guides the laser beam, a condensing lens (677) which condenses the laser beam from the in-head lightguide member, a reflective mirror (678) which applies the condensed laser beam to the operation object part, a mirror turning means (684) which holds the reflective mirror rotatably around a laser beam axis, a distance adjusting means (674) which adjust a relative distance between the reflective mirror and the condensing lens and a transfer means (665) which transfers the reflective mirror and the condensing lens in a laser beam axis direction while the relative distance between the reflective mirror and the condensing lens is maintained. The in-head lightguide member, the condensing lens and the reflective mirror can be carried into/from the operation object part which is formed in, for instance, a small gap between the structural units. With this constitution, the preventive maintenance/repair work by a laser beam in, for instance, a small gap between structures in the nuclear reactor can be performed automatically, and further, safely, and more efficiently.