UNPLUGGING OF HIGH LEVEL WASTE TRANSFER PIPELINES:Method of Characteristics

Stephen Wood DOE Fellow

• At least one cross-site transfer line in Hanford is plugged. Several other pipelines may be partially plugged.

• Pipeline plugging can happen during cross-site slurry pipeline transfers from single shell tanks to double shell tanks.

– Plugged pipelines are difficult to repair and put back into operation. They are often abandoned and new ones are constructed.• Schedule delays• Increased costs

• Unplugging technologies are needed to remove the blockages in transfer lines.

• 149 Single Shell tanks store waste at Hanford – To date seven single-shell tanks have been emptied (ORP

09-006)

Background

NuVision Testing

Results

AcknowledgementsDr. Seckin GokaltunDr. Leonel LagosProfessor George DulikravichDOE/FIU Science & Technology Workforce Development Initiative

Differential Evolution

Method of Characteristics

k=generation=0, n=population size =20

F=mutation=0.8,CR=crossover=0.6

Choose randomly three members of P (α,β,γ)

Generate a random number R;

0<R<1

A

Go to A

R<CR?

Replaces in P

Best member is the optimum

Xik +1 = ∂1Xi

k +∂2 α + F(β − γ )[ ]

U Xik +1( )< U Xi

k( )

∂1 = 0∂2 =1

∂1 =1∂2 = 0

Xik +1

Xik

k = k +1

Xik

Convergence?

1- Maximum number of iterations reached2- U(best member) reaches 03- 90% of population hasn’t improved for 10 generations.

YES

YES

NO

NO

NO

YES

Xik =

ith friction _coeff .ithgeom._ loss

=

fik

cgik

U Xik( )= PMax _ Exp. − PMax _ i

k

Minimize

Design Variables

Coded based on algorithm’s presented in EML 5509 Spring 2009

Objective function

is the i-th individual vector of parameters. α, β and γ are three members of the population matrix P. k is the number of generations In the minimization process, if ,

then replaces in the population matrix P.Otherwise, is kept in the population matrix.

Xik

U Xik +1( )< U Xi

k( )

Xik +1

Xik

Xik

is kept in P

Hr(t)

Method of Characteristics Model of 285ft NuVision Test case

Hr(t)

Modified Method of Characteristics Model of 285ft NuVision Test case

Optimized from parameter ranges:f = [ 0.01 : 0.04 ]

cg = [ 0 : 1 ]

20 generations1.67 CPU Hours

@ 1.3 Ghz on Tesla-1285 min clock time

Over estimates peak pressure by 0.01% an

improvement of 0.9%

Peak pressure advanced 0.4% and improvement of 2.6%

f = 0.021cg = 0.3

Basic Differential Equations for Transient Flow

Conclusions & Applications

Derivation of Momentum Equation Derivation of Continuity Equation

By neglecting small terms, using a Darcy-Weisbach friction factor, and simplifying with steady flow assumptions:

By expansion, and grouping of material and restraint conditions for a pipeline anchored throughout:

• The inclusion of a loss factor that accounts for the presence of 90° elbows enhances accuracy of the model.o Peak pressure predictiono Wave form shape

• The use of differential evolution to determine model parameters (e.g. f, cg, m) provides timely solutions which accurately characterize a pipeline.

• Once a pipeline is characterized, appropriate inlet pressures to achieve desired transients can be determined through differential evolution.