CPR1000核电厂反应堆冷却剂泵电机绝缘问题分析

文章介绍了CPR1000反应堆冷却剂泵（主泵）电机轴电压产生的原理,针对轴电压对主泵电机设备运行产生的危害和影响,剖析影响主泵电机轴绝缘失效的原因,通过主泵电机轴绝缘故障问题实例,阐述了轴绝缘故障排除处理方法,并提出了几种改善轴绝缘的相关措施。     

自然循环蒸汽发生器瞬态热工水力建模与分析

应用瞬态分析专用程序建立了CPR1000蒸汽发生器几何模型,对CPR1000蒸汽发生器在功率运行期间停运一台主泵时的热工水力瞬态响应、主蒸汽管道破裂和蒸汽/主给水流量同时+10%阶跃扰动工况下的瞬态响应进行了模拟与分析,获得了蒸汽发生器内部热工水力参数如流量、温度、换热系数的响应特性,分析结果表明,瞬态分析模型满足蒸汽发生器设计瞬态分析的要求。     

CPR1000核电机组主泵电机轴绝缘低问题处理和预防研究

结合中国改进型三环路压水堆(CPR1000)宁德核电厂3号机组反应堆冷却剂泵电机(简称主泵电机)轴绝缘丢失事件,对造成主泵电机轴绝缘低的3个主要原因进行分析和研究,形成14步标准化排查步骤,解决了主泵电机轴绝缘低问题,并提出核电现场防止轴绝缘低的5点措施。     

CPR1000反应堆冷却剂泵的安装与管理

对CPR1000反应堆冷却剂泵施工中的典型案例处理和方案改进等方面进行探讨和总结,对后续CPR1000项目主泵施工提出一些建议.     

压水堆核电站一回路工况变化对主泵主要机械性能的影响

论述了大亚湾和岭澳1000MW压水堆核电站反应堆冷却剂回路(一回路)主要瞬态工况对反应堆冷却剂泵的主要机械性能参数的影响,为避免主泵受瞬态干扰,以及通过改变系统参数调整来改善主泵机械参数提供了理论依据。     

CPR1000机组100D型主泵振动故障诊断

CPR1000机组各运行模式下100D型主泵的振动现象表明,当处于蒸汽发生器冷却正常停堆或余热排出冷却正常停堆工况时,主泵电动机的瓦振幅值往往存在大范围冲击波动甚至触发振动高报警的现象。根据机械振动原理综合分析电动机瓦振、主泵轴位移信号的频域和时域特征,诊断振幅波动受某7~9Hz的低频随机振动影响;通过分析堆内构件振动噪声监测系统采集的信号判断该低频振动对应一回路主冷却剂流动过程中诱发的堆芯吊篮梁式振动。根据流体诱发振动理论分析了影响主泵电动机振动波动的主要因素,并通过主泵历史运行记录进行了验证。系统性提出优化CPR1000机组运行策略缓解主泵电动机振动波动的建议,为主泵安全稳定运行提供参考。      

CPR1000核电机组主泵动平衡的一次加准方法研究及应用

受核电站一回路复杂运行工况的影响,一回路冷却剂泵(下称"主泵")经常发生振动高的问题,现场动平衡是解决主泵振动问题的重要手段,也是影响和制约核电站机组启动上行的关键因素之一.通过对大量同类型主泵动平衡数据的总结,提出了主泵动平衡的一次加准方法.该方法给出了 CPR1000机组主泵动平衡中加重质量、加重角度和残余振动的计...     

反应堆系统冷却剂泵流量特性计算模型

反应堆的发热是靠反应堆系统一回路冷却剂循环带出堆芯之外的。一般情况下，冷却剂的流动是靠冷却剂主循环泵（主泵）来唧送的，特殊情况下，也需要靠回路中冷却剂的自然循环流动来完成。不论是哪种情况，主泵的流量特性直接影响着反应堆的安全。本文根据主泵的四象限特性图提出了一种用于计算反应堆系统稳态和瞬态工况下主泵流量特性的计算方法。该方法便于使用，其计算结果与Ｒｅｌａｐ５／ＭＯＤ２的计算结果进行了比较，二者符合很好，证明本文的模型完全可用于反应堆系统的稳态设计和瞬态事故分析。     

