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某研究性反应堆一回路压力边界气体泄漏率试验受容积小和设备冷却水等因素干扰,试验数据存在极端样本点,在不改变试验方法的基础上,通过使用回归模型的显著性检验和方差分析等方法确保试验结果的有效性。试验方法借鉴压水堆安全壳泄漏率试验方法,本文选用ANSI/ANS-56.8、RCC-G-1988、ПНАЭГ-10-021-90这3种常用的安全壳泄漏率计算方法进行计算分析,结果表明3种方法计算结果基本相同。通过对线性回归模型中残差的独立性、正态性以及等方差性进行分析,探讨回归诊断对计算结果的影响;同时对于回归诊断发现方差不齐、自相关和极端样本点等问题,结合残差加权最小二乘法和去除极端样本点对最终结果进行修正,提高了结果的可靠性。本文分析方法已应用到核安全审评中。 相似文献
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对国际上常用的3种安全壳整体试验泄漏率计算方法进行了系统介绍。分别应用上述3种方法对田湾核电厂安全壳整体试验数据进行计算分析,同时对各计算方法的差异以及对结果的影响进行了探讨。结果表明,试验工况下应用3种计算方法所得到的泄漏率计算结果基本相同。 相似文献
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安全壳试验期间安全壳内气体在泄漏率测量平台经历了温度、蒸汽分压等参数波动并再次进入平稳的弛豫过程,本文针对判断新稳态建立的标准、气体弛豫时间、影响弛豫过程的因素等内容进行分析,以期通过计算检验统计量进行平稳性检验的方法给出判断平稳的标准,并对弛豫过程中各项参数的时间序列进行序列分解,对各参数的弛豫过程分别进行分析。研究结果表明,安全壳内气体因安全壳加压造成的蒸汽分压不均匀是影响弛豫时间的主要因素。因此,进一步提出控制蒸汽分压不平衡势,以缩短泄漏率结果的弛豫时间。 相似文献
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双层安全壳核电机组的环廊密封性是核安全的重要保证,需在机组装料前完成测试。气体泄漏幂函数模型在计算民用建筑泄漏时比二次函数模型有更大的压力适用范围和更高的精度。本文以气体泄漏幂函数模型为基础,推导了环廊泄漏率的计算模型,以及带环廊负压修正的幂函数拟合方案,并采用某双层安全壳环廊密封性试验实测数据对该计算模型进行验证。结果表明,本文计算模型比带环廊负压修正的二次函数拟合方案和国外某公司使用的线性拟合方案有更高的精度,与双层安全壳实际泄漏情况更加吻合。 相似文献
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为进一步探究核电厂安全壳内环境条件影响泄漏率测量的基本规律,自主研发了压降法安全壳泄漏率数据分析程序,并通过在大尺度安全壳模拟体上开展的泄漏率实验对测量结果进行验证。结合相应的实验数据研究了准稳态与非稳态环境条件下安全壳内温度和相对湿度变化对泄漏率测量值的影响。结果表明,在升温条件下,各温度传感器因所处热环境的差异而形成的不同升温速率会明显影响泄漏率的测量,测量值相比升温前的相对偏差可超过20%。此外,在壳内局部温湿度变化的非稳态环境下,压力与温度传感器的固有延迟效应还会导致泄漏率的测量出现异常。而当壳内温湿度维持恒定或各传感器的温湿度变化速率近似一致时,泄漏率测量值较稳定,可确定其为实际的泄漏率。该研究结论可为进一步认识安全壳泄漏率测量机理和方法优化提供参考。 相似文献
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《核标准计量与质量》2017,(2)
安全壳强度试验是对安全壳结构的强度和完整性的重要验证。某两个核电厂作为国内首次进行的钢制安全壳结构强度试验,为后续设计和试验积累了丰富的经验和数据。文章根据两个项目的试验数据以及过程中遇到的问题,对安全壳变形和应变结果、安全壳最终变形复核的必要性和安全壳冬季试验等试验中遇到的问题等进行了分析。分析表明试验结果与理论分析整体上有较好的一致性,在局部施工变形较大区域应根据最终成形进行复核计算,并给出了试验中需要关注的其他问题。通过分析给出了建议,为后续的设计和试验提供指导。 相似文献
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The most important part in the calculation of the containment leakage is to perform the linear regression on time for a series of data measured at different times. The significance test of the regression and residual analysis are the substantial means to evaluate the test results. This paper analyzes the data of the containment test during the commissioning and startup phase of a power plant based on the statistical software R, and explores the regression diagnosis before the leakage calculation by examining the independence, normality and heteroscedasticity of the regression model and the elimination of extreme sample points impact on the reliability of the result. Through the regression diagnosis on the examples, it was found that in the samples which leakage rate is calculated, there may be problems that affect the regression results and then the affect the final results, such as autocorrelation, non-normality and heteroscedasticity. Therefore, the validity of the data shall be evaluated by the regression diagnostic methods, while calculating the leakage rate, and the final results shall be corrected by appropriate methods for samples that fail the test. 相似文献
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为建立安全壳喷淋覆盖率可靠、快速的计算方法,以对安全壳喷淋系统的设计研究提供新的辅助手段,本研究采用理论分析的方法,建立了基于蒙特卡罗模拟法的安全壳喷淋覆盖率计算模型。通过与基于计算机辅助设计(CAD)的安全壳喷淋覆盖率计算结果进行对比,验证基于蒙特卡罗喷淋覆盖率计算方法的适用性。结果表明,两种方法的计算误差在1%以内。因此,本研究建立的基于蒙特卡罗模拟法的安全壳喷淋覆盖率计算方法可靠且具有广泛适用性,对比CAD软件的喷淋覆盖率计算法,新的方法计算速度更快,人因错误率更低,有利于敏感性分析,可大幅提高安全壳喷淋系统设计能力。 相似文献
