1.1 本指南涵盖了轻水反应堆（LWR）监测项目的物理剂量测定的分析和解释。主要目的是应用调整方法来确定中子损伤暴露参数及其不确定性的最佳估计。 1.2 本指南也适用于研究反应堆的辐照损伤研究。 1.3 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的用户有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性。 1.4 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认标准化原则制定的。 ====意义和用途====== 3.1 调整方法提供了一种将中子输运计算结果与中子剂量测量结果相结合的方法（见试验方法 E1005年 和NUREG/CR-5049），以获得具有指定不确定性的中子损伤暴露参数的最佳估计。测量值的包含减少了这些参数值的不确定性，并为测量值和计算之间以及不同测量值之间的一致性提供了测试（参见 3.3.3 ). 然而，这并不意味着可以降低输入数据的测量和计算标准；任何调整程序的结果只能与输入数据一样可靠。 3.2 输入数据和定义: 3.2.1 本节中介绍的符号将在整个指南中使用。 3.2.2 剂量测量以一组反应速率（或等效物）表示，由以下符号表示: 目前，这些数据主要来自辐射剂量计，但也可能包括其他类型的传感器（见 4.1 ). 3.2.3 中子谱（见术语 E170 )在剂量计位置，通量或通量率Φ( E )作为中子能量的函数 E ，通过适当的中子学计算获得（使用离散纵坐标或蒙特卡洛方法的中子输运，见指南 E482 ). 计算结果通常以多群注量或注量率的形式给出。 哪里: E j 和 E j +1 是 j -分别为th能源集团和 k 是组的总数。 3.2.4 剂量测定传感器的反应截面来自评估的截面文件。的横截面 一、 -th反应作为能量的函数 E 将由以下内容表示: 与群通量相关联使用， 公式2 ，是计算出的组平均横截面σ ij公司 . 这些值通过以下等式定义: 3.2.5 必须为所有输入数据提供方差和协方差形式的不确定性信息。如果不确定性是由于产生偏差的效应（例如，光反应的效应）引起的，则必须进行适当的校正。 3.3 程序摘要: 3.3.1 调整算法修改中定义的输入数据集 3.2 按照以下方式（例如，调整后的数量由波浪号表示， ã 一、 ): 或用于组注量率 或用于组平均横截面 调整后的数量必须满足以下条件: 或以群体注量率的形式 由于 等式11 比调整次数小得多，除非进一步限制，否则问题不存在唯一的解决方案。 当前调整代码中的数学算法旨在使调整相对于相应输入数据的不确定性尽可能小。代码，如STAY'SL、FERRET、LEPRICON和LSL-M2（参见 表1 )明确基于统计原理，如“最大似然原理”或“贝叶斯定理”，这是众所周知的最小二乘原理的推广，并考虑了输入通量、剂量测定和横截面数据的方差和相关性（见 4.1.1 , 4.2.2 和 4.3.3 ). 关于数学推导的详细讨论见NUREG/CR-2222和EPRI NP-2188。即使是较旧的代码，尤其是SAND-II和CRYSTAL BALL，也应用了最小化算法，尽管支持文档中没有明确说明统计假设。 表1 列出了一些可用的展开代码；然而，列出的前四个代码:SAND-II、光谱、IUNFLD/UNFOLD和窗口具有严重的局限性，因为它们通常不能提供结果未展开光谱和调整的损伤暴露参数的不确定性表征。 （A） 括号中的黑体数字指的是本指南所附的参考文献列表。 3.3.1.1 反应堆监测中的一个重要问题是在无法进行剂量测定的位置确定压力容器壁内的中子注量。这些位置的暴露参数值的估计值可以从调整代码中获得，该代码在给定不同位置的通量之间的互相关时，同时调整多个位置的通量。 LEPRICON规定了通量的互相关估计和同时调整。LSL-M2也允许同时调整，但必须给出互相关。 3.3.2 调整后的数据 ã 一、 等等，对于任何特定算法，都是输入变量的唯一函数。因此，调整参数的不确定性（方差和协方差）原则上可以通过传播输入数据的不确定性来计算。如果调整后的数据是输入数据的非线性函数，则可以在计算输出数据的不确定性之前使用线性化。 3.3.2.1 与相应的输入值相比，调整码的算法倾向于减少调整数据的方差。线性最小二乘调整码以最小方差产生输出数据的估计，即“最佳”无偏估计。这是使用这些调整程序的主要原因。 3.3.3 适当设计的调整方法提供了检测输入数据中不一致性的方法，这些不一致性通过大于相应不确定性的调整或通过较大的chi值来体现- 正方形，或两者兼有。（见NUREG/CR-3318和NUREG/CR-3319。）任何不一致的检测都应记录在案，不应使用从不一致输入中获得的输出数据。当发现不一致时，应仔细审查所有输入数据，并努力解决以下不一致问题。 3.3.3.1 如果需要进行较大的调整，则应仔细调查输入数据是否存在重大误差或偏差。注意，错误数据可能不是需要最大调整的数据； 因此，有必要审查所有输入数据。如果无法确定正确的更正，则可以消除有效性可疑的数据。任何数据消除都必须记录在案，并说明独立于调整程序的原因。如果不一致的数据对调查的结果贡献不大，也可以省略。 3.3.3.2 输入方差太小也可能导致不一致。因此，应审查输入数据的不确定性分配，以确定实验和计算数据的假设精度和偏差是否不现实。 如果是这样，差异可能会增加，但应记录这样做的原因。请注意，在基于统计的调整方法中，列在 表1 输出不确定性仅由输入不确定性确定，不受输入数据不一致的影响（见NUREG/CR-2222）。还要注意，过大的调整可能会产生不可靠的数据，因为即使这些调整与输入不确定性一致，也会超过线性化的限制。 3.3.4 使用调整后的注量谱，可以计算损伤暴露参数值的估计值。 这些参数是中子注量的加权积分 或用于团体通量 具有给定权重（响应）函数 w ( E )或 w j 分别地在实践中列出了铁的dpa响应函数 E693 . 大于1.0 MeV或大于0.1 MeV的通量表示为 w ( E ) = 1用于 E 超过限制和 w ( E ) = 0用于 E 在下面 3.3.4.1 寻找损伤暴露参数及其不确定性的最佳估计值是使用反应堆监测调整程序的主要目标。 如果根据 等式12 或 等式13 ，参数的无偏最小方差估计 p 结果，前提是调整后的通量Φ是无偏最小方差估计。的方差 p 可以直接从调整后的注量谱的方差和协方差计算。响应函数的不确定性， w j 如果有，则在计算输出方差时不应考虑标准响应函数，例如实际中铁的dpa E693 ，使用。损伤暴露参数及其方差的计算最好是调整代码的一部分。

1.1 This guide covers the analysis and interpretation of the physics dosimetry for Light Water Reactor (LWR) surveillance programs. The main purpose is the application of adjustment methods to determine best estimates of neutron damage exposure parameters and their uncertainties. 1.2 This guide is also applicable to irradiation damage studies in research reactors. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. ====== Significance And Use ====== 3.1 Adjustment methods provide a means for combining the results of neutron transport calculations with neutron dosimetry measurements (see Test Method E1005 and NUREG/CR-5049) in order to obtain optimal estimates for neutron damage exposure parameters with assigned uncertainties. The inclusion of measurements reduces the uncertainties for these parameter values and provides a test for the consistency between measurements and calculations and between different measurements (see 3.3.3 ). This does not, however, imply that the standards for measurements and calculations of the input data can be lowered; the results of any adjustment procedure can be only as reliable as are the input data. 3.2 Input Data and Definitions: 3.2.1 The symbols introduced in this section will be used throughout the guide. 