Long-lived activation products in reactor materials
Long-lived activation products in reactor materials
复制标题
反应器材料中的长寿命活化产物
DOI：
10.2172/6776358
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发表时间：
1984
影响因子：
1.3
通讯作者：
D. Robertson
中科院分区：
文献类型：
--
作者：
J. Evans;E. Lepel;R. Sanders;C. L. Wilkerson;W. Silker;C. Thomas;K. H. Abel;D. Robertson
该计划的目的是评估反应堆建筑材料中的长寿命活化产物对反应堆退役造成的问题。对不锈钢、容器钢、混凝土和混凝土成分的样品进行了多达52种元素的分析，以建立可活化的主要、次要和微量元素的数据库。有些元素的成分变化很大。例如，人们发现不锈钢中钴和铌的浓度相差超过一个数量级。对所有可能产生长寿命活化产物的核反应进行了彻底的评估。得出的结论是，在迄今为止完成的退役规划研究中，所有主要的活化产品都得到了令人满意的解释。使用测量到的适当材料组成的平均值进行了一系列详细的计算，以预测反应堆内部、容器壁以及压水堆和沸水堆几何形状的生物屏蔽材料中预期的活化产物水平。根据美国联邦法规第10条第61条，将计算的活化水平与浅层土地处置的监管准则进行了比较。这一分析表明，压水堆和沸水堆覆盖材料超过了C类限值，因此通常不适合近地表废物处置。压水堆堆芯筒材料接近C级极限。大多数剩余的大量成分都属于A类或B类废物，即使在激活的最高点，生物防护层也明显属于A类废物。选定的活化钢和混凝土样品进行了有限的放射化学分析程序，作为计算机模型的验证。在可能进行比较的地方，与计算结果相当吻合。特别是，活化不锈钢中/sup 94/Nb的含量达到或略高于预期水平。«少
The purpose of this program was to assess the problems posed to reactor decommissioning by long-lived activation products in reactor construction materials. Samples of stainless steel, vessel steel, concrete, and concrete ingredients were analyzed for up to 52 elements in order to develop a data base of activatable major, minor, and trace elements. Large compositional variations were noted for some elements. Cobalt and niobium concentrations in stainless steel, for example, were found to vary by more than an order of magnitude. A thorough evaluation was made of all possible nuclear reactions that could lead to long lived activation products. It was concluded that all major activation products have been satisfactorily accounted for in decommissioning planning studies completed to date. A detailed series of calculations was carried out using average values of the measured compositions of the appropriate materials to predict the levels of activation products expected in reactor internals, vessel walls, and bioshield materials for PWR and BWR geometries. A comparison is made between calculated activation levels and regulatory guidelines for shallow land disposal according to 10 CFR 61. This analysis shows that PWR and BWR shroud material exceeds the Class C limits and is, therefore, generally unsuitable for near-surfacemore » disposal. The PWR core barrel material approaches the Class C limits. Most of the remaining massive components qualify as either Class A or B waste with the bioshield clearly Class A, even at the highest point of activation. Selected samples of activated steel and concrete were subjected to a limited radiochemical analysis program as a verification of the computer model. Reasonably good agreement with the calculations was obtained where comparison was possible. In particular, the presence of /sup 94/Nb in activated stainless steel at or somewhat above expected levels was confirmed.« less