9/8/17 – Events

So you think you have the plant mastered? Well time for some events.

Events are abnormal conditions that sometimes happen in real plants. The events in my simulation aren’t too severe. With practice, you will be able to handle anything the program throws at you!

There are 9 events, or 10 counting normal operation. There is also an additional one called Random. It will pick 1 of the 9 events to happen. When the events happen is random (of course…). After an event has been selected, a random reactor power level is selected. Then a random time (in seconds) is selected. So after you reach the reactor power level and the elapsed time has gone by, the event springs into action. Example: Main Feed Pump Trip, 354 seconds after you reach 76% Reactor Power.

Of course you don’t know the random power level or the elapsed time. If you picked a random event, you won’t know the event either! So you always have to be on guard, watching the controls – just like a real plant.



1. Loss of Offsite Power

  • All pumps trip
  • Status lights will update


  • Start Diesel Generator
  • Close  Breaker
  • Restart pumps
  • Recover levels


2. Reactor Coolant Pump Trip

  • Drop in Primary – Secondary energy transfer
  • Rise in Primary Temp and Pressure


  • Restart pump before Rx trip

3. Main Feed Pump Trip

  • Dropping Steam Generator level


  • Restart the pump that tripped
  • If you don’t catch this quickly or if your Steam Generator levels are getting too low, max out other Feed Pump and start Aux Feed pumps


4. Turbine trip (Load Rejection)

  • Steam/Feed mismatch Annunciator
  • Steam Generator levels rise
  • Primary Temp / Pressure Rise


  • Steam Dump on
  • Control Rods in
  • Reduce Feedwater flow. If Steam Generator levels become hard to control, start Aux Feed pumps / Shut down Main Feed pumps
  • Primary PORV as needed
  • Secondary PORV as needed


5. Circ Water Pump Trip

  • Available Secondary energy drops


  • Restart Circ pump
  • Steam Generator levels may rise – cut back Feedwater flow rate
  • Primary Temp and Pressure may rise – use Pressurizer Heater/Spray to control


6. Feedwater Valve Fully Closed or Fully Open

  • Steam Generator level drops / rises


  • The faulted valve remains – does not clear.
  • Trip feed pump that has bad flow control valve
  • Aux Feed start
  • Electrical load run back
  • Control Rods in


7. Primary PORV Open

  • Secondary energy drops
  • Primary pressure drops


  • Re-close Primary PORV
  • Watch Pressurizer level. Depending on how long it stays open, Safety Injection may be needed in addition to Makeup


 8. Secondary PORV Open

  • Secondary load increases


  • Reclose PORV
  • Electrical load runback
  • Steam Generator levels may drop


 9. Letdown or Makeup Fail

  • Slow Pressurizer level changes


  • This faulted pump will remain faulted.
  • Correctly identify faulted pump. Either start Safety Injection or increase Letdown rate


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