Evaluation of IAEA Clearance Concept for Low-level Radioactive Waste from a Radioisotope Research Institute
| Autor: | Yasuhiro Yumoto, Eiichi Nakayama, Tomohiro Nagamatsu, Ikuo Kinno, Kazuhiro Nouso, Shigeru Okada |
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| Rok vydání: | 2016 |
| Předmět: |
Radioisotopes
Radionuclide Epidemiology Health Toxicology and Mutagenesis Nuclear engineering waste disposal Radiochemistry low-level Academies and Institutes Radioactive waste Incineration Waste Management Radioactive Waste Environmental science operational topics Humans Radiology Nuclear Medicine and imaging waste Waste disposal Half-Life |
| Zdroj: | Health physics. 110(5 Suppl 2) |
| ISSN: | 1538-5159 |
| Popis: | The clearance of solid low-level radioactive laboratory waste (LLRW) after decay-in-storage (DIS) obtained from a research institute and thoroughly separated using the separation and classification protocols presented in this study was evaluated. METHOD: The radioisotope (RI) content of incinerated LLRW from the specified RI research group (group A); the RI content of LLRW obtained in fiscal year 2000, which contained radionuclides with half-lives of less than 164 d (LLRW2); and the RI content of the LLRW reported in group A's disposal records were compared. The LLRW2 and LLRW of group A were incinerated after 2 y of decay-in-storage and immediately after storage, respectively. RESULTS: The highest ratio of the RI of incinerated LLRW to the value in the disposal records was 2.52 for ⁵¹Cr. The radioactivities of radionuclides in both the LLRW2 and LLRW for ³⁵S, ⁴⁵Ca, ⁵¹Cr, ¹²⁵I, ³²P, ³³P, and ⁹⁹mTc and the incinerated ash after 1 y later of decay-in-storage were below the clearance level defined by the RS-G-1.7 of the International Basic Safety Standard without contamination by ³H and ¹⁴C. These remains contained very small amounts of some long-half-life radionuclides of natural origin after 7 y of decay-in-storage. CONCLUSION: This LLRW separation protocol was effective for the separation of ³H and ¹⁴C. LLRW2 after 2 years of DIS and its incinerated ash after one year later of DIS were below the clearance level for radioactivity and radioactivity concentration. |
| Databáze: | OpenAIRE |
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