DOE-NRC Technical Exchange Radionuclide Migration

-"o

Groundwater chemistry modeling

Michael H. Ebinger, LANL

(

What is the Groundwater Chemistry Model?

One Attempt to Understand Water-hock Interactions at Yucca Mountain

Conceptual Model (QualitativeQuantitative) " Geochemical Processes (Dissolution) " Reactions (Description of Processes)

Los Alam,•s SK Prelimin )

I

X)aftI,

What is the Groundwater Chemistry Model?

Mathematical Model• Quantitative (UncertaintyiSen"." -••-i...

Predictive Capability

Los AlamosDraft

KPrelimint'

Purpose of the Groundwater Chemistry Model

SCP Specifies GWC Model (Study 8.3.1.3.1.1)

Predictive Capability (Performance Assessment)

Support Other Investigations "• Sorption "* Radionuclide Solubility

An "Integrating Study"

Los Alamos Preliminý Draft

Progress to Date

Study Plan a Review Comments Completed * Revised Draft

Preliminary Modeling * Processesm-Sepiolite Formation * ReactionsmmpH Stability "* "Most Active Groundwater"

Review of pH, Eh in Preparation

Los Alamos Preliminý Draft

Sepiolite Formation During Evaporation

Evaporation of Well A Water (Tuff)Concentration

Factor 1 2 5 10 50

100

Predicted mineraI

C, D C, D C, S,D

COs CS

C = Calcite, D = Dolomite, and S Sepiolite

Los AlamnsPrelimin)a 3)raft

pH vs. U022+ Added, US W HI & UE 25p#1 Water

Los AlamosPrelimina( )raft

Los Alamns relimini Draft

Np Speclatfon, Jim 13 ;.,ý,nd UE 25p#l Water

6J=13

NP02+ (99%)

UE 250#

NP02+ (67%) NP02SO4-(31%)

NP02+ (96%) NP02CO3-(3%) NP02CO3-(3%)

NP02+(46%) NP02CO3-(38%)

N P02+ (60%) NP02SO44.

NP02(CO3).6 (97%) NP02(CO3)-6(2

8w6

Np Speciation, UE 25p#1 Water

Los Alamos Prelimin(K

Draft

Planned Work

Study Plan Revisions

Identify Geochemical Processes

Testing "* pH Control (Bicarbonate?) "• Eh (Oxygen Pressure?)

"* Mineral/Water Interactions

Los AlamrnsPrelimin X)raft

Planned Work., continued

Develop Conceptual Model(s) * Hypothesis formulation

Descriptions ofProbable Models..

Develop Mathematical Model(s) "• Test Hypotheses " Uncertainty and Sensitivity

Los AlamrsPrelimin D fD)raft

Conclusions

Study Plan Revised

Preliminary Modeling Showing Results.

Several Tasks and Tests Planned

Support of Other Investigations

Los Alam-ns Prelimini Draft

0 'R

DOE-NRC Technical Exchange

Radionuclide Migration

Actinide Carbonate Speciation Studies by PAS and NMR Spectroscopies

David Lo D.

Clark, Palmer,

Scott and

A. C.

Ekberg, Phillip Drew Tait

Isotope

Los A

and Nuclear C] Division

iamos National

hemistry (INC)

Laboratory

PRELIMINARY DRAFT

K

Approach

Photothermal and LIF Spectroscopies

I

NMR, Vib Spectrosc.

I I II I I I I II

I " I I ..A

I

Iog[Radionuclide

KConcentration]

PRELIMINARY(

I II

-9

I

-8I

-7

lAFT

ME)q)lb* I mistlon

w w m

I!

wy domain MIMI AW, -OIL =minimizes wyme-ftma-flon

mm n Z8-8--

0.0025

0.O0054--1 474

0.0040

0.0020 -474

479 484 489 494 Wavelength (nm)

499

. . . .. . ..=... . .

479 484 489 494 499 Wavelength (nm)

0.0005+ 474

0.0028

0.0008 474

479 484 489 494 499 Wavelength (nm)

479 484 489 494 499 Wavelength(nm)

0.0025

,I

0.0005 474 479 484 489 494

Wavelength(nm)499

0.0020

0.0000 47 4 479 484 489 494

Wavelength (nm)

PRELIMINARY DRAFT

pH = 8.37

499• . . . i.. . . . . . . . . .

0.0025

0.0033"

4 0.0013

474 479 484 489 494 Wavelength (nm)

499

PRELIMINARY DRAFT

250 nM Pu(IV) Vary [NaHCO3] pH = 8.4 to 8.9

.6M

.1M

w .... . T

0 ) 0

cJ�

0

0

0

0d

6

absorbance at 486 nm

o om m m •

C C

0 0

k)3

relative

go

3. (0

0

tTl

VI

-L

0

0 0

mm Ia +

mU.

*1 U +

* ,,+

*04- U + PBU

|

486 nmm I m M m I

500492 nm

'I)

('3

0

C('3 0

I

0 4-, LJ

a) 0

10

HC0 3 I11 12

Co.2C3

PRELIMINARY DRAFT

I 7m ImI

0

-1

-2

-3 III I

m m I I m m

nm

nm513 1

(9 pHI I I I

b

50 0l)

" 0.00001- 23 C

0.

-0.0014 . , 1 , V I I I . . . . 474 479 484 489 494 499

Wavelength (nm)

PRELIMINARY DRAFT

0.8

0.5

0.4 -

S- Pu(VI) 1.0 M NaHCO3 .21 .

0.3

50- 40- 4u(7 1.0 480• o3 450 460 470 480

-- I .1OMNaHCO3 --- - .003 M NaHC O3

Wavelength (nm)

PRELIMINARY DRAFT

Q,)

CL

Proposed Monomer and Trimer Structures in Uranyl Carbonate System

U0 2 (C0 3 )34 -

0 U

(U0 2)3 (C0 3)66-

C C

0. 0

PRELIMINARY DRAFT (

Kf

62.9 MHz 13 C NMR Spectra at 0 'C, and pH 6.5

(U0 2 )3 (C0 3 )66 -

U0 2 (C0 3)34 "

(U0 2 )3 (C0 3 )6 6 "

C0 2 \

vw-w'J

122.1 ppm

CO3 2-/HCO3-

157 ppm

PRELIMINARY DRAFT

167 166 165 164 163 162 161 160 159 158

/

13C NMR titration of U02(CO 3)34- system at 0 'C.

Uo 2(CO3 )3 '4

(Uo 2 )3 (CO3 )6 6"

7.016.87

6.786.51

6.326.23

6.06

pH

PRELIMINARY DRAFT K.

7.247.36

7.467.53

168

7.627.77

7.92

166 164 ppm

KK'.

I

z/

170 NMR spectrum of fully170-enriched U02(CO3)34 - at pH 9.7 and 0 'C.

bound C0 3 2

8•= 225

free C0 32

8 = 1858 = 1098 O=U=O

IIIII wIIII II.Ia ..I . . . , I ..ll ..... I 5 I III la IIII . I I. .l i , . 1u .sI 5,r,, 5r

280 260 240 220 200 180 160 140 120 ppm

-- ------.-.-------

I 1 1 1 1a i . . . . . . . . . . . . . . . . .

1000 8006 600 400 200 ppm

PRELIMINARY rDRAFT

K

I •wmuI

33.8 MHz 170 NMR Spectra

3 U0 2 (CO3 )34 - + 6 H+ (UO2)3(CO3)66- + 3 CO2 + 3 H2 0

1105 (UO 2 )3 (CO 3)6 6"

1098 U0 2 (CO3 )34 -

7.00

7.28

7.81

6.00

6.23

6.50

i7

pH

1095.0 ppm

PRELIMINARY DRAF

1 I . 1105.0 1100.0

6.6

I I ' . I ' I

100

80 80- ML3

60

40

20 M3 L6 0 0 000

7.0 7.5 8.0 8.5 9.0 9.5 10.0

p[H]

PRELIMINARY DRAFT ) • )

62.9 MHz 13 C NMR Spectra at 0 'C

3 NpO2 (CO3 )34 - +

C0 3 2- / HCO3

6 H+ + 3 C0 2 + 3 H2 0

NpO2 (CO3 )34 "

(NpO2)3(CO3 )66 -

i5I I I 5'0

00 150 100 500 -50 -100 ppm

PRELIMINARv `RAFT21

Z

(

170 NMR Spectra of actinyl ions

NpO 2 (OH 2)n+

1635 1

NpO2(OH2)n 2 + UO2(OH 2 )n2 +

1220.9 1120.9 1

1235 1225 1215 1205 1123 1121 1119

PRELIMINARY DRAFRT

1660 1640 1620

0

-jL.

FUTURE DIRECTION(both Absorption and NMR)

NpO2+

- un-ambiguous oxidation state in natural environments

- low sorption coefficients

- possible multinuclear species (?)analogy to U022+ and NpO22 +, but discounted in lit

some preliminary results from UV/Vis absorption:

PRELIMINARY DRAFT

f \

Other Studies

1. Solubility (Double Salts)

from Ueno & Saito (1975):

rcarbonatel (M)1.6 1.2 0.6 0.4 0.3 0.2 0.1 0.05

1.6 1,6

9.7 3.2 2.0 8.5 1.2. 6.9

Np(V)(M) x 10-2 x 10-2 x 10-3 x 10-3 x 10-3 x 10-4 x 10-4

x 10-5

-1.5

z

0

-2.5

-3.5

-4.5"-1.5 -1.0 -0.5 0.0 0.5

log[carbonate]

2. At pH = 8.

log[HCO3 O -ý

-1

-2

-3-

"I

5 G. Bidoglio, G. Tanet, and A. Chatt (1985) "Studies of neptunium(V) complexes under geologic

•-] repository conditions" Radiochim. Acta 38, 21-26. (solvent extractions)

NpO2(CO3)2]3-1

"Np02(C03)-"

- -- 4Np02+

I 8.s pH

H. Nitsche, E.M. Standifer, and R.J. Silva (1990) "Neptunium(V) complexation with carbonate" Lanthanide and Actinide Res. 3, 203211. (Absorption study)

PRELIMINARY DRAFT

1H0reeece o -mt cel |i)

950 1000 1050Wavelength (nm)

PRELIMINARY DRAFT

(

K

0.6

0.5

0.4

-o

0.3

0.2

0.1

900 1100 1150 1200

IH20 referenced to empty cells(air)l

f

15x 0-3 LII = I .1 w/im'aulNPU (iJ IpH=8.5

1 0 [NaHCO3]=O.59M

5 [NaHCO3]=Oý.36M 0 v C,'

~0

0

-5- [NaHCO3]=O.9

900 950 1000 1050 1100Wavelength (nm) IPRELIMINARY DRAFT]

900 950 1000 1050 Wavelength (nm)

) 20 40 60 Tssm no=rpiros '(or,)

80

* Absorbance (991 nrn)

100PRELIMINARY DRAFT

15x10"'

10

(

cc$ C.)

m 0

5

0

I Is, I

1100

i

I

0)

a) o)

00 Q0

0

0

0.004

0.003 (

- i

DOE-NRC Technical Exchange Radionuclide Migration

AFM studies to elucidate sorption

Pam Z. Rogers, LANL

Alamos Nt ;41A LASORATORY

C;. -,j Ij3

!

DOE-NRC TECHNICAL EXCHANGE

RADIONUCLIDE MIGRATION AND NEAR-FIELD PHENOMENA RELATED TO RADIONUCLIDE

-RELEASES

FROM THE ENGINEERED BARRIER SYSTEM

Atomic Natural

Force Microscopy Studies of Iron-Oxide Mineral Surfaces

Marilyn Hawley (CMS, LANL) and

Pamela Rogers (INC-9, LANL)

Purpose: To determine which surface parameters

(surface structure, orientation, roughness) have the most influence on sorption properties

of iron-oxide minerals.

!

Approach: Different crystallographic surfaces of

goethite and hematite mineral surfaces

both freshly cleaved and weathered

have been imaged in air and under water.

f

Surprises: Many goethite surfaces reacted immediately

on contact with water.

The results of such reactions were greatly

increased surface roughness,

and hence a higher surface area for

sorption.

/

((

To extend these measurements to samples of hematite and maghemite from Yucca Mountain and thereby study the differences in surface structure and reactivity between the sample sets.

To determine why pure iron-oxide mineral samples appear to have much higher measured batch sorption capacities than those from Yucca Mountain tuffs.

Goals:

,Sewý.

6ýýIfl

4,11

,ý'Cjj v

dFlýy)

Conclusions: We have published the first atomic resolution

AFM scans of goethite surfaces.

