Development of JOYO fuel flow monitors

A new safeguards approach of Fast Reactor 'JOYO' has been studied by Japanese government, IAEA and PNC to meet 1991-1995 safeguards criteria. As the result, a fuel flow monitoring system has been introduced in 'JOYO'. Development of the system has been conducted by PNC and IAEA with technical support of Los Alamos National Laboratory. Safeguards measures in unattended mode with the system can detect fuel loading and unloading into and from the reactor core and distinguish what kind of the fuel. The system are consisted of following four monitors using neutron and γ-ray measurements and video surveillance systems. 1) Entrance Gate Monitor (ENGM) in the Fresh Fuel Storage. 2) Cask Car Radiation Monitor (CCRM) on the Cask Car. 3) Ex-vessel Transfer machine Radiation Monitor (EVRM) on the Ex-vessel Transfer Machine. 4) Exit Gate Monitor (EXGM) in the Spent fuel Storage Pond. Installation of these monitors was finished by PNC and acceptance test by Japanese government and IAEA was carried out March, 1991. The system is under long-term test which will continue till September, 1991. (author)