Effect of gamma-ray irradiation on the deoxygenation of salt-containing water using hydrazine

Figures & data

Table 1 Sampling result for water from the spent fuel pool at Fukushima Daiichi nuclear plant unit 4 [2]

Sampling date	Chloride ion (ppm)	N2H4 (ppm)	Cs-137 (Bq/L)	Cs-134 (Bq/L)	I-131 (Bq/L)
2011.9.2	997	59	3.1 × 10^4	2.2 × 10^4	Not detected

Table 2 Chemical composition of artificial seawater (ppm)

NaCl	MgCl2·6H2O	Na2SO4	CaCl2·2H2O	KCl
24,534	11,115	4144	1535	694.5
NaHCO3	KBr	SrCl2	H3BO3	NaF
201	100.5	42.5	27	3

Figure 1 Schematic layout of the ⁶⁰Co gamma-ray source and samples

Figure 2 Comparison of the dissolved oxygen concentrations without and with gamma-ray irradiation at different dose rates for 1 h. Water, distilled water; ASW, artificial seawater; 1/8 ASW, distilled water/ASW = 1:7. Initial [N₂H₄] = 32 ppm

Figure 3 Concentration of dissolved oxygen in the 1/8 artificial seawater with initial N₂H₄ concentrations varying from 0 to 32 ppm at 1 kGy/h for 1 h

Figure 4 Change in the dissolved oxygen concentration with time for distilled water, 1/8 ASW and ASW during 1 kGy/h irradiation. Water, distilled water; ASW, artificial seawater; 1/8 ASW, distilled water/ASW = 1:7. Initial [N₂H₄] = 32 ppm

Figure 5 Change in the hydrazine concentration with time for distilled water, 1/8 ASW, and ASW during 1 kGy/h irradiation. Water, distilled water; ASW, artificial seawater; 1/8 ASW, distilled water/ASW = 1:7. Initial [N₂H₄] = 32 ppm

Figure 6 Amount of dissolved oxygen in distilled water, 1/8 ASW and ASW without N₂H₄ for 0 and 1 h of 1 kGy/h irradiation at room temperature. Water, distilled water; ASW, artificial seawater; 1/8 ASW, distilled water/ASW = 1:7. Initial [N₂H₄] = 32 ppm

Figure 7 Concentration of hydrogen peroxide in distilled water, 1/8 ASW and ASW without N₂H₄ (0 ppm N₂H₄) and with 32 ppm N₂H₄ after 1 kGy/h irradiation for 1 h. Water, distilled water; ASW, artificial seawater; 1/8 ASW, distilled water/ASW = 1:7

Table 3 G(-O₂) values in distilled water and artificial seawater with 32 ppm hydrazine at a dose rate of 1 kGy/h (10⁻⁷ mol/J)

Time (min)	Total dose (Gy)	Distilled water	Artificial seawater
0–10	167	18.0	11.0
0–30	500	–	5.8

Table 4 G(-N₂H₄) values in distilled water and artificial seawater with 32 ppm hydrazine at a dose rate of 1 kGy/h (10⁻⁷ mol/J)

Time (min)	Total dose (Gy)	Distilled water	Artificial seawater
0–10	167	21.5	24.9
0–30	500	10.3	12.9
		13^a	–
0–60	1000	7.6	8.3

Tokyo Electronic Power Company http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_110903_04-e.pdf, handouts at press conference Sep 03, 2011

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