Process control for a continuous uranyl nitrate evaporator

A continuous uranyl nitrate evaporator at the Savannah River Plant (SRP) in Aiken, South Carolina was the subject of this work. A rigorous mathematical model of the evaporator was developed. A difference equation form of the model was then constructed and used for control studies.

Relative gain analysis was done on the system in order to identify any promising multivariable control schemes. Several alternate control schemes were modeled, tuned, and compared against the scheme presently in use at SRP.

As the pneumatic specific gravity instrumentation at SRP is very noisy, the noise was simulated and used in the second phase of the control study. In this phase, alternate tuning methods and filters were investigated and compared.

Finally, recommendations were made as to what method could best be used to control the evaporator.