Fluorination of Uranium Metal by Fluorine Gas

A study has been made on the fluorination of uranium metal chips to UF₆ with fluorine gas in the temperature range of 100° to 400°C. The formation of UF₆ was influenced by the concentration and the flow rate of fluorine gas and by the reaction temperature. The reaction occurred apparently above 200°C. Uranium metal was first converted to low fluorine content compound such as UF₃ or UF_4-x, then to UF₄ and finally to UF₆. The intermediate compounds were confirmed by X-ray analysis and by their color.     

Condensing Heat Transfer in Steam-Water Condensing-injector

An experiment on the direct heat transfer process between supersonic steam and subcooled water jet was performed, using a steam-water condensing-injector. Photographic observation provided information on the state of flow, and establishment of a critical separate steam-water flow was confirmed. The temperature and pressure distributions along the flow were measured and the effective coefficients of condensing heat transfer were evaluated from the observed data, based on a model embodying an idealized interface between vapor and liquid. In the vicinity of the water nozzle exit, where the vapor-liquid interface was distinct, the heat transfer coefficients obtained were 14–28 (cal/°C.cm².sec), and some correlation was observed among Nusselt, Reynolds and Jakob numbers, upon adopting the velocity and the physical properties of the steam phase. The relations Nu=6.0.Re ^0.9(Pr=1.04–1.10), and Re=1.8×10⁸.Ja ^3.0, i.e., Nu=1.6×10⁸.Ja ^2.7 were derived as a rough estimation. No clear correlation could be discerned in the corresponding data obtained from observation points further downstream, where a distinct steam-water interface no longer existed. In conclusion, it is proposed that, in deriving the correlations between Nu and Re or Ja, the physical properties of the vapor and the vapor-liquid relative velocity should be adopted, on account of the strong dependence of condensing heat transfer on steam velocity and water subcooling.     

高温超导带材剩余磁场非接触无损连续测量方法及装置

通过对高温超导带材内部剩余磁场的连续测量，计算机采集数据，并依据超导临界态理论模型计算出临界电流值。为Bi系高温超导带材提供了一种非破坏的连续检测手段，不仅实现了超导带材剩余磁场的实时显示，而且可以给出超导带材均匀性的信息，最终能够计算出整根超导带材临界电流的平均值和不确定度。     

TRT发电机启机故障诊断及技术分析

针对重钢16 MW高炉TRT发电机启机过程出现的在通过临界转速时发生较大振动导致联锁停机这一故障进行技术分析,并提出了整改方案,实施后运行状况良好。     

ADS铅冷却剂临界装置堆芯物理设计

为研究加速器驱动次临界反应堆系统(ADS)次临界堆芯与靶的耦合特性,以验证设计方法和计算程序,本文构建了ADS特有的快中子谱、较高能量放大系数及负温度系数的铅冷却剂临界装置堆芯,以用于开展不同富集度燃料特性、不同外源能谱与强度条件、不同实验样品的反应性影响、中子源与堆芯耦合特性等实验研究。确定了燃料元件构造、靶区结构、堆芯布置、反射层结构与价值、安全控制及反应性价值等物理参数,为下一步ADS铅冷却剂临界装置研制及实验研究提供了工程实施依据。     

快中子临界装置逆动态法反应性测量系统研制与应用

逆动态法可实时、准确地测量反应性,在反应性部件刻度、扰动反应性效应测量、动力堆的瞬态分析等领域具有独特的优点。本文基于逆动态法研制了快中子临界装置反应性测量系统,并对其进行了算法验证与指标分析。实验结果表明,该系统具有测量精度高、响应快、分辨率高、使用方便等优点,满足实验需求。     

UX-30型UF_6运输货包核临界安全分析

利用MONK-9A和MCNP程序对UX-30型UF6运输货包进行了正常与事故工况下的核临界安全分析与评价。首先选取国际公布的临界基准实验数据,验证并确定了MONK-9A和MCNP程序计算分析类似物料形态时的偏倚和次临界限值。其次采取较为包络的临界安全假设条件,计算分析了UX-30型UF6运输货包正常与事故工况下的中子有效增殖因数,评价了运输过程的安全性。计算结果表明,UX-30型UF6运输货包在最严重事故工况下最大的keff小于确定的次临界限值,处于次临界的安全状态。根据临界安全指数的定义,UX-30货包的临界安全指数CSI可定为0。     

新型反应釜釜内物料流动模型的研究

着重研究新型反应釜釜内颗粒的轴向流动模型,采用颗粒受力矢量分析确定单颗粒分别在螺旋叶片和重力作用下的轴向运动轨迹,从而求得为保证实现颗粒轴向流动的螺旋叶片结构,为螺旋叶片的合理设计选择提供可靠的理论依据.     

小议变动成本法的合理性

企业对盈亏临界点的计算通常是以变动成本法为基础，但也有以制造成本法为计算基础的，对于这两种成本方法计算的几种盈亏临界点的情况，本文结合案例，通过比较分析认为：盈亏临界点的计算应当以变动成本法为基础更为合理。     

Thermal-Hydraulics in Uncovered Core of Light Water Reactor in Severe Core Damage Accident, (II)

The SEFDAN is a computer program to analyze the one-dimensional thermal-hydraulics of a partially uncovered core of a light water reactor in a severe degraded-cooling event. In order to verify the code and to obtain better understanding of the severe core damage process, SEFDAN has been applied to analyses of the thermal response of fuel rods in the Power Burst Facility Severe Fuel Damage Scoping Test. This paper presents the calculated results and discusses, based on the results, on the phenomena that are important for prediction of the thermal response of fuel rods to a severe accident under the partially un-covered core condition. The calculated results are in good agreement with the experimental results. Namely the dry-out time of each elevation and the temperature behavior in both the slow heat-up and rapid temperature excursion processes are well simulated. The analysis indicates that fuel cladding temperature of the upper part of the test bundle would have reached the melting point of ZrO₂ and fuel center line temperature would have reached the melting point of UO₂ during a rapid temperature excursion which was caused by rapid decreasing of the dry-out level and accelerated by zirconium-water reaction in the lower part.