TABLE 4, AVERAGE RADIONUCLIDE RATIOS

Location - . MSri/B8ICs — B8putAm — 22py/41Am
Galileo 15 not reported 5.0
Kepler 13 2.0 6.0
Whitney . 2.7 - 320. 99
Diablo 2.0 2.7 5.6
Baneberry 0.25 . 0.69 - 3.9
Smoky ~ 25 0.72 12
Sedan 0.82 10 5.5
Oberon ~* . 1.6 *. 0.13 6.7
Wilson, 19 052° 22
Quay 22 0.26 75
Hornet 33 0.70 8.1
Schooner 0.95 17 0.69
Cabriolet 1.0 1.95 0.90
Palanquin 0.93 0.93 2.6
Johnie Boy 5.2 19 11.
Little Feller 1 & 0 2.0 5 Q.12 . 5.7
Danny Boy 0.63 0.12 4.0
Areas 25 & 26 0.84 0.20 6.5
Area 15 14 13 6.8
Buggy 0.97 1.4 44
Areas 17 & 18 15 1.6 6.3
Areas 12 & 19 0.97 15 6.8
Plutonium Valley 0.58 0.14 5.9
Pinstripe 0.88 1.04 5.8
GMX 0.56 0.14 72
Kay Blockhouse 0.86 0.39 9.2
RWMS 0.68 0.29 19
Frenchman Lake 26 0.31 8.2

One reason for revising the estimates was the inconsistent treatment in previous reports
of upper limit values (ULVs). If the GAMANAL program was unable to find the peaks
associated with a particular radionuclide, it calculated a ULV from the integrated background
counts in the energy window where the peak should have been. In many regions far from a
GZ, most of the measurement results were ULVs. Such regions obviously had low
concentrations, but they often covered a large area and so could contain a substantial part

of the total inventory.

In some of the previous reports, inventories were not estimated at all for regions where
most of the results were ULVs, leading to an underestimate of the total inventory. In the
others, the ULVs were treated as actual measurements, leading to an overestimate. To make
the treatment of ULVs consistent and more accurate, the following rules were applied in
estimating the inventory in these regions:

10


concentrations of 2 radionuclide in a region. Inventories are estimated from the average and
the area of the region by the formula:

1-= average activity (nCi/m?) x area (mi?) x 0.0026,
where the .0026 factor converts nCi/m? to Ci/mi?.

Area 1: The Galileo results are from the polygons of influence method using all the data,
ULVs included (Table 9, Report 1). The Homet region includes parts of regions HO-6 and
QU-6 from Figure 3, Report 3; the calculations used the HO-6 averages. The South Yucca
estimates used the average of the five grid pointsin Area 1. The same values were assumed for
the unsurveyed part of Area 1 except that “Am was given a value of 30 nCi/m? instead of 60
because one South Yucca grid point had high #!Am. No Pu/#1Am ratio was reported for
Galileo, so the Kepler value of 2 0 was used. The ratias used for the Galileo area were also

used for South Yucca and the‘unsurveyed area..

. Area 2: The Whitney, Shasta, and Diablo.results are from Table 6 of Report 2, except
that europium was assunied to be zero'in the background regions. The remaining surveyed
region includes parts of. regions BA-3, SE-3, and WI1-2 (Report 3); the average values were
determined by inspection of the data. The values for the unsurveyed west side of Area 2 were
derived from the Area..17 plots in Report 5, The average of the radionuclide ratios in 11
samples from the Whitney, Shasta, and Diablo areas (Table 3, , Report 2) was used for the other
two regions.

_ Area 3; The Hormet results are the combined inventories in.regions HO-1 through
HO-5 (Table 9, Report 3) plus contributions from regions QU-5, QU-6, and» HO-6
determined by inspection of the data. The South Yucca values were based on the three Area 3
points, The averages of eight measurements east of the Hornet and Quay grids (Figure 2,
Report 3) were used to estimate the inventories in the unsurveyed eastern parts 0 of Areas 3, 7,
and 9,

Area 4: The Kepler results are from Table 6 in Report 2; the 97Cs value in Table A-2 is
0.2 Ci less than the value in Report 2 because a small part of the Kepler area is in Area 1.
Europium was assumed to be absent from the background regions, but the “Eu inventory
was rounded upward to reflect a small area of contamination east of the GZ area (Figure 7,
Report 2).\The Quay results are based on averages in the QU-6 region. The unsurveyed
Tegion was estimated from the four points on the western edge of the Kepler area.

Area 5: Results are from Tables 10 and’ 13 of Report 5.

cS


TABLE 6. RIDP AND NAEG ESTIMATES OF %92“pu INVENTORY
Size of Region (km?) Inventory (Ci)

Region RIDP _NAEG- RIDP _NAEG
GMX 0.97 0.13 14 13
Plutonium Valley 87 48 29 36
Palanquin/Cabriolet ‘12 -3.4 48" 13"
Little Feller It 087 11 27 251031
"Includes !Am inventory

References: "RIDP Reports 4and 5 Gilbert, 1977; Gilbert e al. 1985.

GMX. The NAEG estimate was based on the analysis of 111 soil samples, Of the
65 RIDP in situ medsurements at GMX, 8 were within the NAEG study area. Using the
average of these eight measurements and a 299-240Py/41Am ratio of 7.2 (the average from
three RIDP soil samples) leads to an estimate of 1.1 Ci of 992py in the NAEG area. If
the NAEG’s Pu/Am ratio of 10.3 (based on 89 samples) is used instead, the estimated
inventory for the NAEG study area is 1.4 Ci, in good agreement with the NAEG estimate.

. The area surveyed by the RIDP includes all but the southern edge
of the NAEG study area. The RIDP found a substantial amount of ©0py, about 7 Ci, north
and east of the NAEG area. Consequently, the RIDP estimate for the NAEG area is about
22 Ci, somewhat less than the NAEG estimate. The NAEG estimate was based on 205 soil
samples, while the RIDP estimate was based on 128 in situ measurements.

‘The area surveyed by the RIDP was twice as large as that surveyed

by the NAEG, which partly explains the difference in inventory estimates. In addition, the.

NAEG did not include the regions within 500 feet of the GZsin itssurvey. On the other hand,
the NAEG was able to sample in the rocky area near the two GZs where the RIDP. vehicle
could not go. The difference in regions surveyed makes a detailed comparison of the data
difficult.

Little Feller II. The original RIDP estimate in Report 4 was three times the NAEG _

estimate. Investigation of the discrepancy led to discovery ofa major error in the calculations;
see Appendix C for details. The corrected RIDP estimate (based on 54 in situ measurements)
agrees closely with the NAEG estimate (based on analyses of 712 soil samples).

The results of these comparisons thus tend to confirm the accuracy of the in situ method
as used-in the RIDP.


unexpected. However, under high wind conditions in the wind tunnel, the AIRNET
sampler exhibited about 96% efficiency for 5-um particles and about 60% efficiency for
the respirable fraction represented by 10-ym particles, but overestimation of
concentration for 30-m particles for all wind speeds tested. The overestimation ranged
from 170% for ~12 m s!, 237% for ~15 m s"' and 204% for ~17 m s' wind speeds. The
explanation of this phenomenon could be that the AIRNET housing inlet is sampling
subisokinetically and therefore large particles are impacted through the louvers into the
AIRNET housing with higher efficiency than smaller size particles. Therefore, the open
face filter sampler inside is sampling from atmosphere containing a higher concentration
of large particles than outside the housing. This hypothesis is supported by results from
penetration tests carried out with the open face filter located inside AIRNET housing
facing the air flow, being parallel to it and opposing it. The results of such tests are
presented in Fig. 37 and 38.

AIRNET orlentation

E

g

x
8

—* perpendicular}
= parallet

x
8
s

Penetration (%
a
8

8

2g
8

°

0 6 10 15 20 25 30 35
Particle Diameter (4m)

Figure 37. Comparison of penetration vs particle diameter for the AIRNET sampler with the internal filter i
holder perpendicular to and parallel to the flow stream for wind speeds of ~15 ms”

33


TABLE B-2. CONVERSION FACTORS (j:R/h per nCi/m?) FROM BECK (1980)

relaxation length (g/cm)
{inverse relaxation length (1/cm)]!
16° 48 16
Nuclide 0.9375] {0.3125] [0.09375]
Bam 0.000197 0.000136 0.0000710
SC 0.0254 0.0179 0.00992,
ICs 0.0168 0.0118 ~ 0.00636
ICs 0.00615 0.00432 0.00231
Eu 0.0117 0.00817 0.00446
BeRy 00127 0.00896 ~~ 0.00488
Sky 0.000581 0.000397 0.000203
IHL y 0.00109 0.000767 0.000416 ..,
101Rh 0.00316 0.00212 0.00108
122Rh 0.00395 0.00272. 0.00146
Ssh 0.00461 0.00317 0.00169 ©

culated assuming a soil. density af-1.5 g/cm>. . ..;

Conversion factors for “3Ba and plutonium are not given in Beck (1980). These factors
were calculated as follows. . sos :

1, The energy and branching intensity. of the gamma rays given off during the decay
of each radionuclide were obtained from ICRP Publication 38 (International
Commission on Radiological Protection, 1983). These values are shown in Table
B-3. The gamma rays emitted by “Pu and other gamma rays of lower energy or

. branching intensity emitted by “°Pu were judged to be insignificant and were
omitted from the calculations.

2. Table 7 of Beck et al. (1972) gives exposure rates for various values of a/p and
source energy, for a source strength of 1 gamma ray/cm?-sec. The o/p values used
in that table were multiplied by p = 1.5 g/cm to give o values. The exposure rate
was then plotted as a function of source energy for each of four values of « (Figure
B-1).

3. For the energy of each gamma ray listed in Table B-3, linear interpolation and
extrapolation from Figure B-1 were used to find the exposure rate at the four
values of «. Figure B-2 shows a plot of the resulting values for "Pu. The exposure
rates for the nine o values of interest were then obtained by linear interpolation
and extrapolation from these four values. For example, at « = 0.5/cm, the 43-keV
gamma ray gives an exposure rate of 0.073 R/hr, while the 100-keV gamma ray
gives 0.22 »R/hr.

a


METHODS ;

The strategy developed to meet the RIDP’s objective, as outlined in the project
operations plan (Kordas and Anspaugh, 1982), combined the three methods used in earlier
studies: aerial surveys, soil sampling, and in situ spectrometry. Details of how these methods
were used were given in the RIDP reports, especially Report 1. The following description
is only a summary. ;

Aerial Surveys

Between 1976 and 1984, EG&G, Inc., made a new series of aerial radiological surveys

of much of the NTS:

Ara Date of Survey Reference
Areas 25 and 26 September 1976 Tipton, 1979
Yucca Flat August-September 1978 Fritzsche, 1982
Areas 18 and 20 October-November 1980 Feimster, 1985
- Area it January 1982 Clark, 1983
Area 5 February 1982 unpublished
Areas 16 and 30 June 1983 Bluitt, 1986
Areas 12, 15, 17, 19 October-November 1984 Jobst, 1986

‘The surveys were carried out with an array of Nal(T1) scintillation detectors mounted
on a helicopter. Previous aerial surveys had been made from fixed-wing aircraft; the slower
speed and greater maneuverability of the helicopter slowed wider coverage and better
resolution.

The results of the aerial surveys were used to define the precise areas to be surveyed
with the primary measurement technique, in situ spectrometty.

In Situ Spectrometry

To help coordinate the field: ‘activities, the in situ measurements were carried out in a
series of surveys of different areas (Table 2). Most of tiiese areas contained at least one GZ,
or other localized source of contatnination. Such areas were usually identified by the name
of a test, such as “Galileo,” although the chosen name did not necessarily reflect the most
important source of contamination in the area. The regions covered in the Area 15, Areas
12 and 19, Areas 17 and 18, Pahute* Mesa, and Miscellaneous surveys had no GZs. Soil
radioactivity in those areas was generally uniformly distributed at relatively low levels,

The portions of the NTS covered by the in situ surveys are shown in Figure 1. They
include all the GZs of above-ground nuclear tests, the GZs of underground tests where
significant amounts of radioactivity reached the surface, safety-shot sites, the rocket test
facilities in Area 25, and other places where aerial surveys showed elevated levels of
radioactivity. For the most part, those portions of the NTS not covered by in situ surveys were


Detailed flow profile information in the tunnel is obtained using a Pitot tube
sensors arranged in a six by six array, oriented orthogonal to the flow near the tunnel
outlet. Guidance on the degree of uniformity of the flow profile can be found in the
40CFR53.42 (US EPA 1999b); ”... The wind speed in the wind tunnel shall be
determined during the tests using an appropriate technique capable of a precision of 5
percent or better (e.g., hot-wire anemometry). The mean wind speed in the test section of
the wind tunnel during the tests shall be within 10 percent of the value specified in table
D-2. The wind speed measured at any test point in the test section shall not differ by more
than 10 percent from the mean wind speed in the test section....”. Even though these
tests were not intended to generate data for an EPA certification, they were used as
guidance.

Test aerosols were delivered to the tunnel upstream of the fan with offset-feed

auger box (see Fig 21). The aerosol injection was done from six drop-tubes spread
across the wind tunnel inlet (see Fig

19) to help in deagglomeration of the
test particles, and to obtain uniform
# aerosol mixing in the air stream,

2 Uniformity of the air velocity profile
and aerosol concentration profile
were good as shown in Fig, 22 and
23. The velocity profile was

obtained at six heights and six
locations across the tunnel at the test

Figure 21. Offesct-feed auger box

section. Aerosol profiles were taken

in the center of the tunnel test section at 30, 60 and 90 cm above floor.



2 3
3.3 4
2 2
3
3
3 3
3
3 3 3
3 3
3 é 1
2
2
. ., Measured Activities (nCym?) ”
0 nd, 3 , 800-600
1 100-200 * -°800=1,000
2 200-300 5 1,000-1,360
@ round zero.

Figure C-3. Activity of 37Cs in the Little Feller If area.

&


604000

- 7 N
/. + \ .
+ +| \
\ + “|
*\ .
+ + +
en
+
+ +
oat \" : + |
; Vo |
St
+ + \us iu \ +
PN Ber oy
ria i
* race * ale
+ \ &
48” 48, |
+ Nx gt +
eS Y
+ 4,
®,
807000

Figure C-1. Locations of soil samples in the Little Feller Il area. The dashed
fine encloses the GZ region defined for choosing inverse

relaxation lengths.
+ location of in sity measurement
XX tacation of soll sample

© coun a

|
|
|
i
|
|



LA-UR-00-3091

Approved for public release;
distribution is unfimited.

