NE Seminars

Thursday, January 31, 2001

• Wei Dong, AMCC
• "Control Nuclear Steam Generator in PWR Through Water Mass"
• Abstract:
  
  Control of water mass inventory in nuclear steam generators is important to insure cooling of the nuclear reactor. Since downcomer water level is measurable and is a reasonable indication of mass inventory near steady state, conventional feedwater control system designs attempt to maintain downcomer water level within a relatively narrow operational band. However, the water level measured in the downcomer can temporarily react in a manner opposite water mass inventory changes (shrink and swell effects). These complications are accentuated during start-up or low power conditions. As a result, automatic or manual control of water level can be difficult under these conditions and can lead to reactor trips. Here we introduce a new feedwater control strategy for nuclear steam generators. In this design, the water mass inventory was estimated with feedforward neural networks. The estimated water mass signal allows for the development of a water mass control strategy that can use conventional PI controllers to control the nuclear steam generator over the entire plant power range. Theoretical analysis and simulation results show water mass control improves the operation of nuclear steam generators significantly.

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