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In the context of a severe accident in a PWR nuclear plant, the evaluation of the leakage through the containment wall remains a key point of the safety analysis. Here we calculate the leakage of an air steam mixture through a traversing crack taking into account condensation. A 40 h test has been performed on a representative concrete slab with measurements of crack openings and flow rates. The CAST3M code enables us to simulate this test by making thermo-mechanical calculations and calculation of the leakage flow rate. Thermo-mechanical calculations provide data needed by the leakage calculations which are not measurable in the experiment. These are the internal crack profiles (variation of the opening with the curvilinear coordinate of the crack inside the concrete slab). Thermo-mechanical calculations are difficult to perform because boundary conditions of the test are complicated. Leakage calculations are performed with various hypotheses for the internal cracks profiles. A coefficient is applied on the friction factor to take into account additional complexity of the crack geometry. 相似文献
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G.D. Zakaib 《Nuclear Engineering and Design》1985,90(2):143-151
Based on a general review of current on-power test methods and experience in CANDU multi-unit containments, it is concluded that such tests make a significant contribution to plant safety. In particular continuous monitoring at low pressure differentials merits further development and more widespread application.Current on-power tests include individual component testing, quarterly reduced pressure tests (typically at −15 kPa (g)), and continuous pressure trend monitoring at normal operational pressure of −3 kPa(g). A continuous monitoring concept is outlined which consists of a periodically updated mass balance. Instrument error uncertainty for this technique was estimated to be on the order of a 1 cm hole. However systematic fluctuations (often attributable to physical causes) dominate the error analysis in on-power tests. With precautions on sampling interval, a moving regression may be used to generate a leakage rate time series such that the fluctuations can be bounded or eliminated.Experience to-date has indicated that most containment boundary impairments are detectable by component tests or continuous monitoring. On-power tests methods are capable of addressing a significant portion of the containment failure mode spectrum. Station risk assessment and regulatory testing requirements are identified as means by which these methods can be credited in demonstrating containment integrity. 相似文献
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事故时向环境释放的源项是确定核电厂(NPP)应急响应水平和防护行动决策的重要依据。基于电厂工况估算源项是核电厂严重事故应急响应期间重要的应急评价内容之一。在国际原子能机构(IAEA)和美国核管会(NRC)的有关技术文档基础上,本文介绍了基于压水反应堆(PWR)工况进行事故释放源项估算的步骤和基础数据,并归纳了7种实用的事故释放源项估算方法。基于这些方法,开发了PWR事故时环境释放源项快速估算程序。该程序为不同估算方法提供4种释放途径:安全壳泄漏、安全壳旁通、蒸汽发生器传热管破裂(SGTR)和直接环境释放,除直接环境释放途径外,其他释放途径都估算了核素释放过程中的衰变、滞留、喷淋和过滤等减弱过程。对比发现,软件计算结果与美国核管会的RASCAL软件释放源项计算结果接近。 相似文献