Peter S. Winokur, Chainnan

Jessie H. Roberson, Vice Chainnan

John E. Mansfield

Joseph F. Bader

DEFENSE NUCLEAR FACILITIES

SAFETY BOARD

Washington, DC 20004-2901

August 8, 2012

Mr. David Huizenga

Senior Advisor for Environmental

Management

U.S. Department ofEnergy

1000 Independence Avenue, SW

Washington, DC 20585-0113

Dear Mr. Huizenga:

The staffofthe Defense Nuclear Facilities Safety Board (Board) reviewed the design of

the slurry transport system in the Pretreatment Facility ofthe Waste Treatment and

Immobilization Plant (WTP) at the Hanford Site. The review focused on the nuclear safety

evaluation of hazards and accidents related to pipeline plugging and engineering design

consid~rations for the centrifugal slurry pumping systems. As a result ofthis effort, the Board is

concerned that the design ofthe WTP slurry transport system has a substantial number ofsafety

issues that require resolution.

The Board is also concerned about the lack of early integration ofsafety into the design

ofthe slurry transport system. For example, the existing safety analysis does not address (1) the

hazard of centrifugal pump explosions, and (2) the effect of erosion from a bed ofsliding solids

on pipeline wear analyses, including the corresponding reduction in pipe strength. The Board

also observed that the project has been slow to incorporate new information on waste properties

into the slurry transport system design. For example, the project has not incorporated reported

data on the particle size and density ofHanford waste particles. These data include a Pacific

Northwest National Laboratory report on Hanford waste physical and rheological properties and

reports on the transfer of plutonium oxide particles from the Plutonium Finishing Plant to the

Hanford tank farms. Incorporation ofthese data can lead to greater projected rates of erosion

and a greater potential for pipeline plugging than currently considered in the WTP design basis.

Therefore, pursuant to 42 U.S.C. § 2286b(d), the Board requests a report within 90 days

ofreceipt ofthis letter outlining actions DOE has taken or plans to take to address the issues

related to deficiencies in the safety analysis and the design ofthe WTP slurry transport system

summarized above and discussed in the enclosed report.

Sincerely,

2tt:'--f4

Peter S. Winokur, Ph.D.

Chairman

Enclosure

c: Mrs. Mari-Jo Campagnone
DEFENSE NUCLEAR FACILITIES SAFETY BOARD

StaffIssue Report

June 1,2012

MEMORANDUM FOR:

COPIES:

FROM:

SUBJECT:

T. J. Dwyer, Technical Director

Board Members

R. V. Kazban, A. P. Poloski, and S. A. Stokes

Plugging of Process Lines, Pretreatment Facility, Waste Treatment

and Immobilization Plant, Hanford Site

This report documents a review by the staff of the Defense Nuclear Facilities Safety

Board (Board) of the design of the slurry transport system in the Pretreatment Facility (PTF) of

the Waste Treatment and Immobilization Plant (WTP) at the Hanford Site. The Board's staff

conducted the onsite review during October 25-26, 2011, with representatives of the Department

of Energy-Office of River Protection (DOE-ORP) and the WTP contractors, Bechtel National,

Incorporated (BNI) and DRS Corporation. Based on the results of the onsite review, the staff

concluded that the design of the WTP slurry transport system had a substantial number of

specific safety issues. Therefore, to determine what actions DOE-ORP and the WTP contractors

took towards resolving these safety issues following the initial review, the Board's staff held a

follow-up teleconference on May 8, 2012.

