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为应对欧盟的RoHS指令,中日韩三国建立了标准物质联合定值工作机制。文章系统介绍第一次联合定值合作中应用同位素稀释质谱法 (IDMS)为日本丙烯腈-丁二烯-苯乙烯聚合物(ABS)塑料标准物质中汞定值的方法。首先利用MC-ICP-MS准确测量了202Hg稀释剂、国家标准物质和ABS塑料中汞的全丰度,然后采用国家标准物质标定202Hg稀释剂的浓度,最后利用IDMS测定ABS塑料中汞的浓度。为消除汞的记忆效应,采用5μg/g的Au(2%硝酸溶液)清洗1min,而后用5μg/g的EDTA清洗2min的程序。实验结果验证了实验室的测量能力,首次联合定值为下阶段工作奠定了技术基础。 相似文献
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《核电子学与探测技术》2018,(5)
堆外核测中间量程MSV模式,又称坎贝尔模式,通过测量裂变室输出中子脉冲信号统计涨落,实现高中子通量的量程覆盖。本文通过采用不同反应堆功率台阶测量探测器坪特性的堆上试验方法,对国产化CAP 1400堆外核测系统中间量程MSV模式进行试验验证。本文描述了系统设计、试验方法设计、测试数据,并进行了结果分析,验证了国产CAP 1400堆外核测系统中间量程MSV模式的可用性。 相似文献
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某压水堆核电厂调试启动期间核仪表系统(RPN)中间量程通道(IRC)的输出电流在核功率(Pn)小于30%FP时提前达到饱和值。首循环换料设计方案(FCRS)确定后,IRC提前饱和的主要影响因素是探测器出厂热中子灵敏度(SF)。根据未能紧急停堆的预期瞬态(ATWT)设计功能和RPN安全准则,得出IRC提前饱和造成ATWT允许信号实际阈值低于设计期望阈值是可接受的结论。IRC提前饱和时,必须在饱和点以下选择Pn作为ATWT允许信号阈值,以确保ATWT允许信号可正确触发。提出采用首循环18个月换料设计方案(FCRS18)的机组应选用SF较小的探测器,以降低IRC提前饱和问题发生的几率。 相似文献
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“华龙一号”(HPR1000)机组应用征兆导向法事故规程(SEOP),在设计上,也采用更先进的征兆导向法事故处理导则。事故导则定值在导则中用于执行事故的诊断,根据定值的设置可以通过手动操作缓解事故后果,并通过定值确认电厂处于安全停堆工况。定值的正确设置是事故处理导则设计的重要内容,保障事故处理策略缓解事故工况的效果。本文针对“华龙一号”征兆导向法事故导则,以裂变功率产生/ATWS响应导则为例,详细介绍了该导则定值的分析过程,包括导则策略分析和导则名义值的确定、安全壳不利工况临界值的确定、导则关键定值的判定、仪表误差考虑的因素以及安全壳不利工况仪表误差对导则的影响分析。本文提出一套完整的确定征兆导向法事故处理导则定值的方法。 相似文献
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在反应堆系统中,当反应堆处于异常工况时,如果运行参数超出保护限值,则由保护系统触发相关保护动作,以保证反应堆的状态符合事故验收准则的要求。本文将通过Simulink建立钠冷快堆主要系统模型,在发生反应性意外引入事故时,借鉴快堆事故分析中预期瞬态无停堆保护(ATWS)的分析方法,基于相应保护参数的测量误差和数据处理过程对反应堆一回路的保护参数及其整定值进行研究,并确保钠冷快堆的状态在整个反应性引入事故过程中符合钠冷快堆的事故验收准则。仿真结果表明,当发生补偿棒失控提升5 s和10 s时,目前的堆芯出口钠温、功率、功率流量比等保护参数的整定值、信号测量延迟及落棒时间可取其他值。当补偿棒失控提升15 s时,只要保证保护参数整定值、相应参数的信号测量延迟及落棒时间能使反应堆在36.45 s前进入深度次临界都是可以的。 相似文献
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Taylor M.L. Franich R.D. Trapp J.V. Johnston P.N. 《IEEE transactions on nuclear science》2009,56(2):429-436
Gel dosimeters are of increasing interest in the field of radiation oncology as the only truly three-dimensional integrating radiation dosimeter. There are a range of ferrous-sulphate and polymer gel dosimeters. To be of use, they must be water-equivalent. On their own, this relates to their radiological properties as determined by their composition. In the context of calibration of gel dosimeters, there is the added complexity of the calibration geometry; the presence of containment vessels may influence the dose absorbed. Five such methods of calibration are modelled here using the Monte Carlo method. It is found that the Fricke gel best matches water for most of the calibration methods, and that the best calibration method involves the use of a large tub into which multiple fields of different dose are directed. The least accurate calibration method involves the use of a long test tube along which a depth dose curve yields multiple calibration points. 相似文献
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Thompson D. J. Bertsch D. L. Favale A. Fichtel C. E. Hartman R. C. Hofstadter R. Hughes E. B. Hunter S. D. Hughlock B. W. Kanbach G. O. Kniffen D. A. Lin Y. C. Mattox J. R. Mayer-Hasselwander H. Nolan P. L. Pinkau K. Rothermel H. Schneid E. Sommer M. Walker A. H. 《IEEE transactions on nuclear science》1987,34(1):36-40
The EGRET telescope, one of the instruments to be carried on NASA's Gamma Ray Observatory, is designed to explore the high-energy portion (20 - 24,000 MeV) of the electromagnetic spectrum. A calibration source of ?-rays over this wide energy range has been used at SLAC, together with an appropriate set of intensity-monitoring instruments, to conduct a calibration of the EGRET telescope over this energy range for the full telescope aperture. The calibration method and an overview of the results are described. 相似文献