反应堆冷却剂系统流量测量试验研究与设计

华龙一号（HPR1000）设置了反应堆冷却剂泵进出口压差表用于测量反应堆冷却剂系统（RCS系统）环路流量,取消了二代改进型核电机组设置的弯管流量计。环路流量测量方式的改变直接影响RCS系统流量测量试验的实施。通过研究主泵的运行特性和系统的阻力特性,提出了基于主泵电功率测量RCS系统流量的试验方法。结合理论分析结果和工程实践经验,给出了反应堆冷却剂惰走流量试验的试验方法和验收准则。研究表明,主泵电功率法可以测量RCS系统的流量,反应堆冷却剂惰走流量可以通过主泵惰转过程的转速变化进行验证。      

主泵电机润滑油损失异常的分析和处理

主泵是核电站的心脏,是反应堆冷却剂系统的主要设备和压力边界之一,承担着确保堆芯传热所需的冷却剂流量的重要功能,运行期间必须保证主泵运行的安全可靠。在第11个燃料循环周期中,主泵A电机出现了润滑油损失异常的状况。为了保证电机正常运行,在功率运行期间进行了5次补油的应急处理。针对这个问题,对主泵电机润滑油损失异常的原因和油气散失通道作出了具体分析,在换料检修过程中对主泵电机进行了解体工作。对解决润滑油损失异常的具体解决方案做出了论述。通过具体检修方案的实施,最终使润滑油异常损失得到了很好的控制。     

Preparation of Zn/TiO2 powder and its photocatalytic performance for oxidation of P-nitrophenol

Zn-doped TiO2 catalysts were prepared using a sol-gel method and characterized by XPS,UV-Vis, BET, XRD in this study. Under the irradiation of simulant sunlight, the photocatalytic activity for the degradation of p-nitrophenol was studied too. After irradiation for 2.5 h, the degradation percentage of p-nitrophenol could rise to more than 80 %. The results showed that the spectrum absorption band edge of Zn/TiO2 powder does not broaden obviously comparing with pure TiO2 powder. Zinc exists as Zn （11）. When calcined at 973 K, there is a new phase as ZnTiO3 in Zn/TiO2 catalyst. The order of photocatalytic activity of Zn/TiO2 catalysts calcined at different temperatures for p-nitrophenol is 773 K 〉 673 K 〉 873 K 〉 573 K 〉 973 K and the photocatalytic activity of Zn/TiO2 catalyst calcined at 773 K is better than TiO2 catalysts heated at the same temperature, and outclasses that of commercial TiO2 catalyst. It also showed that the photocatalytic degradation of p-nitrophenol follows first-order kinetics under the irradiation of simulant sunlight.     

Current status of radiation therapy for prostate cancer

Radiotherapy for the treatment of prostate cancer has been extensively explored in the past. Along with the comprehensive understanding of the biology of prostate cancer and rapid advances in terms of technology, the out- come of treatment for the patients with prostate cancer has improved. The authors review radiotherapy as the primary treatment for the disease, with particular emphasis on the technological advances from both the radiobiological and radiophysics aspects. Nonconventional fractionated irradiation like hyper- or hypo-fractionation has been imple- mented in the clinic, the final results still need to be confirmed in the future. Technological advances like IMRT, IGRT, in the last two decades have significantly improved the delivery of external radiotherapy to the prostate. This has re- sulted in an overall increase in the total dose that can be safely delivered to the prostate, which has led to modest im- provements in the biochemical outcome. However, establishing the standard therapy for prostate cancer remains con- troversial. It is hoped that the next decades will bring continued advances in the development of biologicals that will further improve current clinical outcomes.     

水平管内含空气蒸汽强制对流冷凝换热模型研究

为研究含空气蒸汽在水平管内强制对流冷凝换热特性,基于对传热传质过程的分析,建立了管内为环状流与波状流条件下的流动冷凝换热模型。从潜热、显热和液膜3个环节对整个换热过程进行建模,最终得到计算局部冷凝换热系数的理论关系式。模型预测结果与实验数据的对比表明,二者相对偏差在±20%以内,验证了该换热模型的准确性与适用性。通过进一步的研究发现：从换热管入口至出口,随着冷凝的进行,管内换热主要热阻由液膜热阻向气液界面的凝结热阻转变;主流气体对流换热过程基本可忽略。     

Investigations on landmine detection by BF3 detector

Experiments were carried out to investigate the possible use of neutron backscattering for the detection of polyethylene (PE) sample buried in the soil. In detection of landmine by neutrons, the neutron detector and its shield play an important role. In this paper, the effects of graphite, heavy water, polyethylene and boric acid moderators on the flux of back scattered neutrons were investigated. We have also experimentally verified the effect of BF3 detector shield and obtained good agreement with theory.     

