A Simple Core Model with TRACE


Assignment :

  Finish Homework 9, Start Homework 10

First be certain that given a basic geometric description of a core or tube bundle, you can calculate key quantities like available flow area and hydraulic diameter. Given hydraulic diameter and rod diameter, can you calculate an estimate of rod pitch? This later exercise is a good sanity check on input decks.  Take a look at reactorCore.inp.  Based on the pitch and number of rods associated with all heat structures (look for "Surface Multiplier" in the model editor and sum the four values), calculate the actual radial extent of the core region.  Also check to see if the input deck's values for fraction of axial area available to flow are reasonable.

When designing power systems, or checking simulations, it is a very good idea to do simple side calculations on energy and mass balances. These can be done by hand, with a simple standalone program, or via control blocks in TRACE (or most other simulation codes). Today I want to look at a simple program (power.f ) for one such calculation, and  use it to set a power (rpowi) in reactorCore.inp

Copy power.exe to a directory on your Udrive where you are already storing some programs.  Before you use it, you will need to inspect output from running reactorCore.inp to determine the core inlet pressure, temperature, and TOTAL mass flow rate.  Once you've got these numbers, double click the  power.exe icon in your file space and respond to the requests for data.  For the core outlet, just give it the same pressure as the inlet, and a temperature 50K higher than the inlet value.  It will give you the total power required to get that temperature change.  Enter that number as "rpowi" in the power component of reactorCore.inp.  Run TRACE with this revised input and compare TRACE's prediction of the core outlet temperature to outlet temperature that you gave to power.exe.

I recommend that you keep power.f in your personal set of analysis tools.  With minor modifications it can be used to generate reasonable approximations to steam and water properties, or perform other energy balance calculations.


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