Vessels atmospheric

Differcntial Pressure Fired-lnDircct Coniact-Tubcd- 3.6.1.2 Vessels-Atmospheric-... 

Taxonomy No. 3 6 11 Equipment Description VESSELS-ATMOSPHERIC-METALLIC ... 

Minimal pretreatment such as pelletizing, briquetting, grinding Acid digestion/dissolution in open vessels (atmospheric pressure)... 

Comparing these results with those of the earlier CSE tests, one finds a quite similar behavior of cesium, but pronounced differences in iodine removal from the vessel atmosphere. While in the ACE experiment the major part of the iodine was transported together with the aerosols to the vessel sump, in the corresponding... 

In safety analyses it is frequently assumed that the rate of penetration of fission products through the usually very narrow slits would be identical to the leak rate that would be measured using air as a penetrating medium. To be sure, this assumption is true for the fission product noble gases for airborne aerosols, however, narrow slits can act as a trap, so that under otherwise identical conditions aerosol leak rates will usually be lower by some orders of magnitude than the air leak rate. Early observations in this field showed that the presence of steam in a heated vessel atmosphere results in a drastic decrease of the leak rate to values that are well below those measured with dry air at ambient temperature (Witherspoon, 1970). Likewise, quick plugging of natural leak paths was observed when higher steam contents were introduced into the containment atmosphere under such conditions, even artificially made leaks in the vessel effected an appreciable retention of both airborne iodine and particles (Witherspoon and Postma, 1971). 

Perkin-Elmer DSC 7 sample mass 3 mg heating rate 20 °C minp A1 sample vessel atmosphere N. ... 

Wellheads, flowlines, and headers Pressure vessels Atmospheric tanks... 

Regarding the containment, the main problems are related to the thermal hydraulics even if the conditions of the first test FPTO are less severe than those of FFTl for which a high humidity ratio near 1 is requested. Any way, the control of the parameter is known to be very complex Furthermore this quantity is highly dependent of local unhomogeneity in the vessel atmosphere or "cold points" on the vessel wall which mi t be associated with instrumentation penetrations. The present status of the codes does not allow to represent the containment behaviour with such a level of detail. Therefore we cannot be totally confident of our ability to obtain a correct control of the condensation rates and the humidity ratio. A preliminary programme of thermal hydraulics tests of the containment and its condenser device is planned both for appredation of the technolo cal constraints of these components and a correct appredation of the code ability to compute their behaviour. 

---