Development of reactivity feedback effect measurement techniques under sub-critical condition in fast reactors

Kitano, Akihiro; Nishi, Hiroshi; Suzuki, Takayuki; Okajima, Shigeaki; Kanemoto, Shigeru*

Proceedings of International Conference on Physics of Reactors; Advances in Reactor Physics; Linking Research, Industry, and Education (PHYSOR 2012) (CD-ROM), 14 Pages, 2012/04

The "Synthesis Method", a systematic and sophisticated method of sub-criticality measurement, is proposed in this work to ensure the safety margin before operation. The "Synthesis Method" is based on the modified source multiplication method (MSM) combined with the noise analysis method to measure the reference sub-criticality level for MSM. As a result of numerical simulation, it was suggested that a neutron detector located above the core center and three or more neutron detectors located above the radial blanket region enable the measurement of sub-criticality within 10% uncertainty from -0.5 to -2 and within 15% uncertainty for the deeper sub-criticality.