Conceptual proposal of new detection method for unauthorized removal from glovebox

Nakamura, Hironobu ; Tanigawa, Masafumi ; Mukai, Yasunobu ; Nakamichi, Hideo; Umino, Yoshinori; Fujisaku, Sakae; Kimura, Takashi ; Kurita, Tsutomu 

In the MOX handling facilities, many types and amount of nuclear materials (NM) that are relatively easy to access are used in a GB. In order to prevent unauthorized removal of NM from the GB by an insider, based on the Japanese regulation which was referred from INFCIRC/225 Rev.5, the 2 person rule are being introduced at the area where NM handling GB are installed. As an example of usage of the security counterplan for the detection of unauthorized removal of NM, a new proposal of detection concept for the unauthorized removal by operators were investigated with implementation of several experiments considering actual GB operation. In general, it is considered that normal concept is to use radiation monitor ( or neutron) to detect the event by checking the variation of monitoring data. However, it is thought that distinguish between authorized NM movement during operation and the unauthorized removal (sample bag-out from GB) is very difficult. To solve this subject, JAEA studied and proposes a new concept about negative pressure monitoring in the GB in addition to the radiation monitoring. It is thought that the hybrid monitoring concept between pressure and radiation provides the detection alarm for it with central alarm station (CAS) accurately and rapidly with high integrity, and helps to complement current 2 person rule.