AFM imaging of surface reactions under water

is possible and has lead to some fascinating

observations.

PRELIMINARY DRAFT

Conclusions: Goethite surfaces were seen to react very

quickly in water.

Both surface dissolution and precipitation

reactions were observed.

The location of surface precipitates was

observed to be controlled by the by the

underlying crystal structure.

PRELIMINARY DRAFT

Conclusions: The net result of the reactions was greatly

increased local surface area.

This would increase the sorption capacity both

by increasing the surface area and by increasing the number of the most reactive sites on the surface.

PRELIMINARY DRAFT

/

7

BUT

More (non-AFM) compositional measurements

are needed to confirm that the reacting

surface really was goethite and not a very thin covering of some other mineral.

PRELIMINARY DRAFT

Conclusions:

The size regime most important for sorption

reactions is on the scale of step heights,

or generally 10 angstroms.

This is precisely the spatial resolution readily

obtained in an AFM scan.

PRELIMINARY DRAFT

PRELIMINARY DRAFT

Conclusions: Rapid surface reactivity probably precludes easy imaging of sorbates on goethite at the level of atomic resolution the surfaces just become too rough.

However, lower resolution methods of gauging site reactivity are being tested.

(

The burning question: "How do the surface structure and reactivity of

mineral separates from Yucca Mountain

compare with these, and how might that

influence sorptive capacity?".

We are presently working with small samples

of maghemite from Yucca Mountain to try to

resolve this issue.

PRELIMINARY DRAFT

DOE-NRC Technical Exchange Radionuclide Migration

Surfacecomplexation models

James Leckie, Stanford University

A w4 s j 9J

ADSORBENT PROPERTIES

ADSORPTION EXPERIMENTS

2-x 2-n *.S'-. U02(OH)-' U02 A (UO,),(yH)

L

W20 .Se- MA;*Nm*...

e Saq)

-'I

ADSORBATE PROPERTIES

H20 solid

Uo u02 ,... 1?

e -solidsoi

q -

ADSORPTION BEHAVIOR I

I

Table 2

Characteristics of Soil Samples

N16 N21 N33

Parameter Surface Area m2/g(dry wt) 3.7 9.0 8.0 Water Content

% (wet wt) 21 47 37 Extactable Organic

mg/g 3.6 18.8 6.8 Total Organic* mr/g(dry wt) 11 260 17

*Based on 50 percent carbon content.

Table 3

Range of Site Densities for Soil Components*

Minerals Site Densities Site Densities Percent sites/nm2 moles/m2 Carbon

Clays 0.5-4 0.8 - 6.6x 10-6

Oxides 3-17 5 - 28 x 10-6

Organics** mole sites/g

Humic 3- 11 x 10-3 54-59

Fulvic 7 - 16 x 10-3 40_-_53

Polysaccharide 0.5 - 6 x 10-3 45

*From Buffle (1988) **Carboxylic and phenolic sites

(

Table 2

- N.

(

Cadmium sorption to soil N4-33(6.3g/I) and N4-16(13.5g/l); 1.5x10-6M total cadmium; 0.01N and O.1N NaCI

100 ,

9 0 -- - - - - - - - - -- - - --,- - - - -- - - -- - - - - --- --- ---- --- ---- --o B B

8 0 -- - --.- - - - - - - - - - --.. . . . . . .•. . . . . . . . . . -- -- -- ----- -- -

80- - --- - -- - - - ---------

3 ---------- ' ---------- -- - ----.. ---------- .......... --- --- -- ...... 1.... ...... r....

2 0 --- -- -- ----- --- -- -- -. . .. .. .4 -- -. - -- ---- - . . . .. . .-- - - - -- - - --.- - - -. ...... . ... .. . . .

. . . .. ... .. . . . . . . . . . . .

70 I '

60'''''

50--------------------------*.. .. . . . . . . . . . . . . .. . . B . . . . . B . . . . . B . . . . J . . . . . .

40''

3 0 .. .. .. . . .. .. .. " * B BB B BB B

B B B B B B B B BB B B B B * B B BBB 20-----------------:-- -B

B B B

* B B *^ , ,BB

Bu . . .. . . . .B.. . . . i . . . B . . . . . . . . . . B . . . . . B . . . . Bo' • . . . . . .

10B B B B B B B

* B B B B B Bo Bo . B B B B

B BBB

2 3 4 5 6 7 8 9 10 11 12

pH

- N33; 0.OIN A N16; 0.01N 0 N33; 0.IN . N16;0.1N

m

/ C

Kent, Davis, Anderson and Rea (1992)

20 30 40- 50

Days After Injection

Fe(OH) 3 (s) + ZnEDTA 2

= FeEDTA

+ SOH

+ SOZn+

S2H+

+ 3H2 0

C Co

0.30

0.25

0.20

0.15

0.10

0.05

0

ýF(4IXt6O1 Sw4..cL S;4es

11

.0 0 0 .5 U

z 0 U U U-

ex164-

2468 10 12

pH

14

-,.�.--

PERCENT METAL ADSORBED 00

0 ro . 2ro•

(.M 0 0 0o

o _"-4

o -._ (DiI+

0

SORPTION COMPLEXES

- l w

>6 ADSORPTION "Outer sphere complex"

No metal ions in 2nd CN Shell

ADSORPTION "Inner Sphere Complex, S[. Fe] in 2nd CN Shell

Ol

Sd-.,.p

ECIPITATE Pb] in 2nd CN Shell

F~urc Z

".W

SYPE OF SURFACE COMPLEX

INNER SPHERE

SOH + M2+ SOM + H+

SOH + L2- +H= SL + H20

OUTER SPHERE

SOH + M2+ = SO,-M 2 + H+

SOH + L2-+ H÷= SOH2+-L2

.p !

"_OMPETITIVE REACTIONS IN ADSORPTION

COMPETITIVE ADSORPTION

SOA + B = SOB + A

COMPETITIVE LIGAND

SOM + L = SO + ML

COMPETITIVE SURFACE

SOM + TO = SO + TOM

LIGAND EFFECTS ON CATION ADSORPTION

COMPETITION FOR SURFACE SITES

SOH + M =SOM + H

SOH+L+'H=SL+H 20

COMPETITION WITH SURFACE SITES

SOM +L= SO + ML

FORMATION OF TERNARY SURFACE COMPLEXES

SOH + ML = SOML + H

SOH + ML + H= SLM + H20

'I

OVERALL REACTIONS STOICHIOMETRY

Exchanize witb proton

Exchanee with hydr-oxvl

S +bMm++cV-+dH++eH H Lc

a(OH)a 20 =Sad Mb(OH)8 + (a + e)OH-,

H OH)BYH+)(a+e) K ((Sa dLcMb( c O)e (Sa(OH)a )(Mm+)b(L,-)c(H+)d(H2

I

SoaHa +bMm+ +cV- +dH+ +eH20 =(SO)aMb(OH)eHdoc +(a+ e)H+,

K= ((SO)aMb(OH)eHdL8cyH+)(a+e) (SOaHa )(Mm+)b(L,-)c(H+)d(H20) e

PROTON STOICHIOMETRY

Cation Binding

CKM SH +M = SM+XH

Anion Binding

CKA SH + XH + A - SH(1+X)A

ADSORBED PHASE

-OMe

-L

- OMeL

MeL

- LMe

SCHEMATIC REPRESENTATION OF SURFACE COMPLEXATION REACTIONS

SOLUTION PHASE

Me

+

L

I

Me-L

1

L- Me

2

M

I L

3

L* Me

Me L

4 5

POSSIBLE CONFORMATIONS FOR

TERNARY SURFACE COMPLEXES

-OOC-(CH2)2 -CH -COO. i

NH 3 +

glutamic acid in mid-pH region

N COO

(000

2, 3-PDCA in mid-pH region

N COO

picolinic acid in mid-pH region

OH GLUTAMIC ACID

OH 2*--OOC-(CH2)2 -- CH -COO

OH NH 3+

OH -OOC

OH2 *- NV

OH2 * ----------- N

PICOLINIC ACID

OH

OH OHC

OH2+-

2. 3-PDCA

OH

/ / /

/

% COPPER ADSORBED N 4 m0 0 0 0 o 0 0

n \0

"[p

cy 0 00'

G--x - 4

*

Sii

00

0) x

.m~4

Ag +

sa 02614-*ýS203 Ag AgsOi 9 Ag(S203)2

A4+ + Cl- Ag(CI)1-1'

SOLID

Fe(OH)3

DAVOU AMIL Lccle4 (114Y')100

a w M, Ck:80 0 C/)

~60

w

~40

U) 52O2 T

0'~ 0

3I

4

0 I _

p -u

5 6 7I

8

pH

'I

'0

TH lOS ULFATE TOT0 U

-7 4xl0 M 4X10' 6 M

Fe (0H) 3 (a m), 10O3 M, 16.2 m2/I

0 250CQIM NaNO3

S a.

0 @0e

9

II I I

% SILVER ADSORBED

o 3,I

0,

.4

a

a

zD

Adsorption of U(VI) onto 1 g/l Goethite I =0.1 MNaCIO 4 ; [U(VI)Ja 1 -10- 6M (STb)

(Ri)1 SOH +UOz + H2 O < SOUO 2OH +2H+ + (R2):, SOH + 3UOz~ + 5H2 0&+4 SO(UO2) 3 (OH) 5 + 6W~

100

80

60In

0 :P' u I'

40

20

24 pH8 10

tok&r . fb 0 1 )a" W&W L ac,ý C u*^

Fraction [%]

0 0 0 0 0

N-"

0

COC

2<z_

• •_cn

• .4_• r, 00

N44INI4N N

NNVNNN

/

Fraction [%]

0 0 0 0 0

v z N 000

0

C-O

C W _. _. 3 "- _

o oO

N

Hydraqi Model of the Adsorption of U(VI) onto 1g/l Goethite

I -0.1 M NaCtO4; [U(VI)] _ - 1 1-6 -. The Effect of Pcoz,

2 3 4 5 6 7 8 9 10

KA6, A~&wa^. "~. LeA %A 6w% rtf)

100

80

60

40

20

0

.0

.2

U.

Experirnents

0 2.10-2atrn * 3.1 0-atm A 0Oatm (absent)

mom PC02:

1-'.10-4 atr, nourany - car bon ato copl ex a = 2.10-2atm, no uranyi -carbanat comrpi ex

30 3-10'4atrn, uranyl - car banao camnpI ccs S2.10 0 2atm, uranyl - car bcxnato comrplexces

Distribution of Adsorbed Uranyl Species I = 0.1M NaCI04; [U(VI)]= 1.10" 6 M

PCm = 3.10" 4 atm

a. SaJO2 0H

- SaHgUM2(CU3)

p SUM

02 3 4 5 6

pH7 8 9 10

100

CL

Cn 0.

cc

a' L.0

ti0

0

Cu U-

80

60

40

20 1

Schematic illustration of hypothetical neptunyl reactions

ONpN (1)

OL K. (2)

"ONpL 4•w (3)

NPL (4)

-OLNp (3')

L = carbonate, EDTA

* EDTA Sorption onto hematite: effect of variation in ionic strength

EDTA - 33;tM hematile= iglA NaCIO4

Ol 0.005M o 0.01M

0 0.05M 0 0.1M

S

2 4 6I

8 10 12

pH

L Ci Ls

U100

80s

60-I C

40

20"-

0 *9 -

I

Effect of EDTA on Neptunyl Sorption

2 ~468

N No EITA

*No EITA

ANoEYrA

o 33 g.iM N

E3 33ILM Ca.EDTA

A33I±M Ca-EDTA

-Model: 33PM EDTA

10 12

pH

K*wq~~ wo4 Lod4AUJ (;-A Prf)

EDTA solution complexes considered:

NpOý + EDTA' = NpO 2EDTA3' NpOý + HEDTA' = NpO2HEDTA2 -

100

z

CEO

so

60

40

20

0

Adsorption of Neptunyl in presence of Humic acid and EDTA

100

8o

60

40'

20

2 4 6 8 10 12

pH

vjAw4.A *,4 Laclu* cu.e

0

cc I-to

0

Cu 0.

Lm U.

