Monju system startup test report control rod reactivity worth measurements

Kato, Yuko; Yabuki, Kentaro*; Okawachi, Yasushi 

The prototype fast breeder reactor MONJU resumed the system startup test (SST) on May 6th 2010 after fourteen years and five months shutdown since the sodium leakage of the secondary heat transport system in December 1995 and reached criticality on May 8th. Core confirmation test (CCT) is the first step of SST which consists of three steps, and finished on July 22nd after 78 days test. Control rod reactivity worth measurements were carried out in order to calibrate the reactivity worth of control rods and back-up rods. In addition, we also aimed at a basic data acquisition for the control rod reactivity worth calibration.