Background. The high-level waste slurries to be processed in PTF vary widely in their

rheological properties, from Newtonian to Bingham plastic fluids, a type of non-Newtonian fluid

with a semisolid structure. When designing a slurry pipeline, engineers typically establish a

requirement for the minimum transport velocity, often called critical velocity. Critical velocity is

defined as the mean flow velocity needed to prevent the accumulation of a layer of stationary or

sliding particles on the bottom of the pipe (i.e., the pipe invert). Critical velocity is a crucial

design parameter because it is undesirable to operate with a bed of particles that partially block

the pipeline and can lead to increased pipe wear. Partial blockage also leads to increased head

losses and fluctuating flow conditions, potentially resulting in a plugged process pipeline

(Crowe, 2005). In addition to particle deposition mechanisms, other plugging mechanisms exist

at WTP, including chemical plugging through formation of gels and precipitates due to changes

in temperature, pH, and unintended chemical reactions (External Flowsheet Review Team,

2006).

StaffIssue. The PTF design strategy, which addresses plugging of process lines due to

settling of solids, is to minimize the likelihood of plugging by implementing several design

guides written by BNI. BNI uses these design guides to determine the critical velocity, pressure

drop, and flush requirements for each process line in PTF. For process lines that transfer

Newtonian slurries, the design guides state that flow in these pipelines should be turbulent and

exceed an empirical prediction of critical velocity. These requirements prevent formation of a
bed of sliding solids on the pipe invert. For process lines that transfer non-Newtonian slurries,

the design guides rely on pressure drop and line slope requirements and do not impose critical

velocity or turbulent flow criteria. This design strategy does not preclude a bed of sliding solids

from forming in process lines that transfer non-Newtonian slurries. Furthermore, BNI engineers

expect formation of sliding beds in some process lines. However, the existing WTP

erosion/corrosion allowancesfor piping assume that fluid velocity remains above the critical

velocity, and sliding beds do not form. The PTF design strategy also includes a requirement that

each transfer of a Newtonian or non-Newtonian slurry is followed by a flush with water to

minimize the likelihood of plugging. The design guides also provide a methodology to establish

minimum flush volume and velocity for post-transfer flushes. Currently, the WTP design does

not have a capability to obtain representative waste samples and, therefore, has only a limited

ability to prevent material outside of the design basis from being present in the WTP process

lines (Defense Nuclear Facilities Safety Board, 2010). Therefore, the high-level waste properties

used to develop critical velocity and line flush requirements must be properly justified as

bounding.

Observations. The staff reviewed the following elements of the PTF slurry transport

system design bases: (1) the nuclear safety evaluation of hazards and accidents related to

pipeline plugging; and (2) engineering design considerations for the centrifugal slurry pumping

systems. Specific observations resulting from the review are detailed below.

Preliminary Documented Safety Analysis Deficiencies-The staff reviewed the

Preliminary Documented Safety Analysis for PTF (Hinckley, 2011) and identified several safety

issues. Specifically, the staff observed that BNI has not performed accident analyses for

energetic releases due to pump explosions and fragmentation that would lead to a loss of primary

confinement. This accident can occur when a centrifugal pump is operated for a prolonged

period during a loss of flow. The loss of flow can be initiated by pipeline plugging (either

chemical plugging or due to settling) or valve misalignment, which causes the contained solution

to heat up and vaporize, resulting in pump over pressurization. This accident is more energetic

than the spills and spray releases associated with pipeline breaches currently considered in the

safety analysis and poses additional hazards from fragmentation to other structures, systems, and

components. Centrifugal pump explosions have previously occurred at a defense nuclear facility

(Gubanc, 1998), and are a recurring problem in the mining industry, where pumping slurries is a

common activity. To address this safety issue, the Mine Safety and Health Administration

(MSHA) has issued a bulletin (MSHA Program Information Bulletin Pll-32) detailing safety

controls that should be used to prevent this accident. BNI currently does not have such controls

in the WTP design. During the onsite portion of the staffs review, the WTP project team agreed

with the staffs observations regarding this issue and committed to complete a project issue

evaluation report (i.e., PIER) and address this potential hazard in the planned updates to the

hazard analysis for PTF. During the May 8, 2012, follow-up discussion, the staff determined

that BNI has extended this evaluation to all WTP facilities, but made no progress in resolving

this issue.

