Modification of STACY for study of criticality characteristics of fuel debris, 4; Evaluation of the effect of the sample loading instrument in the reactor core on the core parameters

Arakaki, Yu; Izawa, Kazuhiko ; Gunji, Satoshi  ; Araki, Shohei   ; Suyama, Kenya

JAEA has been modifying the Static Experiment Critical Facility (STACY) to experimentally study on the criticality characteristics of fuel debris. Although arbitrary detectors or activation samples can be placed in the core of STACY, they must be contained in sheath tubes (insertion tubes) that have been approved by the regulatory authorities. This report presents the status of the design study of the insertion tube for the experiments in the modified STACY.