Evaluating nuclear data

Aim of the thesis: Development of a new method for determining concentration of the radionuclides in enviromental samples by mean of gamma spectroscopy. Establishing a data set of the soil-plant transfer factor (TF) of radionuclides 238U, 232Th and 40K for some vegetables in Truong Sa island and that of 238U, 232Th, 40K and 137Cs for tea tree from Luong My farm, Hoa Binh province, Vietnam and evaluate the influence of natural radionuclide concentration to the soil-plant transfer process of artificial radionuclide 137Cs.

30p extraenglish 24-05-2021 24 3   Download

Trong nghiên cứu này, các tác giả đánh giá lại giá trị tham số mật độ mức a, tham số mật độ mức tiệm cận aasy và tham số năng lượng dịch ngược trong mẫu khí Fermi dịch chuyển ngược của hạt nhân 153Sm. Quá trình đánh giá dựa trên các số liệu thực nghiệm về sơ đồ mức hạt nhân trong Thư viện số liệu cấu trúc hạt nhân được đánh giá (ENSDF - Evaluated Nuclear Structure Data File), khoảng cách mức trung bình tại năng lượng liên kết của neutron (D0 ), và số liệu cập nhật về sơ đồ mức hạt nhân trong nghiên cứu thực nghiệm phân rã gamma nối tầng được thực hiện trên Lò phản ứng hạt nhân Đà Lạt.

5p kethamoi10 29-01-2021 29 3   Download

Bài viết này trình bày các kết quả tính toán tiết diện tán xạ nơtron nhiệt không đàn hồi đối với tinh thể bismuth và sapphire. Trong tính toán này các ảnh hưởng của tán xạ nơtron lên dao động phonon trong các tinh thể và các tham số tinh thể nhận được thông qua sử dụng chương trình NJOY.

6p quenchua10 18-01-2021 41 2   Download

Quantitative conclusions by the International Atomic Energy Agency (IAEA) regarding States' nuclear material inventories and flows are provided in the form of material balance evaluations (MBEs). MBEs use facility estimates of the material unaccounted for together with verification data to monitor for possible nuclear material diversion.

10p christabelhuynh 30-05-2020 10 2   Download

The intent of this paper is to describe the procedures used in the evaluation of the RP and RPC, the use of the RPC in benchmark calculations and to assess the impact of the 16O nuclear data uncertainties in the calculate dkeff for critical benchmark experiments.

13p christabelhuynh 30-05-2020 15 2   Download

The goal of this study is to look after the amount of information that is mandatory to get a relevant parameters optimisation by data assimilation for physical models in neutronic diffusion calculations, and to determine what is the best information to reach the optimum of accuracy at the cheapest cost.

8p christabelhuynh 31-05-2020 17 2   Download

Evaluating the neutronic state (neutron flux, power . . . ) of the whole nuclear core is a very important topic that has strong implication for nuclear core management and for security monitoring. The core state is evaluated using measurements and calculations.

9p christabelhuynh 31-05-2020 17 1   Download

This paper presents a Bayesian approach based on integral experiments to create correlations which do not appear with differential data. Some quantities such as the fission cross section (s), neutron multiplicity (n¯p), neutron spectra (x), etc. are usually neither modeled together nor measured in coincidence, thus there is no correlation matrices in evaluated nuclear data libraries.

8p christabelhuynh 30-05-2020 15 0   Download

In this paper, a traditional adjoint method is used to propagate ND uncertainty on reactivity and reactivity coefficients and estimate correlations between different states of the core. We show that neglecting those correlations induces a loss of information in the final uncertainty.

9p christabelhuynh 30-05-2020 12 2   Download

This article shows how the most recent gadolinium cross sections evaluations appear inadequate to provide accurate criticality calculations for a system with gadolinium fuel pins. In this article, a sensitivity and uncertainty analysis (S/U) has been performed to investigate the effect of gadolinium odd isotopes nuclear cross sections data on the multiplication factor of some LWR fuel assemblies.

11p christabelhuynh 30-05-2020 16 2   Download

The paper describes the holistic and inclusive approach of these projects that have also worked together to coordinate the European nuclear data research capabilities to improve the facilities, detectors, models and evaluation, validation and simulation tools.

8p christabelhuynh 29-05-2020 10 1   Download

Most work has been done since then with spectacular achievements and enhanced understanding both of the uncertainty evaluation process and of the data utilization in V&V. This paper summarizes some key developments and still open challenges.

5p christabelhuynh 29-05-2020 8 2   Download

This paper discusses some uncertainty quantification methodologies in use today, their strengths, their pitfalls, and alternative approaches that have proved to be highly successful in other fields.

6p christabelhuynh 29-05-2020 10 1   Download

Key reactions have been selected to compare JEFF-3.3 (CIELO 2) and IAEA CIELO (CIELO 1) evaluated nuclear data files for neutron induced reactions on 235U and 238U targets. IAEA CIELO evaluation uses reaction models to construct the evaluation prior, but strongly relied on differential data including all reaction cross sections fitted within the IAEA Neutron Standards project.

5p christabelhuynh 29-05-2020 11 0   Download

This paper gives an overview of the evaluation processes used for nuclear data at CEA. After giving Bayesian inference and associated methods used in the CONRAD code [P. Archier et al., Nucl. Data Sheets 118, 488 (2014)], a focus on systematic uncertainties will be given.

8p christabelhuynh 29-05-2020 6 1   Download

In this paper, we will make explicit the error in the mean value and the standard deviation when using different types of distribution laws. We also employ the principle of maximum entropy as a criterion to choose among the truncated Gaussian, the fitted Gaussian and the lognormal distribution.

8p christabelhuynh 29-05-2020 12 1   Download

Most recent evaluated nuclear data files exhibit excellent integral performance, as shown by the very good agreement between experimental and calculated keff values over a wide range of benchmark integral experiments.

6p christabelhuynh 29-05-2020 14 1   Download