Third Order Adjoint Sensitivity and Uncertainty Analysis of an OECD/NEA Reactor Physics Benchmark: II. Computed Sensitivities

This work presents the results of the exact computation of (180)3 = 5,832,000 third-order mixed sensitivities of the leakage response of a polyethylene-reflected plutonium (PERP) experimental benchmark with respect to the benchmark’s 180 microscopic total cross sections. This computation was made possible by applying the Third-Order Adjoint Sensitivity Analysis Methodology developed by Cacuci. The numerical results obtained in this work revealed that many of the 3rd-order sensitivities are significantly larger than their corresponding 1st- and 2nd-order ones, which is contrary to the widely held belief that higher-order sensitivities are all much smaller and hence less important than the first-order ones, for reactor physics systems. In particular, the largest 3rd-order relative sensitivity is the mixed sensitivity of the PERP leakage response with respect to the lowest energy-group (30) total cross sections of 1H (“isotope 6”) and 239Pu (“isotope 1”). These two isotopes are shown in this work to be the two most important parameters affecting the PERP benchmark’s leakage response. By comparison, the largest 1st-order sensitivity is that of the PERP leakage response with respect to the lowest energy-group total cross section of isotope 1H, having the value , while the largest 2nd-order sensitivity is . The 3rd-order sensitivity analysis presented in this work is the first ever such analysis in the field of reactor physics. The consequences of the results presented in this work on the uncertainty analysis of the PERP benchmark’s leakage response will be presented in a subsequent work.

Third-Order Adjoint Sensitivity Analysis of an OECD/NEA Reactor Physics Benchmark: I. Mathematical Framework

This work extends to third-order previously published work on developing the adjoint sensitivity and uncertainty analysis of the numerical model of a polyethylene-reflected plutonium (acronym: PERP) OECD/NEA reactor physics benchmark. The PERP benchmark comprises 21,976 imprecisely known (uncertain) model parameters. Previous works have used the adjoint sensitivity analysis methodology to compute exactly and efficiently all of the 21,976 first-order and (21,976)2 second-order sensitivities of the PERP benchmark’s leakage response to all of the benchmark’s uncertain parameters, showing that the largest and most consequential 1st- and 2nd-order response sensitivities are with respect to the total microscopic cross sections. These results have motivated extending the previous adjoint-based derivations to third-order, leading to the derivation, in this work, of the exact mathematical expressions of the (180)3 third-order sensitivities of the PERP leakage response with respect to these total microscopic cross sections. The formulas derived in this work are valid not only for the PERP benchmark but can also be used for computing the 3rd-order sensitivities of the leakage response of any nuclear system involving fissionable material and internal or external neutron sources. Subsequent works will use the adjoint-based mathematical expressions obtained in this work to compute exactly and efficiently the numerical values of these (180)3 third-order sensitivities (which turned out to be very large and consequential) and use them for a third-order uncertainty analysis of the PERP benchmark’s leakage response.

The 3^(rd) Work Meeting of the 2^(nd) Editorial Board Committee of China City Planning Review Convened

On Oct.25,2015,the 3rd Work Meeting of the 2nd Editorial Board Committee of China City Planning Review(abbreviated as CCPR hereafter)was convened at the School of Architecture,Tsinghua University in Beijing.The Editorial Board members participated in the meeting.At the meeting,the Editorial Department of CCPR presented a Work Report of the 2nd Editorial Board Committee(2013–2015)and a Work Report of the Editorial Department,followed by open discussions.

The 3rd Plenary Session of the 2nd Editorial Committee of Chinese Herbal Medicines Held in Nanjing, China

The 3rd plenary session of the 2nd Editorial Committee of Chinese Herbal Medicines （CHM） was held in Nanjing, China, on July 19, 2014. The participants included the associate editors-in-chief of CHM, Prof. Li-da Tang （China）, Prof. De-an Guo （China）, Prof. Guido E Pauli （USA）, Prof. Pulok Kumar Mukherjee （India）, and Prof. Rudolf Bauer （Austria）, and some members of CHM Editorial Board, such as Prof. Leslie Gunatilaka （India）, Prof. Peter Hylands （UK）, Prof. Alexander Shikov （Russia）, Prof. Shi-shan Yu （China）, Prof. Zheng-tao Wang （China）, and Prof. Hong-xi Xu （China）, and the editors of Editorial Office of CHM.