Design Deficiencies, Formation ofSliding Beds-The BNI design guide on minimum

flow velocity for slurry lines consists of two major sections for use in determining (1) the critical

pipeline velocity needed to prevent a bed of sliding solids from forming on the pipe invert and

(2) the design of the flush system. BNI personnel stated that the design guidance for critical

velocity applies only to Newtonian process lines with turbulent flow conditions; the guidance for

2
flushing applies to both Newtonian and non-Newtonian process lines, in which each waste

transfer is followed by a flush with water. BNI has provided no guidance for determining critical

velocity in non-Newtonian process lines and, instead, relies on pressure drop and line slope

requirements. The BNI design guide for process lines with Bingham plastic fluids provides a

methodology to calculate the pressure drop for homogenous (non-settling) slurries and uses a

decision criterion regarding the potential for solids settling based on particle size distribution and

fluid properties. This decision criterion (Le., the yield stability parameter) is valid in a stagnant

fluid but is not appropriate to describe particle suspension when the fluid is sheared and particles

are in motion relative to the fluid (Shook et al., 2002). BNI's criterion indicates that particles

will not settle in the WTP process lines with non-Newtonian slurries, contrary to findings

documented in Pacific Northwest National Laboratory (PNNL) reports (Poloski, 2009a, 2009b).

The current design strategy will produce laminar flow in several non-Newtonian process lines

(see Appendix A). Laminar flows of particle-laden Bingham plastic fluids do not have either

turbulent eddies or a solid-like structure for complete suspension of large or dense particles,

resulting in formation of a sliding bed of particles. Also, process lines thought to contain

Newtonian slurries may instead contain non-Newtonian slurries during a pump transfer because

of elevated concentrations of particles near the bottom of underpowered pulse-jet-mixed vessels

(Winokur,2012). Presently, the BNI design guides do not address this phenomenon.

Design Deficiencies, Erosion/Corrosion from Sliding Beds-The staff observed that the

WTP project team has not evaluated the extent of erosion due to a sliding bed of particles.

Therefore, the calculation to determine wear allowances for piping containing non-Newtonian

fluids is incomplete (see Appendix B for details on abrasivity of WTP slurries). The presence of

a sliding bed of particles in non-Newtonian process lines will lead to increased erosion/corrosion

rates of the pipe invert and result in uneven pipe wear, with reduced pipe wall thickness at the

invert location (Miller and Schmidt, 1984; Pagalthivarthi et al., 2009; Roco and Addie, 1987).

BNI's analyses do not consider asymmetric wear patterns due to a sliding bed. Uneven wear

patterns can also be shown to impact the stresses within the process piping (American Society of

Mechanical Engineers, 2007).

Design Deficiencies, Use ofNon-conservative Design Inputs-The staff observed that

BNI is using several design bases to establish design requirements for various WTP systems that

process the same particles. These design bases are not based on the latest Hanford tank waste

characterization data. At the time ofthe staffs follow-up review, DOE-ORP had not directed

the WTP project team to alter particle size and density in the design bases to include the latest

data on the particle size and density of Hanford waste particles. These available data include:

• a recently issued PNNL report titled Hanford Waste Physical and Rheological

Properties: Data and Gaps (PNNL-20646); and

• recently issued reports on the transfer of plutonium oxide particles from the Plutonium

Finishing Plant to the Hanford tank farms titled Historical Overview ofSolids in PFP

Aqueous Waste Transferred to Tank Farms: Quantity ofPlutonium, Particle Size

Distribution, and Particle Density (24590-CM-HC4-WOOO-00176-T02-01-00001) and

Review ofPlutonium Oxide Receipts into Hanford Tank Farms (RPP-RPT-S0941,

Rev. 0).

