中文摘要：

N,N-二甲基羟胺（DMHA）是用于动力堆乏燃料后处理U与Pu和Np分离的新型无盐还原剂,本文研究了硝酸对DMHAγ-辐解及液态辐解产物的影响.研究结果表明：在U、Pu分离循环和Pu纯化循环的辐照剂量下,在0.3-1.0 mol·L^-1的硝酸溶液中,0.1和0.5 mol·L^-1DMHA具有较好的辐照稳定性.当吸收剂量为5-25k Gy时,DMHA硝酸溶液的液态辐解产物主要有单甲基羟胺、甲醛、甲酸和亚硝酸.有机物的浓度远远高于亚硝酸浓度,且随着剂量和硝酸浓度的增加而增大.对于相同的硝酸浓度和剂量,0.1 mol·L^-1DMHA辐解产生的一甲基羟胺的浓度高于0.5 mol·L^-1DMHA,但前者辐解产生的甲醛浓度低于后者;当硝酸浓度较高时,0.1 mol·L^-1DMHA辐解产生的甲酸浓度高于0.5 mol·L^-1DMHA.亚硝酸浓度与硝酸浓度及剂量的关系取决于起始DMHA和硝酸浓度.

英文摘要：

N,N-dimethylhydroxylamine（DMHA） is a novel salt-free reductant used for the separation of U from Pu and Np in the reprocessing of spent fuel. We investigated the effect of HNO3 on the radiolysis of DMHA and its radiolytic liquid product. Results show that 0.1 and 0.5 mol·L^-1DMHA containing 0.3-1.0 mol·L^-1HNO3 have good radiation stability at a reasonable dose level during the U/Pu separation cycle and the Pu purification cycle. For 5-25 k Gy the main radiolytic liquid products are N-methyl hydroxylamine, HCHO,HCOOH, and HNO2. The concentration of these organic compounds is much higher than that of HNO2 and increases with both HNO3 concentration and absorbed dose. At the same HNO3 concentration and dose,the concentration of N- methyl hydroxylamine in irradiated 0.1 mol·L^- 1DMHA- HNO3 is higher than that in irradiated 0.5 mol·L^-1DMHA-HNO3. However, the HCHO concentration in 0.1 mol·L^-1DMHA-HNO3 is lower than that in 0.5 mol·L^-1DMHA-HNO3. The HCOOH concentration in 0.1 mol·L^-1DMHA-HNO3 is higher than that in 0.5 mol ·L^- 1DMHA- HNO3 at higher HNO3 concentrations. The relationship of HNO2 concentration with HNO3 concentration and dose depends on the original DMHA and HNO3 concentrations.