Title:

Author(s):

Submitted to:

Los Alamos

NATIONAL LABORATORY

‘Los Alamos National Laboratory, an affirmative action/equal opportunity

Performance Evaluation of LANL Environmental
Radiological Air Monitoring Inlets At High Wind
Velocities Associated with Resuspension

John Rodgers (PI), Piotr Wasiolek, Jeff Whicker, ESH-4
Craig Eberhart, ESH-17
Keith Saxton, David Chandler, Washington State University/USDA,

Pullman, WA

FINAL REPORT for TDEA committee

ity employer, is operated by the University of California for the U.S. Department

of Energy under contract W-7405-ENG-36, By acceptance of this article, the publisher recognizes that the U.S. Government retains a nonexclusive,
royalty-fiee license to publish or reproduce the published form of this contribution, oF to allow others to do so, for U.S. Government purposes. Los
‘Alamos National Laboratory requests thatthe publisher identify this article as work performed under the auspices of the U.S. Department of Energy. Los
‘Alamos National Laborstory strongly supports academic freedom and a researcher's right to publish; as an institution, however, the Laboratory does not
‘endorse the viewpoint of « publication or guarantee its technical correctness.

FORM 636 (1098)

{
|
§
|

7


velocity conditions can be evaluated. Generating such test conditions is particularly
challenging and not easily done in smal] wind tunnels. That may be why data on inlet
efficiency of these types of environmental monitoring inlets at high wind speed is
practically non-existent. The requirements for aerosol inlets performance evaluation, and
basic factors that should be considered for such tests were analyzed by Mark ef al.
(1992). Their recommendation combined with the EPA procedures (EPA 1999b) were
the basis for the test program of the commonly used inlets in the LANL under ambient air
conditions. It was determined that a high-velocity, large cross-section aerosol wind

tunnel was needed to meet the objectives of the test program.

IL. Inlets’ tested in the study

1. Open-face-inverted Inlet
Open-face-invested inlets for atmospheric sampling consist of a simple filter
holder operating face down, as shown in Fig. 2. These two particular filter holders (HI-Q

model RVPH-102 or RVPH-25)', are for filters of 102-mm and 47-mm diameter,
tespectively. Both open-

face inlets are operated at a
flow rate of 113 L min.
Inverted inlets have been
previously tested by the
Southern Research Institute
(SRI) GBird ef al., 1973).
Their DP so efficiencies

were found to be 39%,

Figure 2. 102-mm and 47-mm filter holders as inverted open-face 0,
atmospheric aerosol samplers. 30% and 20% for 5 um

: AD particles at wind
speeds of 2.6, 12.8 and 18.9 m s'', respectively. For 12-4m AD particles the DPso
efficiencies were 35%, 12%, and 35% at the same wind speeds. In this project the
invested inlets were used to established baseline performance in field test with

uncharacterized ambient aerosols.


‘The values used in the GAMANAL analysis were just the opposite: 0.1/cm for points in the
GZ region and 0.5/cm for points outside.

Therefore, the concentrations of #1Am and 7Cs were recalculated using inverse
relaxation lengths of 0.5/cm for the GZ region and 0.1/cm for the outside region. The general
effect of this correction was to decrease the computed concentrations in the GZ region and
increase those outside. The corrected values are plotted along with hand-drawn
concentration isopleths in Figures Cc -2 and C-3.

Corrected inventory estimates are included in Table C-1, a revision sof Table 7 in Report
4. The estimated '57Cs inventory is essentially unchanged; the estimated "Am inventory,

however, decreases by about a factor of three.

REFERENCES

ee vs Ros

Essington, E.H. 1985, Progress.of soil radionuclide distribution studies for the Nevada

Applied Ecology Group. In Howard, W.A., PB. Dunaway, and R.G. Fuller, eds., The

Radioecology of Transuranics and Other Radionuclides in Desert Ecosystems. NVO-224,
U.S. Department of Energy, Nevada Operations Office, Las Vegas, pp. 145-184.

42


Figure 3.

y aah;

Ml -{\s
we y 6

_ of

234/287 POTS f

Distribution of “Pu on the NTS as of January 1, 1990. Isopleth
Jevels are 100, 1,000, and 10,000 nCi/m?, No measurements of
238Py were made in the Galileo area in Area 1.

14


TABLE A-2. ESTIMATED RADIONUCLIDE INVENTORIES

Radionuclide inventory (Cl)

Area _ Region im) am op em eco aS MEE B
. 4. 7202143002206
+ femet Fi re <r ye 2 re
3, Yucca ce he ss 0 0 0
Whitney 27 04 14 48 16 40 112 194 0.7 OF
2 Sa Fn ne 9 0.3
Diablo 40 0 2:7 S6 04 9:0 iso 04 0 0.1
Sedan 61 04 42 633 02 32 «79 0 0 9
“ 19.7 23 8.6 at 3.4 at 69.3 OY tr 03
$0 3A RS TBS BLA
2 Eee bir ee Se Oe 9 ° o
4 27 $8. 11.6 34.8 39° 108 14.0 130 09 0.2
Say er yee es ex ee © ° 0
5 Prenchman Lake 220 O04 02 34 10 04 1d 12.2 08 0
GMX, etc. 2 ; 4 4 B he +
6 8, Yueea 30017 33 OS i 9 0 0 0
7. Quay 61 OLE | Od ALR. 2 28 + 62 299 24 OM
unmurveyed og 42 4. + + t. i: 4 o $ ~2
8 $2 0.9 0.7 36 89° 264 6.6 0 ° 0
Eerie N30 AS67107 106-7. +21 13.4 171, 600407
9 Wilson 15 5 3% 19 75.6 15 7.0 133° 32.0 29 O.4
wavered Ma EC att Ht ah he
10. . Sedan 2:7 -ABA | ABA 101 247 83.7 6 380 4 60
nenrveyed ‘¢ att bh -b -h
11 Pu Valley 34°33 0S 29.0 00 04 02 0 ° °
Pinstr
" 4.0 3G. 73.0 0.0 +H +
12 39.60 «5.7 8S S22 2.02. 0 0
15. Yueca Flat 43°25 24s 2130 03 88 121 0 9 0
E aide 2:20 06° «6080 (430 00 eS. 0 0 0
16 east half 4.3 0.7 ws 37 0.1 3.2 47 ° ° °
17 -Yucea Prat W200 18 28 113 14 9.2 1408 ° ry)
18 Lite Fetier I 06 860 O7 336 OF OF OF 0 0 0.1
Litte Falter It 03 47 06 370 O09 9. 06 o1 0 0.1
Johnie Boy 400 10 19 106 O8 21 109 O8 O04 O18
Daszy Boy 09 866 Of 26.0 O02 23 14 OF O14 - O83
comer oat Ht ot Et et ty ter th
» 148,300 21.20 31.8 144.2 1.9 39.9 38.7 OO 0 0
20. Schooner 179.40 16.00 64 8.7 ES OTS
Cabslotet
. 23.4 Bred T w) 6.0 “16.6 “TB. R
25 NRDS 09 00 00 00 of 02 O02 OF oO 0
26 bunker 02 00 00 00 00 00-00 oO 0 0
30 Buggy 039 32 45 M1 14 17 1600 09 «04 02

Note: One decimal place was retained In these tabulated values to reduce rounding errors in later calculations. None of the

estimates should be considered accurate to more than two significant figures.

32



B. High Velocity Aerosol Wind Tunnel Testing

Wind tunnel setup

A high velocity portable wind tunnel (Fig 18) was used in the study for inlet
testing. The tunnel was designed and built at the USDA/ARS Palouse Conservation Field
Station near Pullman, WA (Pietersma : : ==
et al., 1996) as part of a soi] erosion
project. It is 13.4 m long and has a
working section 7.3 m long, 1.2 m
high and 1.0 m wide. Power is

supplied by a 33-kW gasoline

| | . . : Figure 18, USDA/ARS portable wind tunnel
industrial gas engine, which drives a adapted for inlet testing

1.4-m industrial axial vane fan (Joy Series 1000 Model 54-26) (Fig 19). Variable-pitch

“ee blades and variable engine speed allow the

wind speed to be set manually. Using 13
available engine speeds, the velocity can be
adjusted from <2 to 20 ms’. There is @
transition from the fan inlet height to the
ground level (Fig. 20). Intensive flow
conditioning is an option in this wind tunnel.
Fan-induced turbulence and swirl can be

eliminated using 2 perforated plates, a

Figure 19, Wind tunnel motor and
axial vane fan

honeycomb and a small mesh screen spaced
over a distance of about 2 m. For these tests
however, flow conditioning was limited in

orders to achieve the highest wind speeds.

Figure 20. Tunnel transition to the ground level


DOE/NV/10845-02

f: DESERT RESEARCH INSTITUTE >" |
OI UNIVERSITY OF NEVADA SYSTEM

RADIONUCLIDES IN SURFACE SOIL
AT THE NEVADA TEST SITE ©

Richard D. McArthur ws

August 1991

WATER RESOURCES CENTER
Publication #45077


For the experiments the outlet of the tunnel was modified by building 3 m-x 3 m
extension to accommodate large samplers and to avoid excessive blockage. The design

of the extension is shown schematically and as built in Fig. 24.

End of windurne— Free-ar
Aitow sreartne~* i [Testinlet
esse tool
Test pt”

Figare 24, Tunnel extension for testing large
inlets

7


Helgnt (om)

Figure 22. Velocity profile in the wind tunnel for u=17 ms"!

u=~17ms" d=10
123 y-—--_--rkrkrxwroomo t

8

s
3

a
$s

Mass Concentration (mg/r}
&

8

20 60 30
Height (em)

Figure 23. Center-line vertical aerosol concentration profile of 10 wm particles and at a wind
speed of ~17 ms"


Figure 26, Results of Microtrac analysis of grinded soils samples used for inlet testing


’
.
.
a4 ‘ie
. .
> .
- S
.

Figure 12. Locations of in situ measurements where the 4?2"py level exceeds 500 pCi/g.

2s


TABLE 5. ESTIMATED INVENTORIES OF MAJOR MANMADE
RADIONUCLIDES IN NTS SURFACE SOIL AS OF JANUARY 1, 1990

ann

Radionuclide Inventory (Ci)

Area lim 3Py Pu Weg OCs a i
1 42 6.5 24, 11 88 15. 15. 0.1 0.5
2 29 8.6 22. 12 24. 46, 14. 0. 0.4
3 4.6 3.1 37. 10. 12. 33. 18. 0.1 0.5
4 66 = 13. 40. 16 12. 13. 91 0. 0.2
5 0.6 0.1 48 06 60.4 09 10. 0.2 0.
6 1,7 33 8.4 02 28 3.5 0. 0. 0.
7. 22 0.6 16. 10 52 92 2. 0.2 03
8 17. 8.0 110. 5.7 °42, © 250 4.4 0. 0.6
9 42 2.2 89. 0.7 87) 613. > 2B. 02 03
10 «19. 19. 110. 9.7% 84. 55. 22. 03 5.0
11 33 0.5 29. 0. 05 -.03 0. 0. 0.
12 5.7 8.5 39... 12 «20. 17. 0. 0. 0.
15 8.0 718 63. 03 19. 22. . 0. 0. 0.
16 0.7 15 3.7 01 2.9 3.7 0. 0. 0.
17. 28 45 18. ‘10,15... 19. 0. 0. 0.
18 «19. 5.6 100. 0.7 10.07 17. 110 0.1 0.8
19 «2h. 32. 140. 11 36. 31. 0. 0. 0.
20. «23. 30. 41. 79°55 43 13. 1.6 48
25 0. 2, .02, 0 “0.2 0.1 04°50. 0.
26 0. 0° 0. 0. ne 0.
303.2 4.5 14, 08 1.5 13 07.01 0.2

Total 150.___160. 910: -* 35..° 310.._ 330130. 2.8 14.
1. 37Cs was almost always present in measurable amounts, 80 the few ULVs were
treated as valid data. oe .

2, #1Am and ®Co were assumed to be present at one-half the ULV, as determined

by inspection of the data. For example, if the *1Am values in a region tended to
be ULVs in the 25 to 35 nCi/m? range, avalue.of 15 nCi/m? was assumed.

3. The three europium isotopes were found only relatively close to a GZ. They were
assumed not to be present at all in regions where only ULVs were reported. Some
previous inventory estimates for these radionuclides were therefore not used in

making Table 5.
Inventories of the plutonium isotopes and "Sr were estimated from #1Am and Cs
inventories using the radionuclide ratios from the nearest GZ area.

Additional recalculation was necessary for Yucca Flat because the original estimates in
Reports 1, 2, and 3 were not made for separate NTS areas.

n

Lesepuelle?
(ka)


Figure 6.

i]
ty

Distribution of 87Cs on the NTS as of January 1, 1990. Isopleth
levels are 100, 1,000, and 10,000 nCi/m?.

17


aA ne Ne

Figure 2. Distribution of "Am on the NTS as of January 1, 1990. Isopleth
levels are 100, 1,000, and 10,000 nCi/m?,

13


Radionuclide ratios. The ratios used to estimate inventories of 8Pu, 792pu, and %Sr
were averages of values measured in soil samples. The number of.samples involved was *
usually small, and the variability in the measured ratios was usually large, so the values used
to estimate inventories have a high uncertainty. Errors in the ratios affect the inventory
estimates directly, so if the average ratio is too high by 50 percent, the inventory estimate will
also be too high by 50 percent.

Upper Limit Values. When ULVs were used in a data set, they were treated as valid
measurements, so the resulting estimates are larger than they should be. The areas within
which inventories were estimated were usually set up to include as.few ULVs as possible, so
the error involved in the total inventory figures is probably negligible.

Sampling error. Sampling error results from estimating the total inventory in an area
from measurements at relatively few locations. The size of the sampling error depends on
the distribution of radioactivity in the area, the number of measurements, and how the
measurement locations are chosen.

The only RIDP study areas where the sampling variability can be estimated directly are
the four GZs in Area 18, where importance sampling was used to select the measurement
locations (Report 4). The sampling standard deviation at these sites ranged from 5 percent
to 40 percent of the total inventory.

Most of the other GZ areas were sampled on a regular grid, with 400-foot or 500-foot
grids being used in the regions of highest activity. The sampling variability of the grid design
at Frenchman Lake was estimated to be about 20 percent (Report 5, pp. 46-48), and the
variability at similar GZ areas is probably comparable. The sampling variability is probably
somewhat larger at safety shot sites like those in Plutonium Valley, where contamination
occurs in discrete particles that are typically not as uniformly distributed around the GZ as
is the radioactivity from a fission explosion.

Lasation. The locations of the in situ measurements were usually determined with a
microwave ranging system. The errors in the computed locations can be anywhere from 10
feet to 250 feet or more, depending primarily on the relative positions of the location and
the two microwave transponders. The effect of such errors on the inventory estimates and
distribution maps is hard to determine, but it is believed to be relatively small compared to
other uncertainties.

Comparison with Earlier Studies

During the course of the RIDP, surveys were made of four regions that had previously
been studied by researchers from the Nevada Applied Ecology Group (NAEG). The
estimates of “py inventory obtained by both groups for these regions are shown in Table
6. While the estimates are not entirely comparable because of differences in the areas
surveyed, the comparison is still of some interest.