0

14

Adsorption of Neptunyl on Gibbsite in presence of Humic acid (data from Rhigetto et al., 1991)

100. , 3C

"0 0

60 ,

o 60K

C• P "0i

> 31 C- 40 , t z

€: ~o ! o e '* HA0ppm O 20 * / -* HA5ppm L , LO HA50ppm

A x

0=

48 10 12

pH

Fraction Np(V) adsorbed [0/6

0 01 0

mooom

Cp

30) C,

OD - "

0

-AI

ypo-f(H ,z

E DTA4 -

OtI2

Np -OH I-" I I . z

1*111HzO

0

CHI-CO07I/

"Ooc-

N:pO7PY 2--

N1>02Y 2ý-

0

() () c - PLC "'ý

Hc- Coo no

HOOCA"

AJO

NpO2 "Yz

41- OH

oz

Co WIPLE Y E S.,S U Prr--A- ý,E

Me ýa rv tý

ý2u Y-fa ce ro t, ALI Y2-

It me-jai - Ll*etf, "" 6S.ý nJ- b'ke-,

P, DS

F//

ff�9cI/vOs -

ft Io-vw 2H $ -

07L1 p.

el1/ L/ 9jJ 2��J N 2'(Q$) + H/GS)

HQ0

Ho-

cl/v �1� 0 f�P'2

2

s ýx-z, r", V C

+1H -zjti' r 4- H03

4 11Z

-ý- -9 ý

alp/ - 0 --)y,:jf i

0. Ho b!

flu

C4-SE

"Ll( AIID- Lli(ýýF " C oc)/2 L) / 1\1,4 -F (0 /\j

0 0", ON W,v ?-

c 00H 0 0 0

4; RL - OtY

I

(2Hz

2

A/P, 11a vrl

u

0

0 2

0

-Al\,,ýAl

(5014)7 ý ML

A. ý (/ýCý) >> 4 C7(ebelat)

. it

S2 L 74 S2- L-,\4

e (Modifiýý S t )LI )(ýISE Z S-ill(ilace - 51,44

AJ '!'ý N-IL

ý, 0

4::ý7

0

ou

PL-0

o

AL- 0

/110 ý ýOcpe+

ýe4o Ll' ke

= SZ7/I

66OeD11\JA-7701J

11

p itlivit 0

Cl) Q-1

(!

,;ýi

CA

<�0

C-,'

'N

-S.

C-,'

N

'-'I

':1)

LA'

sý-1

U

�zŽ.

DOE-NRC Technical Exchange Radionuclide Migration

Retardation sensitivity analysis

George A. Zyvoloski, LANL

Alamps N D~ A I p9JTOI

Bottom Line -

Prevent Radionuclide escape to

the environment

h.

Groundwater Flow at Yucca Mountain

1) Uncertainty in Infiltration

rates

2) Fracture flow important

3) Stratigraphy and faults can be important

Issues Affecting Radionuclide Transport

1) Release rates

2) Sorption - Geochemistry

3) Air flow (C 14)

4) Ground water flow

Porous Flow and Fracture CODE PHYSICS - George Zyvoloski and Bryan Travis

FEHM Finite element heat, mass (and stress) "* 3-D geometry "* Flow of air, water and heat . Multiple chemically reacting and sorbing tracers * Coupled stress solution * Saturated and unsaturated media * Double porosity, double permeability treatment * Finite element/finite volume formulation e Algorithms:

- Preconditioned conjugate gradient solution of coupled linear equations;

- Newton-Raphson solution of nonlinear equations

Porous Flow and Fracture CODE PHYSICS - George Zyvoloski and Bryan Travis

(continued)

TRACR3D

"* 3-D geometry "* Flow of air and water "* Multiple chemically reacting and sorbing tracers "* Saturated and unsaturated media "* Biokinetics "* Adjolnt sensivity capbilitles "* Finite difference formulation "* Algorithms:

- Preconditioned conjugate gradient solution of coupled linear equations;

- Newton-Raphson solution of nonlinear equations

IF

..0

Construction of Flow Model

1) Use information from the Sandia Data Base

2) Block values identified with hydrogeologic units

3) Structured or Unstructured meshs

I -j

a) Ii 'I

a)Well Log Data b)Model of Stratigraphy c)2D Computational Mesh d)3D Computational Mesh

�s-,v.

d)

b)'.1 -

c)

Air Flow at Yucca Mountain

1) Needed for C 14 transport calculations

2) Thermal convection and barometric changes are the driving forces

MM OM O

Ii

Yucca Mountiahi topography on a grid with 250ft. centers.

71

.100o0

a15000

50flfl

4 ?')[1

4'1_ Li"WOaa

100ILi

110 37511

3 5 0lP

Elevation (ft)

/ N

0 n

0

CL -r

0

Coupled flow and Geochemistry

1) Important to understanding processes at Yucca Mountain

2) Interaction with Ebinger's task

hh.

Multiple Reaction Module

* User specifies a system of chemical reactions involving one or more components

- Stoiciometry - Reaction rate laws - Identification of phase(s) participating in reaction (fluid, sorbed, etc.)

* Code solves transport equation with reaction for each component at each time step

Types of Chemical Species

* Liquid Phase

* Vapor Phase

* Solid Phase (chemical reaction only)

* Henry's Law-solute partitions between liquid and vapor subject to Henry's Law equilibrium

S Sorption is included through the use of linear and nonlinear sorption isotherm (equilibrium) models

(

-'4

( (

Students Activities Related to Flow and Transport

New Mexico Tech Colarullo (Philips) - heterogeneities, flow, transport

University of Illinois Viswanathan (Valocchl) - flow and coupled geochemistry

University of Utah Snelgrove (Forester) - vapor transport, air flow

University of Arizona Levin (Neuman) - heterogeneities, flow, transport

or- NOWMENOMMOM

W010

I

DOE-NRC Technical Exchange Radionuclide Migration

Retardation sensitivity analysis

George A. Zyvoloski, LANL

<su�i.>

V I cz,>

FLOW MODEL

* 76 m (250 ft) by 152 m (500 ft) plan view

* 35 vertical nodes (10 meters)

* 2 - phase flow

* Uniform flow (0.1 mm/yr)

* Finite element / finite volume

ý4 Od

CROSS-SECTION OF YUCCA MOUNTAIN ALONG ANTLER RIDGE (5x vertical exaggeration)

1500 -r--

1400 --

1300

1200 -

"*1100

Q) U,

S10000 -0

0

> 900 wJ

800 -I-

700 ----

1500 -=--

1400 ----

300 -1---

anhydrous tectosilicates

vitric nonwelded

glass & smectite vitrophyre

l__

zeolites

-00

roll.

e~l

mw

''7 .4

4'

'4

4.

4'

* -4'

'V.

* .1'

* . jt' * . 4*,

.4 . 4*�

*�'

* - *4

* * .4�

* . 4i U U

- N: .4 -at' *' '$4

*a 14. * S. *

'it

-'C �

fl .4

4.

P fl 14 .1

I

I I *1

wwo

+

Steady State Saturation Field

V

A

Saturation 1.0

a0.0

•"wU~l-'•..•n,. . ....

Concentration ( -)fditioiis)

'B-.

--

Concentratio1 i 2!-)00 Years)

da-

I 7.'

I

4

9 A

b �

I

/

IV0

Concentration 'I Conditions)

I i

Concentration (10,000 Years)

4-

----1-

Pb

" STRUCTURED VERSUS UNSTRUCTURED GRIDY"'

• 4 )k

K,

Issues Affecting Radionuclide Transport

1) Release rates

2) 5.ption - Geochemistry

3) Air flow (C 4 )

4) Ground water flow

E IMMO

IMPORTANT ISSUES FOR THE FUTURE

• Distributed flow

• Model faults better

o Dual porosity/dual permeability

* Thermal repository

- Affects gas and liquid flow

L.

/

TRANSPORT MODEL

* Kd values from PACE- 90

- Radioactive decay

- Coupled geochemistry

- Gas phase tracers

dý mmqký

/

(

DOE-NRC Technical Exchange Radionuclide Migration

International

Robert S. Rundberg and D

Programs

avid B. Curtis, LANL

Alamos

((

Np Sorption Onto Iron Oxides

NAGRA/USDOE TECHNICAL COOPERATIVE PROJECT

MECHANISTIC APPROACHES TO SORPTION

Objectives

1. Determine the mechanisms for adsorption of radionuclid ýs onto minerals and rocks.

2. Indentify critical parameters affecting sorption in the field. These parameters can be mineral composition, pH, groundwater carbonate concentration, and cation composition.

3. Measure the adsorption isotherms for minerals and rocks. The reasons for measuring isotherms are twofold. One is to determine the limit of applicability of the linear isotherm (Kd concept). The other is to get insight into the mechanism.

4. Develop improved methods for characterizing mineral and rock surfaces

5. Develop a model that will predict radionuclide sorption under field conditions.

NEPTUNIUM (V) ADSORPTION ONTO GOETHITE AND HEMATITE

Robert S. Rundberg, Los Alamos National Laboratory

Yngve Albinsson, Chalmers University of Technology

Karl Vannerberg, Chalmers University of Technology

presented at ACTINIDES-93, Santa Fe, New Mexico September 20, 1993

Definition of Sorption Coefficients

Concentration in solid phase per unit mass Kd=

Concentration in the aqueous phase

Concentration in solid phase per unit area Ka=

Concentration in the aqueous phase

Crystallographic Structure of Goethite Showing the A-type, B-type, C-type oxygens and Lewis Acid Site in the C plane..

[001] A

A 8 Q

ABC

ýýYy <-Lewis Acid Site

[ [100]

[010]

EXPERIMENTAL

Preparation of Goethite, FeOOH

Goethite was prepared according to a method of Atkinson et al. as described in more detail by Machesky and Anderson. The goethite was prepared from A.R. quality reagents using a OH/Fe ratio of 2 in the preliminary aging step. The goethite was repeatedly washed with >16 megaOhm water until the conductivity no longer decreased with further washing. The conductivity of the rinse water in the last washing was less than or equal to 30 microSiemens (measured with a Philips PW9529 conductivity meter). The N2 BET surface area was 76.2 m2 /g. Suspensions were prepared as needed from freeze-dried solid.

Preparation of Hematite, Fe 2 03

"* The hematite was analytical reagent grade Fe 2 0 3 (Merck). "* The N2 BET surface area was 3.8 m2 /g.

EXPERIMENTAL

A 0.5 M stock solution of 2 3 7 Np was prepared by dissolving Neptunium in 1 M HCIO 4 . A secondary stock solution was prepared by diluting with deionized water to 5 x 10-4 M. Each sample was prepared by adding 0.2 ml of the secondary stock to 10 ml of emulsion.

" The sorption measurements were made holding electrolyte concentrations to 0.01M or 0.10 M with sodium perchlorate.

" The pH was adjusted by adding perchloric acid or sodium hydroxide.

" The suspensions were made to a concentration of 0.2 grams of goethite per 10 ml.

" The solutions were contacted with goethite in hermetically sealed vials for 2 days before phase separation. The solid phase was separated by centrifugation at 12000 RPM for 1 hour using a Beckman model J2-21 centrifuge with a type JA-20.1 rotor.

" The aqueous phase was sampled by taking a 1 ml aliquot immediately after centrifugation. Solution concentrations were .determined by liquid scintillation counting The 2 3 7 Np alpha activity was determined by setting a energy window on the liquid scintillation counter discriminating nearly all of the beta activity from the 2 3 3 Pa daughter of 2 3 7 Np. The measurements were checked by measuring the 2 3 3 Pa activity using a gamma counter after 6 months to ensure that secular equilibrium was established.

Np(V) Sorption onto Goethite, 0.01M NaC1O 4

1E-2 ___ 1E-5

A A 1E-.................. .........."

