TRACY experiment for SILENE experiment simulation Expert Group on Criticality Excursion Analysis September 22, 2005 2005-09-22 TRACY experiment for SILENE experiment simulation Yuichi YAMANE, Yoshinori MIYOSHI Japan Atomic Energy Research Institute

Expert Group on Criticality Excursion Analysis TRACY Core Core specifications Fuel : 10wt% enriched uranyl nitrate aqueous solution Shape : Annular (50cm/7.6cm) Transient rod at the center hole Limitations Maximum Power ：5000MW Total energy : 32 MJ/experiment ( = 1018 fissions) Maximum excess reactivity: 3.0 $ Reactivity insertion method Rod withdrawal Pulse withdrawal (Step insertion) Ramp withdrawal Fuel feed Ramp feed TRACYでは、調Ｔｒ棒の交換により、 新たに、添加反応度2.8２$までの超臨界実験を行なえるようになった。 今回は、過渡特性を測定した結果について報告する。 まず、測定の概要について September 22, 2005 Expert Group on Criticality Excursion Analysis

Experimental Condition September 22, 2005 Expert Group on Criticality Excursion Analysis

Expert Group on Criticality Excursion Analysis Kinetic Parameters SRAC + TWODANT with JENDL-3.2 Neutron generation time : 4.92x10-5 beff : 7.51x10-3 Reactivity Temperature Coefficient : -4.7 cent/K, -2.5 cent/K2 Reactivity Void Coefficient : -4.4x101 cent/%, -1.7x10-1 cent/%2 1 2 3 4 5 6 Delayed neutron fraction 2.51x10-4 1.63x10-3 1.47x10-3 2.96x10-3 8.77x10-4 3.19x10-4 Precursor decay constant (s) 1.27x10-2 3.17x10-2 1.15x10-1 3.12x10-1 1.40 3.87 Calculated for 370 gU/Lit. U conc. and 0.7mol/Lit. acid conc. September 22, 2005 Expert Group on Criticality Excursion Analysis

Result of experiments: R317,318 The 1st peaks were greater than S2-300’s. R318 reached the peak 1s faster than R317. September 22, 2005 Expert Group on Criticality Excursion Analysis

Result of experiments : R319 The 1st peak was greater than S3-300. R319 reached the peak 1s faster than S3-300. September 22, 2005 Expert Group on Criticality Excursion Analysis

Result of experiments : R321,322 R321, R322 >> LE1-641 in the 1st peak power. R321(0.14$/s) reached the peak at almost the same time as LE1-641 (0.097$/s) and that is 9s faster than R322(0.097$/s). R321,R322 shutdown at about 300s by the regulation for max. fissions. September 22, 2005 Expert Group on Criticality Excursion Analysis

Preliminary Result and Summary Total release energy ratio ~ volume ratio for the case of 0.97$ insertion. Total release energy ratio > volume ratio for the case of 2.31$ insertion. Maximum power ratio looks independent of volume ratio. September 22, 2005 Expert Group on Criticality Excursion Analysis