燃烧试验在煤的放射性环境评价方法研究中的应用

采集康平、沈北、东梁、辽阳、阜新、浑江、舒兰、海拉尔、珲春、凉水、七台河共11处煤矿样品，设置了燃烧试验，使煤在近密闭燃烧炉中燃烧，杜绝飞灰造成的物质损失，然后测定煤及其对应灰分的²³⁸U、²³²Th、²²⁶Ra、⁴⁰K活度.分析得出：在理论燃烧状态下，假设燃烧无飞灰产生，煤灰的²³⁸U、²³²Th、²²⁶Ra、⁴⁰K天然放射性核素富集因子f与煤灰分比Ad的乘积为1.根据煤燃烧后核素的迁移富集规律和影响辐射水平的核素权重，提出了应用于煤的比活度、吸收剂量率、年吸收剂量、内辐射指数等放射性环境评价参考值.经11处煤矿验证，评价结果可以反映煤灰的辐射水平，辐射水平排序与实际测量结果基本一致.

COMBUSTION TEST IN STUDY ON RADIOACTIVE ENVIRONMENT EVALUATION OF COAL

Samples from 11 coal mines in Kangping, Shenbei, Dongliang, Liaoyang, Fuxin, Hunjiang, Shulan, Hailar, Hunchun, Liangshui and Qitaihe in Northeast China are collected for combustion test. Burn coal in a nearly-closed burner to prevent material loss caused by fly ash and then measure the ²³⁸U, ²³²Th, ²²⁶Ra and ⁴⁰K activity of coal and corresponding ash. The analysis shows that in the theoretical combustion state, assuming no fly ash is produced, the product of natural radionuclide enrichment factor (f) and ash content ratio(Ad) is 1. According to the migration and enrichment rule of nuclide after combustion and the nuclide weights affecting the radiation level, the paper proposes the reference values of radioactive environment evaluation applied to coal, such as specific activity, absorbed dose rate, annual absorbed dose, and internal radiation index. Verified by 11 coal mines, the results can reflect the radiation level of coal ash with the ranking basically consistent with the actual measurement.