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本文介绍了基于MicroTCA.4标准的新型宽带射频前端的设计。该射频前端可以实现300MHz~6 GHz频率范围内的下变频及50 MHz~6 GHz范围内的矢量调制上变频。同时射频前端具有可调衰减、温度监测、功率检波、IQ校准、板卡管理等功能。通过测试,板卡下变频端口间隔离度大于70d B,下变频线性区间大于35 d B,幅度误差小于0.03%,相位误差小于±0.03°;上变频载波泄露小于-45 d Bm,边带抑制大于50 d B。 相似文献
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In this paper, we present an energy calibration method based on steep Compton edges of the laser Compton scattered(LCS) photon energy spectra. It performs consecutive energy calibration in the neighborhood of certain energy, hence improves calibration precision in the energy region. It can also achieve direct calibration at high energy region(several MeV) where detectors can only be calibrated by extrapolation in conventional methods.These make it suitable for detectors that need wide-range energy calibration with high precision. The effects of systematic uncertainties on accuracy of this calibration method are studied by simulation, using the design parameters of a LCS device—SINAP Ⅲ. The results show that the SINAP Ⅲ device is able to perform energy calibration work over the energy region of 25–740 keV. The precision of calibration is better than 1.6% from 25 to 300 keV and is better than 0.5% from 300 to 740 keV. 相似文献
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通过研究γ探测器实验室校准的技术条件,在考虑中国实验快堆(CEFR)现场校准的各种影响因素后,根据CEFR实际情况组装一套校准专用装置,并选择替代法为现场校准方法,选择合适的参考仪器对CEFR厂房内固定式γ探测器进行现场校准实验。结果表明,采用CEFR校准专用装置和建立的现场校准方法可满足固定式γ探测器的现场校准要求。 相似文献
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本文报道作者在气球法测氡应用中积累的有关相对湿度对其影响的数据和为此目的所作的一些实验研究的主要结果。结果表明,气球法测氡计数随相对湿度的增加而明显增加。文中强调在相对湿度变化较大的地表大气中应用气球法时,需了解当地的相对湿度变化范围,并用实验测定不同相对湿度下的刻度系数;即使在相对湿度变化较小的矿井下,亦宜按不同深度的采掘段,分别测定相应的刻度系数;且均应定期刻度。 相似文献
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使用Sr-Spec树脂对90Sr-90Y进行分离后采用液闪谱仪对90Sr和90Y的效率刻度和猝灭校正进行了系统研究,确定了90Y效率刻度所用化学回收率,考察了闪烁液种类、载体加入、烘干处理、放置时间、化学猝灭对90Sr和90Y效率刻度的影响及其校正方法。结果表明:GoldStar LT2闪烁液适用于90Sr和90Y的测量,90Sr刻度源是否烘干和90Y刻度源有无钇载体对切伦科夫效率刻度无影响;90Y的效率刻度应在90Sr-90Y分离后10 h内完成,并且有无钇载体对90Y的液闪测量效率无影响;90Sr的刻度源应经过烘干处理,也应在90Sr-90Y分离后10 h内完成测量。当待测样品与效率刻度源的制备方法相同,且待测样品的SQP(E)值在偏离标准样品SQP(E)值8.9%范围内时,可直接使用相对测量法。 相似文献
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The Load and Resistance Factor Design (LRFD) format, which is a generic form of most current mechanical and structural design criteria, is accepted to be appropriate for load combination purposes. The meaning of the load factors in the framework of a LRFD format is discussed from a theoretical point of view. These load factors can be obtained by suitable calibration procedures. The problems that arise in the application of these procedures are analysed.A new calibration methodology is formulated and its operative aspects are dicussed. In this approach, the structure is designed to have a high reliability under permanent and quasi-permanent loads. Consistent degrees of safety for different design situations are achieved by calibrating the combination factors to be applied to the short-duration loads. Some numerical examples of this new calibration procedure are presented.The applications in reactor technology may be of some interest. The structural components of a nuclear power plant are generally subjected to several actions of different nature. By adopting the approach discussed in this paper, the reliability of every sub-structure has to be assessed only when the sub-structure is subjected to a set of few actions in combination. Moreover the safety analyses can be conducted in a deterministic context, all probabilistic calculations being limited to a preliminary investigation on the loads. 相似文献
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阻塞计是监测钠中杂质浓度水平的最重要的在线测量仪表,为提高阻塞计的测量精度,提出了一种新的校准方法--冷阱控制法。实验通过控制冷阱冷点温度来控制钠中杂质的饱和温度,进而对阻塞计进行校准。实验中采用闭环控制模型准确控制了冷阱冷点的温度,冷阱冷点温度的波动范围为±0.5 ℃。共进行了28组实验,通过实验得到了阻塞温度的经验校准曲线。阻塞温度经校准后,校准值与理论值间偏差的范围为-0.654~0.653 μg/g,平均绝对偏差为0.298 μg/g,平均相对标准偏差为4.40%,校准曲线的残差概率图散点基本上呈直线趋势,残差服从正态分布,校准曲线的可信度较高。冷阱控制法较为简单,易于推广,该方法对阻塞计校准后,可提高其测量准确度。 相似文献