Influence of Heating and Water Exposure on Liquid Limit of Bentonite

Bentonite has been considered as the buffer material for embedding canisters with high-level radioactive waste(HLW)in the deep geology repositories. GMZ bentonite deposit which is located in Xinghe County,Inner Mongolia has been proposed as buffer/backfill material for HLW repository in China. Liquid limit of natural Na-bentonite GMZ01 and commercial Na-bentonite MX80 which were previously put in the oven at 80℃and 95℃,and exposed to water for different times were measured.The liquid limit of GMZ01 increased slightly at the beginning, and then decreased as the heating time increased.

Influence of heating and water-exposure on the liquid limits of GMZ01 and MX80 bentonites

Bentonite has been considered as a buffer material for embedding canisters with high-level radioactive waste（HLW） in deep geological repositories.GMZ bentonite deposit,located in Xinghe County,Inner Mongolia Autonomous Region,China was proposed as a buffer/backfill material for HLW repository in China.The liquid limits of natural Na-bentonite GMZ01 and commercial Na-bentonite MX80,which are previously heated at 80 ℃ and 95 ℃,respectively,and exposed to water for different times are measured.It is observed that the liquid limit of GMZ01 increases slightly at the beginning,and then decreases as the heating time increases,while the liquid limit of MX80 decreases with the heating time.The liquid limits of both GMZ01 and MX80 decrease with increasing water-exposure time.After the samples are heated at 80℃and 95 ℃ for several months,the mineralogical composition of GMZ01 does not exhibit evident change,whereas MX80 experiences some changes.In addition,the chemical composition,cation exchange capacity（CEC） and exchangeable cation of all the samples do not change significantly.

大型放射性废液贮罐顽固沉积物回取装置设计的仿真模拟研究

为获得大型放射性废液贮罐顽固沉积物回取装置的选型参数,采用Solidworks建立三维实体模型,使用EDEM软件对装置中用于破碎盐饼层的旋耕刀进行离散元仿真分析;使用ANSYS软件在吸尘过程中对不同吸力、吸尘口形状进行有限元仿真分析,并对拟采用的主要受力零部件进行强度校核。结果表明,旋耕刀平均受力最大为330 N、最佳吸力19 kPa,最佳的吸尘口形状为扁平入口、圆形出口,主要受力零部件在仿真分析中未产生明显变形。研究结果可为后续装置的现场验证实验提供技术支持。

高放废液贮槽的设计、建造和检验

综述了高放废液贮槽的设计、建造、质量检验以及运行经验。叙述了高放废液贮槽设计的一般考虑,包括贮槽、槽室、冷却系统、仪表、液体转移、通风、搅拌及腐蚀的考虑,并举典型实例加以说明。强调了按照美英标准规范对贮槽的建造进行质量检验。根据20多年的运行经验,证明采用不锈钢贮槽是安全可靠的。

Effect of Rare Earth Elements on Exchange Performances of Cesium Ion-Sieve

The exchange performances and the distribution coefficient of Cesium Ion-Sieve (Cs-IS) for cesium and for some rare earth elements were compared. In particula r, the effects of neodymium on the cesium ion exchange and the Cs+ selectivity v ariation on Cs-IS owing to introduction of rare earth elements into HLLW were s tudied. Though rare earth elements exhibit a small influence on the distributio n coefficient for Cs+, they impair Cs-exchange capacity of Cs-IS to some ext ent. This interruption on the selectivity to Cs+ can be significantly eliminat ed provided an appropriate ratio of liquid to solid V:m is used.

气力输送技术在放射性废液暂存设施中的应用

为确保放射性废液气力输送系统冷调试安全,验证设计的合理性和可靠性,利用伯努利方程,推算了冷调试的工艺操作参数,并对理论计算与实测值间的偏差原因进行了条件输入验证。结果表明,推算的工艺操作参数与冷调试试验结果符合较好,放射性废液气力输送系统工艺设计合理,本研究推荐的方法可用于同类系统工艺操作参数计算。通过分析管径和真空系统设计对放射性废液暂存设施安全运行的影响,提出了技术改进方法及建议。

放射性废液贮槽多样化液位报警系统的设计及应用

为有效预防放射性废液贮槽发生放射性物质泄漏,采用液位测量和报警系统进行监测。将增量报警技术与传统技术相结合,设计了多样化液位报警系统。测试数据和实用效果表明:报警系统功能强大、性能可靠精准,可在贮槽内任意液位高度发生异常液位变化时,准确预警,自动记录报警信息,有效地预防放射性物质泄漏。

从多重故障角度探讨高放废液贮存系统DEC

设计扩展工况(DEC)分析是核电设施超设计基准事故分析的重要内容,目前后处理设施领域尚无这方面实践。以后处理设施高放废液贮存系统为研究示范对象,基于工程判断和确定论方法,从多重故障的角度识别DEC。研究结果表明:在高放废液贮存系统的29例工况中,14例不会造成放射性物质向外环境的超标释放,属于DEC;8例可能造成放射性物质向外环境的超标释放,如果混凝土浇筑层对废液具备包容功能、设备室具备泄爆或抗爆功能,则这8例工况不会对外环境造成超标释放,也可纳入DEC;剩余的7例会造成放射性物质向外环境的超标释放,应通过提高橙区过滤器间排风过滤、烟囱的设备可靠性,实现放射性气溶胶向外环境释放的量级不超过选址假想事故的释放水平。