SE-3. 1 E-6

1E-4 --1E-7

0

SE-6 -1E-9 Z

1E-7 -i-1E-10

1E-8 1 E-11 3 6 9 12 15

pH

-A- Run 1 Lierse 1985 -Run 2 Nagasaki 1988

-"-- Allard 1980

Np(V) Sorption onto Goethite, 0.10 M NaCIO 4

1 E-2 1E-5

1E-3 --1E-6

1E-4 -1 1E-7 y

S~/ 0N 1E-5 -/ -1E-80

""-1E-9

E-7 -lE-10 3 6 9 12 15

pH

-&-A- Run 1 - Allard 1980

-4- Run 2 - Uerse 1985

Run 3 Nagasaki 1988

E

1

1

1

Np(V) Sorption onto Hematite, 0,01 M NaClO 4

1E-2 --

1E-5

1 E-3

1E-4

•"12-5-

1 E-6

1 E-7 -

-1E-6

"-1E-7

-1E-8

-1E-9

1 E-8 i

3 9 12 15

pH

-- Run 1 - Ailard 1980

-4- Run 2 - Lierse 1985

- Run lx Nagasaki 1988

0

"0-

Np(V) sorption onto hematite

1E-5

-1E-7

-1E-8

71E-9

T1I

69 12 15

1E-10

-*-Run 1 - erse 1g85 -Run2 Nagasaki 1988

Allard 1980

1E-2

1E-3

1E-4

(U

1E-5

1E-6 7

1E-7 3

0

C

z

-1E-6

The hydrolysis constants listed are defined as follows:

[NpO: (OFYI) /P = [',po.][ou ]

Hydrolysis Constants used in EQ3 calculations

Reference log P31 log 132 Allard 1980 5.1+0.8 (,10.(+2)a Lierse 1985 2.3±.6 4.89±0.05 Nagasaki 1 988 6.0 9.9

EQ3 fixed input parameters

Parameter Innut Value Temroerature 25 C loa (02 fuacitvl -.6794

+ 1.0 x 10-5 M [Np0001

[Na+] 0.01,0.1 M

S ] 0.01,0.1 M

aEstimated

Langmuir Adsorption Isotherm

cl KQ_ " C', + (K -]I

q K KQ., _ KQ.. c c C+(K - )c I +K c

CONCLUSIONS

* Neptunium (V) adsorption onto iron oxides does not depend electrolyte concentration

" Neptunium (V) adsorption onto iron oxides goes an inner sphere surface complexation mechanism

" The magnitude of the sorption coefficient, Ka, does not depend strongly on the crystal structure of the oxide.

" The sorption coefficient is inversely proportional to the hydrogen ion concentration suggesting neptunyl hydrolysis is involved.

" There are discrepancies in the neptunyl hydrolysis stability constants between potentiometric titrations and solubility measurements. This disagreement makes the .interpretation of the surface complexation mechanism equivocal.

Application of Neptunyl Surface Complexation Data to Tuff and J-13 ground water

Predictions of Neptunium(V) Sorption onto Tuff

Data

Iron Content - 1% pH = 8.4 Alkalinity = 1.0 e -3 M Estimated crystal size of oxide = 0.01 to 1 micrometer

Calculation

Iron oxide surface area = 0.011- 1.1 m2 / g tuff

EQ3NR calculations for J-1 3 water

NpO 2 OH(aq)

0.2331 E-07 0.7230E-07 0.5794E-06 0.1423E-05 0.2293E-05

NpO 2 +

0.9896E-05 0.9706E-05 0.7779E-05 0.4799E-05 0.2445E-05

Ka

6.5 2.0 1.6 4.0 6.8

Kd

E-6 E-5 E-4 E-4 E-4

0.07 - 7.2 .22-22 1.8-180 4.4 -440 7.5-750

Measured Ka/Kd in J-13 (Triay et al., Thomas. and Schroeder and Meii er)

GoethitepH 7.1 8.5

Hematite 7.1 8.5

Ka 6.0 E-5 1.5 E-3

9.2 E-5 3.5 E-4

Tuff Zeolitic

pH 8.4 6.5

Devitrified 8.5 8.3

pH pH pH pH pH

6.3 6.8 7.8 8.4 8.9

Kd 6 7

2 .5

Predicted Neptunyl Adsorption with a C02 Atmosphere

Conditions pH

Hematite. 2% C02

Hematite .03% C02

7.0 7.5 8.0 8.5 9.0 7.0 7.5 8.0 8.5 9.0

Ka measured

(m) 9.0 E-5 2.1 E-4 1.6 E-4 6 E-5 2 E -7 9.0 E-4 4.9 E -4 6.9 E -4 >7.0 E-4 >7.0 E-4

Ka predicted

(m) 8.9 E-5 1.9 E-4 9.7 E-5 7 E-7 1 E-10 9.4 E -5 2.9 E -4 8.1 E-4 1.4 E -3 6.1 E-4

I Kohler, Honeyman and Leckie

RESULTS OF NEPTUNIUM SORPTION ON TUFFS TREATED WITH THE BORGAARD METHOD

Sample Dithionite + EDTA

G1-1941 3.62 G4-270 1.3G2-770 G4-1067 G4-1506 G2-1813 YM-22 G1-1271

2.94 11.17 5.93 2.43

3.15 1.55

2.84 9.73 6.14 2.75

EDTA

7.69 0.38 1.17 3.3 7.29 1.7 2.23 13.76

Untreated

7 1.51 1.39 3.09 6.21 1.35 1.84 4.99

1.8 0 0.2 0.2 3.9 1 0.4 1

1.9 0.2 -0.1 0.4 3.6 1 0.5 0.1

Triple Layer Model of Surface Complexation

K, "K1 SOH + Hs"

(S) K2

O- + SO +H(S)

I1. Surface Complex formation

NO 3(S

int Na+

- SO

int NO"P 3SOH2

3

OSeO2 OSeO2-Na+

2 OSeOH

2 0OH

.O- Na+

OH .

OH+. OH+.

OH2

NO3 "NO3

""NO32 SeO

"'HSeO3

0 ,immobile layer

Na Na+ NO;

Na+

Na+ Na+ 2SeO

3

Na+

Na+ 2

SeQ3

Na+ NO3 Na

ddiffuse layer

,

I. Site activation

SOH + 2

SOH

SO- + Na(+ N(S)

SOH++ 2

f, I \

(

Triple Layer Model Capacitance

Gouy-Chapman Double Layer

Gd = -11.74C sinh ( zeAkm T)

Concentrations in double layer

[H+]s = [H+] exp( -eWI{/kT)

[Na+]s= [Na+] exp(-e~ikT)

XV W1

C0I yd

I~

I2

Diffuse

Layer

BULK

•1'E 1

[NO 3Is = [NO3] exp(+ey,/kT)

A

Equations Which Comprise the Surface Complexation Model

1. K int [SOH][H +][exp(-e'V0 /kl)] [SOH2 +

2

2. K int [SO ][H+][exp(-e.- 0 /kT)] a2 =.

[SOH]

K int [SO :Na + ][H+] exp[e( yo W 0 )/kT] 3. K Na =..

[SOH][Na +]

* int [SOH ][H+][CI J exp[e( ý - Y•o)/krj 4. Kci-=

[SOH2- CI2C]

5. Gd = -11.740 1/ 2sinh (zeNTd )pC/CM 2 • ) C/om

Equations Which Comprise the Surface Complexation Model

6. Mass B Ns= B

7. Charge To=B

cy0= B(

alance ([SOH+] + [SOH2 -Cl + [SOH] +

[S I + [SO -Na+])

and Charge Balance ([SOH I+ [s +H C,] [SO2] + [SOH2-Cl I + ISO]- + [SO -- Na + ])

[SO -Na+ ] + [SOH2 -CI)

(To + (71P+

8. Charge and

0'O

Capacitance T /C1

=-Gd/C 2

(d = 0

Cation Exchange

Consider the general case of cation B, valence ZB, in the aqueous phase exchanging with cation A, valence ZA, bound to the clay mineral surface, the exchange reaction can be written as follows:

ZBA-Cay+zA.B # ZA.B-Clay+zB.A (5a)

BK_ = NZA aZ'. NZB aZA (5b) RA B

aA and aB are the solution activities of nuclides A and B, respectively. NA and NB are equivalent fractional occupancies defined as the equivalents of A (or B) sorbed per unit mass divided by the cation exchange capacity, in equivalents per unit mass.

0 1=0.01M

0 1=0.03M

A I=0.1M

A i=0.3M

- •

0

A A

0 0 0

A A

0 0

A A

00

A

AA

A

S= I.5g/I

T=3 days

[Ca]=3xl0 6-M

CEC=85meq/1 00g

6 7 8 9

pH

Ca sorption on Na-montmorillonite ENTSORGUNG Effect of ionic strength and pH

5

4

T 3

0)

0 2

0

A

5 "0

1

5

4

- 3

02

I I I I II I I

s=1.

pH=

[Ca]:

CEC=

/ -A

-/ i/ , ,

.] I I I

/ / /

-t /

/ /

/

/ /

/ /

S/

/

, II I I I I I I I I I

/I / -

I I I I

-2.0-1.0 -1.5

log I (~aC166)

Ca sorption on Na-montmorillonite Effect of ionic strength at fixed pHENTSORGUNG

&

5g/l

7

=3x10-6 M

:85meq/1OOg

/

0.0 -0.5

S. .. . . I I I I I I I I I

I I I I I I I II I

ITLr UN

EN TSO RG UN G

5

4

0

3

2

INi sorption

Effect of

ot, Na-montmorillonite

ionic strength and pH I

5 6 7 8 9

pH

10

NI2.PiC

ionic strength and pH

( -I

HOTLABOR

Sorption und Reversibilitoet von Ni-63 auf Mylonit

Zeit: 21 TageNiTOT=5* 1 06 fM

a - - I

U

*~ E U 000 0 0 -b

U

100

90

80

70

60

50

40

oNi-63 'Sorption S.=29.7 g/I *Ni-63 Reversibilitoet

, p p p I p p p p I , * I . * I . .

8 9 10pH

rever~pic

01

aU

Ut

0

I-

U

0

U

30

20

10

0 1�

3

'59

4 .5 6 711

Zeit: 21 Ta e

CONCLUSIONS

" Neptunium sorption ratios for zeolitic tuff increase after treatment with EDTA and increase still further with dithionite + EDTA. This suggests either opening of detritus plugged channels and/or removal of competing species (i.e., calcium and rare earths)

"* Neptunium sorption ratios for zeolitic tuff do not exhibit a pH dependence consistent with surface complexation.

" Some devitrified tuffs exhibit an increase in Kd with EDTA stripping and a decrease with the dithionite + EDTA treatment. This suggests both removal of competing species and removal of surface complexation site.

"* The adsorption of Np in tuffs cannot be attributed to iron oxides

alone.

"* Iron oxides appear to be passivated in Yucca Mountain tuffs.

"* The method of iron oxide extraction alone is not adequate to determine the mechanism of Np sorption in tuff.

"• Competetive isotherms similar to those done under the NAGRA program should be applied to actinide adsorption in tuff.

PRODUCT GEOCHEMISTRY

ora naiguo Project Consortium

Preseht6d by bavid B. Curtis

ATOMIC tki t o~'ACAiADA L"TD. AUSTRALiAN NUCLEAR SCIENCE & TECHNOLOGY ORG.

LOS ALAMOS NATIONAL LABORATORY LAWRENCE LIVERMORE NATIONAL LABORATORY

"" UNIVERSITY OF ROCHESTER

cdan FaisOn-Prbdu t de5ch~mical Cycle

Natural Sources..::: Anthropogenic Sources

DiffutIon". Soil Nuclear Processes Dissolution., So.

, •'- •-'•Processes

= L ~~~~Asorption.fl d!WAI . • ~ ~~~Precipitation- ..... .

