Water purification defects

Later, in 1995, other very prominent and pnbhc instances of GxP noncompliance affecting compnter systems occurred. These involved a water purification plant, an integrated materials control and electronic batch record system, and a tabletting control system. These were owned and operated at the Burroughs-Wellcome plant in the U.S. and the Ciba-Geigy site in Switzerland. Defects revealed by the FDA inspection inclnded the following ... 

Even during normal operation, the primary coolant contains a certain amount of radioactivity, partly due to nuclides formed by the irradiation in the core of elements dispersed in the coolant (oxygen, hydrogen, cobalt, iron, etc.) and partly due to the presence of defective (fissured) claddings in the core which let a part of the gap inventory escape into the coolant. The concentration of radioactive products in the water depends on the entity of fissures (in general, it is assumed that 1-2 per cent of the elements have fissures) and on the effectiveness of the primary water purification system. 

Synthesize defect-free thin film zeolite membranes for H2 isolation and purification, and use as water management membranes in proton exchange membranes (PEMs). 

The quality of water in a recipient is negatively influenced by wastewater discharge, which becomes obvious from aesthetic defects, chemical and bacterial pollution, deterioration of biocenosis, retardation of self-purification processes, sludge deposits and other negative phenoqiena. 

Thermocyclic cracks were revealed in pipes connecting a reactor with pressurizers, in internal headers for water supply from purification system to reactor coolant pumps, in internal shells of pumps flow chambers, etc. The indicated defects became the reason for in-depth analytical and experimental studies of equipment operating conditions in the propulsion and test reactor plants, particularly thermal and strain parameters monitoring. 

Theoretical treatments of the tensile strength of a pure liquid take into consideration the intermolecular attractive forces which cause its cohesion. In water, the theoretical strength is nearly 10 bars. o it js therefore expected that the stress required to produce cavitation should be of a similar order of magnitude. The fact that water (without protracted purification) is able to cavitate under acoustic pressures of ca. 1 bar ( 10 Pa) suggests that inhomogeneities in the bulk act as "structural defects" reducing the tensile strength. In this sense, the minimum acoustic pressure required to induce cavitation corresponds to a threshold, i.e., the cavitation threshold. 

The maximum level of the activity concentrations in the coolant is probably reached at the moment when the gap of the failed fuel rod is filled with water and when there is no further movement of the liquid front and no convection within the liquid phase. After this point, additional fission products may reach the leak position and escape to the coolant by diffusion in the liquid phase only, which within the gap is probably a comparatively slow process and does not cause a significant further increase of the activity concentrations in the coolant, which are already high at this moment. Therefore, the activity concentrations in the coolant begin to decrease at a rate which corresponds to that effected by the action of the purification system. Following a reduction in the coolant pressure, however, an additional fraction of the liquid phase can be transported from inside the rod to the coolant by the action of temporary pressure differences, leading to the formation of the secondary depressurization spikes as shown in Fig. 4.9. When the reactor is started up again after the shutdown period, water which still remained in the gap of defective fuel rods, containing dissolved fission products, is transported out to the coolant, forced by the increase in temperature of the fuel pellets. 

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