Experimental study on transport behavior of cesium iodide in the reactor coolant system under LWR severe accident conditions

Figures & data

Figure 1. Schematic view and basic specifications of the experimental setup of the TeRRa

Table 1. Experimental conditions of the reproductive experiment for CsI transport behavior

Parameters	Conditions
Simulant FP
Material	CsI powder
Amount	2.8 g
Heating temperature	1000 K
Temperatures
High frequency Induction furnace	> 1000 K (preheat)
Electric resistance furnace	1273 K
TGT	1000–400 K
Inlet gas
Composition	Ar + 20 vol% steam
Temperature	400 K
Normal flow rate (NTP; conditions 273 K, 1.013 × 10^5 Pa)	2 NL/min ^a

^aThis flow rate corresponds to the gas flow velocity of about 0.14 m/s (1273 K region) to about 0.04 m/s (400 K region).

Table 2. Amount of Cs and I obtained by ICP-MS on each sample

Position from inlet of the TGT [mm]	Temperature [K]	Cs amount [10^-3 mol]	I amount [10^-3 mol]	I/Cs molar ratio [-]
0–100	1000	0.014 ± 0.0007	0.00024 ± 0.00002	0.017
100–200	950	0.0028 ± 0.0002	0.0	0.0
200–300	900	0.0041 ± 0.0003	0.0	0.0
300–400	850	0.41 ± 0.03	0.36 ± 0.02	0.90
400–500	800	0.24 ± 0.02	0.21 ± 0.02	0.88
500–600	750	0.042 ± 0.003	0.042 ± 0.003	0.99
600–700	700	0.029 ± 0.002	0.028 ± 0.002	0.94
700–800	650	0.022 ± 0.002	0.021 ± 0.002	0.97
800–900	600	0.012 ± 0.0006	0.012 ± 0.0007	1.0
900–1000	550	0.026 ± 0.002	0.028 ± 0.002	1.1
1000–1100	500	0.014 ± 0.0008	0.014 ± 0.0007	0.98
1100–1200	450	0.015 ± 0.0008	0.014 ± 0.0008	0.96
1200–1300	400	0.021 ± 0.002	0.021 ± 0.002	1.0
Outlet filters ^a	Not controlled	0.94 ± 0.05	0.83 ± 0.05	0.88
Liquid traps ^b	Not controlled	0.010 ± 0.0006	0.063 ± 0.004	6.0

^aIncluding both the sintered filter and the aerosol filter.

^bIncluding two liquid traps.

Figure 2. Results of SEM/EDS observations of the deposits on the sampling coupons (a) No. 3 (980 K), (b) No. 9 (860 K), and (c) No. 32 (400 K)

Figure 3. XRD patterns of the deposits on the sampling coupons (a) No. 3 (980 K), (b) No. 9 (860 K), and (c) No. 32 (400 K)

Figure 4. Raman spectrum of the deposits on the sampling coupon No. 9 (860 K)

Figure 5. Size distributions of the airborne aerosol particles extracted from each 100 K point of the TGT (‘N = ’ in red letters means total number of aerosol particles in Ar/steam atmosphere)

Figure 6. Cumulative amount of Cs and I obtained by ICP-MS on each cascade impactor plate, the backup filter, and the liquid traps during 5-min-extraction from 400 K point of the TGT

Figure 7. I chemical forms in the high-temperature region (>900 K) calculated by (a) chemical equilibrium calculation and (b) chemical reaction calculation