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UCRL-ID-124984

Water Quality Considerations =

Project Travois

J. B. Knox

July 16,1968

This is an informal report intended primarily for internal or limited external distribution. The opinions and conclusions stated are those of the author and may or may not be those of the Laboratory. Work performed under the auspices of the U.S. Department of Energy by the Lawrence Livermore National Laboratory under Contract W-7405-ENG-48.

*,.

' . . .

: hw-ence Radiation Jaboratory ': L-42 K-Division, T-16

July 16, 1968

- m i 6 -docme No. 3=bf -- .-_ -

To: Distribution

J. B. I@ox

SUBJXCT: Water Quality Considerations - Project Travois.

The technical concept for Project Travois (6/1/68) contains one

simple analysis of the poten t ia l hazard of contaminating the Arrowrock Reservoir on the Boise River (some 16 miles from the Travois S i te ) , with some of xhe radionuclides produced.

homogeneous and prompt mixing of a l l the tritium and tungsten isotopes,

.

This previous analysis assumes

and \?85, i n tliis reservoir with the result t h a t CT = 2.0 I4PC (w)

This simple analysis is physi- and ~~$81 = .5 "PCw, Clr.+05 = 4.0 MPCw.

c a l l y unrea l i s t ic since there is, as we shall see, no way of transporting a l l of these radionuclides t o the reservoir, promptly.

paper reanalyze the contamination problem i n such a way that we define

We shall i n t h i s

t he t y p e of s i te geology nnd hydrology information that must be developed.

(a) T r i t i u m :

Assumptions:

1. The 40 kt Plotishare ExcavatioE Explosive'nrakes 800 kilocuries of tritium (Ref. unclassified source statement).

2. "Tne produced mixed i n the

3. The proposed

L

tritium is in the form of HM and uniformily 7 X 10

depth of bu r i a l is 200

6 cu yards of rubble.

DISCLAIMER

This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or use- fulness of any information, apparatus, product, or process disclosed, or represents that its usc would not infringe privately owned rights. Reference herein to any spe- cific commercial product, process, or service by trade name, trademark, manufac- turer, or otherwise does not necessarily constitute or imply its endorsement, Iccom- mendrtion. or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.

DISCLAIMER

Portions of this document may be illegible in electronic image products. Images are produced from the best available original document.

-. -- ?we 2

Problem I: The T r i t i u h i n the Retru'c.

Step 1.

Step 2.

Step 3.

If the proposed retarc could be completely f i l i e d with water the tritium concentration i n the water- f i l l e d voids i s

6 CT ( 0 ) = .8 >: 10 Ci/Vr Q

6 3 6 where Vr = the volume of rubble = 7 X 10 (.92) x 10 cc

Q = porosity (m.25)

Hence,

cT ( 0 ) = -54 pCi/cc

o r

CT ( 0 ) = 540 MPCu

where

Physically, CO(T) = 540 MPCw (T) cons t i tu tes the

dsymptotic value of the concentration f o r a pulse

of clean water precolating in to the retarc .

The maximum 24 hour r a i n f a l l ( i n 50 years of record)

I n the area is 3 inches. The volume of ra in vater f a l l i ng within the 515 foot-radius r e t a rc is

2 9 3 V = f i (16000) x 10 cc = 8 x 10 cc = 8000 m P

This volume of r a i n water is -4/1000 of the pore

space i n the retarc ,

Questlon: How fast does t h i s pulse of t r i t i a t e d trztcr nave out of the re ta rc?

IIydrology experience gives an estimated upper value for sub-surface, downhill flow of ground water i n f i s sures may be of the order of lOO'/day o r 3000

cnl/day ( B i l l Schell, pr ivate communication). From

c

Muskat (p. 425 Flow i n porous media), we can calcu- late the corresponding fracture width as .O3 cm. The da i ly volume flow f o r one fissure connecting re ta rc t o the h i l l s ide (See Figure 1) is

.03 (3000) L cc

where L is the lateral length of the fissure on the

h i l l s i d e (16000 cm); it is reasonable t o assume

about - ten such f issures since the postulated pulse of r a i n water f i l l s only 4/1000 of the r e t a r c ' s

pore space.

