Observations relating to the mechanisms of swelling and gas release in uranium dioxide at high temperatures

Chubb, W.; Storhok, V.W.; Keller, D.L.

doi:10.1016/0022-3115(72)90092-x

Cited by 15 publications

(5 citation statements)

References 10 publications

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“…2 from [21]. In the subsequent period of irradiation ( 10 5 s) sintering pores intensively shrink in the central hot zone of fuel pellets (2000-2500 К), in accordance with results of pore shrinkage rate measurements in this temperature range [22] and with direct observations [23] of a notable fuel densification in the pellet central part during the first  300 hours of fast reactor operation (also observed in [2]). This conclusion can be also confirmed by calculations (see below Section 3).…”

Section: Formation Of Non-equiaxed and Columnar Grainssupporting

confidence: 88%

“…6) are also in a good agreement with observations in depleted zone of UO 2 pellets (i.e. in the lack of fission gas bubbles) at temperatures 1400-1600C after  10 7 s of irradiation in the Battelle Research Reactor tests [2].…”

Section: Formation Of Non-equiaxed and Columnar Grainssupporting

confidence: 88%

“…In fast reactors this restructuring affects the fuel performance in many ways (fission gas release, swelling, actinide, oxygen and fission product redistribution) and involves important matter transport processes within the fuel. The mechanism of this restructuring has been studied for many years and it was concluded that formation of columnar grains is related to the migration of pores with a particular shape, elongated in the direction perpendicular to the thermal gradient [1][2][3]. These pores, which have been called 'lenticular', are thought to be formed in fuel elements from cracks [3,4] and their migration is thought to be mainly responsible for the formation of columnar grains in the central hot fuel region.…”

Section: Introductionmentioning

confidence: 99%

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New models for UO2 fuel structure evolution under irradiation in fast reactors

Veshchunov

2011

Journal of Nuclear Materials

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On the base of analysis of experimental observations and critical assessment of existing models for oxide fuel structure evolution under operation conditions of fast reactors, new models for fuel restructuring and coring are proposed. The restructuring model describes coherent motion in the temperature gradient of various voids (gas bubbles, sintering pores and large lenticular pores) and grain boundaries, to which the voids are attached. As a result, the model explains elongation of thermally growing equiaxed grains and formation of columnar grains, and predicts a rapid formation of extended columnar grain zone during a relatively short initial period of fast reactor irradiation. The coring model describes formation and growth of the central void in the fuel pellet, activated by mass transport from the inner to the outer zone of the pellet under stresses induced by inhomogeneous fuel densification in the initial period of irradiation.

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Section: Formation Of Non-equiaxed and Columnar Grainssupporting

confidence: 88%

Section: Formation Of Non-equiaxed and Columnar Grainssupporting

confidence: 88%

Section: Introductionmentioning

confidence: 99%

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New models for UO2 fuel structure evolution under irradiation in fast reactors

Veshchunov

2011

Journal of Nuclear Materials

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“…On the other hand, Chubb et al (1972), Turnbull andTucker (1974), andZimmermann (1978) reported much higher rates for high-temperature (but isothermal), unrestrained U02 samples subject to gas-induced swelling. These conditions are atypical for fuel in commercial power reactors because the fuel pellets in power reactor rods are non-isothermal, are constrained by the cladding, and operate at low to moderate temperatures.…”

Section: Introductionmentioning

confidence: 91%

“…These plateau values of ultimate cumulative gas-induced swelling are plotted as a function of temperature in Figure 4.2. The basis for this function is out-of-reactor swelling induced in heated but unconstrained samples (Chubb et al 1972;Turnbull and Tucker 1974).…”

Section: Experimental Evidence For Eliminating the Gaseous Fission Prmentioning

confidence: 99%