In experiments with pulsed and stationary reactors, optical fibers are used to withdraw the laser or luminescent radiation from the region close to the reactor core to the registering instruments located behind the biological shielding. The influence of reactor radiation on the properties of the optical fibers was examined in a number of studies (see for example [40, 45]).

Resolution of the problem of the fibers’ radiation resistance is closely associated with development of radiation-resistant optical materials. For example, develop­ment of the method for manufacturing quartz with an extremely low content of impurities made it possible to produce fibers that can be used to withdraw light in the visible range at doses of ~107 Gy [46, 47], which corresponds to the annual radiation exposure inside the core of a stationary reactor. To increase radiation resistance of fibers, small controlled impurities can be added, for example, molec­ular hydrogen [47, 48].