A SCREENING SURVEY EXERCISE FOR THYROID INTERNAL EXPOSURE FROM RADIOIODINE AFTER A NUCLEAR ACCIDENT

• Published in: Radiation protection dosimetry 2019-06, Vol.183 (4), p.482-488
• Main Authors: Yajima, Kazuaki, Kim, Eunjoo, Tani, Kotaro, Tatsuzaki, Hideo, Li, Chunsheng, Kurihara, Osamu
• Format: Article
• Language: English
• Subjects: Humans; Iodine Radioisotopes - adverse effects; Iodine Radioisotopes - analysis; Nuclear Power Plants; Radiation Dosage; Radiation Monitoring - methods; Radioactive Hazard Release; Risk Assessment; Surveys and Questionnaires; Thyroid Gland - radiation effects
• ISSN: 0144-8420; 1742-3406
• DOI: 10.1093/rpd/ncy175

In the aftermath of the 2011 Fukushima nuclear disaster, a screening survey for thyroid internal exposure from intake of radioiodine was performed on 1080 children using handheld NaI(Tl) survey meters. This article presents the design and results of a practical exercise conducted to develop the skills of personnel who would be potentially engaged in such a survey. Participants of this exercise were asked to measure manikin heads in which point sources were installed under normal (~0.05 μSv h-1) and elevated (~0.5 μSv h-1) background conditions. The results demonstrated that the measurements were less dependent on the background radiation level, and the deviation of net signals obtained by the participants were within 10-20% for dose rates above 0.2 μSv h-1. This result suggests that dose rates can be reliably obtained above a provisional operational intervention level for the device, 0.5 μSv h-1 under a real nuclear accident situation.