Enzymatic Responses to Low-Intensity Radiation of Tritium

The present study considers a possible role of enzymatic reactions in the adaptive response of cells to the beta-emitting radionuclide tritium under conditions of low-dose exposures. Effects of tritiated water (HTO) on the reactions of bacterial luciferase and NAD(P)H:FMN-oxidoreductase, as well as a coupled system of these two reactions, were studied at radioactivity concentrations ≤ 200 MBq/L. Additionally, one of the simplest enzymatic reactions, photobiochemical proton transfer in Coelenteramide-containing Fluorescent Protein (CLM-FP), was also investigated. We found that HTO increased the activity of NAD(P)H:FMN-oxidoreductase at the initial stage of its reaction (by up to 230%); however, a rise of luciferase activity was moderate (<20%). The CLM-FP samples did not show any increase in the rate of the photobiochemical proton transfer under the exposure to HTO. The responses of the enzyme systems were compared to the ‘hormetic’ response of luminous marine bacterial cells studied earlier. We conclude that (1) the oxidoreductase reaction contributes significantly to the activation of the coupled enzyme system and bacterial cells by tritium, and (2) an increase in the organization level of biological systems promotes the hormesis phenomenon.     

CFETR水冷陶瓷增殖剂包层模块产氚率实验验证

水冷陶瓷增殖剂（WCCB）包层作为中国聚变工程试验堆（CFETR）候选包层之一，承担着氚增殖、核热提取、屏蔽等重要涉核功能，其中子学设计的可靠性直接影响CFETR氚自持目标的实现。为验证中子学设计工具，即MCNP和FNEDL3.0数据库，在WCCB包层中子学设计中的可靠性，基于研制出的WCCB包层模块，在DT中子环境下开展中子学实验，对以产氚率（TPR）为代表的中子学参数进行了模拟值（C）和实验值（E）对比分析。结果表明，模块中轴线位置处TPR的C/E为0.97?1.08，而模块边缘位置处TPR的C/E为0.65?0.82；模块钛酸锂层边缘区197Au（n，γ）198Au反应率的C/E为0.72?0.90，表明模块边缘区存在非期望的散射中子，导致该区TPR模拟值和实验值偏离较大。     

氧化物陶瓷阻氚涂层的研究进展

利用阻氚涂层(TPB)降低结构材料中的氚损失,是聚变堆发展中的热点研究之一。陶瓷具有低氚渗透性、耐腐蚀性、高硬度和高热稳定性等特性,是目前聚变堆阻氚涂层首选材料。相对于硅化物、钛基等非氧化物陶瓷材料,氧化物陶瓷涂层具有熔点高、化学性质稳定、耐腐蚀性和阻氚渗透因子(PRF)高等优势,因此针对氧化物陶瓷阻氚涂层的研究较多。主要综述了单一氧化物陶瓷、复合氧化物陶瓷阻氚涂层近年来的研究现状与发展,如Y2O3、Er2O3、Al2O3等及其复合氧化物陶瓷材料,其中,因Al2O3及其复合物涂层具有优异的阻氚性能,得到了广泛的关注和研究。重点阐述了制备工艺、基体效应和辐照等影响氧化物陶瓷涂层阻氚性能的因素及氚在材料中的渗透机制,并分析了当前阻氚涂层在材料制备以及模拟服役环境等方面存在的不足与今后的研究重点,指出了未来可能的氧化物陶瓷阻氚涂层,以期为阻氚涂层的研究与后续实验提供一定的方向。     

氚灯亮度的Monte-Carlo模拟研究

本文基于氚灯物理模型，运用Monte-Carlo方法研究氚气压强和氚灯几何条件对氚灯亮度的影响，得到与文献实验值吻合较好的理论结果。该方法为氚灯工程设计和优化提供了有力的手段。     

Development of In-Situ Gas Analyzer for Hydrogen Isotopes in Fusion Fuel Gas Processing

To develop a real time and in-situ process gas analyzer for fusion fuel gas processing systems, application study of laser Raman spectroscopy was performed by measurement of hydrogen isotopes. Using an Ari on type laser of which wavelength 488 nm, power 0.7 W, and single pass irradiation method, Raman spectra of hydrogen isotopes were measured and intensities of the Stokes rotational lines and Q-branch were quantitatively analyzed. The Stokes rotational lines at 587, 443 and 415 cm¹ were selected as suitable ones for quantitative analysis of H₂, HD and D₂. Normalizing the Raman intensity of partial pressure H₂ as 100, relative Raman intensity ratio of H₂:HD:D₂ was obtained as 100:58:47. The detection limit for hydrogen was estimated as 0.05 kPa in partial pressure and 500 ppm in concentration. But multiple pass method further improved the detection limit to 100 ppm.     

