Preliminary design of a graphite irradiation tensile creep experiment in the target region of the high flux isotope reactor

Laser ultrasonic assessment of the effects of porosity and microcracking on the elastic moduli of nuclear graphites

“…When used in the reactor core, graphite is exposed to high temperatures and neutron irradiation as well as oxidative species with the precise conditions being dictated by the type of reactor under consideration. Operational temperatures can cause changes in stiffness and strength and creep can occur when graphite is subjected to fast neutron irradiation under mechanical loading [9][10][11]. Graphite oxidation has the effect of increasing material porosity and this can impact material stiffness and strength [6,12,13].…”

HTV Post Irradiation Examination (PIE) Results and Analysis

“…The mean of the expansion TM data indicated median temperature was 869°C (Table 4). Taking into account the predicted [18] graphite specimen temperatures, it appears likely that sub capsules 2 and 4 ran cooler than design expectations and the graphite irradiation temperature was ~ (869-30°C), or ~840°C. From Figure 9 -Figure 12 and Table 4 it is seen that annealing occurs over a range of temperatures spanning 30-70°C.…”

“…The graphical temperature analysis data is summarized in Table 4. A thermal analysis of the HTV Capsule was reported by McDuffee [18]. The temperature monitors in sub-capsules 2 and 4 (design irradiation temperature ~ 900°C) were expected to run 30-40°C hotter than the graphite specimens contained therein.…”

Irradiation induced creep behavior of H-451 graphite

“…[2][3][4][5]. Recently it has been recognized that creep strain produces significant modifications to the dimensional change component (behavior) of the stressed specimen compared to that of the control and that this must be accounted for in the correct evaluation of creep data.…”

“…Graphite irradiation induced creep data are needed for NGNP design and licensing purposes. Consequently, new irradiation creep experiments are being planned and designed to furnish the required data [1,2]. In a parallel effort compressive creep data for grade H-451 graphite is being re-analyzed and previously unpublished data for the high dose tensile creep behavior of H-451 are analyzed and reported.…”