Brown Steven H, Chambers Douglas B
*SHB Inc., Centennial, CO, USA; †ARCADIS Canada Ltd., Richmond Hill, Ontario, Canada; ARACDIS Canada LTD, 121 Granton Drive, Richmond Hill, Ontario, Canada L4B 3N4.
Health Phys. 2017 Jul;113(1):13-22. doi: 10.1097/HP.0000000000000673.
All soils and rocks contain naturally occurring radioactive materials (NORM). Many ores and raw materials contain relatively elevated levels of natural radionuclides, and processing such materials can further increase the concentrations of naturally occurring radionuclides. In the U.S., these materials are sometimes referred to as technologically-enhanced naturally occurring radioactive materials (TENORM). Examples of NORM minerals include uranium ores, monazite (a source of rare earth minerals), and phosphate rock used to produce phosphate fertilizer. The processing of these materials has the potential to result in above-background radiation exposure to workers. Following a brief review of the sources and potential for worker exposure from NORM in these varied industries, this paper will then present an overview of uranium mining and recovery in North America, including discussion on the mining methods currently being used for both conventional (underground, open pit) and in situ leach (ISL), also referred to as In Situ Recovery (ISR), and the production of NORM materials and wastes associated with these uranium recovery methods. The radiological composition of the NORM products and wastes produced and recent data on radiological exposures received by workers in the North American uranium recovery industry are then described. The paper also identifies the responsible government agencies in the U.S. and Canada assigned the authority to regulate and control occupational exposure from these NORM materials.
所有土壤和岩石都含有天然存在的放射性物质（NORM）。许多矿石和原材料含有相对较高水平的天然放射性核素，对这些材料进行加工会进一步增加天然存在的放射性核素的浓度。在美国，这些材料有时被称为技术增强型天然存在放射性物质（TENORM）。NORM矿物的例子包括铀矿石、独居石（稀土矿物的一种来源）以及用于生产磷肥的磷矿石。对这些材料进行加工有可能使工人受到高于本底水平的辐射照射。在简要回顾这些不同行业中NORM的来源以及工人接触的可能性之后，本文将概述北美地区的铀矿开采和回收情况，包括讨论目前用于传统（地下、露天开采）和原地浸出（ISL，也称为原地回收，ISR）的采矿方法，以及与这些铀回收方法相关的NORM材料和废物的产生情况。然后描述所产生的NORM产品和废物的放射性组成以及北美铀回收行业工人最近接受的辐射照射数据。本文还确定了美国和加拿大负责监管和控制这些NORM材料所致职业照射的政府机构。