Under these conditions the volume of w a t e r seeping from the re ta rc t o the h i l l s ide (and hence t o the

stream) i s (10) x 1500 x 10 CC. The da i ly 3

tritium burden" given t o the stream under these I f

conditions is

540 (MPCw) 1500 X lo3 X 10.

Step 4. 'If the d i lu t ing power of the stream at l ow flow i s

suff ic ient , then no problem exis t s i n regard t o tritium from the retarc under the assumed conditions.

Such is the case if the "daily tritium burden''

divided by the minimum observed da i ly f low on the Boise River (124 c f s = 29 X 10" cc/day) is much smaller than 1.

540 TOL X 1500 X lo3 X 1O/day = -028 << 1.0 29 x 10'' X cc/day

Hence, we conclude for the assumed system t h a t tritium originating i n the re ta rc and percolating

t o the stream can be diluted suf f ic ien t ly by the low flow such that Clq (T) an entry t o the Arrowrock Reservoir i s less than X P C . This seepage source,

of the form discussed above, could last 8000/15 days. Th& current uncertainity i n the .028 EKP is large i n

1

Page 4

view of the absence of si te geologic data on f rac ture width s i ec t r a and t h e i r hydrologic

connection,

Discussion:

parameter i n the abuve analysis is, in my judgment, the f racture width in tha t the steady-state flow through a fracture i s proportional t o the cube of

the fracture width.

f rac tures connecting the re ta rc t o the h i l l s i d e

(or stream) are equally important. of the pre-shot f racture frequency and width at the Travois s i t e do not exist at t h i s t i m e , but are now planned by XCG. This organization has measured pre- and post-shot fractures a t Danny Boy (Paul

Fisher, private cornmication, 1968) with the

following results:

In t h i s regard,-the most sens i t ive

Pre-shot as vel1 as post-shot

Measurements

HOIX coimra P?X-SHOT POST- SHOT 7

. DA 2 edge of c ra te r 12/64" = -5 crn 14/64 I' DA 5 two cra te r r a d i i 10/64" = .5 cm 13/64"

These above fracture widths measured on Buckboard Mesa are > 10 times that assumed above. Should such

pre-shot fractures be shovn t o ex i s t at the Travois site, the above analysis would show 8 tritium w a t e r qua l i ty problem in the Boise River. I n t h i s event rn operational solution would be required, such a s p las t i c sheeting covering the retarc (and e j ec t a )

during precipitation (average annual -13 or 14 inches) for the post-shot operational phase.

L

Problem 11: T r i t i u m i n E j e c t a Outside of Retarc.

The surface area of the ear th covered with e j ec t a from the detonation w i l l be of the order of three times the radius of the r e t a rc (16000 cm) . The volume of ra in water falling on th i s e j ec t a is (from Problem I) -80,000 m 3 for conditions of extreme

da i ly r a i n f a l l . The "tritium burden" delivered t o the stream i n sheet runoff of t h i s extreme day is

6 540 X 80,000 x 10 (TOL) cc/day

The tritium concentration i n the stream after di lu t ion of the above tritium burden is given as follows as a function of average

da i ly flow:

Observed da i ly flow

124 c f s 1174 11200

Comments

min. in 50 years average max. in 50 years

Tritium Concentration i n the stream ( a f t e r mixing)

135 !rQL 13.0 TOL 1.2 TOL

The CT i n the stream result ing from leaching of HIXI from surface rubble suggests tha t in the absence of surface runoff diversion works near the retarc, there i s a r e a l poss ib i l i t y of a pulse of .

tritium i n excess of MPC star t ing downstream. engineers can, I believe, devise a scheme f o r re ta ining i n storage 80,000 m If aggregate is t o be washed pr ior t o use, such a provision f o r storage would be required, anyway.

