A new optical instrumentation system for advanced light water reactor

A new optical nuclear instrumentation system such as that in core power and temperature monitor using radiation-resistant optical fibers was demonstrated. Developed radiation-resistant optical fibers as a sensing component kept their good transmission characteristics even in a reactor irradiation. Optical fibers generated strong radio luminescence wavelength ranged 400 nm to 1400 nm with some of peaks and thermal radiation in infrared during irradiation in a core region of fission reactor. Intensities of radio luminescence were found to be directly proportional to the reactor power. Also, temperatures could be estimated by thermal radiation of Planck's law. The optical measuring method using optical fibers could be composed simple and convenient nuclear instrumentation system of the reactor power and temperature. (author)