Title: Sensitivity analysis for characterizing the impact of HNGD model on the prediction of hydrogen redistribution in Zircaloy cladding using BISON code

Abstract

Hydrogen in zirconium cladding is able to precipitate into zirconium hydrides which impacts cladding integrity. The Hydride Nucleation-Growth-Dissolution (HNGD) model in the BISON code accounts for the precipitation and dissolution kinetics of hydride in Zircaloy material. This paper presents global sensitivity analyses of the HNGD model aiming to enhance our understanding of the hydride precipitation phenomena by quantifying the variance that key parameters have on the prediction of hydrogen behavior under various environmental conditions. Here, model predictions are compared to experimental data obtained under two different conditions: 1) with uniformly precharged specimens subjected to a linear thermal gradient, and 2) specimens precharged with a cathodically applied hydride rim at one end of the sample and subjected to an asymmetric thermal gradient. The Sobol sensitivity analysis identifies the key parameters in the HNGD model for both types of specimens. For linear temperature cases, the heat of transport dominates the accuracy of predictions when no precipitation occurs at the cold end, while Terminal Solid Solubility for Dissolution (TSSD) is the most important parameter when precipitation occurs. A large variation in the predicted hydrogen concentration profiles is found in the range of high TSSD due to the occurrence of precipitation. For asymmetric temperaturemore » cases, the solubility coefficient gives the largest impact on the predicted hydrogen distribution, as it determines the amount of solute hydrogen dissolved from the initially applied hydride rim. A large discrepancy in hydrogen distribution between simulations and experiments exists with the asymmetric specimens because BISON simulations fail to predict the precipitation of hydride at the cooler end. Comparative studies using former and updated models verifies the significant impact of the hydride growth mechanism on predicted hydrogen concentration profiles. In particular, when hydride initially exists, changes in TSSD generate a large variation in the predicted amount of precipitation by hydride growth, giving large uncertainty in predicting the hydrogen distribution over the sample length. The outputs characterize the significant impact of the hydride growth mechanism in the HNGD model on predicting hydrogen behavior, and improve the understanding of the precipitation of hydride in Zircaloy cladding within a range of expected environmental conditions. The analyses indicate work is still needed to improve the hydride solvus models in the BISON code to accurately predict experimentally observed hydride concentrations and distributions.« less

Authors:

Seo, Seok Bin ^[1]; Duchnowski, Edward M. ^[1]; Motta, Arthur T. ^[2]; Kammenzind, Bruce F. ^[3]; Brown, Nicholas R. ^[1]

---

+ Show Author Affiliations

1. Univ. of Tennessee, Knoxville, TN (United States)
2. Pennsylvania State Univ., University Park, PA (United States)
3. Bettis Atomic Power Laboratory (BAPL), Pittsburgh, PA (United States)

Publication Date:

Mon May 23 00:00:00 EDT 2022

Research Org.:

Idaho National Laboratory (INL), Idaho Falls, ID (United States)

Sponsoring Org.:

USDOE Office of Nuclear Energy (NE); USDOE Office of Science (SC), Basic Energy Sciences (BES). Scientific User Facilities (SUF)

OSTI Identifier:

1981727

Alternate Identifier(s):

OSTI ID: 1870322

Grant/Contract Number:  

AC07-05ID14517; IRP-17-13708

Resource Type:

Accepted Manuscript

Journal Name:

Nuclear Engineering and Design

Additional Journal Information:

Journal Volume: 393; Journal ID: ISSN 0029-5493

Publisher:

Elsevier

Country of Publication:

United States

Language:

English

Subject:

36 MATERIALS SCIENCE; hydrides; fuel performance; zirconium; sensitivity analysis; HNGD model; BISON