Cladding collapse

An increase in the clad-pellet gap, with pressurization to obviate cladding collapse... 

The allowable maximum cladding temperature can be determined from the cladding collapse criterion for overheating events in this case, the fresh fuel rod is limiting. The collapse pressure of the cladding is conservatively determined by the equation for an infinite length cylinder, (2.21). 

Cladding collapse has been excluded in LWR fuel rod design. However, in the Super FR, pressure difference between internal gas and coolant is higher than that of PWRs. Collapse of cladding is kept as one possible cladding failure mode in the Super FR design. The pressure difference is limited by the buckling collapse pressure with a safety factor of 3 as in the Super LWR (see Chap. 2). 

Figure 16.11. (a) Deposition of cladding and (b) tube collapse in optical fiber production. 

In another approach, two cascaded microstructure-collapses on a photonic crystal fiber are intentionally introduced by C02 laser or electric arc heating31. In this way, the mismatch of core size along the fiber causes light coupling between the core and cladding modes. 

The problem of UO2 pellet densification under irradiation causes contraction and leads to collapse of the cladding in axial gaps in sections of the fuel columns. The solution is to control the manufacturing process to ensure the production of pellets with higher density and stabilized pore structures (pore size and grain size). Prepressurizing the fuel rod with helium also avoids clad flattening,... 

The young RAF officer was sent to collect the corpses after the clouds of nerve gas had supposedly dispersed. Although clad in gas mask and protective suit, Cockayne collapsed. It was the end of his RAF career. While in hospital recovering from the gas s attack on his nervous system he was discharged from the force, and later diagnosed as a psychiatric case. For all his civilian life Cockayne was to... 

The MCVD modified chemical vapor deposition) method also relies on the production of glass from halide vapors. The deposition process occurs inside a vitreous silica tube, which is heated from the outside and which serves as the cladding for the fiber. The reaction of the vapors now occurs without contamination by gases from the flames, which never contact the deposited material. Consolidation of the soot occurs simultaneously with deposition. The process continues until the desired layer thickness is reached, after which the entire tube is collapsed by increasing the external temperature to complete the preform. 

The incident was caused by considerable snowfall which led to the collapse of the tram A turbine hall roof Part of the cladding fell on the high-voltage equipment of tram A causing a zero-phase sequence on the mam transformer and therefore opening of the line circuit breaker... 

Thin-walled collapsible Zircaloy-4 cladding for neutron economy and improved heat transfer. Neufron economy ultimately leads to reduced electricity costs, and improved heat transfer leads to low temperature and high fission gas retention... 

The RELAP5-3D MASLWR model was used to calculate the sequence of events for an ADS line break and a steam vent line break. The break cases serve to bound transients that involve inadvertent opening of the ADS or steam vent valves. Fig. I-8(a) shows the core hot channel collapsed liquid level and fuel cladding surface temperature at the core hot location for the ADS line break scenario. The results show that core collapsed liquid level is sufficient to provide cooling to the fuel and that neither the fuel nor its cladding experience a thermal excursion. 

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