| Autor: |
YANG Jianxun, DING Youqian, WANG Xiufeng, MA Peng, ZHANG Xi, BAI Long, HUANG Kun, ZHANG Shengdong, MAO Guoshu, YANG Zhihong |
| Jazyk: |
English<br />Chinese |
| Rok vydání: |
2024 |
| Předmět: |
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| Zdroj: |
Yuanzineng kexue jishu, Vol 8, Iss 58, Pp 1697-1703 (2024) |
| Druh dokumentu: |
article |
| ISSN: |
1000-6931 |
| DOI: |
10.7538/yzk.2024.youxian.0502 |
| Popis: |
The measurement of nuclear parameters (especially fission yield) of short-lived fission products plays an important role in studying nuclear structure models, or fission reaction theory and determining nuclear fuel burnup. Its accuracy mainly depends on the separation ability of fission products and the measuring precision of instruments. When using off-line method to measure the yield, it is hard to implement as the life-time of some fission products are too short or too long, and consequently the yield of about a quarter of the mass chain could not achieved. In order to improve the measurement accuracy of nuclear parameters of short-lived nuclides in neutron-induced fission of uranium, it demands to separate high-activity and radiochemical-purity samples from fission targets rapidly. SISAK system is a fast chemical separation system for short-lived nuclides based on AKUFVE. Under a certain suitable chemical separation system, the extraction equilibrium time can be obviously improved and the phase separation can be completed quickly. And that means SISAK has a positive effect on the rapid separation of short-lived fission products. In this work, two stages of centrifugal extraction unit were applied to form the SISAK system, and solenoid valves were installed in the liquid flow path. The opening and closing time of these solenoid valves was matched with the result extraction kinetics through the program. Consequently, the automatic operation of the separation procedure was fulfilled. 94Sr, one of the neutron induced uranium fission products, has a short half-life (75 s) and a high independent yield (4.3%), which was the suitable nuclide to verify the fast separation ability of SISAK system. The optimum extraction efficiency was obtained using 0.1 mol/L dicyclohexyl-18-crown-6-tetrachloroethane to extract strontium from aqueous phase of 1.0 mol/L nitric acid medium and back-extracting with 0.1 mol/L sodium citrate solution. In addition, the high speed stirring (65% to 70% of full revolution speed of 1 400 r/min) made the two phases reaching extraction equilibrium in 10 s. A completely automated fast chemical separation procedure of strontium was established based on SISAK system. The target solution obtained by irradiating 14 μg 235U for 20 s through the reactor could get the sample within 100 s, and the characteristic peak of 94Sr can be detected obviously without interference by HPGe γ spectrometer. The chemical recovery of Sr is better than 80%. This research used the “batch irradiation plus fast chemical separation” technique to obtain fission product samples with half-life of minutes, which is of great significance for the determination of nuclear parameters and the study of decay characteristics of fission products with half-life of minutes. |
| Databáze: |
Directory of Open Access Journals |
| Externí odkaz: |
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