拖步式桶装废物测量装置在核材料衡算中的应用与展望

Application and Forecast of Shuffler in Nuclear Material Accounting

核材料质量的准确测量是核材料衡算的重要内容,特别是在后处理厂中,对大体积废物中的^(235)U、^(239)Pu的质量测量,一直是难点。如用化学分析的方法,会无法取样;如用伽马谱法进行测量,因伽马射线自吸收很严重等因素,会造成较大的测量误差。拖步式桶装废物测量装置(Shuffler)的一个明显优势就是通过测量样品中产生的中子,可以对大质量、大体积的铀、钚进行高精度地分析,且本底很低。就Shuffler的发展历史、原理、仪器的结构进行介绍,并与其他非破坏性分析(NDA)仪器进行比较,阐述其在国内、外的应用,最后对影响分析结果的因素进行了讨论。Shuffler的应用对α废物的检测与分类提供了支持,是实现核材料衡算不可或缺的技术,制备合适工作标样或参考样品将是本技术首要突破的地方,使用蒙卡模拟也是将来要发展的方向。在核设施中,Shuffler可用于测定燃料组件的坯料挤压过程中废金属罐中^(235)U的质量,也可用于测定后处理设施中大体积铀、钚废物,也可用于核材料管制视察,快堆和MOX(铀钚氧化物混合)元件厂等领域,对核材料的测量将发挥巨大的作用。

The accurate measurement of nuclear material mass is an important part of nuclear material accounting,especially in the reprocessing plant,the measurement of the mass of ^(235)U and ^(239)Pu in large volume waste has always been a difficult point.If chemical analysis is used,sampling will not be possible;if used gamma spectral method is used for measurement because gamma X-ray self absorption is very serious and other factors will cause large measurement errors.One of the obvious advantages of Shuffler(drag step neutron measuring device)is that it can conduct high-precision analysis of large mass and large volume of uranium and plutonium,and the background is very low.It can analyze the neutrons generated in large samples.This paper introduces the development history,principle and instrument structure of Shuffler,compares it with other NDA(Non Destructive Analysis)instruments,expounds its application at home and abroad,and finally discusses the factors affecting the analysis results.Shuffler’s application toαwaste detection and classification provides support and is an indispensable technology to realize nuclear material accounting.Preparation of appropriate working standard samples or reference samples will be the first breakthrough of this technology,and the use of Monka simulation is also the direction of future development.In nuclear facilities,Shuffler can be used to measure the mass of ^(235)U in the scrap metal tank during the blank extrusion process for fuel assembly production,as well as the mass of uranium and plutonium waste in reprocessing facilities,and also can be used in nuclear material control inspections,fast reactors and MOX(uranium plutonium oxide mixture)component plants.It will play an important role in the measurement of nuclear materials.