3
Instead, BNI is using a design basis from early characterization studies that consists of

particle size distributions from a smaller set of tank waste characterization data. BNI analysts

assume that the largest fraction of these particles is agglomerates and use an average agglomerate

density to predict the critical velocity of the PTF pipelines. Results of PNNL tests (Poloski,

2009a, 2009b) indicate that use of an average density to describe the large particles is not

conservative, and that particle density has a large influence on the overall critical velocity

predicted by the correlation used in the BNI design guide. Further, high-density particles of

moderate size are more challenging to transport and can form sliding beds more readily than

large particles with a lower density.

Conclusions. The staff determined that the current design of the non-Newtonian WTP

pipeline systems is susceptible to frequent formation of sliding beds on the pipe invert.

Increased wear from erosion/corrosion at the pipe invert can occur if a pipeline with a sliding bed

is operated. The presence of a sliding bed also can increase the likelihood that pipeline plugging

events will occur. Chemical plugging is also a concern. Pipeline plugging events can lead to

frequent plant shutdowns. Moreover, prolonged operation of a centrifugal pump with a plugged

process line can cause the pump to overpressure and explode, resulting in the loss of primary

confinement and damage to adjacent structures, systems, and components.

4
References

American Society of Mechanical Engineers, 2007, Fitness-For-Service, API 579-1/ASME

FFS-1, Second Edition, New York, NY, June 5.

American Society for Testing and Materials, 2001, Standard Test Methods for Determination of

Slurry Abrasivity (Miller Number) and Slurry Abrasion Response ofMaterials (SAR Number),

G75-07, West Conshohocken, PA.

American Society for Testing and Materials, 2007, Standard Test Methods for Determination of

Slurry Abrasivity (Miller Number) and Slurry Abrasion Response ofMaterials (SAR Number),

G75-07, West Conshohocken, PA.

Bauer, A., 2011, Line Sizing and Head Loss Calculation for Ultrafiltration Circuit Pumps UFPPMP-00042A/B, 24590-PTF-M6C-UFP-00002, Rev. E, Bechtel National, Inc., Richland, WA,

November 15.

Crowe, C.T. (ed.), 2005:4-69, Multiphase Flow Handbook, CRC Press, Boca Raton, FL,

September 19.

Defense Nuclear Facilities Safety Board, 2010, Recommendation 2010-2: Pulse Jet Mixing at the

Waste Treatment and Immobilization Plant, Washington D.C., December 17.

Duignan, M.R., 2002, RPP-WTP Slurry Wear Evaluation: Slurry Abrasivity, WSRC-TR-2002-

00062, SRT-RPP-2002-00022, Rev. 0, Savannah River Technology Center, Westinghouse

Savannah River Company, Aiken, SC, January 31.

Elmore, M.R., 2000, Simulant Erosion Testing, WTP-RPT-001, Rev. 0, Pacific Northwest

National Laboratory, Richland, WA, October 26.

External Flowsheet Review Team, 2006, Comprehensive Review ofthe Hanford Waste

Treatment Plant Flowsheet and Throughput Assessment Conducted by an Independent Team of

External Experts, March 17.

Gubanc, P. F., 1998, Activity Report for Week Ending August 7, 1998, Weekly Report for

August 7, Defense Nuclear Facilities Safety Board, Oak Ridge, TN, August 7.

Hanks, R.W. and B.H. Dadia, 1971:554-557, TheoreticalAnalysis ofthe Turbulent Flow ofNonNewtonian Slurries in Pipes, AIChE Journal, 17(3), Hoboken, NJ, June 17.

Hinckley, J., 2011, Preliminary Documented Safety Analysis to Support Construction

Authorization; PT Facility Specific Information, 24590-WTP-PSAR-ESH-01-002-02, Rev. 4w,

Bechtel National, Inc., Richland, WA, December 7.

Hodgson, K. M., 1995, Tank Characterization Report for Double-Shell Tank 241-AZ-I01, WHCSD-WM-ER-410, Rev. 0, Westinghouse Hanford Company, Richland, WA, July 24~

Miller, J.E. and F.E. Schmidt (ed.), 1984, Slurry Erosion: Uses, Applications, and Test Methods,

ASTM Special Technical Publication, Ann Arbor, MI, May.