轻型汽油车国Ⅲ与国Ⅱ法规蒸发污染相关性分析

通过对大量的试验数据进行统计和分析,确定现阶段我国轻型汽油车适用国Ⅲ法规的蒸发排放现状。同时通过比较国Ⅱ和国Ⅲ试验数据,计算出2个排放水平之间的差异和数值关系。最后展望更加严格的排放法规以及应对措施。

孕中后期中低等强度有氧运动对高龄孕妇产前生活质量和母婴结局的影响探讨

目的探讨孕中后期中低等强度有氧运动对高龄孕妇产前生活质量和母婴结局的影响。方法选2017年8月—2018年12月我院接收的560名高龄孕妇作为研究对象,随机分成数量相等的两组。对照组采取常规孕期保健服务和健康教育,观察组则在此基础上增加孕中后期中低等有氧运动的干预,问卷法调查两组孕妇的抑郁情况、睡眠质量、产前生活质量,并比较两组孕妇的母婴结局。结果χ2检验结果显示,研究组对象平均每周运动次数≥3次及平均每次运动时间≥30 min的比例高于对照组(P=0.001)。研究组对象的EPDS抑郁分值和SRSS睡眠质量分值均低于对照(P=0.006)。研究组对象产前GQOLI-74生活质量问卷中生活质量总得分高于对照组(P=0.0001)。研究组对象的妊娠糖尿病、妊娠高血压、难产率、巨大儿发生率均低于对照组(P=0.039),但自然分娩率高于对照组(P=0.004)。结论以瑜伽、慢走或散步为主的中低强度的有氧运动可能有助于提供高龄孕妇的产前生活质量,预防妊娠疾病和不良母婴结局,在临床上具有一定的推广意义。

Review of the treatment of metastatic non small cell lung carcinoma:A practical approach

In recent years,as we have a better knowledge and understanding of the biology of non small cell lung carcinoma(NSCLC),which leads us to targeting biomarkers driving the NSCLC carcinogenesis and metastatic potential,we now have an increased number of options to offer our patients with NSCLC.We also realize the importance of distinguishing squamous and non squamous histology to guide our treatment decisions of NSCLC.The palliative care concomitant with therapies from the very start of the treatment also showed an impact on survival.This review examines the treatment options in all lines of therapy for metastatic NSCLC that have been approved in Canada,the United States,or Europe.

我国核电涂料现状和第三代核电涂料技术

我国当前已建核电站基本都是采用二代或二代加核电技术,所用涂料也随之是属于二代核电涂料。AP1000型第三代核电技术已经逐渐成为我国在建和拟建核电站的主流核电技术,其对涂料的要求也较"二代加"核电涂料有了明显的提升。对二代核电涂料涂层配套以及第三代AP1000核电涂料的技术要求和相关试验方法、主要试验的试验标准、主要涂料的施工要求分别进行了介绍。

Fourth-Order Adjoint Sensitivity Analysis of an OECD/NEA Reactor Physics Benchmark: I. Mathematical Expressions and CPU-Time Comparisons for Computing 1^st-, 2^nd- and 3^rd-Order Sensitivities

This work extends to fourth-order previously published work on developing the adjoint sensitivity and uncertainty analysis of the numerical model of a polyethylene-reflected plutonium (acronym: PERP) OECD/NEA reactor physics benchmark. The PERP benchmark comprises 7477 imprecisely known (uncertain) model parameters which have nonzero values. These parameters are as follows: 180 microscopic total cross sections;7101 microscopic scattering sections;60 microscopic fission cross sections;60 parameters that characterize the average number of neutrons per fission;60 parameters that characterize the fission spectrum;10 parameters that characterize the fission source;and 6 parameters that characterize the isotope number densities. Previous works have used the adjoint sensitivity analysis methodology to compute exactly and efficiently all of the 7477 first-order and 27,956,503 second-order sensitivities of the PERP benchmark’s leakage response to all of the benchmark’s uncertain parameters. These works showed that largest response sensitivities involve the total microscopic cross sections, which motivated the recent computation of all of the (180)3 third-order sensitivities of the PERP leakage response with respect to these total microscopic cross sections. It turned out that some of these 3rd-order cross sections were far larger than the corresponding 2nd-order ones, thereby having the largest impact on the uncertainties induced in the PERP benchmark’s response. This finding has motivated the development of the original 4th-order formulas presented in this work, which are valid not only for the PERP benchmark but can also be used for computing the 4th-order sensitivities of response of any nuclear system involving fissionable material and internal or external neutron sources. Subsequent works will use the adjoint-based mathematical expressions obtained in this work to compute exactly and efficiently the numerical values of the largest fourth-order sensitivities of the PERP benchmark’s response to the total microscopic cross section and use them for a pioneering fourth-order uncertainty analysis of the PERP benchmark’s response.