Tritium Isotope Separation by Multiphoton Dissociation of CF3CTCIF

A conception of the advanced water chemistry diagnosis system for detection of anomalies and preventive maintenance of system components is proposed. Extension of anomaly diagnosis knowledge and more reliable water chemistry data are indispensable to the advanced system. Then, correlations between water chemistry (conductivity and pH) change in reactor water and anomaly occurrence in the components of the feed water line are analyzed theoretically. These correlations are verified as applicable to extension of the diagnosis knowledge for anomalies in the components of the feed water line, such as resin intrusion, sea water Leakage at the condenser, and a breakdown in ion exchange capacity of resin at the condensate demineralizer.     

Measurement of Tritiated Moisture in Gas Stream by Collection Method Using P2O5 Desiccant

A measurement method of tritiated moisture in gas stream has been developed by taking advantage of the high hygroscopic and deliquescent performances of phosphorus pentoxide P₂O₅. The method includes two techniques; one is of collecting moisture from gas stream using the desiccant, the other is of preparing homogeneous liquid scintillation cocktails containing the phosphide and the collected moisture. By introducing an idea of common use of standard vials as the collector cells disposable and the scintillation cocktail containers, the treatment process has been simplified and the chances of error arising in process for subsequent tritium analysis have been decreased. From results of a typical experiment, a relationship between the collection efficiencies and the moisture contents of P₂O₅ has been obtained and the isotope effect on the moisture collection has been elucidated. The collecting performance and the isotope effect are discussed here considering the mass transport phenomena in collector cell.     

Characterization of Chemical Densified Coating as Tritium Permeation Barrier

In a fusion blanket design, ceramic coating on structural materials has been considered to be used as a tritium permeation barrier. The Chemical Densified Coating (CDC) method has some advantage compared with another coating method. This method is capable to form densified coating on either the outer or the inner surface of a tube or a container. This process temperature is low (450°C). The fabrication technique of Cr₂O₃-SiO₂ coating had been developed using CDC method. However, Cr₂O₃-SiO₂ coating had open pores in the coating. For filling open pores, the densification treatment by CrPO₄ was examined. In this study, the verification of open pores, the thermal shock resistivity, the adhesion strength and the deuterium permeability were evaluated and compared with Cr₂O₃-SiO₂ (Type 1) coating and Cr₂O₃-SiO₂ including CrPO₄ (Type 2) coating. From these results, it was confirmed that Type 2 coating had a good adhesion property, and permeation reduction factor of SS316 with Cr₂O₃-SiO₂ including CrPO₄ coating reached about 1,000 at 600°C.     

Hydrogen solubility in liquid lithium–sodium alloys (90, 50, and 20 at% Li)

Hydrogen solubility in liquid Li–Na alloys (20, 50, and 90 at% Li) at 673, 773, and 873 K was investigated by adding and extracting hydrogen through the wall of a capsule made of pure iron. Hydrogen solubility in the Li₉₀Na₁₀ alloy was almost similar to that in pure Li while for Li₅₀Na₅₀ and Li₂₀Na₈₀, it was one and two orders of magnitude smaller, respectively. No obvious difference in temperature dependence was observed, similar to the case for pure Li. Li–Na alloy can thus be a potential liquid breeding material with almost all of the advantages of the Li blanket system and free of most of its drawbacks.     

工艺尾气氚测量装置的研制

通过选择装置材料、优化结构及参数,设计制作了有效体积为11.0 mL的测氚电离室,用于工艺尾气中氚含量的测量。用质谱法标定绘制了工作曲线,工作曲线线性范围为0.013 4%～0.168%(体积)。测试表明:装置泄漏率为5.5×10^-7 Pa·m³/s,密封性良好;本底电流为2.98×10^-14A;装置探测下限值为1.35×10^-4 %(体积);变异系数≤1.50%;仪器响应时间≤10 s,响应速度快,测量周期短,满足工艺样品的检测需求。