5
Pagalthivarthi, K.V., J.S. Ravichandra, S. Sanghi, and P.K. Gupta, 2009:263-282, Wear

Prediction in Fully Developed Multi-Size Particulate Flow in Horizontal Pipelines, Journal of

Computational Multiphase Flows, 1(3), United Kingdom, November 3.

Poloski, A.P., H.E. Adkins, J. Abrefah, A.M. Casella, R.E. Hohimer, F. Nigl, M.J. Minette,

J.J. Toth, J.M. Tingey, and S.T. Yokuda, 2009a, Deposition Velocities ofNewtonian and nonNewtonian Slurries in Pipelines, WTP-RPT-175, PNNL-17639, Rev. 0, Pacific Northwest

National Laboratory, Richland, WA, March 25.

Poloski, A.P., M.L. Bonebrake, A.M. Casella, M.D. Johnson, P.J. MacFarlan, J.J. Toth,

H.E. Adkins, J. Chun, K.M. Denslow, M.L. Luna, and J.M. Tingey, 2009b, Deposition

Velocities ofnon-Newtonian Slurries in Pipelines: Complex Simulant Testing, WTP-RPT-189,

PNNL-18316, Rev. 0, Pacific Northwest National Laboratory, Richland, WA, July 1.

Prado, E., 2011a, Pump and Line Sizing for HLP-PMP-00017A/B, 24590-PTF-MPC-HLP00017, Rev. B, Bechtel National, Inc., Richland, WA, June 5.

Prado, E., 2011b, Pump and Line Sizing for Pumps HLP-PMP-00019A/B, 24590-PTF-MPCHLP-00016, Rev. B, Bechtel National, Inc., Richland, WA, June 5.

Roco, M.C. and G.R. Addie, 1987:35-46, Erosion Wear in Slurry Pumps and Pipes, Powder

Technology, 50(1), The Netherlands, March.

Shook, C.A., R.G. Gillies, and R.S. Sanders, 2002, Pipeline Hydrotransport with Applications

in the Oil-Sand Industry, SRC Publication No. 11508-1E02, Saskatchewan Research Council,

Saskatoon, Canada.

White, F.M., 1994, Fluid Mechanics, McGraw-Hill, Inc., New York, Third Edition.

Winokur, P.S., Chairman, Defense Nuclear Facilities Safety Board, 2012, Letter to

D. Huizenga, Senior Advisor for Environmental Management, U.S. Department of Energy

concerning the basis for selection of validation data set for FLUENT model for Waste

Treatment and Immobilization Plant, Washington, D.C., April 3.

6
Appendix A

Flow Regimes for Centrifugal Pumps at the Pretreatment Facility

The first step in determining a flow regime in the transport system for Bingham plastic

fluids is to calculate the Hedstrom Number as follows (Hanks and Dadia, 1971):

where

D2 • p. r

He=--- /12

He is the Hedstrom Number (dimensionless);

D is the pipe diameter (m);

p is the slurry density (kg/m3);

T is the slurry yield stress (Pa);

Jl is the infinite shear viscosity (Pa·s).

(A.1)

The next step is to determine the transitional Reynolds Number, Ret, that represents the

transition from laminar-to-turbulent flow as follows (Polaski, 2009a):

(A.2)

where Co is a constant equal to 1,050 for the lower bound and 1,500 for the upper bound of the

transitional flow region (i.e., 2100 < Re < 3000 when He =0).

The last step is to calculate the Reynolds Number based on the velocity of the fluid in the

pipe, V, as follows (White, 1994):

p·V·D Re=---

/1

Then, the obtained value of the Reynolds number is compared to the transitional Reynolds

Number to establish the flow regime in the pipe (i.e., laminar, transitional, or turbulent).

