Department of Radioecology, Institute for Environmental Sciences, Rokkasho 039-3212, Japan.
CLIMATEC, Inc., Tokyo 171-0014, Japan.
Radiat Prot Dosimetry. 2022 Sep 9;198(13-15):1175-1182. doi: 10.1093/rpd/ncac144.
14C is the most important radionuclide for assessing exposure dose around the Rokkasho nuclear fuel reprocessing plant, Aomori Prefecture, Japan. A simplified model with ample margins has been used so far for the assessment of the dose derived from 14C. Realistic dose estimate of 14C using more realistic model is necessary for safety. Apple production is an important core industry in Aomori Prefecture. To construct the dynamic model for apple, using 13C as a tracer to substitute for 14C, we collected data on 13C abundance in organs including fruit after 13CO2 exposure at various fruit growth stages. We developed 13CO2 exposure systems for three intact fruit-bearing shoots (1), whole mature tree (2) and young potted trees (3). Systems (1) and (2) also can determine net amounts of carbon and 13C photoassimilated. System (3) is capable of precise feedback control of 13CO2 and 12CO2 concentrations based on on-time determination.
14C 是评估日本青森县六所村核燃料再处理厂周围辐射剂量的最重要放射性核素。迄今为止，评估 14C 衍生剂量一直采用具有充分余量的简化模型。为了安全起见，有必要使用更现实的模型对 14C 进行更实际的剂量估算。苹果生产是青森县的重要核心产业。为了构建苹果的动态模型，我们使用 13C 作为示踪剂来替代 14C，在果实生长的不同阶段收集了包括果实在内的器官中 13C 丰度的数据。我们为三个完整的结果实枝条（1）、整个成熟树木（2）和年轻盆栽树木（3）开发了 13CO2 暴露系统。系统（1）和（2）还可以确定净碳量和 13C 光同化量。系统（3）能够根据实时测定，对 13CO2 和 12CO2 浓度进行精确的反馈控制。