Processes

Solubility Radio:Speclation Decay

:"••:::"•"::••::••"":'•:; a i active D eIcay ,..•.::. ;::•

~~~~- a.. i i i i• .. . ..

(

NATURAL NUCLEAR REACTION PRODUCT GEOCHEMISTRY Objective:

Characterize the timing, rates, and chemical effects of processes affecting radionuclide release, transport, and retention in geologic systems.

K&M Company POLY-VU

Toiraqce. CA 90503 N PV1 19G

NUCLEAR PRODUCTION OF RADIONUCLIDES

Fission Decay

Uranium 9 9 Tc + 1291

Neutron Capture

Uranium 2 3 9 pu

Decay

f f

Dse'q` iulibriub Factor)(baughter/Parent) Meas(Daughter/Parent) Equil

!I,

.1.

(1AO A 4ti*

2 V, i:d

XAQOOX T41'4

k

�i.

'sq

&

I

4AOO-A TOO, A 0O' I ,

Plutonium

0 2 4 6 8 10 Measured

Picograms 239Pu/gms U

8

7

6

5

4

3

21

* Cigar Lake

n KoongarraPL ON

012 14

(f.

(

TECHNETIUM

5 10 15Measured (Atomic x

99Tc/U E+12)

5

4

3+O 0

2

1

00

Iodine

1 2 3 4Measured

S(Atom x1291/U E+12)

6

5

4

3

+

*0

2

1

0+0

/

1.0GI+1O

!.00000,

1o.•

100006

100,

1001

Residence Time (Yr)

. Emanation Rate (C) =Transfer Rate to Water/Production Rate in Ore

(E E 0

NU

\,

1"00+4'06

r Lake Ore Zone

Cigar Lake Ore Zone 100000 Koongarra Ore Zone

I o OW ................. . li eo . . .•i o . . . m 100

10

Residence Time (Yr)

Emanation Rate (e) =Transfer Rate to Water/Production Rate in Ore

E

E 0

o.' cc

AI..

/

I

A 129 1

PROCESS RATE (yr -1) = A

(

1.0

I 0.5

cI n

/

01

10-4

Zod:ine-1 29 11

010"910-5

Cigar Lake Ore Zone "-- -Koongarr Ore Zone

Cigar Lake

Cigar Lake Ore Zone

0

l•a, '0

"'r"

0~

I

0

a: 4-.

C')

0--

(D-L)

0

b.. 0 b.

0 0

-V

Ir CIn c;

! (

CONCLUSIONS 1) Processes that release and transport radionuclides from uranium minerals are operative in geologic systems representing a wide range of hydrogeochemical conditions.

2) These processes have been operative in the time domain between the present and 108 years ago.

3) Release processes for 1291 are orders of magnitude faster than for uranium.

4) Water residence times at Cigar Lake are more than an order of magnitude longer than at Koongarra.

5) Radionuclide release rates are smaller at Cigar Lake than at Koongarra.

6) Processes operative at Cigar Lake concentrate 99Tc and and possibly 239Pu in rock.

U

Natural Nuclear Product Geochemistry

David Curtis, June Fabryka-Martin, Paul Dixon, Don Rokop; Los Alamos National Laboratory. Carol Bruton, Lawrence Livermore Laboratory, and Jan Cramer; AECL Whiteshell Laboratory.

An understanding of processes involving radionuclide distribution and transport is inherent to safety assessment protocol. Such assessments associated with the development of geologic repositories for high-level radioactive wastes are uncertain because of uncertainties inherent in our understanding of fundamental processes in relevant environments and over relevant time scales. To aid in constraining the results of safety assessments of these geologic repositories,we are developing information from studies of uranium deposits to enhance our understanding of radionuclide behavior, rates at which key processes proceed, and factors influencing changes in these rates in geologic environments. Uranium deposits represent natural analogues of processes associated with the release and transport of radionuclides from spent fuel. Our work involves measurement abundances of the natural radionuclides 99 Tc, 1291, and 2 3 9 Pu in rock, water, and minerals from uranium deposits. Measured abundances are compared with those produced by nuclear reactions to determine the nature and extent of radionuclide enrichment or depletion. No enrichment or depletion indicates that the system has been undisturbed over relevant time domains (106 yr for 9 9Tc, 1 08 yr for 1291, and 105 yr. for 2 3 9Pu), or processes rates were significantly less than rates of radionuclide production, or processes did not chemically enrich or deplete parent from daughter element. Conversely, measures of enrichment or depletion show that the system has been disturbed in the relevant time domain and the rate of the disruptive process was significant relative to the rate of radionuclide production, and the processes chemically fractionated parent from daughter. We then seek to resolve our interpretations regarding the timing, rate, and chemical effects with our understanding of system parameters believed to control processes that influence these properties

in the system being examined. We have studied uranium deposits in two extremely different hydrogeochemical settings. The Cigar Lake deposit is an impermeable deposit in a reduced environment. It appears to have been largely undisturbed for most of the 1.3 x 109 yr since its formation. The

Koongarra deposit can be considered as two zones, with an intervening transitional zone. The near surface zone is weathered rock in an oxidizing environment. Uranium has been dispersed by water flow. The sub-surface zone. is unweathered, but has been altered from primary ore at some time in the geologic past. There is no obvious evidence for uranium dispersion in the unweathered zone at Koongarra.

At this time interpretations of our measurements suggest the following conclusions:

1) Processes that release and transport radionuclides from uranium minerals are operative in both the Koongarra and Cigar Lake deposits.

2) These processes have been operative in the time domain between the present and 108 years ago.

3) Release processes are orders of magnitude faster for 1291 than for U. 4) Water residence times at Cigar Lake are more than an order of magnitude longer than at Koongarra. 5) Radionuclide release rates are slower at Cigar Lake than at

Koongarra.

6) Processes operative at Cigar Lake concentrate 9 9Tc and possibly 2 3 9Pu in rock.

Kd Modeling

John W. Bradbury

Hydrology and Systems Performance Branch Division of High-Level Waste Management

U. S. Nuclear Regulatory Commission

presented at

NRC/DOE Technical Exchange

Radionuclide Migration

and

Near-Field Phenomena Related to Radionuclide Releases From the Engineered Barrier System

Los Alamos National Laboratory October 13 - 15, 1993

KD Approximation Testing

When is it appropriate to use KD to calculate retardation?

VrMD

Equation is valid when

1) Isotherm is linear 2) Sorption/desorption is fast and reversible

(Freeze and Cherry, 1979)

Why must the isotherm be linear?

What effect does the shape of the isotherm have on radionuclide transport?

Method of Testing

Simulate ion exchange (a sorption mechanism)

PHREEQM, a mixing cell code

Flow-through column experiment

K*+NaX=Na "+KX

K÷, Na÷ can be considered analogs for radionuclides

W is more strongly sorbed than Na÷

Varied concentrations and flushing solution

Concentration of Radionuclide on Solid

Concentration of Radionuclide on Solid

0 0 0

0

0

0

0

00

0-

0 0 0

0

0

0

0

0

t-4

(

j

1.0

0.9

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

0.01 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 1S 19 20

Cell Number

_Shift 4 - Shift 6 - Shift 15 Shift 20 Column: solid, I meq/l X- I meq/l Na+; liquid, Imeq/1 Na+ Flushing solution: Imeq/1 K+

0.14

0.12

00

I I

0.1

0.08

006

0.04

0.02

0

0.7

0.6

0.5

2,0.4

0.3

0.2

0.11 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Cell Number- Shift 4 - Shift 6 - Shift 15 - Shift 20

Column: solid, Inmeq/1 X- Imeq/1 Na+; liquid, I meq/1 Na+ Flushing solution: Imcq/1 K+

0 0.1 0.2 0.3 0.4 .0.5 0.6 0.7 0.8 0.9 1 Thousandths

Concentration (meq/ml) Column: solid, Imaeq/l X- Imeq/l Na+; liquid lImaq/1 Na+ Flushing solution: I meq/I K+

1.1

0

IIU

.a.

Op

I

I I I I I I

,

2.50.7

2

0

U

0.5

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 1920

Cell Number

- Shift 4 .Shift 8 _Shift 12 . Shift 16 Shift 20 Shift 24

Column: solid, I meq/1 X- I meq/1 Na+; liquid, I meq/l Na+ Flushing solution: 2 meq/1 K+

2.5

2

0D

I

U

11.5

0.5

0

0.6

0.5

0.4

•0.3

0.2

0.1

01 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Cell Number .- Shift 4 -Shift 8 _Shift 12 .Shift 16 -Shift 20 -Shift 24

Column: solid, 1 meq X- Imeq Na+; liquid, I meq/1 Na+ Flushing solution: 2 meq/1 K+

1 2 3 4 5 6 7 8 9 1011 12 13 14 15 16 17 18 1920 Cell Number

_Shift 4 _Shift 8 _Shift 12 -Shift 16 _Shift 20 -Shift 24

Column: 1 meq/1 X- I meq/! Na+; liquid, lmeq/I Na+ Flushing ,n: 2 meq/! K+

I I. I I I

I1.1 1

0.9

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1 0

1 2 3 4 5 6 7 8 9 1011121314151617181920 Cell Number

.Shift 4 - Shift 8 -Shift 12

-Shift 16 - Shift 20 .- Shift 29 Column: solid, I nwq/i X- Imeq/1 K+; liquid, I msq/1 K+ Flushing solution: I meq/l Na+

0.14

0.12

no 0.1

I0.08

"0.06

0 0.04

0.02

0

/Column: s( Fku.qhing so

0.13 0.12

0.11

0.1

,..0.09 0.08

0.07

0.06

0.05

0.04

0.03

0.02

123456 7 8 9 101112 13 14 15 1617 18 1920 Cell Number

_Shift 4 , Shift 8 Shiftl 12 -Shift 16 . Shift 20 - Shift 29

Column: solid, I meq/o X- Imeq/! K+; liquid, I meq/i K+ Flushing solution: I meq/i Na+

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 "homusandths

Co'centration (meq/mi) lid, I mtq4 X- I r •-; liquid, I mcq/I K+ lution: ImeQ/I Nai ..

4)

0

I 4) C.)

0 U

0

Q

1.1

0.9

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

01 2 3 4 5 6 7 8

Cell Number .Shift 100 - Shift 200 . Shift 400

Shift 600 , Shift 800 Column: solid, 167 meq/I X- 167 meq/! Na+; liquid, I mcq/! Na+ Flushing Solution: I meq/l K+

0.025

0.02

,,9,10.015

0.01

0.005

0

110,

100

90

80

70

60

50

40

30

20

IA9 .10 1 2 3 4 5 6 7 .8

Cell Number _ Shift 100 _ Shift 200 , Shift 400

-- Shift 600 . Shift 800 Column: solid, 167 meq/l X- 167 me/I Na+; liquid, I meq/i Na+ Flushing solution: I moq/l K+

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 Thousa-bhs

Concentrat: )eq/ml) Column: solid, 167 mcq/! X- 167 m%4 Na+, ,.id I meq/l Na+

9 10

)

1.1

0.9

0.8 0.7 0.6

0.5

0.4

0.3

0.2

0.1

01 2 3 4 5 6

Cell Number

4

3.5

M 2.5

2

1.5

7 8 9 10

__Shift 100 -Shift 200 _Shift 400

-Shift 600 . Shift 800 Column: solid, 167 meq/1 X- 167 meq/! K+; liquid I meq/l K+

Flushing solution: I meq/l Na+

00

4)

0

8 0 U

3.5

3

2.5

1

0.5

0

Column: F"1whinp

1 2 3 4 5 6 Cell Number 7 8 . 9 10

Shift 100 - Shift 200 . Shift 400 Shift 600 _. Shift 800

Column: solid, 167 meq/l X- 167 mcq/l K+; liquid, I meq/l K+

Flushing solution: I meq/l Na+

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 Thouanth

C--"•entration (meq/ml) solid, 167 mq/i X- I K+; liquid I meq/I K+ solution: I meo/l Natf

1 1.1

4)

0

I 4) U

0 U

S.J

A.1A

0.9

0.8

0.7

0.6 0.5

0.4

0.3

0.2

0.1

0

0.1

0.6

0.5

"~04

S0.3

0.2

0.1

01 2 3 4 5 6 7 8 9 1011 12 13 14 15 16 17 18 19 20 Cell Number

_-_ Shift 20 . Shift 40 -.- Shift 60

-- Shift 80 , Shift 100 Column: solid, I meq/I X- I mWq/l Na+; liquid, 1 meq/! Na+ Flushing solution: 0.001 meq/! K+

0.7

0.6

S0.5

0.4

" 0.3

c• 0.2

0 0.1 0.2 0.3 0.4

Cowr Column: solid, I mnq/1 X- I meqd Flushing solution: 0.001 mwq/l K+

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Cell Number

-.- Shift 20 . Shift 40 . Shift 60-,-Shift80 -.--Shift 100

Colum: solid, I meq/! X- I meq/i Na+; liquid, I mcq/i Na+ Flushing solution:0.001 meq/i1 K+

0.5 0.6 0.7 0.8 0.9 MilliontLh "ýqi.on (meq/mN) ýIud, I awo/ Na+

I 1.1

0'

U

1.1

I

0.9

0.8

0.7

0.6

° 0.5

0.4

0.3

0.2

0.1

01 2 3 4 5 6 7 8 9 1011121314151617181920

Cell Number

_Shift 4 , Shift 8 _Shift 12

-Shift 16 _._ Shift 20 Shift 24 Column: solid, Imcq/l X- I meq/% K+; liquid, I mq/1 K+ Flushing solution: 0.001 meq/l Na+

0.03

0.025

Coot 0.02

•~ j 0.015

0.01

0.005

00 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

Milionths

Concentration (meq/ml) Column: solid, I moq/o X- I meq/1 Kj- "id, I meq/1 K+ Flushing solution: 0.001 mWq/l N&)+

1 2 3 4 5 6 7 8 9 10 If 12 13 14 15 16 17 18 19 20 Cell Number

_Shift 4 - Shift 8 -Shift 12 _-Shift 16 ,. Shift 20 -- Shift 24

Column: solid, I meq/I X- I meq/I K+; liquid, I meq/I K+ Flushing solution: 0.001 meq/I Na+

1 1.1

0.03

0.025

0.02

f,0.015

0.01

0.005

0

4)

0

I 4) U

0 Q

--7 .,,,/'

i i t t I I I

/

Conclusions Isotherm need not be linear to calculate retardation from KD. If isotherm is convex up, retardation corresponds to

KD at maximum concentration.

Isotherm is linear when radionuclide is trace relative to the competing cation

However, J-13 is a very dilute solution. Therefore, U, Np, Cs, and Tc may not be occur in trace amounts.

SORPTION MODELING FOR HIGHLEVEL WASTE PERFORMANCE

ASSESSMENT

PRESENTED,

by

David R. Turner

AT THE NRC/DOE TECHNICAL EXCHANGE Los Alamos National Laboratory

October 13, 1993

CENTER FOR NUCLEAR WASTE REGULATORY ANALYSES SOUTHWEST RESEARCH INSTITUTE

San Antonio, Texas

CNWRA Project Manager: H. Lawrence McKague NRC Project Manager: G. F. Birchard

Investigators: Roberto T. Pabalan, David R. Turner, and Paul Bertetti

T"H EXCHD 10l pg.1

SORPTION MODELING FOR HLW PERFORMANCE ASSESSMENT

OBJECTIVES:

TASK 2 - SORPTION MODELING:

DEVELOP SIMPLIFIED SORPTION MODELING APPROACHES AND EVALUATE THEIR ADEQUACY FOR PERFORMANCE ASSESSMENT NEEDS

INVESTIGATE APPLICATION OF EXISTING COUPLED HYDROGEOCHEMICAL TRANSPORT CODES

TASK 3- SORPTION EXPERIMENTS:

DERIVE EXPERIMENTAL DATA ON SORPTION OF URANIUM AND OTHER RADIONUCLIDES

EVALUATE EFFECTS OF SOLUTION CHEMISTRY AND ROCK/MINERAL PROPERTIES ON RADIONUCLIDE SORPTION

IDENTIFY SORPTION PROCESSES/MECHANISMS IMPORTANT TO THE YUCCA MOUNTAIN ENVIRONMENT

TECHEXCH-10I93 pg2

SORPTION MODELING FOR HLW PERFORMANCE ASSESSMENT

ACCOMPLISHMENTS FROM PROJECT INCEPTION (9/90):

COMPLETED EXTENSIVE LITERATURE REVIEW OF SORPTION MODELING AND REACTIVE TRANSPORT (TASK 1)

TASK 2:

• IDENTIFIED, ACQUIRED AND INSTALLED SORPTION CODES

-MINTEQA2 SORPTION/SPECIATION CODE (Allison et al., 1991) -FITEQL PARAMETER OPTIMIZATION CODE (Westall, 1982)

• DEVELOPED RADIONUCLIDE THERMODYNAMIC DATABASE FORMATTED FOR SORPTION MODELING USING MINTEQA2

ANALYSIS OF POTENTIOMETRIC TITRATION DATA TO DERIVE. MODEL-SPECIFIC ACIDITY CONSTANTS FOR SIMPLE (HYDR)OXIDES

COMPILATION AND ANALYSIS OF AVAILABLE RADIONUCLIDE SORPTION DATA USING SURFACE COMPLEXATION MODELS

TECHEXCH- 10W93 pg.3

f

r

SORPTION MODELING FOR HLW PERFORMANCE ASSESSMENT

TASK 3:

CONDUCTED EXPERIMENTS ON URANIUM SORPTION ON CLINOPTILOLITE, ALUMINUM-OXIDE, AND MONTMORILLONITE

DISTINCT MINERAL STRUCTURE AND SURFACE PROPERTIES

VARIABLE SOLUTION CHEMISTRY (E.G., pH AND YU), BUT FIXED pCO2 (ATMOSPHERIC).

VARIABLE SURFACE-AREA/SOLUTION-VOLUME RATIO

CONDUCTED CAREFUL CONTROL EXPERIMENTS TO CHARACTERIZE EXPERIMENTAL LOSS TO CONTAINER, FILTERS, PIPETTES, ETC.

TECHEXCH- 10/93 pg.4

(

SORPTION MODELING FOR HLW PERFORMANCE ASSESSMENT

SURFACE COMPLEXATION MODELS (SCMs): ALL MODELS CORRECT FOR ELECTROSTATIC EFFECTS REPRESENTATIONS OF MINERAL-WATER INTERFACE

USING DIFFERENT

CONSTANT CAPACITANCE

K7OH 0

-OH2

OH

- OH2An

0I)

0

DIFFUSE-LA YER

rOH -0

OH2 +

- OH

- OH2An*

(+0)

0 a.

+2 Cat

An Cat+2

An

I-,

4)

0 a4J

Distance

TRIPLE-LA YER

-OH

-0

-OH

Cat÷g

An

Cat~s

(*d)

a ,=-O.117411 sinh(zF*d/2RT)

XdDistanceDistance

;/

SORPTION MODELING FOR HLW PERFORMANCE ASSESSMENT

GOAL: A UNIFORM APPROACH TO DETERMINE BINDING CONSTANTS FOR SURFACE COMPLEXATION MODELS

NEEDS:

DATA:

MODEL-SPECIFIC PARAMETERS TO DESCRIBE MINERAL ACID-BASE BEHAVIOR BASED ON UNIFORM DATA

MINERAL POTENTIOMETRIC TITRATION DATA FROM OPEN LITERATURE

Mineral Generalized PHzpc Reference(s) Asp (m2/g) (_1 )

Goethite 50 8.0±0.8 Hsi and Langmuir (1985); Hayes et al. (n-l ) (1990); Yates and Healy (1975); Balistrieri

and Murray (1981); Mesuere (1992)

Ferrihydriteca) 600 8.0±0.1 Hsi and Langmuir (1985); Davis (1977); (n-9) Swallow (1978); Yates (1975)

Magnetite 5 6.7±0.1 Regazzoni et al. (1983) (n-2)

Pyrogenic-SiO2 175 2.8±0.3 Abendroth (1970); Bolt (1957) (n-3)

ct-A1203 12 8.9±0.4 Hayes et al. (1990) (n-4)

y-AI0 3 120 8.4±0.3 Huang and Stumm (1972); Sprycha (1989) (n-3)

5-MnO1 270 1.9±0.5 Murray (1974); Catts and Langmuir (1986) (n-7)

TiO,(anatase) (b) 6.1±0.2 Sprycha (1984); Berube and de Bruyn (1968) (n-2)

TiO,(rutile) 30 5.9±0.3 Berube and de Bruyn (1968); Yates (1975) (n-4)

(a)Values recommended in Dzombak and Morel (1990). (b)The reported value of 16 m2/g used with data of Sprycha (1984); 125 m2/g used with data of Berube and de Bruyn (1968).

SORPTION MODELING FOR HLW PERFORMANCE ASSESSMENT

Model Comparison

Goethite-Weighted Values0.00010

0.00005

0.00000

-0.00005

-0.000104 5 6 7 8 9 10

pH

Rutile-Weighted Values

0 E

00 F--

0.00020

0.00010

0.00000

-0.00010

-0.000204 5 6 7 8

pH

TECHEXCH-1 0/g3 pg.7

0 E

-0

SORPTION MODELING FOR HLW PERFORMANCE ASSESSMENT

SORPTION OF U(VI) ON GOETHITE Experimental data from Hsi & Langmuir (1985)

U(VI)T = 10-5 M; 0.1 M NaNO3; No CO2

Diffuse Layer Model (DLM) Constant Capacitance Model (CCM) 100. I -aQQ m

.0 (0

80

60

40

20

03 4 5 6 7 8 9 10

pH

3 4 5 6 7 8 9 10

pH

Triple Layer Model (TLM)

3 4 5 6 7 8 9 10

LEGEND

0 Experimental -XOH-UO

2 + -- - XOH-UO20H -XOH-UO

2 (OH) 2 .

------.XOH-UO

2 (OH) 3 -XOH-UO

2 (OH) 4 - XOH-UO

2(OH) 4 with wtd Log K

pH

TECHeOCH.-I pg.8

"-a

0 V,,

5

100

80

60

40

20

0

.0

D N./

100

80

60

40

20

0

SORPTION MODELING FOR HLW PERFORMANCE ASSESSMENT

Kaolinite [A12Si20 5(OH)J - SiOH0 :AIOH0 = 1:1 Biotite [K(MgFe)3A1Si30 10(OH)2 l -- SiOHO:AIOHo = 3:1

SORPTION OF U(VI) ON KAOLINITEDiffuse Layer Model (DLM)

U(VI)T= lxlO-' M0.1

=1 =4

M NaNO3

1 m2/g

g/l

(a)-

LEGEND 0 Experimental Data

- Model Results

(XO-UO 2+ 2'

X0H-UO22 +

and XO-U0 2iOH)

Data fro~m Payne et al.

0

3 4 5 6 7 8

pH

SORPTION OF Np(V) ON BIOTITE.2

Diffuse Layer Model (DLM)

* ' i *" I ' I

NNp(V)T= 6x10- 6 M

I = 0.1 M NaNO3 A = 8 m 2/g

C3 = 1 g/l

L Data from Nakayama and Sakamoto (1991)

4 5 6 7 8 9

(b)

(

10 11 12TECHO(CH- IO/3 pg.9

a, .0

03

5

100

90 80 70 60 50 40 30 20

10 0

a, -o 0

z N

100 90

80 70 60 50 40 30 20 10

0

LEGEND 0 Experimental Data

-Model Results

(XO-NpO2 OH and XOH-NpO2÷)

I.=

J

I =!

I i •

pH

SORPTION MODELING FOR HLW PERFORMANCE ASSESSMENT

URANIUM CONCENTRATIONS IN CLINOPTILOLITE SORPTION EXPERIMENTS:

Clinoptilolite Expt.: Final U conc. vs pHeu, 600

400 E CCOGC 0

4 0 0- 0 400 E- - o

200 7 9:

- .Ui i - 500 ppb 0

- - -6 . . . . , . . . . , . . . . .. , .. . . .

o. so.- •O~o0 go 0 6 . cc

.9 4 I- 0-1

.2 40F 30 0

o 20E-0

S~ E~s -o~ -50 ppb ~ 00

s E- •bg 9 o 0 8

4 .

3•

1- 0 0

1[-- u . -_i -Uim 5 ppb

1 2 3 4 5 6 7 8 9 10 pHeqi

TECHEXC4-10/W3 m10

SORPTION MODELING FOR HLW PERFORMANCE ASSESSMENT

URANIUM CONCENTRATIONS IN a-A120 3 EXPERIMENTS:

A12 0 3 Experiment: Final U concentration vs pH,.•

Surface area: 0.0686 m2/g

120

. 100

0. L =• 80

-0-

o •

o 40i

20 "

Surface area: 0.229 m2/g

,I ,

CZ 00

' .. 0 '•0

120

100

80

60

40

20

0 m

FSurface area: 2.09 m2Ig

2 3 4 5 6 7 8 9 10

TECH EXCH-1013 pg,1 I

120 ,

100 V

so F-

60

40

2 0 ,

*1

4

-4 �1 -I

2 -4

j J

I

I

