Safety performance comparation of MOX, nitride and metallic fuel based 25–100 MWe Pb–Bi cooled long life fast reactors without on-site refuelling

In this paper the safety performance of 25–100 MWe Pb–Bi cooled long life fast reactors based on three types of fuels: MOX, nitride and metal is compared and discussed. In the fourth generation NPP paradigm, especially for Pb–Bi cooled fast reactors, inherent safety capability is necessary against some standard accidents such as unprotected loss of flow (ULOF), unprotected rod run-out transient over power (UTOP), unprotected loss of heat sink (ULOHS). Selection of fuel type will have important impact on the overall system safety performance.

The results of safety analysis of long life Pb–Bi cooled fast reactors without on-site fuelling using nitride, MOX and metal fuel have been performed. The reactors show the inherent safety pattern with enough safety margins during ULOF and UTOP accidents. For MOX fuelled reactors, ULOF accident is more severe than UTOP accident while for nitride fuelled cores UTOP accident may push power much higher than that comparable MOX fuelled cores.     

Effect of γ-ray irradiation on Nd–Fe–B alloys

We report on how γ-ray irradiation affects the magnetic properties of a powder sample of Nd–Fe–B, which was irradiated at room temperature with doses up to 700 kGy. Both the magnetic properties and surface morphology were changed by the effects of the γ-ray irradiation. The unirradiated and irradiated samples were then characterized using the VSM, XRD and SEM techniques.     

EH4仪器阻抗估算技术缺陷分析

基于StrataGem(EH4)大地电磁测量仪的实测数据,剖析了该系统计算阻抗过程(IMAGEM软件完成)中两个重要不足。一个是以常相干度为工具控制由机械叠加形成的原始谱而计算互功率谱过程,容易造成放大单个原始谱点在互功率谱计算中的作用,也可能舍弃了许多有用信息;另一个是以最小二乘算法估算阻抗容易造成所估算的阻抗不稳定。     

The European pressurized water reactor Result of the French–German cooperation of experienced NPP suppliers and operators

In 1989 Framatome and Siemens, the two most experienced European nuclear power plant suppliers, decided to join the efforts for the development of a new reactor type for the next generation in their equally owned subsidiary Nuclear Power International (NPI). In 1992 Electricité de France and the major German utilities operating nuclear power plants merged their own development programs with that of Nuclear Power International and initiated the European Pressurized Water Reactor (EPR) project. In order to reach the two major targets of the project, the licensability in both countries, France and Germany, and the competitiveness of nuclear energy with other alternative energy sources, the design basis which had differently developed in the two countries needed to be harmonized. In parallel, the licensing authorities of both countries extended their existing cooperation in the field of a safety survey of existing nuclear power plants to the definition of safety criteria for the next generation of nuclear power plants. Through this cooperation the licensability of EPR in France and Germany will be assured. Continuously performed cost analysis show in addition that also the second target of the project, the competitiveness with alternative primary energy sources, can be achieved. Thanks to the fruitful cooperation between all parties involved, satisfactory results have been achieved not by a simple superposition of existing design features but through a careful evaluation and combination of the best available alternatives. At the end of 1997 the basic design results were compiled in a final report. Subsequently an optimization phase was launched that further improves the competitiveness of the power generation costs.     

FT3 FT4 放射免疫分析（直接法）方法学研究

自行研制了~(125)I标记的T_3X、T_4X(酰胺类衍生物)。免疫所得抗T_3抗体滴度1:160000,K=1.13×10~(11)l/mol;抗T_4抗体滴度1:6000,K=7.6×10~(10)l/mol。以PR试剂为分离剂,建立一步直接放免测定法。灵敏度FT_3为0.24 pmol/l;FT_4为0.16pmol/l。方法精确、特异、稳定。临床应用结果与英国Amersham Amerlex—M法相关极好。     

Influence of Deposition Temperature on the Structure Of Si3N4 Thin Film Prepared By MWECR-PECVD

The Si3N4 thin film is prepared by MWECR-PECVD at different deposition temperature and the structure of the Si3N4 thin film is investigated. The results indicate that the structure of the Si3N4 thin film prepared at low deposition temperature is in the amorphous phase. However, when the deposition temperature increases to 280℃, the Si3N4 thin film changes to crystalline a-Si3N4. With a further increase of the deposition temperature, the grain of the Si3N4 thin film becomes more fine, uniform and flat. XRD analysis shows that the structure of the Si3N4 thin film prepared at 280℃ is of a crystalline structure.     

Simulation of the defect pair VPb–VO in PbMoO4 crystals

A simulation study has been performed to investigate the defects in PbMoO₄, based on the interatomic potentials empirically fitted to the known crystal properties. The formation energies of the isolated point defects , , the cluster defects , and have been calculated. It is theoretically demonstrated that most of and in the as-grown PbMoO₄ crystal exist in the form of the vacancy pair , which would play important roles in the formation and transformation process of photo-chromic effect in PbMoO₄ crystal.     

Study of the magnetic modifications of Fe3O4 ferrite thin films induced by 2.03 GeV Kr ions irradiation

The effect of 2.03 GeV Kr²⁶⁺ ions irradiation on antiphase boundaries (APBs) of polycrystalline Fe₃O₄ ferrite thin films has been investigated. The structure, magnetic and electrical transport properties of samples were characterized. The initial crystallographic structure of the Fe₃O₄ remains unaffected after Kr-ion irradiation, but the magnetic and electrical transports properties are sensitive to swift heavy ions (SHI) irradiation and exhibit different behaviors depending on the Kr-ion fluence range. The energy deposition is mainly due to the electronic energy loss (S_e) and the large value of energy transferred induces an unusual density of defects, stress and heat annealing effect in the samples, which can affect on the arrangement of magnetic moments and APBs density strongly. On the basis of our observations we conclude that the production, accumulation and free of the defects and stress induced by SHI irradiation is more dominant in the case of the magnetic and electrical transport properties modifications of the Fe₃O₄ thin films.