Travois project ,

3 of t r i t i a t e d water fo r controlled release o r disposal.

Oar consideration of Problems I and I1 i l l u s t r a t e s two principles of water quali ty control - dilut ion ard isolat ion.

Winen the waterAsolution:, can be developed. The discussion of

these problems, hopefully, i l l u s t r a t e s t h i s approach. It also i l l u s t r a t e s the need t o use s i t e hydrology and f rac ture s tudies t o evaluate roughly, the problems of water quality.

+ ' tp grspW. e L p c h l k t % I y d e L.$, -c-&z~,

L

(b) Radionuclides other than tritium:

It i s per t inent t o examine some other radionuciides i n the same context of ProSlem I (leaching of re tarc material) and Problem I1 (leaching of e j ec t a and sheet-runoff t o tne strem). we consider L?" and whose rodqction on Travois have been

estimated to be 2.6 x 10

communication, 1968) .+' Ion exchange effects will be estimated as

For t h i s purpose

6 4% K I O b C ; CiA respectively (Howard Tewes, pr ivate

we assume 1/(1 i- K&D), the f ract ion of the nuclide appears

. . . . - . . . ~ ~ -. . .. .... . . .

Page 6

i n equi l ibrated solute, is equal t o or smaller than t h a t f o r Sr i n the same ion exchange material (crushed grani te) ( B i l l Schell and

H. Tewes, pr ivate communication, 1968). p. 26) estimated 1/(1 K

1/25. and ejecta, then we may generate the following estimates.

-- f iox (1963, UCRL-7350,

) f o r Srgo i n grani te chimney material as If the W-nuclides are homogeneously mixed i n chimney rubble

dp

Conc. i n solution . (wCi/cc/dry) with .ion exchange

The analysis f o r W-nuclides is now para l l e l t o that given abwe for tritium result tha t :

, Problem I

. (I) 50 year low da i ly flow provides suf f ic ien t dilution.

w185 '!

Problem I1

(11) Diversion of sheet runoff from max. storm is required.

Comments: through diversion, storage, and planned release (or disposal) , the controll ing fac.tor i s the sub-surface flow containing tritium,

Since the overland sheet runoff i s presumably controllable

For the postulated cases analyzed, t h i s source of potent ia l water contamination w a s shown t o be acceptable because of stream dilution. However, f rac ture premeability is proportional t o the cube of the fracture width (Phskat, p. 425); hence, we a re no% certain t h a t explosion produced fissures a t grea te r than two c ra t e r radii a r e < - .O3 cm, as assumed i n the analysis. t ha t :

A.

I strongly recommend

(a) Fracture widths be measured a t 1, 2, 3, o r more c r a t e r r ad i i and pre-shot a t Project Excavator and at the proposed Travois

s i t e as soon as possible.

(b) - A sui table t racer study for the re ta rcs of Project Excavator

be designed t o develop data in seepage rates and hence on

average connected fracture widths.

We request t ha t the NVOO contxactor (IDJS) perform the sui table

ion exchange measurements on coefficient is reported t o be very pH dependent.

( c ) and &85 whose dis t r ibut ion

Distribution :

Gibson, T . A. Higgins, G. H. Knox, J. B. Korver, 3. A. Hordyke, M. E. Shore, B. W. Tewes, H. A. Toman, J. Werth, G. C,

l/14 A 2/14 A

4/14 A

6/14 A

8/14 A 9/lk A

3/14 A

5/14 A

7/14 A

HoLxes, R. S. 10114 A Hughes, 13. C. 11/14 A Stead, F. (USGS) 32/14 A F i l e 13 44/14 A

. c

- 1 . . .

- ! 9 c

c-- Seepage paths

Schematic Profile: Travois

Figure 1.

i

‘\F I pulse f r

(4/1000 of rets =&M---maX. stc