~~~1 1 1-.. . . . . . . . . . I l, - 1 1 1 1 1 . . .

, , f • . I I I

SORPTION MODELING FOR HLW PERFORMANCE ASSESSMENT

URANIUM CONCENTRATIONS IN CONTROL EXPERIMENTS (NO MINERALS PRESENT):

Clinoptilolite Expt.: Initial U conc. vs pHequil 550 ...

5 0 0 % =0 0

450- " I r 0

400 rU

-� -Ui• 500 ppb

350 '

CL

3 0. 0.

0J

60 .. ,

40i

30 E Uim - 50 ppb

20 i

6

5

4

3

2

1

01 2 3 4 5 6 7 8 9 10

TECHEXCH-+1G'W 1.12

(

SORPTION MODELING FOR HLW PERFORMANCE ASSESSMENT

SURFACE CHARACTERIZATION:

*MOLECULAR DYNAMICS SIMULATION OF URANIUM SORPTION (MOLECULAR SIMULATIONS SOFTWARE; M. LUPKOWSKI, SwRI)

-THEORETICALLY-BASED THROUGH ENERGY MINIMIZATION AND NEWTON'S SECOND LAW (F = me a)

-SIMULATE EFFECTS OF AQUEOUS SPECIATION AND MINERAL STRUCTURE

-COMPLEMENTS INFORMATION DERIVED FROM SORPTION EXPERIMENTS AND SPECTROSCOPIC STUDIES (E.G., EXAFS)

*INITIATED CHARACTERIZATION OF MINERAL SURFACES USING ATOMIC FORCE MICROSCOPY

TECHEXCH- 10/93 pg.13

SORPTION MODELING FOR HLW PERFORMANCE ASSESSMENT

MOLECULAR DYNAMICS: U0 2(CO 3)34- -BOND ANGLES AND LENGTHS BASED ON CRYSTALLOGRAPHIC DATA

TECHEXCH-10/93 pg.14

(

SORPTION MODELING FOR HLW PERFORMANCE ASSESSMENT

MOLECULAR DYNAMICS: U0 2(CO3 )34- ADSORPTION ON c-A1203 ENERGY DISTRIBUTION (NEGATIVE SURFACE CHARGE):

1ECHEXCH-10/93 pg. 15

Potential Energy of uco3 on olumina

0 E

C,,

0

Uj

1 400

1 200

1 000

800

600

400

200

0

total electrostatic vdw

0 1 2 3 4 5 6 " 7 8 9 10 11 distance (Angslrorns)

<V?