(A.3)

Figures A-I through A-3 below depict flow regimes for centrifugal pumps at the

Pretreatment Facility (PTF) for transferring non-Newtonian slurries (Prado, 2011a, 2011b;

Bauer,2011). These figures show that the current design strategy for non-Newtonian pipelines

at PTF will produce laminar or transitional flow in several non-Newtonian process lines, which

may lead to pipeline plugging.
1.E+05

aU

.D

E

:s

z

tI) 1.E+04 .-0

o

C

>

t:!

Turbulent Flow

x

•

+

•

-_.Upper Bound

- --lower bound

• Mode 1: HlP-27 to HLP..

28, Suction

• Mode 1: HlP-27 to Hlp·-

28, Discharge

.. Mode 3: HLp·-27 to Tank

Farms, Suction

>< Mode 3: HlP-27 to Tank

Farms, Discharge

• Mode 4: HlP-27 to UFP1, Suction

1.E+03

1..E+04

Laminar Flow

1.E+05 1.E+06

Hedstrom Number

+ Mode 4: HLP.-27 to UFP-

·1, Discharge

1.E+07

Figure A-I. Flow Regimes for Centrifugal Pumps HLP-PMP-OOOI7A/B

A-2
1.E+05

--Upper Bound

Turbulent Flow

l-

.e»

.a

E

::I

Z

·CIJ 1.E+04

-a

15

c

:>

e»

ax:

- - - lower bound

• Model: HtP-28 to

HlW, Suction

() Mode 1: HLP-28 to

HtW, Discharge

Mode 3: HLP-28 to HLP27, Suction

X Mode 3: HLp·-28 to HtP--

27, Discharge

• Mode 4: HLP-28 to Tank

Farnls, Suction

+ Mode 4: HtP-28 to Tank

Farnls, Discharge

1.E+07

Laminar Flow

1~E+05 1~E+06

Hedstrom Number

Figure A-2. Flow Regimes for Centrifugal Pumps HLP-PMP-00019A/B

1.E+03

1~E+04

A-3
1.E+06

--Upper Bound

Turbulent Flow

..

til

.c

E

z

=

en 1.E+05

"

(;

C

>-

1.E+04

1.E+06

Laminar Flow

1.E+07

Hedstrom Number

- --lower bound

• Min Case,

Suction

• Min Case,

Discharge

A Normal Case,

Suction

>< Normal Case,

Discharge

• Max Case,

Suction

+ Max Case,

Discharge

1.E+08

Figure A-3. Flow Regimes for Centrifugal Pumps UFP-PMP-00042NB and UFP-PMP-00043NB

A-4
AppendixB

Slurry Abrasivity Data for Actual and Simulated Hanford Wastes

Duignan (2002) produced seven WTP waste stream simulants and performed a standard

abrasivity test per ASTM G75-01, Standard Test Method for Determination ofSlurry Abrasivity

(Miller Number) and Slurry Abrasion Response ofMaterials (SAR Number) (American Society

for Testing and Materials, 2001), to determine a Slurry Abrasion Response (SAR) number for

two types ofstainless steel used by the WTP project, 304L and 316L. The ASTM G75 method

uses a Miller number machine to determine the severity of abrasion-corrosion of the slurry on the

wear materials by measuring the rate of mass loss from the material specimen and converting

these data to a SAR number. During a test, a stainless steel wear block is attached to a

reciprocating arm that slides the block at a controlled rate across a trough filled with slurry.

Mass loss of the wear block occurs as the bottom of the block abrades from the sliding action of

the block, slurry, and bottom of the trough. The ASTM method specifies that the bottom of the

trough is made of a standard lap material, neoprene. The block is machined to dimensions

specified by the standard and loaded with a total downward force of 22.24 N (5 Ib). SAR

number results from the seven simulated WTP slurries are shown in Figure B-1 along with a

rating scale that shows regions of low to severe abrasion-corrosion. The results indicate that

process chemistry, e.g., the addition of the submerged bed scrubber (SBS) solution, plays an

important role in abrasion-corrosion of WTP process streams.