6

wt tt ne ete nnn


The soil samples were usually collected at sites of in situ measurements located along
two perpendicular transects through the GZ, if one was present. At most sites, a profile of
four samples to a total depth of 15 cm was collected using the pit-scoop method described
in Report 1. Ata few sites such as Sedan, where it was suspected that radioactivity extended
deeper into the soil, six increments were collected to a depth of 30 cm. The samples were
dried and homogenized, then seived through a 10-mesh (1.7-mm) screen. Only the fine
fraction was analyzed.

All samples were analyzed by gamma spectrometry to determine radionuclide depth
distributions. The activity of each radionuclide was assumed to decrease exponentially with
depth, with the rate of decrease characterized by an inverse relaxation length (a). The method
for calculating inverse relaxation lengths from the gamma-spectrometry results varied during
the course of the project, as described in Reports 1, 3, and 4.

Average values of the calculated inverse relaxation lengths for each radionuclide were
used as parameters in the GAMANAL analysis of the in site measurements. In many surveys,
the depth distributions in the region near a GZ were different from those farther away. The
measurements from the GZ region were therefore analyzed using a different set of inverse
relaxation lengths. The inverse relaxation length values used in GAMANAL are gummarized~
in Table 3.

A few top~increment soil samples from each survey were analyzed radiochemically for.
Sr, B8Py, 2Mpy, U7Cs, and “Am. The ratios of Sr to 97Cs, “Pu to.%Am, and
239.240Py) to 41Am were then calculated. Average values of these ratios, listed in Table 4, were
used to estimate the inventories of Sr, Pu, and * 239.240py from the estimated inventories
of 37Cs and “Am.

‘Aset of procedures for quality assurance (QA) was part of the analytical protocol for
all soil samples except those from the Galileo area. These procedures, carried out under the
direction of E. Essington at Los Alamos National Laboratory, included analyses of hidden
replicate samples, analyses of reference blind and background samples, and interlaboratory
comparisons, The results were presented in appendices to the last four RIDP reports. Two
separate reports will summarize the QA procedures (Essington and Mead, in preparation)
and results (Essington, in preparation).

RESULTS te
Radionuclide Inventories 7 . .

‘Table 5 gives the estimated inventories of the nine most important manmade
radionuclides in surface soil in each NTS area. All inventory values except those of #!Am,
28Pu, and 20py are decay-corrected to January 1, 1990.

The estimates in Table’S are based on the inventory estimates from the individual surveys
published in the previous reports. ‘ However, all of the earlier estimates were reevaluated for

this report, and many of them were révised.


AIRNET front

g
|

we 212.5 mis
me e147 mis
= = 18.6

a3 8 ¢

Penotration (%)

100 F

50

0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0
Particle Diameter (um)

Figure 35, Penetration curve for the AIRNET sampler with the internal filter holder facing the flow stream
for three wind speeds u=~12, ~15, and ~17 ms"!

* Several observations can be made based on the data presented in the foregoing
penetration curves. First, with regard to the ECAM data, it is clear that the test design did
not perform as respected for a design goal of a Dso cut-point of 10 pm. A possible
explanation for this unexpected outcome is that the addition of the experimental dust trap
cone changed the cyclone properties such that the cut-point was moved back to less than
5 um AD. The shape and position of this cone are clearly sensitive design parameters.
Further investigation of the critical design parameters of this element of the cyclone are
planned for future work on this inlet. A an earlier study with slightly different version of
the ECAM inlet (Murray Moore personal communication, June 2000) at lower wind
velocity of 6.7 m s! showed that this inlet has regular penetration curve with around 60%
penetration for 10-ym particles. With the version of inlet used in this study it was found
that for wind speeds above 10 m s the penetration drops to around 20%. For this high
wind speeds there was still finite probability for 30-1m particles (penetration values
around 5%) to penetrate the ECAM inlet.

The UM 1PM sampler has been tested by its designers Liu and Pui (1981) for 8.5-,
11.0- and 13.4-m diameter at low wind speeds. In their paper the penetration efficiency
was over 100% for particles of 8.5-, 11.0- and 13.4-ym diameter at wind speed of 0.6 m
s', and dropped to 90% for 8.5 and 11.0-4m particles and to 80% for 13.5-ym at wind

31


Test aerosols

To obtain values of sampler efficiency as a function of different size aerosol particles
and wind speed conditions, large quantities of mono-disperse test particles were needed.
Environmental impact considerations (the wind tunnel exhaust to the open environment
without filtration) restricted the type of test aerosols for used in this evaluation to
nontoxic, natural particles. As contaminated soil particles are of primary concern for the
LANL, we decided to obtain test
particles in the form of ground and size
classified soils. A commercial
particulate vendor’ was identified and
contracted to prepare 200 Ib each of
narrowly distributed (approximately 5-,
10-, and 30- jum) red kaolin clay soil
particles, The system used for test
particle preparation is shown in Fig. 25.
Soil samples were grounded using the
RSG “Ultra Fine Grinding” Mill (seen
on the left) and classified with ASC air
classifiers. The UFG mill introduced by

Figure 25. The RSG, Inc. system (UFG mill and
ACS-005 air classifier) used in soil test particle

Preparation (courtesy of RSG. Inc) RSG in 1999 is used to grind mineral

samples as small as 2-1m particle diameter. To classify soil particles according to their

aerodynamic sizes the RSG used their patented Advance Classification System (ACS).
The RSG, Inc. performed size analysis on each soil sample with their Microtrac

X-100 system that uses tri-laser diffraction analysis®, The results of the analysis for 5-,

10-, and 30-jum soil particles are presented in Fig. 26.

7 RSG, Inc.119 Crews Lane, Sylacauga, AL 35150
8 Microtrac Inc. at 148 Keystone Drive, Montgomeryville, PA 18939

18


For example, the PMio (particles with an aerodynamic diameter less than or equal to
a nominal 10 micrometers) air quality standard for particulate matter is defined by the
U.S. EPA (EPA 1999a) as 50 micrograms per cubic meter (ug m 3) annual arithmetic
mean concentration, and 150 jag ni? 24-hour average concentration measured in the
ambient air. Only inlets fulfilling the performance parameters of PMio samplers
prescribed in EPA (1999) in terms of their sampling efficiency can be used for
measurements to demonstrate compliance with the standard. One such performance

parameter is the particle size

100 transmission characteristic (i.e., sampler
effectiveness) of the sampler inlet for

60 o particles in the PMjo size range. Of

cS) particular importance is the particle size
at which the sampler effectiveness is

g
3

Penetration (%)

\ Another variable of sampler inlet

iN
&

amin performance is its collection efficiency as
6 okmn | a function of wind speed. Wind speed

” can greatly influence collection of larger

Ne size particles, and deposition losses on

2 4° 6 8 10 20 4 inlet surfaces. For example, collection
Aarotynamic Particle Diameter (um)

Figure 1. Collection performance (Yopenctration) efficiency for the Andersen 321A PMio
imeem en ings, ints shown in Figur | based on dt
PM jo inlet (adapted from McFarland et al. 1984). by McFarland et al. (1984).
In light of the dependency of inlet performance on particle size and wind speed, the
sampling inlet is a critical element in every aerosol measuring system. Inlets must be
- designed with care, and their performance characteristics under ambient conditions
understood. An ideal inlet should be designed such that all particles of interest (including
toxic components that might be present), enter and arrive at the collecting zone, while
excluding precipitation (rain and snow), insects, plant matter, and other debris (Liu and
Pui, 1981). And most importantly, the desired performance characteristics (DPso cut
point, intemal losses, etc.) of the inlet should be unaffected by wind speed up to the

1 50% (ie., the DPso particle size cutpoint).


yee oy

Pe WA ww -~p

10.
iL

12,

TABLES

Important Manmade Radionuclides in NTS Surface Soi!

Summary of RIDP Surveys
Inverse Relaxation Lengths Used in GAMANAL Analyses

, Average Radionuclide Ratios

Estimated Inventories of Major Manmade Radionuclides
in NTS Surface Soil

RIDP and NAEG Estimates of TM?Pu Inventory

FIGURES

. Portions of the NTS surveyed by the RIDP

Distribution of 41Am on the NTS as of January 1, 1990
Distribution of 28Pu on the NTS as of January 1, 1990

. Distribution of py on the NTS as of January 1, 1990
. Distribution of ®Co on the NTS as of January 1, 1990

Distribution of 87Cs on the NTS as of January 1, 1990

. Distribution of Sr on the NTS as of January 1, 1990

Distribution of §Eu on the NTS as of January 1, 1990

. Distribution of “Eu on the NTS as of January 1, 1990

Distribution of Su on the NTS as of January 1, 1990

Locations of in situ measurements where the‘exposure
rate exceeds 100 pR/h

Locations of in situ measurements where the 72Py level
exceeds 500 pCi/g

13

14

15
16
17
18

“19

20
21

25


Figure 11.

Locations of in situ measurements where the
exposure rate exceeds 100 uR/h.

3


deceleration as airflow impinges on the inlet, and also provides protection from rain. The
shrouded probe concept has been shown to provide excellent aerosol transmission
efficiency regardless of velocity and particle size. Each of the six nozzles discharges into
the base of an inverted cyclone. The cyclone design parameters as such that the 50%
transmission cut point is at 10-y1m aerodynamic diameter. Note in the cross-section
drawing that there is a small conical trap at the top of the cyclone that is meant to capture
large particles removed from the sample by the induced cyclonic flow. The exact
configuration of the trap was still under development at the time of these tests, and a
temporary design was installed for evaluation. The output of the inlet passes out of the
base through the cyclone outlet tube down into the CAM head attached below.

Ill. Methods

A. Field Testing

The initial filed test of relative collection efficiencies of selected inlets was
performed in the vicinity of the 46-m meteorological tower at the LANL TA-54 site.

Site Description
The TA-54 station is located in a clearing just off

the eastern tip of Mesita del Buey on the Pajarito
Plateau at longitude of 106° 13' 22.1", latitude 35°
49° 32.8" and elevation of 1996.3 m (6548 ft)
above sea level. The terrain drops 15 m into
Canada de! Buey to the north and drops 10 m into
Pajarito Canyon to the south. To the east-
southeast, the terrain drops gently about 75 m to
the eastern edge of White Rock Canyon. The
station is shown in Fig. 12 looking southeast
toward the residential area of White Rock. The
eastern escarpment of White Rock Canyon

Figure 12. Bird view of the TA-54 site.

can be seen near the top of the photo. The
photograph presents the site during construction of the meteorological tower. Since then,

10


designed to compare inlet efficiencies of the several types for ambient aerosols relative to
each other. No reference sample was collected as a basis for comparison. Several
configurations of inlets were tested for three one-week-long sampling periods. The first
arrangement consisted of the UM IPM, the inverted 102-mm and AIRNE-station inlets
(Fig. 15). In the next configuration the 102-mm inverted inlet was replaced with a 47-
mm inverted inlet equipped with the filter type routinely used by ESH-17 in the
AIRNET-station (Fig 16). To establish comparison against the PMjo standard, the G-A
PMyio inlet replaced the inverted one (Fig. 17). The UM IPM and G-A inlets were
operated using 102-mm Gelman A/E filters. The filters were collected weekly using
methodology specific for individual inlet.

A summary of operational parameters of all tested inlets are presented in Table 1.

Figure 17. G-A, UM IPM and AIRNET inlets

12


Table 1. Operational parameters of tested inlets

Inlet Filter type Nominal
Flowrate
L min" (cfm)

UM IPM 102-mm Gelman’ A/E (glass fiber) 113 (4)
102-mm Inverted 102-mm Gelman A/E 113 (4)
47-mm Inverted 47-mm Gelman A/E & Dynatech polypropylene 85 (3)
G-A inlet 102-mm Gelman A/E 113 (4)
AIRNET station 47-mm_ Dynatech polypropylene 113 4)

Airflow to any two of the inverted, UM IPM, and G-A inlets, when operational),
was provided from a single high capacity oil-less vacuum pump located in a separate
housing (see Fig.14). AIRNET-station airflow was provided from a built-in oil-less
pump with exhaust to the outside. For consistency and to avoid additional biases, the
actual flow rate to all samplers was measured at the beginning and at the end of sampling
period with the same, calibrated flow meter’, After approximately 170 h of sampling and
after 24-h delay for humidity equilibration, filters were analyzed gravimetrically on
calibrated balances with precision of 0.001g. AIRNET-type filters were analyzed by
New Mexico Department of Health Scientific Laboratory Division Air & Heavy Metals
Section. Filters from UM IPM, Inverted, and G-A inlets were analyzed in LANL ESH-4
HPAL facilities using ANSI traceable Mettler Precision Balance PM1200°, Duration of
sampling in hours was taken from a timer built into AIRNET station. Meteorological
conditions: average wind speed, maximum gust, and soil moisture for the test, were
obtained from an automatic data logging station operated by ESH-17. The average
weekly mass concentration C, was calculated as,

3 _ (Wg- Wt) :

Cc 3 = (We- Wo) 2
(ye mTM) V, x ATime 2)
where, Wt and Wg is the tare and gross weight of the filter in grams, V, is the actual
volumetric flow rate in m min’! calculated as an average of the flow rates measured at

the beginning and at the end of sampling, and 7Time is elapsed time in minutes.

* Gelman Sciences, 600 South Wagner Road, Ann Arbor, MI 48103

§ SAIC RADeCO Model C-828 S/N 1909
6 Mettler-Toledo, Inc. 1900 Polaris Parkway Columbus, Ohio 43240



Figure 9.

Distribution of “4Eu on the NTS as of January 1, 1990. Isopleth
levels are 100, 1,000, and 10,000 nCi/m2,

2


IV. Results

Field Test Intercomparisons (Relative)
The comparison of relative performance of different inlets under ambient

conditions at TA-54 site is presented in Table 3. The table contains weekly averages of

aerosol particle mass concentration and wind speed, as collected in tested inlets and by a
propeller anemometer on a tower at 12 m. The test were carried out between March 2-

May 5, 2000.

Table 3. Summary of inlet performance field test. Each test involved simultaneous sampling for
approximately 170 h under ambient aerosol conditions.

Test No Inlet Mass Average Wind | Soil moisture
Concentration | Speed (ms"') (%)
gm)

UM IPM 9.8

1 102-mm Inverted 8.2 2.6 7.2
AIRNET 5.1
UM IPM 10.3

2 102-mm Inverted 43 2.5 8.2
AIRNET. 37
UM IPM 43.5

3 102-mm Inverted 20.8 3.3 10.2
AIRNET 15.4

23


RADIONUCLIDES IN SURFACE SOIL
AT THE NEVADA TEST SITE

by
Richard D. McArthur
Water Resources Center
Desert Research Institute
University of Nevada System
Las Vegas, Nevada

Prepared for i
the U.S, Department of Energy ;
Field Office, Nevada
under Contract DE-AC08-90NV10845


‘This report was prepared as an account of work sponsored by the United States Government. Neither the United
States nor the United States Department of Energy, nor any of their employees, makes any warranty, express or
implied, ‘or assumes any legal liability or responsibility for the accuracy, completeness or usefulness of any
information, apparatus, product or process disclosed, or represents that its use would not infringe privately
owned rights. Reference herein to any specific Commercial project, process, ’of service by trade name, mark,
manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or
favoring by the United States Government ar 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.

