Final Project


Counts as 25% of your grade

Due Monday, 17 December 2007


This project involves obtaining a baseline steady state of a PWR, and demonstrating the ability to automatically adjust the system to a second operating point with at least 5% change in thermal power.  The project report should be written so that someone with a nuclear engineering background, but no knowledge of this class can understand what you did.

The first section of your final project will be a general description of your power system. As a minimum, this system must contain:

  1. a full reactor vessel with heat structures representing the vessel wall and the core barrel;
  2. a core with appropriate power from rods, and reasonable irrecoverable pressure losses across the core support plates;
  3. component models for all primary loops in your chosen plant, including a pressurizer on one loop;
  4. steam generators with active level control or other means of obtaining appropriate feedwater flow as power changes; and
  5. a control block simulation of turbine shaft power output.

You will be able to obtain most information from an FSAR.  However, the FSAR's that I've been through neglect to give you piping lengths for the coolant loops.  Take those from PWR information provided by Dr. Hochreiter for NucE 430.  Remember that I'm not asking you to model a specific plant.  Your final product must be representative of a PWR, and well documented.

Give a complete description of the "as built" system geometry , including component lengths, volumes, and cross-sections. Include sketches with dimensions marked with specific attention to the appearance of the core region. Reference your source (or sources) of information, and document assumptions that you make due to inadequate system descriptions.  Describe how you choose to divide this system into finite volumes for TRACE and include all calculations that provide values of DX, FA, VOL, and HD for the input deck. Describe, calculations for any area change loss coefficients that you use (e.g. lower and upper core support plates). Provide a table of key parameters, such as: power; primary and secondary pressures and mass flows; and core inlet and outlet temperatures and pressures. Note both your model's values and those for your chosen plant.

Provide information on the performance of the active components. Give the type of pump used, and its characteristics (rated head, rated flow, rated speed, rated torque). You may select one of the default head curves from the TRACE pump component. Give a full description of your chosen turbine performance model, including at least one reference to a text or journal article. Your model may be as simple as a constant efficiency turbine, but be careful to use standard definitions of turbine efficiency. For the steam line temperature at your chosen operating point, and a fixed turbine exhaust pressure, your hydraulic model of the turbine will provide the turbine mass flow rate through an appropriate loss coefficient at the steam line exit. One or more control blocks must provide an edit of the rated turbine power for any reasonable turbine inlet conditions. This can be implemented as a table of turbine power as a function of turbine inlet pressure, but the table must be fully documented and justified (show all calculations and equations) in your report. ( In practice you only need 2 points in this table to cover your baseline operating condition and 2nd power point). Clearly specify the chosen operating conditions at the turbine inlet.

Run one steady state calculation  for your chosen power system at its standard operating conditions. Provide the input deck for this run and printed output of the last major edit. If the code does not declare a steady state provide a plot of turbine inlet temperature and pressure vs. time to justify your choice of a steady state dump.

The system must contain a means to obtain appropriate steam generator feedwater flow for your second power state.  One simple possibility is an  enthalpy balance calculation.  Provide full documentation of your control system including the steps you used to determine the gain and integration time scale of any PI controller.

Run a transient changing the thermal power to your chosen off-design value. Provide time history plots of :

  1. Steam Generator Feedwater and exit steam mass flow rates;
  2. Steam Generator Downcomer water level; and
  3. Cold leg and Hot leg temperatures

If necessary provide two copies of these plots with different time scales, so the details of the early transient are clear, as is the approach to a second steady state. Also provide a file containing of the last major edit of the run.  End time for the transient should be long enough to see conditions close to a new steady state.

Attempt the same transient from the design point to off-design power with twice and four times as many cells (fluid and wall) in your steam generator tubes and corresponding section of the boiler.  Report the results in the same way as before, noting any major changes.  Apply a Richardson extrapolation to the turbine inlet mass flow (steam generator exit steam flow), and estimate the error in the mass flow at a point in time where mass flow is undergoing its largest rate of change.  Document your choice of this second point in time.

As an alternate you can do the mesh sensitivity study using an isolated steam generator model.  Starting from your base steady state, initiate a transient by stepping the feedwater mass flow up or down by 5%.  As with the base option, apply a Richardson extrapolation to the turbine inlet mass flow (steam generator exit steam flow), and estimate the error in the mass flow at a point in time where mass flow is undergoing its largest rate of change.  Document your choice of this second point in time.

To prevent the inevitable attempts to do this project as an all-nighter just before it is due, I am setting some intermediate deadlines.  You will get one of three marks on these assignments:

  1. Complete, you've met all requirements for this section of the project, and may include the writeup as-is in your project report;
  2. Incomplete, you need improvements indicated by my comments in your final report to receive full credit for this section; and
  3. Nothing Submitted, at best you can receive 50% of the total points assigned to this section of the report.
Intermediate Deadlines:

Friday November 16:  A full description of the Steam Generator that you will use, including the "real" configuration and your finite volume implementation.  Implement the model in a deck very similar to stgenSS3.inp with feedwater flow set by a control block.  Demonstrate that given the rated hot leg temperature and flow, the steam generator produces something close to the rated cold leg temperature.  Check these results for the finer tube nodalizations.

Friday November 30: A full description of the vessel and core that  you will use, including the real configuration and your finite volume implementation.  Implement the model in a deck very similar to reactorCore.inp with a run showing that a combination of your plant's mass flow, cold leg temperature, and core power, produce something close to the correct hot leg temperature.  At this point you should have consistent behavior between your core and steam generator models.

Thursday December 6:  Provide me with a steady state at the base power.  Include plots demonstrating that it is a steady state, the input model (ASCII input file or SNAP project file), and a table comparing key model inputs (e.g. power, primary mass flow), and outputs (e.g. important primary and secondary  temperatures and pressures, and secondary mass flow rate) between your original plant specifications and values obtained from the calculation.

Note that these deadlines do not imply that I recommend waiting until December 7 to start running your power step transient.

Remember the TRACE or SNAP may do strange things to you during this project. Do not beat your head against a brick wall too long.  Contact me when troubles occur.

The project report must be submitted as a single word processor document.  Input models for the steady state and transient  should be submitted separately as either ASCII or SNAP project files.