N,N-二甲基羟胺辐解产生的氢气和一氧化碳的研究

摘要

With the development of nuclear power industry, more attentions have been paid on reprocessing power reactor spent fuel. Up to now, PUREX process is the only process available commercially. The process achieves uranium and plutonium separation by means of quick and quantitative reduction of Pu (Ⅳ) to Pu (Ⅲ). Therefore the reductant is very important in PUREX process. Preliminary experiment results[1] show that N, N-dimethyl hydroxylamine not only reduces rapidly Np (Ⅵ) and Pu (Ⅳ) to Np (V) and Pu (Ⅲ), but also stabilizes the Np (V)and Pu (Ⅲ) in acid solution. It may become a salt-free reductant with promising future for applications in the area[2]. However, organics decompose under intense radiation environment, and this affects its reduction efficiency,and products from the degradation may affect separation of the radioactive elements.This paper reports the qualitative and quantitative analysis of hydrogen and carbon monoxide produced by 60Co y-ray degradation of N, N-dimethyl hydroxylamine. The analyses of hydrogen and carbon monoxide were performed by gas chromatography, in which a 2m column packed with 5A molecular sieve and thermal conduc tivity detector[3] were used. The analysis of hydrogen employed argon as carrier gas, the column temperature was 80℃ and the detector temperature was 110℃. The analysis of carbon monoxide used hydrogen as carrier gas, the column temperature was 50℃ and the detector temperature was 80 ℃. The results show that when the concentration of N, N-dimethyl hydroxylamine was between 0.1 mol/L and 0.5 mol/L and the dose delivered by the irradiation was 10-1000 kGy, the volume fraction of hydrogen was (8.0-303.9)× 10-3; and the volume fraction of carbon monoxide is (0-1.7)× 10-3. The volume fraction of hydrogen increased with increasing dose, and it has little relationship with concentration change of N, N-dimethyl hydroxylamine when the irradiation dose was bellow 500 kGy, whereas it increased with the increasing concentration of N, N-dimethyl hydroxylamine when the dose was higher than 500 kGy. The volume fraction of carbon monoxide has little relationship with both the irradiation dose and N, N-dimethyl hydroxylamine concentration.