300

m304t

~316t

High

Slurry Abrasion-Corrosion

Severe

~.= -~-- '-"""r'~~"""'l"'''''' '''''1'""'''~ """'r"""""~'"""W"""i

HlW@ HIWwith Sr/TRU @ HlW H1W"w"ith HlW :HlW

25C SBS@ 25C 25C leached .@ SBS w"ashed@Wasned

2.5C (leached) 25C and

@ 25C leached@

8SC

Figure B-1. SAR Number for Simulated WTP Process Streams

o

50

250

i 200 ~~.~~~~~~~,~,-~. .D

E

i 150

c::

.~ 100

BNI's wear calculations assume that the stainless steel piping will experience little

erosion at low flow velocities due to the small size and amount of hard waste particles. ASTM

G75-07 (American Society for Testing and Materials, 2007) states:

"Experience has shown that slurries with a Miller Number or a

SAR Number ofapproximately 50 or lower can be pumped with

minor abrasive damage to the system. Above a number of50,

precautions must be observed and greater damage from abrasion
is to be expected. Accordingly, the Miller Number and the SAR

Number provide information about the slurry or the material that

may be useful in the selection ofpumps and other equipment and to

predict the life expectancy ofliquid-end parts ofthe pumps

involved. "

For sliding beds that are expected to occur in the WTP piping, abrasion-corrosion

depends on the frictional force between the sliding bed and the pipe invert that is impacted by

several key parameters such as the height of the sliding bed, particle and liquid densities, void

fraction, and centrifugal forces from the bed moving through pipe elbows. BNI has not analyzed

the specific conditions for abrasion-corrosion in WTP piping due to sliding beds of particles.

The Board's stafffound a large number ofpublications in the technical literature on the topic of

wear rates in piping with sliding beds (e.g., Miller and Schmidt, 1984; Pagalthivarthi et al., 2009;

Roco and Addie, 1987).

During a May 8, 2012, conference call, BNI stated that they do not consider the Duignan

(2002) data to be significant because of the simulants used, i.e., approximately 7 wt% of the

simulant solid consisted of tungsten oxide. BNI indicated that tungsten oxide is a very hard

material that is not representative of the Hanford wastes. To the contrary, the simulant was

developed by Pacific Northwest National Laboratory as documented in a report by Elmore

(2000). Elmore provides the basis for selecting tungsten oxide and states:

"Hardness ofthe particles is an important parameterfor

abrasiveness, but there is no specific information on that property

ofthe actual tank wastes. It is felt that uranium compounds in the

waste could be rather hard particles, and may represent a

significant fraction ofthe larger particles in the waste. Uranium

minerals such as uraninite (U02) are not part ofthe waste

simulants (despite representing 2 to 9 wt% ofNCAW solids),

because they are radioactive. Therefore, uranium minerals were

simulated in this recipe by adding -10 wt% tungsten oxide ofan

appropriate particle size distribution (See Table 1). "

Elmore then presents ASTM G75 test results for the simulant on three types of materials and

compares them to a test result for actual Hanford waste from tank AZ-101 (Hodgson, 1995). The

results shown in Table B-1 demonstrate that the simulant with tungsten oxide and the AZ-101

core sample both have "low" slurry abrasivity response with the 27 percent chromium-iron alloy.

When the same simulant is tested with 316L stainless steel and C22 Hastelloy the slurry

abrasivity response is categorized as "severe."

Table B-1. SAR Number for different Wear Materials

Slurry 27% Cr-Fe Alloy 316L e22 Hastelloy

AZ-101 Core 3 8 (Low) nlm nlm

Simulated Waste Slurry 32 (Low) 431 (Severe) 405 (Severe)

n/rn--notmeasured

B-2