3.2.2 Dosimetry measurements are given as a set of reaction rates (or equivalent) denoted by the following symbols: These data are, at present, obtained primarily from radiometric dosimeters, but other types of sensors may be included (see 4.1 ). 3.2.3 The neutron spectrum (see Terminology E170 ) at the dosimeter location, fluence or fluence rate Φ( E ) as a function of neutron energy E , is obtained by appropriate neutronics calculations (neutron transport using the methods of discrete ordinates or Monte Carlo, see Guide E482 ). The results of the calculation are customarily given in the form of multigroup fluences or fluence rates. where: E j and E j +1 are the lower and upper bounds for the j -th energy group, respectively, and k is the total number of groups. 3.2.4 The reaction cross sections of the dosimetry sensors are obtained from an evaluated cross section file. The cross section for the i -th reaction as a function of energy E will be denoted by the following: Used in connection with the group fluences, Eq 2 , are the calculated group-averaged cross sections σ ij . These values are defined through the following equation: 3.2.5 Uncertainty information in the form of variances and covariances must be provided for all input data. Appropriate corrections must be made if the uncertainties are due to bias producing effects (for example, effects of photo reactions). 3.3 Summary of the Procedures: 3.3.1 An adjustment algorithm modifies the set of input data as defined in 3.2 in the following manner (adjusted quantities are indicated by a tilde, for example, ã i ): or for group fluence rates or for group-averaged cross sections The adjusted quantities must satisfy the following conditions: or in the form of group fluence rates Since the number of equations in Eq 11 is much smaller than the number of adjustments, there exists no unique solution to the problem unless it is further restricted. The mathematical algorithms in current adjustment codes are intended to make the adjustments as small as possible relative to the uncertainties of the corresponding input data. Codes like STAY'SL, FERRET, LEPRICON, and LSL-M2 (see Table 1 ) are based explicitly on the statistical principles such as “Maximum Likelihood Principle” or “Bayes Theorem,” which are generalizations of the well-known least squares principle, and are taking into account variances and correlations of the input fluence, dosimetry, and cross section data (see 4.1.1 , 4.2.2 , and 4.3.3 ). A detailed discussion of the mathematical derivations can be found in NUREG/CR-2222 and EPRI NP-2188. Even the older codes, notably SAND-II and CRYSTAL BALL, apply a minimization algorithm although the statistical assumptions are not spelled out explicitly in the supporting documentation. Table 1 lists some of the available unfolding codes; however, the first four codes listed: SAND-II, SPECTRA, IUNFLD/UNFOLD, and WINDOWS have severe limitations in that they do not typically provide uncertainty characterization of the resulting unfolded spectrum and the adjusted damage exposure parameters. (A) The boldface numbers in parentheses refer to the list of references appended to this guide. 3.3.1.1 An important problem in reactor surveillance is the determination of neutron fluence inside the pressure vessel wall at locations which are not accessible to dosimetry. Estimates for exposure parameter values at these locations can be obtained from adjustment codes which adjust fluences simultaneously at more than one location when the cross correlations between fluences at different locations are given. LEPRICON has provisions for the estimation of cross correlations for fluences and simultaneous adjustment. LSL-M2 also allows simultaneous adjustment, but cross correlations must be given. 