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Latest News
WEST claims latest plasma confinement record
The French magnetic confinement fusion tokamak known as WEST maintained a plasma in February for more than 22 minutes—1,337 seconds, to be precise—and “smashed” the previous record plasma duration for a tokamak with a 25 percent improvement, according to the CEA, which operates the machine. The previous 1,006-second record was set by China’s EAST just a few weeks prior. Records are made to be broken, but this rapid progress illustrates a collective, global increase in plasma confinement expertise, aided by tungsten in key components.
R. C. Lloyd, E. D. Clayton
Nuclear Science and Engineering | Volume 60 | Number 2 | June 1976 | Pages 143-146
Technical Paper | doi.org/10.13182/NSE76-A26870
Articles are hosted by Taylor and Francis Online.
A series of experiments was performed providing new criticality data on plutonium-uranium nitrate solutions in cylindrical and spherical geometry. For the experiments in cylindrical geometry, the plutonium content of the total uranium plus plutonium was ∼30 wt%; whereas, in the case of the water-reflected spheres, measurements were performed with both 15 and 30 wt% plutonium. The uranium in the mixture was slightly depleted, containing 0.66 wt% 235U. The plutonium concentration covered by these experiments ranged between 12.4 to 97.3 g Pu/ℓ (uranium plus plutonium concentrations between 30 to 310 g/ℓ. The 240Pu content of the plutonium was 5.6 wt% in the first case and 4. 7 wt% in the second. The experiments were analyzed using ENDF/B-III cross-section data, and criticality factors were computed in each case. Some comparative calculations also were made, showing the differences obtained with ENDF/B-II, ENDF/B-III, and GAMTEC cross sections. The KENO code, with ENDF/B-III cross sections, as well as the HFN code, provide conservative results on the criticality factors for these systems. The average value of the computed keff for the cylinders, using KENO, was 1.022, and for the spheres, 1.024 using HFN. Thus, using these methods and cross-section data, the computed critical masses and volumes would be expected to be smaller than those measured by ∼2% in terms of keff.