Core losses mounting

What do we learn here That by increasing the gap of the core we can move to smaller core sizes. Yes, powdered iron cores for example have a distributed air gap, and come in various effective permeabilities. So actually, lower permeability materials should in principle always lead to smaller core sizes, as they have a larger air gap in effect. All this is rather counter-intuitive I admit. The restricting factor is that to use very low permeability materials, we need more and more turns, and so we will either just run out of enough window space to accommodate these extra turns, or we will have our copper losses mount to the extent that the core size becomes a secondary issue. 

Instead of cutting a piece of rebar to get an isolated probe, an external preconditioned corroding piece of steel can be mounted into the structure, usually contained in a concrete core (Figure 17.3) that is put into a hole drilled in the structure. This measurement arrangement allows the same information to be obtained as from the isolated piece of rebar. Experience from several years (Figure 17.7) has shown that in this way correct corrosion rates (when compared to weight-loss measurements) can be obtained and the prediction of future corrosion rates for a given exposure condition becomes possible [15]. 

CEDM incorporates a rotary step motor used for motion of control rods under all normal and emergency modes of NSSS operation. The step motor is backed up with a spring-type actuator that inserts the rods in the core in case of loss of power to the step motor or control system under any position of the reactor, including its capsizing. Implementation of this engineering solution is especially important having in view that the reactor is to be mounted on a ship. 

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