‘This report has been reproduced directly from the best available copy.

Available to DOE and DOE contractors foom the Office of Scientific and Technical Information, P.O. Box 62,
Oak Ridge, TN 37831; prices available from (615) 576-8401, FTS 626-8401.

‘Available to the public from the National Technics! Information Service, U.S. Department of Commerce, 5285
Port Royal Rd., Springfield, VA 22161.


TABLE 3, INVERSE RELAXATION LENGTHS (1/cem) USED IN GAMANAL ANALYSES

Location ay a2 ory aq as
Galileo Gz 0.6 0.4 0.4 0.05 0.6
others 0.6 04 0.4 03 06
Kepler GZ 0.6 a4 0.4 0,05 06
Others 0.8 04 0.4 03 06
‘Whitney GZ 0.8 01 04 0.05 06
others as 04 04 03 06
Diablo GZ 08 0.4 0.4 0.05 0.6
others 0.8 0.4 04 03 0.6
Baneberry 0.6 0.6 06 03 0.6
Smoky GZ 0.6 01. 0.4 0.05 0.6
others 0.6 0.4 0.4 03 0.6
Sedan GZ. 0.05 0.05 0.05 0.05 0.05
others 0.4 04 04 03 0.4
Oberon 0.6 0.4 0.6 0.05 0.6
Wilson GZ 06 0.1 0.4 0.05 0.6
others 06 04 04 03 06
Quay GZ 10 0.05 10 0.05 10
others 10 04 10 04 1.0
Hornet GZ 04 0.05 03 0.05 04
others 04 04 0.4 03 0.4
Pahute Mesa 04 04 04 0.4 0.4
Schooner GZ 01 Oo. 01 O41 Ot
others 0.6 0.6 0.6 0.6 0.6
Cabriolet 0.4 0.4 04 0.4 04
Johnie Boy GZ 0.1 0.1 01 0.1 01
others 04 0.4 0.4 0.4 0.4
Little Feller I GZ 0.1 0.1 0.1 0.1 0.1
. others 05 05 05 05 05
Little Feller IT GZ 05 05 05 0.5 05
other 0.1 0.1 0.1 0.1 01
Danny Boy GZ 0.05 0.05 0.05 0.05 0.05
others. 03 03 03 03 03
Areas 25 & 26 03 0.05 03 0.05 03
Area 15 0.6 0.6 0.6 , 0.6 06
Bugey GZ 02 0.2 02 02 02
others 05 05 05 0.5 05
Areas 17 & 18 04 04 0.4 0.4 04
Areas 12 & 19 0.2 01 _-01 01 01
Platonium Valley 06 0.6 06 06 06
Pinstripe & GMX 05 0.05 0.5 0.05 05
Frenchman Lake GZ 0.1 0.05 0.1 0.05 01

others 04 0.05 04 O0s 04

Note: ay used for 41Am, 28py, 239,
@z used for Co, }01Rh, 02mRp, 125g5
a3 used for 157Cs,
ag used for 133Ba, 14Cs, 152Ey, Ey
as used for 55Ey, 174Lu


CONTENTS

Abstract
Tables and Figures
Background
Objective
Methods
Aerial Surveys
In Situ Spectrometry
Soil Samples
Results
Radionuclide Inventories
Radionuclide Distributions
Exposure Rate
=9Pu Concentration
Uncertainty of the Results
Sources of Uncertainty
Comparison with Earlier Studies

References

Appendix A: Calculation of Total Radionuclide Inventories

Appendix B: Calculation of Exposure Rate
Appendix C: Corrections to Previous Reports

vin be

oon es ewe ae wD em

“RBBB SB

24
26

30
35
41


speed of 2.8 m s‘'. No higher wind
velocity was tested. Our high velocity

tests have shown similar inlet behavior
for all tested wind speeds with sharp
drop in penetration from 5- to 10-ym
diameter particles from 120-130% to
30-60% and then constant for 30-pm
diameter particles. These values are

below theoretical predictions of the

ideal “hole-in-an-infinite-wall” inlet by
Zebel (1978). Zebel’s predicted

Figure 36. 102-mm filter used in one of the aspiration efficiency of circular inlet of 9.2
tests showing non-uniform coverage

cm diameter for particles 15-ym
aerodynamic diameter was 100% at low wind speed, decreasing to 90% at a wind speed
of 6.9 ms"! and 80% at 15.8 ms’. In our case inlet diameter was 11.6 cm and for
particles] 0-um AD at wind speeds of 12.5- 14.7- and 16.6 m s'' aspiration efficiency was
about 63%, 49% and 28%, respectively. Similar observation of decrease in aspiration
efficiency for larger particles (13.4-1m) and higher wind speeds was made by the
designers of the original IPM inlet (Liu and Pui, 1981). They observed as well a decrease
in aspiration efficiency of their inlet larger than that predicted by Zebel’s (1978) theory.
Their suggested explanation of the discrepancy was that the actual flow field at the inlet
is more complicated than that assumed by Zebe}. Our experiments, using solid particles
(in contrast to Liv and Pui, 1981 who use liquid particles), have shown another property
of the UM IPM inlet shown in Fig. 36. The deposition pattern of a 10-j1m AD test
aerosol on the 102-mm filter is showing strong directional dependence with higher
loading on the downwind side (top of the picture) of the inlet. This was also observed on
some field samples.

The louvers of the AIRNET sampling station housing an open face filter act as air inlets
to the interior space. The ambient low wind velocity conditions of the field test created
sampling conditions inside the housing very similar to those outside. The similar
performance of AIRNET and inverted open face filter sampler is therefore not

32


Wind tunnel tests

The wind tunnel tests were made between June 19 - 23, 2000. Three selected
inlets; AIRNET, UM IPM, and ECAM were tested for their collection efficiency with 5-,
10- and 30-pm test soil particles and three wind speeds of approximately 12-, 15-, and
17-ms",

Each test consisted of 3 or 5 min runs. Test particles were collected on a filter
and at an air flow-rate specific for the tested inlet. Test particles were collected
simultaneously with a shrouded probe placed in the flow for use as the reference (free

stream) aerosol particle concentration. Each run was repeated 2-3 times to enable
statistical analysis of the outcome results.

The reference probe was position 60 cm above
the wind tunnel floor and inside the original wind
tunnel, along with the Pitot tube used for air velocity
measurements. The reference sampler and Pitot tube is
shown in Fig. 29. The Pitot tube output was interfaced
with a 21X Campbell Scientific datalogger providing
1-min air velocity averages. The datalogger software
allowed for on-line monitoring of air velocity, to detect
and correct any problems with the Pitot tube clogging.

Before a test, the numbered and pre-weighted
Figure 29. ae ah Lan filters were loaded into the sampler under test and into
collect reference values shrouded probe cartridge. The pre-test weighing was
done just before the test on ANSI traceable Mettler
Precision Balance AE100 (latest calibration June 2000). The same balance was used to
obtain the post-test mass of the filter. The balance was located in an adjacent building
and filters were transported to minimize losses of collected soil particles. Filters were
later stored for further analysis if necessary, e.g. for uniformity of filter coverage.
The samplers (AIRNET, ECAM, UM IPM) were positioned in the extension
section of the wind tunnel, 60 cm from the original end of the tunnel in the free jet
regime. The AIRNET, ECAM, and UM IPM samplers undergoing testing are illustrated

in Fig 30, 31, and 32.

25


like those experienced during recent Cerro Grande and Hanford fires, when high winds
resuspended contaminated soils.

The controlled test, performed in the high velocity wind tunnel with test particles of
selected sizes overcomes the limitations of highly variable, uncontrolled ambient testing
with uncharacterized aerosols. The 5-, and 10-pm diameter particles represented the
respirable fraction and 30-ym the resuspendable fraction. The results of the wind tunnel
experiments are summarized in the Tables 4, 5, and 6 and presented in forms of sampler
efficiency curves for three inlets in Figs. 33, 34, and 35. The sampler efficiency was
derived as an average of the ratios between the aerosol particle mass concentration
measured by the tested inlet (sampled mass concentration) to the reference mass
concentration measured by the shrouded probe. The error bars on the graphs represent +1
standard deviation (SD).

Table 4. Results of wind tunnel experiments for the ECAM sampler

Wind Speed Nominal Reference Sampled
(ms”) Particle Mass Mass Ratio (%) SD
Diameter | Concentration | Concentration

(um) (mg m*) (mg mi)
5 97.2 23.1 23.8 12
12.5 10 58.3 8.3 14.2 19
30 34.7 1.8 5.2]. 49
5 116.6 23.2 19.9 1.4
14,7 10 67.3 13.4 19.9 2.4
30 37.4 2.2 5.9 17
5 N76 19.1 16.2 0.5
16.6 10 174.0 22.5 12.9 1.5
30 68.0 1.0 15 16

28


Figure 4,

Distribution of 292py on the NTS as of January 1, 1990. Isopleth
levels are 500, 1,000, and 10,000 nCi/m2. :

1s



Attachment 22:

Martell, E.A. “lodine-131 Fallout from Underground Tests.” Science. New Series, Vol.
143, No. 3602, 10 Jan. 1964, 126-129,


‘Table 5. Results of wind tunnel experiments for the UM IPM sampler

Wind Nominal Reference Sampled
Speed Particle Mass Mass Ratio (%) sp
(ms) Diameter | Concentration| Concentration
(um) (mg mi’) (mg mi)
5 OLS 110.6 120.9 21.6
12.5 10 86.0 53.9 62.7 15,3
30 39.8 20.4 51.3 18
5 89.3 104.4 116.9 18.7
14.7 10 83.3 41.3 49.6 14,4
30 35.6 18.7 52.5 13.4
5 124.3 166.2 133.7 75
16.6 10 88.9 25.1 28.2 0.7
30 62.1 28.6 46.1 6.3
Table 6. Results of wind tunnel experiments for the AIRNET sampler
Wind Nominal Reference Sampled
Speed Particle Mass Mass Ratio (%) SD
(ms) Diameter | Concentration} Concentration
(um) (mg m*) (mg mi*)
5 88 92.3 TL 5.2.
12.5 10 69.4 57.2 82.4 4.5
30 42.0 70.0 166.7 22.7
5 104.8 90.1 86.0 8.2
14,7 10 63.1 39.2 62.1 12.6
30 36.4 85.9 236.0 49.6
5 512 62.0 121.1 34.5
16.6 10 54.3 39.3 24 21
30 22.6 45.6 201.8 14.0

29


Exposure Rate (wR/hr)

2.
a = 6375
1.4
a = 468
a = 309
1
1
1
a = £09375
Os-
A a a a a)

Energy (keV)

Figure B-1. Exposure rate as a function of energy for different depth
distributions (data from Beck et al., 1972).

eevee nen


in surface soil (Beck ef al, 1972; Anspaugh, 1976). This method was used for a survey of
Frenchman Flat in 1978 and 1979, ina cleanup and treatment experiment in Area 11 in 1981,
and in cleanup operations at several off-site areas in the late 1970s. It proved to be a useful
method for surveying large areas much faster and cheaper than would be possible using other

methods.

In 1981, the DOE began a project that would use this new technology to carry out a
thorough radiological survey of the surface soil on-the NTS. This project, the Radionuclide
Inventory and Distribution Program (RIDP), took five-years of field work and another three
years of data analysis to complete. It resulted in estimates of the total amount (inventory)

and the distribution of radionuclides in the soil in n all parts of the NTS that had been affected
by NTS operations. a
The methods and results of the RIDP. were re published i in a series of five reports:

t

1 - -Galileo (Area 1)... . “MeArthur and Kordas, 1983
2 Afeas 2 and4 . -.,McArthur and Kordas, 1985
3 rest of Yucca Flat. . - .. McArthur and Mead, 1987
4 Ageas 18 and 20.. McArthur and Mead, 1988
5 rest of the NTS McArthur and Mead, 1989

The purpose of this report is to update and summarize those results, with the aim of
Presenting an integrated description of the current levels of radioactivity in the surface soil
of the NTS.

OBJECTIVE

The objective of the RIDP was to estimate the distribution and the total inventory of
the important manmade radionuclides'of NTS origin in the ‘surface soil of the NTS.

In the context of this objective, “manmade” refers to radionuclides associated with
nuclear testing. Some of these radionuclides are part of the nuclear device itself; others are
direct products of the nuclear reaction; still others result from activation of materials such
as the device casing and nearby rock and soil by neutrons produced during the explosion.
Several other radionuclides occur naturally in NTS surface soil. Although three of these,“K,
22Th,andTM8U, were measured along with the manmade radionuctides during the RIDP, their
inventory and distribution were not estimated.

Which radionuclides were “important” was not spelled out initially because it was not
known which ones would be found. Most of the radionuclides produced in a nuclear explosion
are relatively short-lived, with half-lives ranging from less than a second to several weeks.
About 20 live long enough that they may be present in measurable amounts several years
after detonation. ‘By the end of the RIDP, 16 manmade radionuclides had been found in’


RADIONUCLIDES IN SURFACE SOIL AT THE NEVADA TEST SITE

BACKGROUND

The United States began testing nuclear weapons at the Nevada Test Site (NTS) in
January 1951. Since then, the NTS-has become the nation’s primary site for testing new
nuclear weapons and studying the effects.of nuclear explosions on structures and military
equipment, Other nuclear energy projects at the NTS have studied safety requirements for
storing and transporting nuclear weapons, explored peaceful-uses of nuclear explosives,and
developed nuclear rockets and ramjet engines. In all,;more than 600 nuclear explosions have
taken place at the NTS as part of these programs.

One result of these explosions is that the surface soil in many parts of the NTS contains
measurable amounts of several long-lived radionuclides. Almost all of the 100
above~ground tests contaminated the soil near the ground zero (GZ). Several underground
tests were cratering experiments that threw radioactive rock'and soil hundreds of feet from
the GZ, and some deeper underground tests vented radioactive material to the surface. A
few safety tests, in which a nuclear device was destroyed by conventional explosives, scattered
plutonium (and in’some cases uranium) over the nearby ground. Finally, radioactive debris
from many tests was deposited as fallout over the northern and eastern parts of the NTS.

Radiation levels at the NTS are monitored regularly, and safety officials have identified
and fenced off the areas where the soil is heavily contaminated. In many other areas,
radionuclide levels are not high enough to warrant closing the area but are still above
background, These areas may pose a long-term risk to people working in them regularly and
to people who may visit them in the future if the NTS is ever returned to the public domain.
Evaluating this risk requires detailed information on the amounts of various radionuclides
in the soil at different locations, Knowledge of the amount and distribution of soil
radioactivity will also be important for the eventual cleanup of contaminated areas.

