AGR-2 Daily As-run Thermal Analyses

Abstract

The purpose of this report is to document the results of the thermal analyses performed to calculate the Advanced Gas-Cooled Reactor (AGR)-2 as-run daily temperatures of the fuel compacts. Time average volume average data provided by this report will be used to determine fuel performance in post-irradiation examination. 8. If revision, please state the reason and list sections and/or pages being affected: NA 9. Conclusions/Recommendations: This report documents the results of thermal analyses to predict the daily as-run temperatures for the AGR-2 experiment. Control gas gaps and compact-graphite holder gas gaps were modeled to change linearly with time (fast neutron fluence). Graphite shrinkage rates were taken from the AGC-1 Experiment. Daily heat rates for each compact and component in the models were input from daily as-run physics analyses. Daily gas compositions and component fast neutron fluences were also input. Six different finite element models were created for the six different AGR-2 capsules. Each capsule had a different gas gap that was implemented to control the temperature of the experiment. Gas mixture thermal conductivity was implemented using kinetic theory of gases. Fluence and temperature-dependent thermal conductivity was used for the graphite components and fuel compacts. Radiation heat transfer was implemented with emissivity of all graphite surfaces being 1.0 and stainless steel at 0.4. Ten of the fourteen predicted temperatures were within 20 to 50 °C of the measured thermocouples temperatures, while three of the other four were within about 100°C. All of the thermocouples failed during the experiment. Heat rates, and hence temperatures, were very sensitive to the outer shim control cylinders, which is typical for B experimental positions in the Advanced Test Reactor. Volume average time average temperature values were calculated and reported herein.

AGR-3/4 Experiment Preliminary Mass Balance

“…AGR-1 burnups and temperatures from (Sterbentz 2013) and (Hawkes 2014a), respectively. AGR-2 burnups and temperatures from (Sterbentz 2014) and (Hawkes 2014b), respectively. AGR-3/4 burnups and temperatures from (Sterbentz 2015) and (Hawkes 2016), respectively.…”

AGR-2 Irradiation Test Final As-Run Report (Revision 4)

“…3-D finite element thermal calculations were performed on a daily basis using ABAQUS. The methods used in the thermal analysis summarized here are described in more detail in a separate report (Hawkes 2014). These calculations were performed using compact and graphite heat generation rates provided by the as-run neutronics analysis described in Sections 2.2 and 2.3 and with additional operational input for sweep gas composition versus time.…”

“…Modeling Data -All data have been stored in NDMAS and capture passed. Qualification of these data (Sterbentz 2014, Hawkes 2014 has been recorded in NDMAS.…”

AGR-2 Irradiation Test Final As-Run Report, Rev 2

“…Three-dimensional (3-D) finite element thermal calculations were performed on a daily basis using ABAQUS. The methods used in the thermal analysis summarized here are described in more detail in a separate report (Hawkes 2014). These calculations were performed using compact and graphite heat generation rates provided by the as-run neutronics analysis described in Sections 2.2 and 2.3 and with additional operational input for sweep gas composition versus time.…”

“…Neutronics and Thermal Modeling Data -All data have been stored in NDMAS and capture passed. Qualification of these data (Sterbentz 2014, Hawkes 2014 has been recorded in NDMAS.…”