Devices and methods used for radiation monitoring of sea water during salvage and transportation of the Kursk nuclear submarine to dock

The paper contains the description and the results of the measurements of the Russian system for radiation control, which was mounted on the hull of the “Kursk” nuclear submarine during its salvage. The main tasks for carrying out measurements with this system were the control of possible leaks of radioactive substances into the ocean water and the assessment of radioactive effects on the environment. The system consisted of eight underwater gamma spectrometric detectors with scintillation crystals of NaI(Tl) 63×250 mm. A special evaluation method and a computer program were developed for carrying out long-term continuous measurements, which allowed for the automation of the control process. International compatibility of the measurement results was provided by the traceability to the national standard. For this reason, each detector was tested for sensitivity to the 137Cs radionuclide, uniformly spread in a quasi-infinite aqueous medium. The measurements showed that no gamma-irradiating radionuclides were released into the environment.