Several studies of radionuclide distribution were done on the NTS in the 1970s, but all
were limited in scope. A series of aerial radiological surveys measured gamma~exposure
rates over much of the NTS, but they did not measure individual radionuclides. The studies
that did measure individual radionuclides usually focused on transuranic elements
(americium and plutonium) and were limited to relatively small areas near GZs and safety
shot sites. The data for those studies were obtained by collecting and analyzing large
numbers of soil samples, a method too expensive and time~consuming to use for large-scale

surveys. :
In the mid-1970s, scientists from Lawrence Livermore National Laboratory (LLNL)

and the U.S. Department of Energy’s (DOE) Environmental Measurements Laboratory
developed in situ spectrometry as a technique for measuring gamma-emitting radionuclides


I. Introduction

Environmental air monitoring for radioactive particles is a vital component of
radiation workers protection during certain contaminated site remediation activities, and
in similar circumstances such as may occur in nuclear accident response in the
environment. Air monitoring is also an indispensable component of site perimeter
monitoring for demonstrating compliance with the Clean Air Act regulations, and related
concems for spread on contamination by wind of federal facilities sites such as LANL.

Assessment of health risks associated with airborne aerosols implies that
measurements be made defining the aerosol characteristics, concentrations and exposures
that contribute to, or simply correlate with, adverse health effects. The application of
sampling and analytical systems for aerosols must recognize that particles exist modally
as size distributions generated by distinctively different source categories and having
distinctly different chemistries. Two important reasons for making size-specific aerosol
measurements are (a) to relate the in-situ aerosol size characteristics to the potential lung
deposition sites, and thus toxicity, and (b) separation of the size distribution modes to
identify sources, transformation processes or aerosol chemistry.

Environmental air monitors contain some combination of a sampling inlet through
which an aerosol sample must be drawn, and an aerosol particle-collecting device inside
of the monitor (e.g., air filter). The sampling inlet design, which may vary considerably
depending on the air monitor application, determines the aerosol sampling efficiency.
The inlet effectiveness (sampling efficiency) of a sampler, E,, is defined as the ratio of
the aerosol concentration for given particle size determined by sampling with the inlet
under defined test condition, Cs, to the aerosol concentration determined with an
isokinetic probe sampling the same test aerosol conditions (assumed to be the true aerosol

concentration), Co (McFarland and Ortiz, 1982):

E,=—!, ()



Feller I and Johnie Boy GZs; “Bu is also assumed to be absent from the Littler Feller I and
_ Little Feller 1 GZ areas. The estimates for "Cs and "Sr in the northeast corner of Area 18

are from Report 5. The remaining estimates were computed using assumed values of 18
nCi/m? of #1Am and 2 nCi/m? of Co and the ratios in Table 16 of Report 5.

Area 19: The 37"Cs and “Sr values are from Report 5. The other estimates were
computed from assumed values of 55 nCi/m? of 41Am and 5 nCi/m? of Co and the average
radionuclide ratios in Table 18, Report 5. : ;

Area 20: Results are from Table 4in Report 4. b

Areas 25 and 26: Results are froin Table 2 in Report 5. Because of the extensive cleanup
of the contaminated sites in these areas, the inventories of “Amand plutonium were
assumed to be insignificant. : :

Area 30: Results are from Table 4 in Report 5.

DECAY CORRECTION

After the inventory estimates had been tabulated, ‘the totals for each area were
decay~corrected to give the final estimates for Table 5. The formula for calculating the
decay-corrected inventory I, is

I= Lexp[-0.693t/t]
where I, is the uncorrected inventory estimate, t is the time in years between the survey date
and January 1, 1990, and ty is the half-life of the radionuclide from Table 1. The survey date
used for each area was the approximate date of the highest in situ measurements:

Susy Dats Survey Date
Galileo 201/81 Danny Boy 06/22/84
Kepler 1008/81 Area 25 03/23/84
Whitney/Shasta 02/16/82 Area 26 03/28/84
Diablo 05/12/82 Area 17 12084
Baneberry 06/29/82, Area 18 08/22/85
Smoky 10/04/82 Area 15 (Yucca) 10/23/84
* Sedan . 09/16/82 Area 15 (E side) 11/18/84
Wilson 12/02/82 GMX, RWMS,
Quay 02/16/83 Kay blockhouse 02/01/85
Hornet 05/04/83 Pinstri 0201/85
South Yucca 06/01/83 Pu 05/15/85
Schooner 10/05/83 Buggy 06/27/85
Cabriolet 08/24/83 Area 12 07/09/85
Johnie Boy 12/12/83 Area 19 07/30/85
Little Feller 1 06/26/84 Area 16 09/17/85
Little Feller II O1/17/84 Frenchman Lake —10/22/85

Unsurveyed regions were given the date of the major survey in a given area. For example, the
unsurveyed part of Area 3 was assigned the same date as the Hornet survey, May 4, 1983.

ce]



Figure 30. Test of the AIRNET sampler in the
wind tunnel

Figure 31. Test of the ECAM sampler in the
wind tunnel

Figure 32. Test of the UM IPM sampler in
the wind tunnel

26



Figures 2 through 10 are only intended to give a general picture of the overall
distribution of soil radioactivity on the NTS. The small size of most contaminated areas
relative to the size of the NTS makes it impossible to label most of the isopleths without
obscuring this picture. The values of any unlabeled isopleth can be inferred by using the
following guidelines:

* Isopleths are drawn for 100 nCi/m*, 1,000 nCi/m?, and 10,000 nCi/m? for all
radionuclides except 797py, where a 50Q nCi/m? isopleth replaces the 100 nCi/m? one.
(Because the 2240py to %lAm ratio exceeds 5 in most areas and the smallest 4!Am
measurements are around 40 nCi/m?, few calculated 20py values are less than 200
nCi/m2,) .

* The general distribution pattern is the same for all radionuclides. In the southern and

western parts of the NTS, concentrations are less than 100 nCi/m? except in isolated
areas. Only 97Cs and Sr exceed’100 nCi/m? over a broad region in the northeast corner.

* All isopleths behave “normally,” with larger-valued isopleths contained within
smaller-valued ones. . ,

Larger-scale, more detailed maps for any contaminated tegion can be found in the five
RIDP reports. :

Exposure Rate ~

The total exposure rate from gamma radiation at each location was calculated by first
multiplying the decay~correctéd concentration of each radionuclide by a
radionuclide-specific factor that converts the concentration in nCi/m? to exposure rate in
uR/h. The exposure rates due to the individual radionuclides were then added to give a total
for each location. The procedures for determining the conversion factors and calculating the
exposure rates were provided by L. Anspaugh (LLNL), the Scientific Director of the RIDP.
Appendix B describes the calculations in detail.

Figure 11 is a map showing the 96 measurement locations where the exposure rate
exceeds 100 R/h. At only 10 locations does the exposure rate exceed 500 pR/h. All 10 are
in Area 20, two near the Schooner GZ and 8 near the Palanquin GZ. Four Palanquin
locations exceed 1,000 R/h, with the maximum value being 1,600 uR/h.
239,240Py Concentration

The value of 500 pCi/g of py in soil is currently being considered as a criterion for
fencing off contaminated areas at the NTS. Measurements of 22pu in nCi/m? are
converted to pCi/g by the formula

pCi/g = 0.1 x (nCi/m?) x a/1.5,

where 1.5 is the soil density in g/cm’. Thus for « = 0.0S/em, 500 pCi/g is equivalent to
150,000 nCi/m4, for a = 1.0, the value is 7,500 nCi/m2.

2



Exposure Rate (wR/hr)

<

values from Figure B-1

43 keV

Oo oF " o2 ° 08 * 4 " O85 06 oy * 08 " 08

o (cm)

Figure B-2. Exposure rate as a function of o for Pu gamma rays.


cs, Sr,Co, ia
Seens 45 be most
mobile (urideproa! S

Figure 10. Distribution of Eu on the NTS as of January 1, 1990. Isopleth
levels are 100, 1,000, and 10,000 nCi/m2.

a


5. ECAM Inlet
The Los Alamos Accident Response Group (ARG) program has, over the past
several years, sponsored development of a new environmental continuous air monitor

(ECAM) to provide radiological air monitoring for accident responders at the scene of an

Figure 10, ECAM inlet

accident involving a nuclear weapon, no matter what the ambient conditions might be.
The instrument design is based on the Laboratory-designed plutonium alpha-CAM
(Canberra Industries Alpha Sentry CAM), with the addition of a special inlet, and on-
board vacuum blower and data communication capabilities. The special inlet has been
designed to meet several objectives: first, the inlet must be capable of maintaining
excellent aerosol collection performance in high wind conditions; second, the inlet must
be protected from precipitation to prevent damage to the detector and the filter; and third,
the inlet should provide size-selective separation of particles in the sample such that the
large particle components of ambient dusts are removed to help prevent sample burial
and interference with the alpha-radiation detection process. To achieve good inlet
performance in high wind as well as calm, the design must decelerate the airflow as it
enters the inlet without at the same time introducing distortions in the particle size
distribution present in the free stream, This is accomplished by and omni-directional
array of six modified shrouded probes making up the inlet. As seen in Figure 10, the
nozzles of the probes are recessed inside shroud cells, which provide the needed


ABSTRACT

In 1981, the U.S. Department of Energy began the Radionuclide Inventory and
Distribution Program, an attempt to assess the amount and distribution of radioactivity in
surface soil at the Nevada Test Site (NTS). Over the next several years, researchers used a
combination of aerial radiological surveys, soil sampling, and in situ measurements to study
the regions of the NTS where soil radioactivity was above background levels. These regions
included the ground zeros of above-ground nuclear tests, underground tests that vented, and
some safety shots, as well as the sites of nuclear rocket experiments.

The results of the program were published in a series of five reports between 1983 and
1989. In this report, those results have been combined to provide an integrated picture of
the current levels of soil radioactivity on the NTS. The estimated inventories of the nine most
important manmade radionuclides have been reviewed (and in some cases recalculated),
decay~corrected to January 1, 1990, and tabulated. New distribution maps have been
prepared that show isopleths of decay~corrected radionuclide concentrations over the entire
NTS. Two additional maps show the measurement locations where the gamma exposure rate
exceeds 100 R/hr and where the 2°2“py concentration exceeds 500 pCi/g,



‘The values in Table 5 also incorporate estimates for the unsurveyed parts of the NTS
areas containing the mountains around Yucca Flat that were inaccessible to the RIDP
vehicles. The unsurveyed parts of other areas (Areas 5,6, 11, 16, 18, 20, 25, 26, and 30) are
assumed to have negligible amounts of soil contamination from NTS activities, as are the
areas not listed in Table 5 (Areas 14, 22, 23, 27, and 29). The total area for which inventories
are estimated is about 500 square. miles, roughly 40 percent of the total area of the NTS.

Appendix A describes in detail how the estimates in Table 5 were calculated. Several
errors in the previously reported results for Areas 8 and 18 are corrected in Appendix C.

Most of the radionuclides listed in Table 1 are not found in global fallout at levels high thet is the Lect
enough to be measured with the methods used in the RIDP. All occurrences of these Ph a ave
radionuclides on the NTS are therefore assumed to result from NTS activities. An exception fe Preset nnn
is Cs, which was present in surface soil southwest of the NTS (upwind) at levels of 30 to A+! fetout?
60 nCi/m? in the early 1980s (McArthur and Miller, 1989). If the average concentration of :
137Cs on the NTS due t6 global fallout is 35 nCi/m? as of January 1, 1990, then about 46 Ci
of the 310 Ci of 37Cs reported in'Table 5 is from’ global fallout. The fraction of Sr due to

global fallout is probably similar.

In addition to the nine radionuclides listed in Table 5, six other manmade radionuclides
were found at a few sites: :

Ba was presentat 23 points near the Johnie Boy GZ. It was also found at four Wilson
points, two Homet points, and one Cabriolet point. The current total inventory is estimated
tobe lessthan 0.1 Ci

TM4Cg was present at Baneberry and at two Cabriolet points. The estimated inventory
was 0.4 Ci, which has since decayed to less than 0.1°Ci. a

¢10'Rh was present at Sedan (3.9 Ci) and at four points near the Palanquin GZ. The
decay-corrected inventory is 1.0 Ci.

¢l2mRh was found at relatively high levels at Sedan (29 Ci) and in lesser amounts at
Smoky (1.7:Ci), Cabriolet (1.4-Ci), and in. Area-15 north of Sedan (0.4 Ci). The current
inventory is estimated to be 6.4 Ci.

“ «TL ji was found at Sedan and Smoky (25 Ci total) and was measured atone Schooner | «-
point. The current inventory is estimated to be 4.9 Ci. :

Radiouuclide Distributions Shey
The distributions of the nine most important radionuclides are shown in Figures 2 v5 dade they
. look at

through 10 . Each of these figures was produced by first plotting all the decay-corrected 27,40..0 3.
values that exceeded 100 nCi/m? on a map of the NTS, then drawing concentration isopleths «!s=

on the map by hand.


RESULTS AND DISCUSSION

The aerosol inlet performance was evaluated under ambient aerosol conditions at
LANL, as well as under the controlled conditions of the high-velocity wind tunnel in
ARS, Pullman. This approach was suggested in the EPA draft document (EPA 1999c)
stating that “...Mark et al. (1992) reviewed the attributes of wind tunnel testing, and
noted that tests using controlled conditions are a necessity to determine whether an
aerosol sampler meets a basic set of established performance specifications. Hollander
(1990) suggested that sampler performance criteria should be evaluated in controlled
outdoor tests, given the inability of wind tunnels to accurately mimic the influences of
outdoor meteorological conditions on sampling...”

During the ambient tests the aerosol size distribution was not monitored, so only
the relative performance of the inlets one to another can be evaluated. Results of ambient
conditions experiments presented in Table 3 and Fig. 27 show that under low wind
conditions (up to 3.8 m s' weekly average) the UM IPM inlet using 113 L min’? flow-
rate captured the largest mass, with the open face filter the second largest, and the
AIRNET station the third largest mass. Similar patterns were repeated for all weekly
tests. The PMyo G-A inlet, which is a size selective inlet with 50% cut off point for 10-
um particles, restricted penetration of larger particles and thus collected significantly less
mass. The AIRNET station performance as an aerosol inlet (as defined here) was slightly
below that of the inverted open-face inlets. However, they are still being used as low cost
solution, for example in the WIPP Environmental Monitoring Project (Carlsbad
Environmental Monitoring & Research Center 2000). The UM IPM inlet, specifically
designed to overcome the deficiency of the inverted open-face inlets, has shown
performance above other inlets.

The relative performance difference between inlets varied depending on ambient
atmospheric conditions. From Table 3 it can be seen that UM IPM inlet measured
aerosol concentrations up to 3 times higher than the AIRNET or the inverted filter holder
inlet. However, the relatively low wind conditions encountered in these tests are only a
limited sample of wind speeds experienced in the LANL environment. There are
situations, when environmental sampling has to be done under higher wind velocities,

27


Attachment 24:

Rodgers, John, et. al. Performance Evaluation of LANL Environmental Radiological Air
Monitoring Inlets at High Wind Velocities Associated with Resuspension. Los Alamos
National Laboratory, LA-UR-00-3091.