Web Services interface of SSRF archive data analysis system

Accelerator database stores various static parameters and real-time data of accelerator. SSRF (Shanghai Synchrotron Radiation Facility) adopts relational database to save the data. We developed a data retrieval system based on XML Web Services for accessing the archive data. It includes a bottom layer interface and an interface applicable for accelerator physics. Client samples exemplifying how to consume the interface are given. The users can browse, retrieve and plot data by the client samples. Also, we give a method to test its stability. The test result and performance are described.     

Assessment of radioactivity levels in some oil samples from the western desert, Egypt

Distributions of natural gamma-emitting radionuclides were determined in 93 oil samples collected from some petroleum fields in the western desert of Egypt. The radioisotope activities in the area under investigation lay in the range of (21 ± 4) to (38 ± 13) Bq?L-1 for 226Ra, (9 ± 2) to (15 ± 5) Bq?L-1 for 232Th, and (154 ± 28) to (303 ± 54) Bq?L-1 for 40K. The mean values were 27, 12, and 201 Bq?L-1, respectively. Among oils, variations in radionuclide ac- tivities could be on account of differences in TDS, HCO3, and Ba, with high or low pH. In this environment, oil prop- erties differently affected the mobilization of natural radionuclides. The range of 226Ra variation had been compared with available data from other countries. The calculated absorbed dose rate ranged from 22.33 to 32.66 nGy?h-1 in lo- cation (B) and (E) respectively, which was less than the accepted value.     

Preparation and properties of 117m Sn(IV)-TTHMP in in-vitro and in small animals

In this work,TTHMP was synthesized and labelled with 117m Sn.The preparation conditions,stability and lipophilicity of 117m Sn(IV)-TTHMP were investigated.Biodistribution of the complex in rabbits and mice was studied.It was found that the quantity of TTHMP and pH value of the prepararion solution had vital effects on the labeling yield of 117m Sn(IV)-TTHMP.It was also found that 117m Sn(IV)-TTHMP was hydrophilic and stable at room temperature and 37℃ in open air 117m Sn(IV)-TTHMP showed unexpectedly high bone uptake and bone-to-blood ratio in the animals.This made it potentially useful as an reagent for skeletal scintigraphy and radiotherapy of bone tumors.     

The role of AGFA high-energy CR in the calibration and quality control of multileaf collimators （MLC）

Linear accelerators equipped with multileaf collimators （MLC） are becoming more common and are widely used in the intensity-modulated radiotherapy （IMRT）. There is an imperative need to ensure the commissioning specification of the linear accelerators for the sake of quality assurance （QA） and quality control （QC）. This paper is aimed to investigate the role of AGFA high-energy CR （Computed Radiography） in calibrating dynamic multileaf collimators and evaluating the accuracy of the leaf position. The result shows that AGFA high-energy CR can easily and conveniently be used to calibrate MLC and verify its position. Hence, the application of AGFA high-energy CR is proved to be an accurate and time-saving method for routine MLC QC, especially when MLC calibration adjustments are required.     

微型X射线管空气比释动能和能谱的测量

为研究微型X射线管的特性,通过电离室测量光管出射口30 cm远处的空气比释动能,使用高纯锗探测器分别测量了Ag过滤和Cu过滤下的X射线能谱。结果表明,空气比释动能随电流的增加有线性增加的趋势,能谱图明显的观察到银的两个特征X射线。完成了微型X射线管空气比释动能和能谱的测量方法以及实验测量的工作,为微型x射线管下辐射质的建立提够了条件基础。     

有效探测面积大于1000 cm2的正比计数器测量系统性能测试

为对自制的活性面积高达1 000 cm²的大面积源进行表面发射率定值,同时作为现有2πα、2πβ表面发射率标准装置能力的扩充,研制了一套内置式大面积2π多丝正比计数器测量系统,并利用活性区直径为8 mm的²⁴¹Am点源及活性区面积为10 cm×15 cm的大面积²⁴¹Am和⁹⁰Sr-⁹⁰Y源对其进行计量学性能测试。结果表明：计数器内计数响应均匀性优于±0.4%,有效探测面积达1 400 cm²;所得²⁴¹Am源高压坪曲线的坪长为1 400 V,坪斜为0.27%/100 V,坪区内计数变化为0.87%;⁹⁰Sr-⁹⁰Y源高压坪曲线的坪长为300 V,坪斜为0.75%/100 V,坪区内计数变化为0.80%;10次测量重复性好于0.4%,8 h内短期稳定性好于0.3%,1 a内长期稳定性好于0.8%。