3.3.2 The adjusted data ã i , etc., are, for any specific algorithm, unique functions of the input variables. Thus, uncertainties (variances and covariances) for the adjusted parameters can, in principle, be calculated by propagation the uncertainties for the input data. Linearization may be used before calculating the uncertainties of the output data if the adjusted data are nonlinear functions of the input data. 3.3.2.1 The algorithms of the adjustment codes tend to decrease the variances of the adjusted data compared to the corresponding input values. The linear least squares adjustment codes yield estimates for the output data with minimum variances, that is, the “best” unbiased estimates. This is the primary reason for using these adjustment procedures. 3.3.3 Properly designed adjustment methods provide means to detect inconsistencies in the input data which manifest themselves through adjustments that are larger than the corresponding uncertainties or through large values of chi-square, or both. (See NUREG/CR-3318 and NUREG/CR-3319.) Any detection of inconsistencies should be documented, and output data obtained from inconsistent input should not be used. All input data should be carefully reviewed whenever inconsistencies are found, and efforts should be made to resolve the inconsistencies as stated below. 3.3.3.1 Input data should be carefully investigated for evidence of gross errors or biases if large adjustments are required. Note that the erroneous data may not be the ones that required the largest adjustment; thus, it is necessary to review all input data. Data of dubious validity may be eliminated if proper corrections cannot be determined. Any elimination of data must be documented and reasons stated which are independent of the adjustment procedure. Inconsistent data may also be omitted if they contribute little to the output under investigation. 3.3.3.2 Inconsistencies may also be caused by input variances which are too small. The assignment of uncertainties to the input data should, therefore, be reviewed to determine whether the assumed precision and bias for the experimental and calculational data may be unrealistic. If so, variances may be increased, but reasons for doing so should be documented. Note that in statistically based adjustment methods, listed in Table 1 the output uncertainties are determined only by the input uncertainties and are not affected by inconsistencies in the input data (see NUREG/CR-2222). Note also that too large adjustments may yield unreliable data because the limits of the linearization are exceeded even if these adjustments are consistent with the input uncertainties. 3.3.4 Using the adjusted fluence spectrum, estimates of damage exposure parameter values can be calculated. These parameters are weighted integrals over the neutron fluence or for group fluences with given weight (response) functions w ( E ) or w j , respectively. The response function for dpa of iron is listed in Practice E693 . Fluence greater than 1.0 MeV or fluence greater than 0.1 MeV is represented as w ( E ) = 1 for E above the limit and w ( E ) = 0 for E below. 3.3.4.1 Finding best estimates of damage exposure parameters and their uncertainties is the primary objective in the use of adjustment procedures for reactor surveillance. If calculated according to Eq 12 or Eq 13 , unbiased minimum variance estimates for the parameter p result, provided the adjusted fluence Φ ˜ is an unbiased minimum variance estimate. The variance of p can be calculated in a straightforward manner from the variances and covariances of the adjusted fluence spectrum. Uncertainties of the response functions, w j , if any, should not be considered in the calculation of the output variances when a standard response function, such as the dpa for iron in Practice E693 , is used. The calculation of damage exposure parameters and their variances should ideally be part of the adjustment code.