Graphical comparison of the relative inlet performance under different inlets
configurations is presented in Fig. 28 in terms of weekly averages of mass
concentrations. Performance was represented by the total mass of ambient aerosols

collected, regardless of size.

Wack 3. 3.3 mts

Week 1: 2.6miy Week 2 2.5m

§ Ma0* Figure 28, Comparison of performance of

g individual inlets under ambient aerosol.

E conditions. Weekly averages of wind speed
are listed above the bars.

Wosle3 22 mvs

Weeks: 25 ms week 2:28 ma

Dx10*
ssa

40m

mm)

35010¢
3010¢

2

350+
2axiae Werk (Je mve Week? Rimes Wonk. 31 ove
$6x10*
1pxtos

Mass Concentration

6uto*
0

e 24

|



ECAM

gs

i
R

y
8

—

Penotration (%]
5 &

“>

0 5 10 15 20 25 30
Particle Diameter (tim)

Om 212.5 me
me 914.7 mis
Te u=16.6 ms

Figure 33. Penetration curves for the ECAM sampler for three wind speeds u=~12, ~15, and~17 m sl

UM IPM

a
3

7

FS

8
8

88

Penetration (%)
8

s
$

Na :
\—
\—

x
8

15 20 25 30
Particle Diameter (1m)

°
°
a
3

35

Figure 34, Penetration curve for the UM IPM sampler for three wind speeds u=~12, ~15, and~17 ms”

30


References

Bird, AN., Jr., D.V. Brady, and J.D. McCain (1973). Evaluation of sampling systems for
use of the M8 alarm aboard ships. Report SRI-EAS-73-064. Southern Research Institute,

Birmingham, AL.

Carlsbad Environmental Monitoring & Research Center (2000). WIPP Environmental
Monitoring Project. Retrieved from the World Wide Web:
http:/Awww.cemrc.org/overview/wipp.html.

Hollander, W. (1990) Proposed Performance Criteria for Samplers of Total Suspended
Particulate Matter. Atmos. Environ. Part A 24: 173-177.

Huebert, B.J., G. Lee, and W.L. Warren (1990). Airborne aerosol inlet passing efficiency
measurements. J. Geophys. Res. 95: 16369-16381.

Liu, B.Y.H., and D.Y.H. Piu (1981). Aerosol Sampling Inlets and Inhalable Particles.
Atmospheric Environ. 15: 589-500.

Mark, D., C.P. Lyons, S.L. Upton, and D.J. Hall (1992). A Review of the Rationale of
Current Methods for Determining the Performance of Aerosol Samplers. J. Aerosol Sci.
23: $611-S614.

McFarland, A.R., and C.A. Ortiz (1982). A 10 2m Cutpoint Ambient Aeroso! Sampling
Inlet. Atmospheric Environ. 16(12): 2959-2965,

McFarland, A. R., C.A. Ortiz (1984). Characterization Of Sierra-Andersen Mode! 321a
jum Size Selective Inlet For Hi- Vol Samplers. College Station, TX: Texas A&M
University, Department of Civil Engineering, Air Quality Laboratory; report no.
4716/01/02/84/ARM.

McFarland, A.R., C.A. Ortiz, M.E. Moore, R.E. Deotte, and S. Somasundaram (1989). A
Shrouded Aerosol Sampling Probe. Environ. Sci. Technol. 23: 1487-1492.

Pietersma, D., L.D. Stetler, and K.E. Saxton (1996). Design and Aerodynamics of a
Portable Wind Tunnel for Soil Erosion and Fugitive Dust Research. Transactions of the
ASAE 39(6): 2075-2083.

US. Environmental Protection Agency (1990). EPA Quality Assurance Manual, April
11, 1990 Section 2.20.0 “Reference Method for Determination of Particulate Matter as

PM10 (Dichotomous Method)”.

US. Environmental Protection Agency (1999a). National Primary And Secondary
Ambient Air Quality Standards. 40 CFR Part 50.7.

37


3. AIRNET Air Sampling Station

For compliance purposes the LANL Air Quality Group (ESH-17) operates
network of more than 50 environmental air stations (called
AIRNET) to sample radionuclides in ambient air. A typical
station is shown in Fig. 5 with its housing open for sample
changeout. Each sampler is equipped with a pump and
sample collectors located inside a 122-cm high x 61-cm
deep x 76-cm wide (48”x 24x30”) weather housing with
dual louvered openings on all four sides of the enclosure”.
A polypropylene filter mounted in a filter holder is used to
collect a particulate matter sample (for gross alpha/beta

counting, gamma spectroscopy and radiochemical
Figure 5. AIRNET Station determinations). A silica gel cartridge in paralle| with the
filter is used to collect a water vapor sample for tritium
determination. The oil-less pump generates a sample flow rate of about 113 L min’!
through the filter and 0.2 L min’! through the cartridge inside the housing, which
therefore is the inlet of this sampler
(Fig 6). Instrumentation within the

ese eee

housing records the total time the  *
pump ran during the sample period |
and the flow in the particle and the

tritium sampling trains. With the

mu

recent heightened interest in the eS
health effects of beryllium, some :

AIRNET filter samples are being

analyzed for this contaminant as ;
Figure 6. Interior of AIRNET station (visible filter holder,

well as radioactivity. tritium cartridge and pump)

2 SAIC RADeCO Model 210B; SAIC, Safety and Security Instruments 16701 West Bernardo Drive, San
Diego, CA 92127


Hicks, H. G., and D. W. Barr. 1984, Nevada Test Site Fallout Atom Ratios: “©Pu/Pu and
A1py/TMpy, UCRL-53499-1, Lawrence Livermore Nationa] Laboratory, Livermore,
California.

Jobst, J. E. 1986. An aerial radiological survey of Areas 12, 15, 17 and 19, Nevada Test Site
(Date of survey: October - November 1984). EGG-10282-1113, EG&G Energy
Measurements, Inc., Las Vegas, Nevada.

Kordas, J. F, and L. R. Anspaugh. 1982. Nevada Test Site Radionuclide Inventory and
Distribution —- Project Operations Plan. UCID-19413, Lawrence Livermore National

Laboratory, Livermore, California.

McArthur, R. D., and J. Kordas. 1983. Radionuclide Inventory and Distribution Program:
The Galileo Area, DOE/NV/10162-14, Publication #45035, Water Resources Center,

Desert Research Institute, University of Nevada System, Las Vegas.

McArthur, R. D., and J. F Kordas. 1985. Nevada Test Site Radionuclide Inventory and
Distribution Program: Report #2, Areas 2 and 4. DOE/NV/10162-20, Publication,
- #45041; Water Resources Center, Desert Research Institute, University of Nevada

System, Las Vegas.

McArthur, R. D., and S. W. Mead. 1987. Nevada Test Site Radionuclide Inventory and
Distribution Program: Report #3. Areas 3, 7, 8, 9, and 10. DOE/NV/10384~15,
Publication #45056, Water Resources Center, Desert Research Institute, University of

Nevada System, Las Vegas.

McArthur, R..D., and S. W. Mead. 1988. Nevada Test Site Radionuclide Inventory and
Distribution Program: Report #4. Areas 18 and 20. DOE/NV/10384-22, Publication
#45063, Water Resources Center, Desert Research Institute, University of Nevada

System, Las Vegas.

McArthur, R. D., and S. W. Mead. 1989. Nevada Test Site Radionuclide Inventory and
Distribution Program: Report #5. Areas 5, 11, 12, 15, 17, 18, 19, 25, 26, and 30.
DOE/NV/10384-26, Publication #45067, Water Resources Center, Desert Research
Institute, University of Nevada System, Las Vegas.

McArthur, R. D., and FL. Miller, Jr. 1989. Off-Site Radiation Exposure Review Project:
Phase II Soils Program. DOE/NV/10384-23 Rev., Publication #45064, Water Resources
Center, Desert Research Institute, University of Nevada System, Las Vegas.

Tipton, W.J. 1979. An aerial radiological survey of Areas 25 and 26, Nevada Test Site (Date .

of survey: September: 1976). EGG-1183-1745, EG&G 3 Energy Measurements Group,
Las Vegas, Nevada. , }


Independent verification of the test soil particles size distribution was performed
by Lovelace Respiratory Research Institute (LRRJ) using API Aerosizer®. The Aerosizer
is equipped witha dual laser beam optical sensor system for time-of-flight measurements
and integral air flow control systems. Results of the analysis are presented in Fig, 27.

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ieoesarys e2UURSIL Ray taken on Tue hep DY OO: TRO POINT PUSTREINTTOR AF WLEECWORIE SHOTS

Figure. 27. Size distributions for 5, 10-, and 30-ym test soil particles measured
with API Aerosizer.

9 TS} Incorporated Particle Instruments Division/Amherst 7 Pomeroy Lane, Amherst, MA 01002-2905

20


APPENDIX A
CALCULATION OF TOTAL RADIONUCLIDE INVENTORIES

Table 5 gives the total estimated inventories of nine radionuclides in each NTS area
where contamination from NTS activities occurs. This appendix gives the details of how those
numbers were obtained.

TABULATION OF RESULTS

The first step was to tabulate the inventory estimates on an area-by-area basis. About
one-third of the estimates were obtained directly from tables in the earlier RIDP reports.
Many others were modified from earlier results to make the treatment of upper limit values
consistent. Also, the estimates for parts of Yucca Flat had to be recalculated to give estimates
for the individual NTS areas. :

In addition, inventory estimates were calculated for regions which could not be
surveyed because of the terrain, but which were known to have some contamination from
NTS activities. The average radionuclide concentrations assumed for these regions are listed
in Table A~1.

TABLE A-1. AVERAGE RADIONUCLIDE CONCENTRATIONS ASSUMED

FOR UNSURVEYED REGIONS
Radionuclide Concentration (nCi/m?)
iam Co BICg

‘West of Yucca Flat

Area 1 30 4 50

Area 4 150 200 450

Area 2 5 100 400

East of Yucca Flat

Areas 3, 7,9 20 8 100

Area 10 : 30 20 500

North of Yucca Flat =

Area 8 30 "300 700

Area 15 “300 4 200 .

West side of Area 17 20 “10 150

The tabulated inventory. estimates are shown in Table A-2. The following notes give
details of how these estimates were derived. Much of the discussion is'in terms of average

w


tt)
Measured Activities (NCU?)
oO nd. § §,000-10,000
1 100-200 6 10,000-20,000
2 200-500 7 2 000.
3 500-1,000 8 80,000-100,000
4 1,000-5,000 9 100,000-140,000
@ ground zero

Figure C-2. Activity of “Am in the Little Feller II area.

45

Hl
j
!
i
1


Figure 7.

Distribution of Sr on the NTS as of January 1, 1990. Isopleth
levels are 100, 1,000, and 10,000 nCi/m?.

18

|
i
}



Site Database/Data Capture

Key Words List
(2 External Dosimetry CT. interna! Dosimetry Radionuclide(s) Other We
U criticality beta
dose O bioassay ¥ Americium LD containment
Di cetection limit 1 detection limit D1 Californium 0 dose
OU exchange
frequency Cintake v¥ Cesium C1 lower limit of detection (LLD)
U1 minimum detectable activity
O film badge Din vitro ¥ Cobalt (MDA)
UO personnel
information O urinalysis 0 Iodine C1 photon :
CO pocket ionization toe :
chamber (PIC) 0 whole body count (WBC) (J Radon Oremediation H
Op O fecal ORedium O solubility |
ae CO Strontium D uncertainty analysis |
DO Medical X-rays O incidentAccident Reports C7 Plutonium i
O1photofluorography criticality “ * CJ Technetium ¥ Environmental Monitoring |
x-ray ‘ : 1 Thorium C1 dispersion model |
(J Workplace Monitoring Data = [] Tritium (H-3) C1 dust sampie i
(C1 Radiolégical Survey - **- [] Uranium
Bo

i
{
|
1
i
{

oe 2 oe
O



4, PM,) Graseby-Andersen Inlet
The PMio Graseby-Andersen (G-A) inlet (Figs. 7 and 8) is part of the Graseby

PMio Medium Flow Air Sampler’. The sampler is designed

and optimized to collect representative samples of

_AETERIAL FLANGE
H i SCREEN
{ H LUPPER PEM

[Sauer sur

_PeTERUAL FLAN

Uf) Ax

U =

Figure 8. Schematic diagram of the G-A PM10 inlet

particulates for gravimetric analysis. The sampler operates

Figure 7, G-A PMI10 inlet” at a nominal flow rate of 113 L min’. Suspended particles

in ambient air enter the inlet and then are accelerated through multiple impactor nozzles.

EFFECTIVENESS, PERCENT
& 8 8

°r 7 + 8 0 ar)

AEROCYMAMNC PARTICLE DUMETER, po

Figure 9. Effectiveness vs particle AD

as a function of wind speed for the G-A

PMiI0 inlet. Adapoted fromMcFarland
and Ortiz (1982).

Particles larger than 10 pm AD are separated from the
rest by inertial effects as the accelerated jets are
deflected in the lower plenum. The combine airflow
flows down the vent tube to the filter, a 102-mm
fiber-glass filter. The Graseby-Andersen (G-A) PMio
inlet was tested by McFarland and Ortiz (1982) in a
large aerosol wind tunnel at Texas A&M University,
with the results presented in Fig. 9. The G-A PMio
inlet design does meet the EPA PMig cutpoint Dso of
10.040.5um. The G-A PMio inlet provides a useful
reference-sampling inlet for the PMio component in
ambient air samples, and was used for that purpose in

this project.

3 Andersen Instruments, 500 Technology Court, Smyrna, GA 30082


Attachment 23:

McArthur, R.D. Radionuclides in the Surface Soil at the Nevada Test Site. Desert
Research Institute, DOE/NV/10845-02. Nevada Office: 1991.



TABLE B-3. ENERGY AND BRANCHING INTENSITY OF GAMMA RAYS

Energy Branching Intensity
Nuclide (keV) (1/Baesec)
Ba 53.15 0.0217
79.62 0.0256
81.00 0.338
160.6 0.00615
223.2 0.00460
276.4 0.0709
302.9 0.184
356.0 0.621
383.9 0.0891
28py 43.48 0.000389
99.86 0.0000747
DPy 38.69 00000586
51.62 0.000208
98.81 0.0000130
1293 0.0000620
203.5 0.00000560
332.8 0.00000505
345.0 0.00000561
375.0 0.0000158
380.2 0.00000307
382.7 0.00000260
393.1 0.00000444
413.7 0.0000151
451.4 0.00000192

aaa ene aemee eaenreeeenael

4. For each value of a, the conversion factor for each gamma ray was computed from
the exposure rate and the branching intensity B by the formula

conversion factor = exposure rate x B x 3.7x10°.

The constant 3.7x1073 has units of Bqem*+sec/nCi, so the conversion factor has

units of (wR/br)/(nCi/m?).