I

!

SORPTION MODELING FOR HLW PERFORMANCE ASSESSMENT

LiT IuMAMUb: UO2(CO 3)34 ADSORPTION ON at-A120, WITH

04,

AWOO

a

�,

0

we.

vrip4.9to'

01%~P .40W*

TECHEXCH4-1013 mg.8

*mr�u � BE A - � a amu�IVIYl~l-%LJLR 3

9

(

SORPTION MODELING FOR HLW PERFORMANCE ASSESSMENT

NEXT YEAR'S PROSPECTIVE

TASK 2

EXPAND AND CONTINUE MODEL COMPARISON AND STREAMLINING; EVALUATE PREDICTIVE CAPABILITIES

HYDROGEOCHEMICAL MODELING OF LABORATORY-SCALE TRANSPORT

CONTINUE TO MODEL U-SORPTION RESULTS FROM TASK 3 - SORPTION EXPERIMENTS

MODEL EFFECTS OF p(CO2), SOLID/LIQUID RATIO, Cradlonuclide, IONIC STRENGTH

RESULTS TO BE PRESENTED AT MIGRATION '93 (CHARLESTON, SC; DECEMBER, 1993)

TECHEXCI--10/93 pg. V

\

/

SORPTION MODELING FOR HLW PERFORMANCE ASSESSMENT

NEXT YEAR'S PROSPECTIVE:

TASK 3:

CONTINUE SORPTION EXPERIMENTS ON CLINOPTILOLITE, MONTMORILLONITE, AND ALUMINUM OXIDE (VARIABLE pCO2)

INITIATE BATCH AND FLOW-THROUGH COLUMN EXPERIMENTS ON URANIUM SORPTION AND TRANSPORT USING WEDRON QUARTZ SAND

INITIATE BATCH SORPTION EXPERIMENTS ON NEPTUNIUM

*INPUT EXPERIMENTAL DATA INTO TASK 2 (SORPTION MODELING)

CONTINUE MOLECULAR DYNAMICS SIMULATIONS OF URANIUM SORPTION

CONTINUE CHARACTERIZATION OF MINERAL SURFACES USING ATOMIC FORCE MICROSCOPY (USING FLUID CELL)

RESULTS TO BE PRESENTEDAT MIGRATION '93 (CHARLESTON, SC; DECEMBER, 1993)

TECHEXCH-1O/93 pg.18

REFERENCES

Abendroth, R.P. 1970. Behavior of pyrogenic silica in aqueous electrolytes. Journal of Colloid and Interface Science 34: 59K-596.

Allison, J.D., D.S. Brown, and Kd. Novo-Gradac. 1991. MINTEQA2IPRODEFA2, A Geochemical Assessment Model for Environmental Systems: Version 3.0 User's Manual. EPA/600/3-91/021. Athens, GA: U.S. Environmental Protection Agency.

Balistrieri, L., and J.W. Murray. 1981. The surface chemistry of goethite (a-FeOOH) in major ion sea water. American Journal of Science 281: 788-806.

Berube, Y.G., and P.L. de Bruyn. 1968. Adsorption at the rutile-solution interface. 1. Thermodynamic and experimental study. Journal of Colloid and Interface Science 27: 305-318.

Bolt, G.H. 1957. Determination of the charge density of silica soils. Journal of Physical Chemistry 61: 11661169.

Catts, J.G., and D. Langmuir. 1986. Adsorption of Cu, Pb and Zn by 8-MnO2: Applicability of the site binding surface complexation model. Applied Geochemistry 1: 255-264.

Davis, J.A., and J.O. Leckie. 1978. Surface ionization and complexation at the oxide/water interface 2. Surface properties of amorphous iron oxyhydroxide and adsorption of metal ions. Journal of Colloid and Interface Science 67: 90-107.

Davis, J.A., and J.O. Leckie. 1979. Speciation of adsorbed ions at the oxide water interface. Chemical Modeling in Aqueous Systems, Speciation, Sorption, Solubility, and Kinetics. E.A. Jenne, ed. Washington, DC, ACS Symposium Series 93. American Chemical Society: 299-317.

Davis, J.A., R.O. James, and J.O. Leckie. 1978. Surface ionization and complexation at the oxide/water interface 1. Computation of electrical double layer properties in simple electrolytes. Journal of Colloid and Interface Science 63: 480-499.

Dzombak, D.A., and F.M.M. Morel. 1990. Surface Complexation Modeling: Hydrous Ferric Oxide. NY: John Wiley and Sons.

Hayes, K.F., G. Redden, W. Ela, and J.O. Leckie. 1990. Application of Surface Complexation Models for Radionuclide Adsorption: Sensitivity Analysis of Model Input Parameters. NUREG/CR-5547. Washington, DC: U.S. Nuclear Regulatory Commission. Hsi, C-K.D, and D. Langmuir. 1985. Adsorption of uranyl onto ferric oxyhydroxides: Application of the surface complexation site-binding model. Geochimica et Cosmochimica Acta 49: 1931-1941.

Huang, C.P., and W. Stumm. 1972. The specific surface area of yL-A1 20 3. Surface Science 32: 287-296.

James, R.O., and G. Parks. 1982. Characterization of aqueous colloids by their electrical double-layer and intrinsic surface chemical properties. Surface and Colloid Science 12: 119-216.

TECHEXCH.-10/M s19

Mesuere, K.L.G. 1992. Adsorption and Dissolution Reactions Between Oxalate, Chromate, and an Iron Oxide Surface: Assessment of Current Modeling Concepts. Ph.D. Dissertation. Beaverton, OR: Oregon Graduate Instituto of Science and Technology.

Mesuere, K.L.G., and W. Fish. 1992. Chromate and oxalate adsorption on goethite. 1. Calibration of surface complexation models. Environmental Science and Technology 26: 2357-2364.

Murray, J.W. 1974. The surface chemistry of hydrous manganese dioxide. Journal of Colloid and Interface Science 46: 357-371.

Nakayama, S., and Y. Sakamoto. 1991. Sorption of neptunium on naturally-occurring iron-containing minerals. Radiochimica Acta 52/53: 153-157.

Payne, T.E., K. Sekine, J.A. Davis, and T.D. Waite. 1992. Modeling of radionuclide sorption processes in the weathered zone of the Koongarra ore body. Alligator Rivers Analogue Project Annual Report, 19901991. P. Duerden, ed. Australian Nuclear Science and Technology Organization: 57-85.

Regazzoni, A.E., M.A. Blesa, and A.J.G. Maroto. 1983. Interfacial properties of zirconium dioxide and magnetite. Journal of Colloid and Interface Science 91: 560-570.

Sprycha, R. 1984. Surface charge and adsorption of background electrolyte ions at anatase/electrolyte interface. Journal of Colloid and Interface Science 102: 173-185.

Sprycha, R. 1989. Electrical double layer at alumina/electrolyte interface. Journal of Colloid and Interface Science 127: 1-11.

Swallow, K.C. 1978. Adsorption of Trace Metals by Hydrous Ferric Oxide. Ph.D. Dissertation. Cambridge, MA: Massachusetts Institute of Technology.

Tripathi, V.S. 1984. Uranium(VI) Transport Modeling: Geochemical Data and Submodels. Ph.D. Dissertation. Stanford, CA: Stanford University.

Westall, J.C. 1982b. FITEQL: A Computer Program for Determination of Chemical Equilibrium Constants From Experimental Data, Version 2.0. Rpt. 82-02. Corvallis, OR: Department of Chemistry, Oregon State University.

Westall, J.C., and H. Hohl. 1980. A comparison of electrostatic models for the oxide/solution interface. Advances in Colloid and Interface Science 12: 265-294.

Yates, D.A. 1975. The Structure of the Oxide/Aqueous Electrolyte Interface. Ph.D. Dissertation. Melbourne, Australia: University of Melbourne.

Yates, D.A., and T.W. Healy. 1975. Mechanism of anion adsorption at the ferric and chromic oxide/water interfaces. Journal of Colloid and Interface Science 52: 222-228.

TECHEXCI-1-193 pg.20

(

GEOCHEMICAL MECHANISMS AND EFFECTS OF VAPORIZATION IN THE NEAR FIELD OF A PROPOSED REPOSITORY

AT YUCCA MOUNTAIN

William M. Murphy Center for Nuclear Waste Regulatory Analyses

San Antonio, Texas

This presentation documents work performed at the CNWRA for the U.S. NRC under Contract No. NRC-02-88-005. The report is an independent product of the CNWRA and does not necessarily reflect the views or regulatory position of the NRC. The author is grateful to Randy Arthur, John Walton, and Richard Codell who contributed intellectual stimulus and creative technical input. Christopher J. Goulet provided talented assistance with computations and graphics. Most computations were performed with EQ3/6 version 7.1 using R12 and R16 data bases (Wolery, 1992).

GEOCHEMICAL MECHANISMS AND EFFECTS OF VAPORIZATION IN THE NEAR FIELD OF A PROPOSED REPOSITORY

AT YUCCA MOUNTAIN

OUTLINE

I. Partial equilibrium, multicomponent, reaction path model for natural conditions

II. Nonisothermal, kinetic, multicomponent, partial equilibrium, reaction path model for heated repository conditions

III. Local equlibrium, multicomponent, 100'C, reaction path model for boiling to 99.6% dry, assuming CO2 buffering, using extended Debye Huckel equation

IV. Rayleigh fractionation model for C02 and H20 volatilization for the carbonate system at 1000C

V. Local equilibrium, multicomponent (with no silica), 250C, reaction path model for evaporation to 99.997% dry, assuming alternate buffered C02 pressures, using Pitzer equations

/

I

-J

z

le-3 l 1 , 0e+0 le-4 2e-4 30-4

Ca MOLALITY

10-4 2e-4 3e-4

Ca MOLALITY

0 0

0

40-4 5e-4

4e-4 54

=

0

D-4

I 2e-4

10-4

50-5

00+0

5e-3

40-3

3e-3

2e-3

1e-3

le-4 20-4 30-4 4e-4 50-4 Ca MOLALITY

0 0+0 1 , 1

0e+0 le-4 20-4 3e-4 4e-4 Ca MOLALITY

:-J

-J 0 =2

F5

le-3

9e-4

80-4

70-4

6e-4 0•

C

0 0 0 0

0 0

00 -0 0

0 0 0

0 0

0

0

+I3+0 50-4

/

vv v A1.2e-3

z 1.0e-305e-3 -z TOTAL SILICA

0 I- I--: 'HCO3 &:< .e-4•

z Iw z o 4e-3 z o 6.0e-4• O z TOTAL POTASSIUM oNa0

< • • 4.00-4-• 0 3e-3 -I• /_

0 Z2.0-4

TOTAL CALCIUM

0 1000 2000 3000 4000 0.00+0 0 1000 2000 3000 4000

TIME, YEARS TIME, YEARS

8.0- 0.016

C D 6e-3 FELDSPAR

7.8 0.014 (DISSOLVED)

vpH

7.6 -0.012 4 S403

40.010 CLINOPTILOLITE

c* o2e-37.2J SMECTITE

2 FUGACITY CALCITE

7.0 5 0.006 00.+0 0 100 200 300 400 500 0 1000 2000 3000 4000

TIME, YEARS TIME, YEARS

�1

6•-3

i

100.4

z

I- 0.3 w Iz ul 0 U z 0.2 0

o 0.1

0.0 0.0 0.2 0.4 0.6 0.8 1.0

FRACTION BOILED

0.01 ý--

0.992 0.994 FRACTION BOILED

0.0 0.2 0.4 0.6 0.8 FRACTION BOILED

9.7

9.6

9.5.

