Grizzly and BlackBear: Structural Component Aging Simulation Codes

Abstract

The operating environment of nuclear reactors imposes extreme challenges on the materials from which the structures within and surrounding the reactor are constructed. Understanding the effects of exposure to this environment is critical for ensuring the safe long-term operation of these reactors. The Grizzly and BlackBear codes are being developed to model the progression of aging mechanisms and their effects on the integrity of critical structures. These codes take advantage of the capabilities of the MOOSE framework to solve the wide range of coupled physics problems that are encountered in predictive simulation of structural degradation. This paper provides an overview of these codes, with a specific focus on two capabilities relevant for light water reactor applications: reactor pressure vessel embrittlement and concrete degradation.

Development, verification, and validation of comprehensive acoustic fluid‐structure interaction capabilities in an open‐source computational platform

“…Different modules can be combined and further enhanced to create applications for specific problems. Developers have built MOOSE‐based “apps” that are used in a wide array of applications such as nuclear fuels performance assessment, [ 40 ] structural material degradation modeling, [ 41 ] and geothermal systems modeling. [ 42 ] Multihazard Analysis of Stochastic Time‐Domain Phenomena (MASTODON) [ 31 ] is one such application for seismic analysis and risk assessment of critical infrastructure.…”

Grizzly Development for Light Water Reactor and Advanced Reactor Applications in Fiscal Year 2021

“…In this quasistatic analysis, the full thermal gradient was applied at a pseudotime of 1.0. Figure 2.25 shows the time history of the average displacement at the top of each of the modeled ducts effort [39 ]. This was originally supported by the Light Water Reactor Sustainability (LWRS) program to address long-term operation scenarios for LWRs, with continued support by the NEAMS program.…”

“…A recent publication [39 ] highlighted Grizzly's ability to perform 3D PFM calculations, but applied a postulated cooling history to the inlet region. More realistic thermal boundary conditions for the RPV are needed to accurately assess the effects of spatially nonuniform cooling, which can be provided through the use of a 3D computational fluid dynamics (CFD) model.…”

High-Temperature Creep Test Suite for Grizzly

“…Grizzly is a code for simulating aging processes and their effects on nuclear power plant components and structures [1 ]. Early efforts focused on light water reactors (LWRs), with an emphasis on reactor pressure vessels and concrete structures, both of which are potentially life-limiting nuclear power plant components because of the extreme difficulty of repair or replacement.…”