5, The conversion factor for each radionuclide was obtained by adding the factors
for the individual gamma rays. Thus for “*Pu with a = 0.5/cm,

43keV: 0.073 x 000389 x 3.7x107
x .0000747 x 3.7x10 0.61 x 10"
Total = 1.66 x 107

100 keV: 0.22

= 105 x 107
7


APPENDIX B
CALCULATION OF EXPOSURE RATE

»

The gamma-exposure rate at each location of an in sifu measurement was calculated

from the formula :
14

exposure rate =" zak
aarat—sl
where X; is the concentration (nCi/m?) of radionuclide i and a; is the factor for converting
nCi/m? of radionuclide i to wR/h. The formula includes only 14 radionuclides because sy
gives off no gamma radiation as it decays. .
Conversion Factors.

‘The conversion factor for a given radionuclide ‘depends on the energy of the gamma rays
it emits and its depth distribution in the soil, as characterized by the inverse relaxation length
«. Table B-1 gives the conversion factors forthe 14 radionuclides at the 9 different x values
used in analyzing the in situ measurements.

TABLE B-1. CONVERSION FACTORS (u®/h per nCi/m?)

aes Ot 02 237, ae OS 06 08 1.0

0.000035 0.000075 0.00011 0.00013. 0.00015 000016 0.00017 000019 = 0.00021
0.0021 002s = 0.0032. 0034 gous §©0.0039 | prota

0.0030 0.0065 010 0.012 0013 a0 OOS. 0016. 0017
0.0042 8.0050 0.0062

0.0026 10,0048 0.0069 0.0080 0.0090 = 0.0098 - 0.0104 0011 - 0012
0026 0.0050 0.0075 0.0089 0.0099 0.0106 0.0123. api 200

. 0.00064 . 0.00090 Qo00ss §=— 0.00103 0.00110
RH 0.00055 0.00105 0.00074 «0.00208 «9 00S AOS onoz73 §8600030 0.0032
0.0035

00032 0.0036 860.0038. 0.0060
0.00090 * Q0027 | Ocns2 0.0038 0.0040 04 = 0K?
10x W*. 90x LixW? 14x10? Sx? 7x10’ 18x10" 21x10? 24x10"
16x10 20x10) 27x" 35x10? Ax? 44x10? 46x10? 51x10? 56x 107

jagl

‘The factors for 11 radionuclides in Table B~1 were obtained from those given in Tables 1
and 2 of Beck (1980) and reproduced in Table B-2. Beck calculated conversion factors for
various values of the relaxation length in g/cm’, these values were converted into inverse
relaxation lengths by dividing them into the soil density 9, assumed to be 1.5 g/cm’. Plots of
conversion factor versus log a are nearly linear over the range of a values in Table
B-2. Values of the conversion factors for the nine values in Table B-1 were therefore
obtained by interpolating and extrapolating from such plots.

3$


the natural vegetation has returned to the area around the tower. Beyond the clearing,
pinion and juniper trees of several meters height cover a most of the surrounding area.
The plateau tilts at about 1.5 degrees to the east-southeast in the vicinity of this station.

During the test period (March 2

pump housing

AIRNET station

lm
2.7m,
OBm' 15m 1.8m 18m
UM IPM = yered = G_ApMt0
Inlet inlet intet

Figure 13. Plain view of the test site and the wind rose for test period

- May 4, 2000) the average wind speed at the site was 3 m s”' with gusts up to 17 m s',
and total precipitation 43.2 mm. The wind conditions during each test are listed in Table
3 and Fig 13, The

schematic diagram of the

site is presented in Fig. 13
and actual view of the test

site in Fig. 14.

Figure 14, View of the experimental set up at the TA-S4test sij



TABLE 2. SUMMARY OF RIDP SURVEYS

Number of
in sits soil chemical approximate
Region measurements profiles analyses dates
Galileo 136 11 3 Aug.-Nov. 1981
Kepler 121 9 4. Dec. 1981~Apr. 1982
Whimey 1B 17 7 Feb.~Apr. 1982; June 1983
Diablo 53 12 4. May 1982
Baneberry 181 15 3 May-July 1982; June 1983
Sedan, Smoky 257 25 10. Aug.~Sept. 1982
Wilson 207 23 3 Oct.~Nov. 1982
Quay + 223 17 7 Dec. 1982-Feb. 1983
Hornet 376 25 12 Feb.~May 1983
Pahute Mesa B 0 0 June 1983
Schooner 62 1 5 July 1983
Cabriolet 220 B 6 Aug.-Oct. 1983
Johnie Boy 132 14 5 Nov.-Dec. 1983
Little Feller] & 94 18 8 Jan.-June 1984
Danny Boy 107 11 5 May-June 1984
Areas 25 & 26 181 24 5 Feb.-March 1984
Areas 17 & 18 - 176 (15 6 Aug.-Nov. 1984 & 1985
Area 15 360—C 4 1 Oct.-Nov. 1984
Pinstripe, GMX 222, * «22 16 —_Jan.~Feb., May 1985
Plutonium Valley 172. 22 11 Mar.~May 1985
Buggy 76 +13 5 June-July 1985
Areas 12 & 19 118 24 13 June-July 1985
Oberon 30 10 5  “Nov.=Deée, 1985
Frenchman Lake 291 29 6 Sept."1985~Jan. 1986
Miscellaneous 81 1 —8 Sept. 1985; Feb. 1986
Tora 3,750 39° «158g

known (from aerial surveys, groynd-based monitoring, and the history of: NTS operations)
to have no contamination from NTS activities. The main exception was the mountain ranges
surrounding Yucca Flat, where aerial surveys have shown above-background levels of
radioactivity. These mountains were inaccessible to the survey vehicle. In addition, for safety
reasons, measurements were not made in craters such as those at Sedan, Schooner, and
Cabriolet.

The in situ measurements were made with a collimated high-purity germanium detector
suspended about 7.4 m above the ground. The detector was mounted on a vehicle capable
of off-road trave}. Inside the vehicle were the other components of the measurement system,
including an amplifier and power supply, a pulse-height analyzer, and a desktop computer.
‘The system was maintained and operated by EG&G. :


Data Capture

Document Discovery
(This form will be used in recording information in the Site Research Database after the document is scanned)

Reviewers — fill out all information that applies to the document then place list in front of the document

Name: Gene Rollin

Site/Facility of Data Capture: NTS Date: 11/06/03

Site/Facility Box Number: NA Accession Number: NA

Site That Document Applies To: Document Type:

DOE Site(s) J oO Dlagnostlc X-rays/Medical Information (i.e.
occupational medical dose, exam frequencies,
equipment performance characteristics)

Name(s): Nev: ‘est Site hog a

Vv. Environmental Data (i.e. ambient radiation, in-site
* releases, on-site radionuclide concentrations)
AWE Site(s) [0 D Facilitles/Processes (i.e.; source terms,

contamination surveys, general area/breathing zone
air sampling, area radiation surveys, radon/thoron
Name(s): monitofing, fixed location dosimeters, missed dose
information, radiological control limits, Radiation Work
Permits, incidents/accidents))

Other: o External Dosimetry (.e.; Thetmoluminescent
Dosimeters (TLDs), film badges, Pocket lon
Chambers, analytical methods, exchange frequency,
detection limits, record keeping practices, codes,

performance characteristics)
(DD Use document titie clearly written on DB internal Dosimetry (i.e.; urinalysis, fecal, in-Vivo,
document breath sampling, radon/thoron, nasal smears,
¥ Document Title & Comments:_ analytical methods, exchange frequency, detection
limits, record keeping practices, codes, performance
Radionuclides in Surface Soil at the NTS. characteristics)

oO Claimant Specific Document

H
!
;
H
i

Keyword(s): Check the Key Words on the Back of this Form

Rev. 02


design limit. Unfortunately, there can be a conflict between the need to protect sampler
components from rain and debris, and the need to obtain a representative sample of the
aerosol of interest under environmental wind conditions. This can lead to design
compromises that balance component protection against sampling performance.
Examples of inlet designs found in ambient air monitoring instruments include the simple
weatherproof louvered housing design used in typical hi- vol monitoring stations such as
the AIRNET stations operated on and off-site at LANL, a modified flat plate University
of Minnesota Inhalable Particulate Matter (UM IPM) air sampling inlet design used with
and without such protective housings for resuspension studies by ESH-4, and the more
elaborate size-selective inlet design developed for the LANL/Canberra alpha
Environmental Continuous Air Monitor (alpha-ECAM) to be deployed by the Accident
Response Group (ARG). For a given inlet design, inlet efficiency E, will be a function of
particle size, wind speed, and sampling flow rate, and sometimes the orientation of the
inlet with respect to the wind direction. High efficiency is easily achieved for particles
having a small aerodynamic diameter (AD<2.5 pm). For larger particles and high wind
speeds, good inlet efficiency can only be obtained by careful design (Liu and Pui, 1981).
The matter of what constitutes acceptable performance depends on the goals of
the air monitoring application. The alpha-ECAM for ARG applications, for example, is
designed to provide worker respiratory protection information on resuspended Pu
contaminated soil particles during recovery operations. Thus its inlet is designed to have
good performance for inhalable particles (AD+ 15 jm) under a wide range of wind
speeds. For resuspension monitors, the aim is to measure environmental levels of
airbome radionuclides associated with wind-blown soil particles, These data can be used
not only for detecting elevated air concentrations, but also to identify and control sources
of migrating contaminants such as contaminated soil at the waste disposal sites. In the
case of contaminant migration, particulate radioactivity that can be transported by wind is
typically associated with soil particles having aerodynamic diameters (AD) ranging from
sub-micron size up to 15 zm or 30 xm. Since particulate resuspension is a threshold
phenomenon, not arising until wind speeds of 5-10 m s’! have been achieved, the
assessment of environmental inlet efficiency should be carried out under wind speed

conditions in the range 5-15 m s"! so that the combination of particle size and inlet



During each measurement, pulses from gamma rays reaching the detector were sorted
into a 4096-channel energy spectrum. At the end of the 15-minute count period, the
Spectrum was transferred to the computer, where a spectral analysis program computed the
concentrations of various radionuclides, Finally, the spectrum was transferred to magnetic
tape for further analysis.

For most surveys, the locations of the in situ measurements were specified in
advance.- The basic arrangement of measurement locations was a grid of points 400 or 500
feet apart. In the early surveys, an irregular pattern of grid points was measured that reflected
the isopleths of exposure rate derived from the aerial survey results. In later surveys,
complete rectangular grids were measured to simplify the data analysis, though the grid
spacing was often increased in areas of relatively low concentration. The measurement
locations at the GZs in Area 18 were selected using importance sampling (Report 4).

The locations of most of the in sits measurements were determined using a microwave
ranging system, with a receiver and transmitter mounted on the survey vehicle and two or
more transponders positioned on remote mountaintops. In the regions that had no GZs,
measurements were made primarily along roads.- The locations of those measurements were
determined with mileposts and odometer readings.

Aseach survey was completed, the spectra were sent to LLNL for analysis by a modified
version of GAMANAL (Gunnink and Niday, 1971), 8 more sophisticated spectral analysis

program than the one used in the field. The analyses were done using assumed values of iercéath
0.001204 g/cm? for air density, 1.5 g/cm? for wet soil density, and 10 percent for soil moisture. “<"“ ° apie
Mass attenuation coefficients for all energies of interest were obtained by interpolation from |, overs verd= wees,

values given by Beck ef al, (1972). Values of the inverse relaxation lengths of. various over me 76°"

rmart

radionuclides were derived from the results of analyses of soil samples as described below. aM it beey “soafe |

The detectors used in the RIDP underwent an extensive series of calibrations and test
measurements before being used on surveys. In addition, the energy calibration of each
detector was checked three times a day during field operations. About 30 percent of the
8,550 spectra recorded during the RIDP were laboratory calibration runs to check the
angular. response and effective area’ of the detector. Another 23 percent were field
calibrations.

All the RIDP spectra have been stored on magnetic tape and archived at the DOE

computer center in Las Vegas. In addition, the results of the in situ measurements will become
part of a database maintained for DOE's Basic Environmental Compliance and Monitoring

Program at the NTS.
Soil Samples

Soil samples were collected and analyzed to determine the distribution of radionuclides
with depth in the soil and to measure the concentrations of radionuclides that either do not
emit strong gamma rays or have very low probabilities of emitting gamma rays.

“ ce Hecace, {


COPYRIGHTED MATERIAL

PLEASE REFER TO CITED JOURNAL
TO VIEW ARTICLE


REFERENCES

Anspaugh, LR. 1976. In situ methods for quantifying © specific radionuclides. IEEE
‘Transactions on Nuclear Science NS~23, 1190. “

Beck, H. L, J. Decampo, and C. Gogolak. 1972,.In sine Ge(Li) and Na(Tl) gamma-ray
spectrometry. HASL-258, Health and Safety Laboratory, Atomic Energy Commission,
New York, N.Y.

Bluitt, C. M. 1986. Anaerial radiological survey of Areas 16 and 30, Nevada Tést Site (Date of
survey: June 1983). EGG-10282-1118, EG&G Energy Measurements, Inc., Las Vegas,

Nevada.

Clark,H. W. 1983. An aerial ridiolgical survey of Area i1, Nevada Test Site (Date of survey:
January 1982). BOG-10282-104, EG&G Energy Measurements Group, Las Vegas,
Nevada. : .

Essington, E.H. Reliability of analytical results for the Radionuclide Inventory and
Distribution Program. (In preparation)

Essington, E.H. and S.W. Mead. Quality assurance procedures for the Nevada Test Site
Radionuclide Inventory and Distribution Program. (In preparation)

Feimster, E. L. 1985. An aerial radiological survey of Areas 18 and 20, Nevada Test Site
(Date of survey: October - November 1980). EGG-10282-1093, EG&G Energy
Measurements, Inc., Las Vegas, Nevada. .

Fritzsche, A. E. 1982. An aerial radiological survey of Areas 1, 2,3, 4, 6,7, 8, 9, 10, 12, 15,

and 17, Yucca Flat, Nevada Test Site (Date of survey: 8 August - 2 September 1978).
EGG-~1183~1808, EG&G Energy Measurements Group, Las Vegas, Nevada.

Gilbert, R. O. 1977, Revised total amounts of pu in surface soil at safety-shot sites. In
White, M. G., P. B. Dunaway, and D. L. Wireman, eds., Transuranics in Desert Ecosystems.
NVO-181, U.S. Department of Energy, Las Vegas, Nevada, pp. 423-429,

Gilbert, R. O., J. C. Simpson, D. W. Engel, and R. R. Kinnison. 1985. Estimating isotopic
ratios, spatial distribution, and inventory of radionuclides at Nuclear Sites 201, 219, and
221. In Howard, W. A., and R.G. Fuller, eds., The Dynamics of Transuranics and Other
Radionuclides in Natural Environments. NVO~272, U.S. Department of Energy, Las
Vegas, Nevada, pp. 381-429.

Gunnink, R., and J. B. Niday. 1971. Computerized quantitative analysis by gamma-ray
Spectrometry. Vol. 1-5, UCRL~51061, Lawrence Livermore National Laboratory,
Livermore, California.


Numerical results of the test soil particles aerosizing are presented in Table 2.