9.49 0.0900.996 0.992 0.994 0.996

FRACTION BOILED

)/

x C.

I0 z w I@1

2

1.0

1.0

0.8

. 0.6 :J

O 0.4

0.2-

NaC

TTOTAL C

HC00 OT

K Si CI

0.990

D

pH

IONIC STRENGTH

1.4

1.2 x I

0

-1.0wU

0.8 2 0

'0.6

'I

(

320

(

R.C. Arthur and W.M. Murphy

Sci. G,•,L,. Dul., 42, 4. p. 313- 327, Stasbours, 1989

AN ANALYSIS OF GAS-WATER-ROCK INTERACTIONS DURING BOILING IN PARTIALLY SATURATED TUFF

Randolph C. ARTHUR* and William M. MURPHY"

- Figure 2

Speciation of dissolved carbonate and H 2 0 relative to the fraction of H 20 remaining in the liquid phase, *, during opensystem boiling. The initial system is represented by values at

1= , and the system evolves to the left.

1.0 Distribution des espices aqueuses dans ke systime C0 2 -H 2 0 en fonction de to faction de La mwwe deau prisente dans /a phase

VATER liquide, V/ , durant rdbulition en systime ouvert. Le systime Initial correspond ý- = 1. et rA'olution du systime seffectue de Ia droite wers la gauche.

(.

.Adl aiI5.OE-1

4.OE-1

3.OE-1

2.OE-1

1.OE-1

0.OE+0

v.Uu

I I U I UI I I I I I

10 20 30 40 50 6

MOLES OF H2 0 EVAPORATED

9.5

9.0

8.5

8.01

Na+

HCO3"

HC0 3 2 01- 1

CO32 .

Cl-

0 10 20 30 40 50 60 MOLES OF H20 EVAPORATED

54.0 54.5 55.0 55.5 5f MOLES OF H2 0 EVAPORATED

III-Io

6.06A0

00)A 4.0

2.0-

0.0 53.5

D

5 I I II I I 1

54.0 54.5 55.0 55.5 56.0

MOLES OF H20 EVAPORATED

(

0

0

0

7-'

H2 0 ACTIVITY x 10

z

0

IONIC

I

H2 0 ACTIVITY S.............. 0.,0

\

E

7-

EVAPORATION MODEL 250C, NO SILICA, DOLOMITE SUPPRESSED, HIGHER p CO 2

PITZER EQUATIONS (HMW)

Percent Boiled

Mineral Assemblage

Dominant Water Chemistry

pH NBS/rational

Ionic Strength

Calcite (CaCO3)

+Magnesite (MgCO3)

+Nahcolite (NaHCO3)

+Thenardite (Na2SO4)

+Halite (NaCl)

+Aphthitalite (NaK3(S04)2)

Na+,HCO3

Na+,HCO3

Na+,C032-,HCO3

Na+,Cl-,(S042-)

Na+,Ci-,(SO42-)

Na+,Cl-,(K+, S042-)

Na+,Cl-,(K+, S042-)

0.0

22.6

99.59

99.973

99.979

99.988

8.0(7.9

8.1/8.0

9.4/9.1

8.7/9.4

8.6/9.6

8.6/9.6

0.014

0.018

4.0

8.5

8.4

8.9

99.997 8.6/9.6 8.9

EVAPORATION MODEL 250C, NO SILICA, DOLOMITE SUPPRESSED, LOWER p C02

PITZER EQUATIONS (HMW)

Percent Boiled

Mineral Assemblage

Dominant Water Chemistry

pH NBS/rational

Ionic Strength

none

Calcite (CaC03)

+Magnesite (MgCO3)

+Halite (NaCl)

+Pirssonite (Na2Ca(C03)292H20)

+Sylvite (KCI)

+Aphthitalite (NaK3(SO4)2)

Na+, HCO3-, Cl

Na+,HCO3-,CI

Na+,Cl-,HCO3

Na+,Cl-,K+,(CO32-)

Na+,Cl-,(K+,C032-)

Cl-,Na+,(K+)

Cl-,Na+,(K+, S042-)

8.0/8.0

8.0/8.0

8.2/8.1

9.0/10.0

9.3/10.1

9.3/10.2

9.3/10.3

0.0

7.1

57.4

99.965

99.983

99.993

99.997

0.005

0.0055

0.009

6.5

7.1

7.8

8.4

/

K

CONCLUDING REMARKS: SPECULATIVE GEOCHEMICAL CONSEQUENCES OF VAPORIZATION

RELEVANT TO REPOSITORY PERFORMANCE

SOLUTIONS AT A REWETTING FRONT WOULD DISSOLVE PRECIPITATED SALTS AND BECOME CONCENTRATED IN SODIUM, CHLORIDE, AND SULFATE

SOLUTIONS THAT DRIP ON CONTAINERS AND EVAPORATE WOULD EVOLVE TOWARD HIGHER pH, AND HIGHER SODIUM (BI-)CARBONATE AND CHLORIDE CONCENTRATIONS

WATER CHEMISTRY CHANGES WOULD AFFECT CONTAINER AND WASTE FORM ALTERATION PROCESSES AND RADIONUCLIDE SPECIATION

VAPOR PRESSURE LOWERING AT EQUILIBRIUM WITH SALTS COULD AFFECT MOISTURE DISTRIBUTION

MINERAL DISSOLUTION AND GROWTH COULD AFFECT HYDROLOGIC PROPERTIES OR FLOW PATHS

FLUID REFLUXING COULD AUGMENT EFFECTS OF VAPORIZATION

(k

U.S. DEPARTMENT OF ENERG

0 C R

"W YUCCA w MOUNTAIN

M

YUCCA MOUNTAIN SITE CHARACTERIZATION

m -- PROJECT

INTEGRATION WITH TOTAL SYSTEM PERFORMANCE ASSESSMENT (TSPA)

PRESENTED TO

DOE/NRC TECHNICAL EXCHANGE

PRESENTED BY

ARDYTH SIMMONS

OCTOBER 13, 1993

(

INTEGRATION WITH TOTAL SYSTEM PERFORMANCE ASSESSMENT (TSPA)

"* December 1991 workshop. "Integration of Geochemistry with

Performance Assessment"

"° Elicitation of Kd's for TSPA 1

"* March 1993 exchange on data needs for TSPA - TSPA defined needed parameters - Refined values of Rn solubilities; data using J-13 - Effect of temperature on solubility

° May 1993 attempted to incorporate colloid transport into TSPA 2

° Input to retardation sensitivity analysis - maintain iterative approach

° Hypothesis testing by PA to determine what information is needed with greater confidence

I NTPALA1 .125/10-12-93

cv)

6 7-Lo

ui

a. I-z

>E c!) w

Cl)

z w 2 cn Cl) w Cl) Cl) 4:x w U z

0 LL cem w am

(D

E E ow

/

SoIWOG Consensus Values for the Potential Range of Actinide Solubilities at Yucca Mountain and Environs

Radionuclide Minimum Maximum Expected Coefficient Distribution

Value Value Value of Variation

Uranium 10-8 10-2 10-4.5 0.20 log beta

Neptunium 5x 10-6 10-2 10-4 1 log beta (10-8) (0.20)___

Plutonium 10-8 10-6 - uniform (1 .0-10) .... ... . .

Americium 10-10. 10-6 - uniform All concentration values are in molarity units.

INTPALA24.125/10-12-93

(

Probability Distributions for Kd

Element (rock type) Distribution Mean value Illustrated in Type* (mI/g) Figure Number

Carbon, Iodine, Technetium constant 0

Tin, Plutonium, Americium constant 100

Uranium, Selenium (devitrified) uniform 2.5 3-11 Uranium, Selenium (zeolitic) beta 10 3-12 Uranium, Selenium (vitric) uniform 2 3-13

Neptunium (devitrified) beta 2 3-14 Neptunium (zeolitic) beta 4 3-15 Neptunium (vitric) beta 0.5 3-16

Cesium (devitrified) beta 50 3-17 Cesium (zeolitic) beta 2000 3-18 Cesium (vitric) beta 50 3-17

from TSPA (SNL, 1992)

INTPALA23.125/10-12-93

I

SUMMARY OF U.S. NUCLEAR REGULATORY COMMISSION AND U.S. DEPARTMENT OF ENERGY TECHNICAL EXCHANGE ON

NEAR-FIELD RADIONUCLIDE RELEASES FROM THE ENGINEERED BARRIER SYSTEM October 14, 1993, Los Alamos, NM

On October 14, 1993, representatives of the Nuclear Regulatory Commission, U.S. Department of Energy (DOE), State of Nevada Nuclear Waste Project Office, Nye County, Nevada, and Inyo County, California, participated in a technical exchange on near-field radionuclide releases from the engineered barrier system. The purpose of the technical exchange was to hold discussions on previous and on-going experiments and computer simulations of near-field phenomena for the Yucca Mountain candidate repository. The technical exchange agenda is included as Attachment 1 and the list of attendees is Attachment 2 to this summary. Copies of presenters' handouts are included in Attachment 3.

The exchange included presentations by DOE representatives from the Yucca Mountain Project Office (YMP) and Lawrence Livermore National Laboratory. Discussions focused on the effects of heat on the engineered barrier system (EBS) and the saturation of the rock, circulation of air and water vapor, effects of fractures, post-waste emplacement changes in water chemistry, and conceptual models of releases of radionuclides from the EBS. The agenda also included a presentation by an NRC consultant from the Center for Nuclear Waste Regulatory Analyses on analyses of thermally driven vaporization, condensation, and flow around waste packages.

All participants and attendees were provided opportunities for questions and discussion during the technical exchange. At the conclusion of technical exchange presentations, Ms. Ardyth Simmons (DOE YMP) provided a brief synopsis of the status of DOE activities to address unresolved NRC Site Characterization Analysis concerns related to the technical exchange topic.

In the closing remarks, all parties agreed that the presentations had been beneficial and that appropriate time had been allowed for discussion. NRC participants commented that key information related to spent fuel degradation should be integrated into experiments and noted the importance of the field heater tests. The State of Nevada representative observed that DOE activities and presentations appeared to emphasize matrix effects, and that future interactions should focus more on discussions of fracture and rock properties and fracture flow. The representative from Nye County stressed the importance of tests and modeling of the Calico Hills tuff because of that unit's importance to radionuclide migration. He also noted the importance of examining bounding scenarios in determining whether or not the hot and dry repository concept will be used. The Inyo, California, representative stressed the need for site data as input to models and the importance of examining mass transport in alternative ways to strengthen hydrochemical

ENCLOSURE 2

2

modeling efforts. He also stated that, because the technical content of performance assessment discussions is limited by the data available at this time, he believed that a discussion on experiments related to radionuclide releases from the waste form should have been substituted for this agenda item.

"Charlotte Abrams, Sr6.P.fject Manager Repository Licensing and Quality

Assurance Directorate Division of High-Level Waste Management Office of Nuclear Material Safety and

Safeguards U.S. Nuclear Regulatory Commission

Chr tian Einbe?•, Gene"ýl En'ine~r Regulatory Integratio Br nch Office of Civilian Radhjctive Waste

Management U.S. Department of Energy

AGENDA DOE-NRC TECHNICAL EXCHANGE

NEAR-FIELD PHENOMENA RELATED TO RADIONUCLIDE RELEASES FROM THE ENGINEERED BARRIER SYSTEM

October 14, 1993 at Los Alamos, NM

8:00 Welcome/Protocol

8:15 Overview of radionuclide release studies

8:45 Modeling effects of heat on the saturation of rock and on the circulation of air and water vapor and modeling of dripping in fractures in the heated zone

10:00 BREAK

10:15 Modeling of coupled processes in the altered zone

11:00 Testing geochemical modeling codes using New Zealand hydrothermal systems

11:30 Radiation effects on environmental conditions

12:00 LUNCH

1:15 Experiments on the interactions of steam and water with the components of the EBS

2:00 Integrated testing

2:45 BREAK

3:00 Conceptual models for releases of radionuclides from the EBS in realistic near- field environments (source term)

3:45 Thermally driven vaporization, condensation, and flow around waste package

4:30 SCA Open Items

5:15 Closing Comments

5:45 Adjourn

DOE, NRC, State, Counties

DOE (Simmons)

DOE (Buscheck)

DOE (Glassley)

DOE (Bruton)

DOE (Van Konynenburg)

DOE (McCright)

DOE (Viani)

DOE (Halsey)

NRC

DOE (Simmons)

DOE, NRC, State, Counties

NOTE: Each topic on the agenda includes time allotted for discussion.

H

14

15

16

17

12

14

15

216

22

23

24

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