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60 Years of U: Perspectives on resources, demand, and the evolving role of nuclear energy
Recent years have seen growing global interest in nuclear energy and rising confidence in the sector. For the first time since the early 2000s, there is renewed optimism about the industry’s future. This change is driven by several major factors: geopolitical developments that highlight the need for secure energy supplies, a stronger focus on resilient energy systems, national commitments to decarbonization, and rising demand for clean and reliable electricity.
W. Breitung
Nuclear Science and Engineering | Volume 108 | Number 1 | May 1991 | Pages 1-15
Technical Paper | doi.org/10.13182/NSE91-A23804
Articles are hosted by Taylor and Francis Online.
Measurements of the total pressure from irradiated (U,Pu)-mixed oxide were analyzed with respect to the fission product release kinetics and availability for pressure generation in Bethe-Tait excursions. Two pressure sources acting on a millisecond time scale were identified: release of grain boundary fission products (gases and volatiles such as cesium) triggered by grain boundary separation and release of formerly intragranular fission products due to fuel boiling. The former process can provide pressures on a megapascal scale early, and the latter process, late in the accident progression. No fission product release was observed from nonboiling liquid fuel. Based on the experimental data, a model was formulated for the total pressure over irradiated (U,Pu)-oxide. Fuel vapor and gases interact by a suppression mechanism: pIF = max(pAG + pFP, psat). The total pressure over irradiated fuel pIF is equal to the pressure sum from ambient gas pAG and released fission products in the gaseous state pFP when this sum is greater than the saturation vapor pressure of fresh (U,Pu)-oxide psat. In this regime, fuel boiling is suppressed. At sufficiently high temperatures when psat > pAG + pFP, the oxide begins to boil and the total pressure pIF reaches the fresh fuel saturation vapor pressure psat. The switch-over in the controlling mechanism occurred at ∼5200 K.