Table 2. Results of test soil particle analysis using API Aerosizer

Nominal Volume GSD Mean Mean GSD
Diameter Median (um) Diameter (um) (um)
(um) Aerodynamic
Diameter (pm)
5 6.49 151
6.49 1.50
6.57 1,54
6.52 1.51
10 12.94 1.46
11,97 1.54
12,55 151
12.49 1.50
30 24.03 1.56
24.41 1.56
23.46 1.59
23.97 1.57

Comparing the results of the size distribution analysis carried with the Microtrac and API
Aerosizer, some differences are noticeable, especially for larger particles. For the
nominal size of 10-um diameter, the Microtrac analysis yielded a diameter 26% smaller
than the API Aerosizer results. For the nominal size of 30-um, the Microtrac
overestimated the size by 36%. These differences could be attributed to different
measuring techniques: light scattering versus time-of-flight, and are indication of
difficulties in aerosol size distribution measurements, The light scatter techniques used
in the Microtrac instrument represents more closely the physical diameter (PD) of the
aerosol particles, whereas the API Aerosizer measures aerodynamic diameter (AD).
These two are related via Equation 2:

AD _
PD Yp,

7)

where ?, is the density of test particles (soil, 2.3 g cm) and ?w is the density of water I

gem,

21



= YO
e 4 “. > a

? 0

J :

Distribution of Co on the NTS as of January 1, 1990. Isopleth

Figure 5.
levels are 106, 1,000, arid 10,000 nCi/m?,

16


Todine-131 Fallout from Underground Tests
E. A. Martell
Science, New Series, Vol. 143, No. 3602. (Jan. 10, 1964), pp. 126-129.

Stable URL:

http-/Mlinks.jstor.org/sici ?sici=0036-8075%28 196401 10% 293% 3A 143%3 A 3602%3C126%3 A PFUT%3E2.0.CO%3B2-H

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Thu Sep 28 18:43:31 2006



As with all of the samplers tested, the AIRNET sampler is particle size and wind
speed sensitive, In the wind tunnel experiments, it collected virtually all of the small
particles (~96% average efficiency for 5-ym particles), more than 50% of the 10-ym
particles (which is comparable to EPA equivalent PMio sampler), while oversampling for
large particles. Therefore, particulate matter mass concentrations would be
conservatively estimated at least for the higher wind speeds (>10 m s') that occurred
during the experiment.

Results obtained during this 1-year project suggest the need for further, more
detailed studies if the full knowledge of the aerosol inlets used in the LANL is to be
accumulated.’ The extreme condition may be experience during accidents with
transportation of nuclear materials or natural disaster like fires. The results of
environmental surveillance, even if it is carried on longer time scales (weeks) can be
distorted by short-term extreme conditions (high winds) if the response of the sampler is
unknown.

ACKNOWLEDGEMENTS
The authors would like to acknowledge the ESH Division TDEA Committee that

provided funding for this project and number of people who help us during the study:
Jeff Baars, Jake Martinez, Bill Olsen ESH-17, Bob Barry USDA/ARS Pullman. Special
thanks for Yung-Sung Cheng from Lovelace Respiratory Research Institute for

performing size distribution measurements of test soil particles.

36


REFERENCES

Beck, H. L. 1980. Exposure rate conversion factors for radionuclides deposited on the
ground. EML-378, Environmental Measurements Laboratory, U.S. Department of
Energy, New York, N.Y.

Beck, H. L, J. Decampo, and C. Gogolak. 1972. In situ Ge(Li) and Nal(T1) gamma-ray
spectrometry. HASL-258, Health and Safety Laboratory, U.S. Atomic Energy
Commission, New York, N.Y.

International Commission on Radiological Protection. 1983. Radionuclide Transformations:
Energy and Intensity of Emissions. CRP Publication 38, Pergamon Press, New York.

ne teen ecto


Figure 12 shows the 133 locations of in situ measurements where the 7920py
concentration exceeds 500 pCi/g. The highest values are near the Oberon GZ in Area 8,
where two measurements exceed 100,000 pCi/g (the maximum is 320,000 pCi/g). Four other
points at Oberon, one at Wilson, one at Quay, and four at Little Feller I exceed 10,000 pCi/g.

The highest concentration calculated for a Plutonium Valley location was 3,000 pCi/g.
However, concentrations are undoubtedly much higher in the immediate vicinities of the four
blast centers. Also, substantial amounts of plutonium are known to be present in the soil in
regions outside the NTS boundary at Frenchman Lake (Area 5) and the Schooner site (Area

20).
UNCERTAINTY OF THE RESULTS

The project operations plan (Kordas and Anspaugh, 1982) specified an overall goal of Aft. lise
providing “a final inventory that is known with 95% confidence within at least a factor oftwo.” yo, isadot —
The project scientists feel that this level of precision has been attained, but this assessment 9 F yee Bs
derives more from their expert judgment than from any numerical analysis. The process by in flese # r?
which the inventory estimates are produced is complex, and uncertainty enters it at a number Samalfe of
of points. A thorough evaluation of how these uncertainties interact to affect the precision So uees.
of the final results is not currently practicable.

Sources of Uncertainty

Listed below are the major sources of uncertainty in the inventory estimates and
distribution maps and an indication of their importance.

Counting error. The random nature of radioactive decay is an intrinsic source of
variation in any measurement of radioactivity. The GAMANAL program calculates the
counting error as a percentage of the activity of each radionuclide, Reported values typically
range from 3 to 40 percent. High activities are usually measured with a smaller percent error
(but larger absolute error) than low activities.

Physical parameters. GAMANAL takes into account air density, soil density, and soil
moisture content when calculating radionuclide activities. As noted on page 7, the same
values of these parameters were used for the analysis of the in situ measurements from every
survey. Differences between the values used and the actual values for a given area could cause
an error of a few percent in the calculated activities.

The inverse relaxation lengths used in GAMANAL were
averages of several values calculated from soil profiles. The calculated inverse relaxation
lengths are usually quite variable, so choosing a single representative value entails a high
degree of uncertainty. The computed conversion factors are extremely sensitive to the value
of the inverse relaxation length, especially at low energies (see Report 1, p. 20).


Area 6: The estimates were made from 25 South Yucca measurements and the
radionuclide ratios used for the Galileo area in Area 1.

Area 7: The Quay values include the inventories in regions QU-1 through QU-4 and
contributions from WI-2, QU-5, and QU-6 (Table 9, Report 3). Inventories in the
unsurveyed region were estimated as in Area 3.

Area 8: The Baneberry results include regions BA-1, BA-2, and 80 percent of BA-3,
while the Smoky results include regions SM-1, SM-2, ‘and 23 percent of SE-3 (Table 5,
Report 3). Contamination from both Co and “Cs extends north of the surveyed area at
Baneberry, so relatively high levels were assumed for the unsurveyed region.

‘Area 9: The Wilson inventories are the sum of the reported inventories for region WI-1
and the portion of region WI-2 that is in Area 9 (Table 9, Report 3). Inventories in the
unsurveyed region were estimated as in Area 3.

Area 10: The Sedan estimates are the sum of the estimates for regions SE-1 and SE~2
and 65 percent of the estimates for SE-3 (Table 5, Report 3). Averages in the unsurveyed
region were estimated from the four easternmost Sedan points.

Area 11: Results are from Tables 7 and 13 in Report 5.

Area 12: Results for "Co, 57Cs, and “Sr are from Report 5. The other estimates were
calculated from an assumed level of 55 nCi/m? of Am (see Table 19, Report 5).

Area 15: The results for Yucca Flat are from Report 5, as are most of the results from
the east side. The “!Am inventory for the east side is based on an assumed average level of
20 nCi/m?, Elevated levels of radioactivity extend into the unsurveyed region north of Yucca
Flat, so relatively high averages were used for that region.

Area 16: The aerial survey showed 47Cs contamination in most of the eastern haif of
Area 16, so the average of the six "Cs measurements along the Mid~Valley Road (85
nCi/m?) was used for the entire region. Assumed levels of 20 nCi/m? of “Am and 3 nCi/m?
of ©Co were used along with the ratios from the west side of Area 1 to estimate the other
inventories,

Area 17: The Yucca Flat results are from Report 5. Contamination extends west of the
surveyed area, 30 above-background levels were used for the unsurveyed area.

Area 18: Most of the estimates for the four GZ regions are from Table C-1 on page 43.
All three europium isotopes are assumed to be absent from the regions north of the Little

33


u=14.7ms* d=5um

100

Penetration (%)
a
8
t

20H 7
10 i H
te)
AIRNET front (perpendicular)  AIRNET side (parallel) AIRNET opposite

Figure 38, Penetration efficiency of 5-ym particles for different orientation of the
AIRNET housing with respect to the wind tunnel flow.

There was a 21% decrease in penetration of 5-m diameter particles into the filter of the
AIRNET sampler when the internal filter holder was facing the flow versus the situation

where the sampler was rotated 180 degrees.

CONCLUSIONS

A number of different types of ambient sampler inlets were tested in this project,
each with a different intended role and application. All the inlets must operate in ambient
environmental conditions that are sometimes unfavorable to good sample collection. As
a result, certain design compromises have been made to accommodate the intended use
under adverse conditions. The simplest inlet of all is a simple filter holder. But when it
is operated in an inverted condition to protect the filter from rain and gravitational
settling of large particles onto the exposed filter, performance is affected, with smaller
ambient mass concentrations estimated in the LANL field trials compared with a
protected, upright filter holder as in the UM IPM sampler design (Figure 27).

Higher ambient wind velocities, which while not common, do occur and are

associated with critical resuspension and transport processes, required a different test

34


d| al ®
“te el |°

Figure 8. _ Distribution of “Eu on the NTS as of January 1, 1990. Isopleth
levels are 100, 1,000, and 10,000 nCi/m2.

19


approach which was provided in this study by a high velocity wind tunnel. Both the
effects of increasing wind speed and increasing particle size were evaluated. The results
show that while wind speed increases do have a significant effect on collection
efficiency, the largest effect was that due to increasing particle size. The UM IPM
sampler is supra-efficient for particles in the 5 pm size range (penetration > 100%), but
then for particles between 10 and 30 ym diameter, the efficiency drops to between 20%
and 40%, depending on wind velocity. It would appear that a significant fraction of
particles above a critical size simply move through the capture zone of the inlet with
sufficient inertia that they are able to cross the curving flow streamlines induced by the
sample flow into the filter and avoid capture. This is a well-known phenomenon that
leads to sub-isokinetic sampling in the case of sample extraction probes facing into a flow
field with a lower inlet velocity than the free-stream velocity. Under such conditions,
inertia tends to carry more large particles into the inlet than would be expected from the
free-stream concentration. Here, since the inertial trajectories are parallel and away from
the filter, the effect is to actually cause fewer of the larger size particles to be captured. It
may be that the addition of a deflection cone on the upper plate, as has been used in some
other designs, would remedy this problem by causing the parallel flow lines to diverge
toward the filter slightly, and thus change the inertial trajectory toward the collection

surface (Fig. 39).

Deflection cone = Upper plate

Filter ring

Figure 39. Modification of the UM design to improve high
wind velocity collection efficiency for large particles

With regard to the ECAM sampler, as has been previously noted, the design of the
large particle trap needs further design work, or perhaps only better placement in the
cyclone relative to the outlet tube, to move the cut point up’to the design target of 10 pm
AD.

35


measurable amounts in soil at one or more locations on the NTS (Table 1). The methods used
in the project do not allow Pu and Pu to be measured separately; all that can be
determined is the total activity of the two isotopes, denoted as 22“py, The ratio of 2°Pu
to py in fallout from nuclear tests conducted at the NTS ranges from about 12 to over 6,600
(Hicks and Barr, 1984).

Finally, radionuclides “of NTS origin” are those resulting from testing on the NTS. All
surface soi] on the NTS contains manmade radionuclides from global fallout, that is, fallout
from high-yield U.S. thermonuclear tests in the Pacific and tests conducted by other
countries. (The contribution of the relatively low-yield fission tests conducted at the NTS
to global fallout is small.) Regions of the NTS where the levels of radionuclides in the soil
were comparable to those due to global fallout were considered sreas of background activity;
such areas were assumed to have no radionuclides of NTS origin in the surface soil. Levels
above those attributable to global fallout were assumed to result from NTS activities,

‘The general areas affected by NTS activities were known before the RIDP began. The
project’s resources were focused on these areas, and only a few measurements were made

in background areas. .

TABLE 1. IMPORTANT MANMADE RADIONUCLIDES IN, NTS SURFACE SOIL

Radionuclide Half-life. (y)!
%Co 5.26
Sr 28.1
Rn : a a “
W2ORh | ” 1290: att
sp 27
pa 10.7
Cg 2.05
a BS, 302° 6. ve
BzEy, - “2B. -
~ ABU . 1
Shu ~ £381
AML yg : 86
ZBepy - * 86.
. 29py 24,400,
. Wpy _. 5,580.
Am - 458.

IMost values are from the CRC Handbook of Chemistry and Physics, 65th Edition
(1984), CRC Press, Boca Raton, Florida; the value for TMBa is from the Table of
Isotopes, 7th Edition (1978), Wiley, New York.


2. University of Minnesota (UM) IPM Inlet

To correct the deficiency of open-face inverted inlets in terms of their aspiration
efficiency, Liu and Pui (1981) proposed a new, modified inlet capable of better
performance under high wind conditions. This new Inhalable Particulate Matter (IPM)
inlet has a flange (2.4-cm wide) surrounding the filter holder, and circular top to keep out
rain and snow. This inlet was
evaluated in a wind tunnel at various
wind speeds up to 2.5 ms"'. The

i 20 cm

aspiration efficiency of the inlet for
8.5- and 11-m AD particles was
about 100+10%. However, it was
less (about 80%) for 13.4 um AD

Figure 3. Schematic diagram of the LANL/CSU inlet
based on design by Liu and Pui (1981) particles at higher wind speed.

The modified UM IPM filter was reproduced for the LANL/Colorado State
University (CSU) collaborative project on airbome transport of contaminated soils via
resuspension. The LANL/CSU inlet
diagram and physica} realization are
presented in Figs. 3 and 4. The inlet
uses a commercial 102-mm diameter
filter holder (Hi-Q Model RVPH-102)
with custom-made parallel plate flanges.
The inlet slot is protected with a coarse
metal anti-bug screen. The typical

airflow rate use for this inlet is 113 L

Figure 4, LANL/CSU inlet based on design by Lui
and Pui (1981). min,

1 HI-Q Environmental Products Company, 7386 Trade St, San Diego, CA 92121


Shrouded Probe — Reference Sampler

In order to determine the effectiveness of each inlet tested in the aerosol wind
tunnel it was necessary to obtain an unbiased reference sample of the test aerosols. It was
essential that this sample be collected rapidly and accurately regardless of the particle
size being generated and of the wind velocity in the wind tunnel. The shrouded probe
(McFarland et al., 1989) provides precisely the sampling performance for these tests.
The shrouded probe is designed specifically to address some of the problems associated
with representative sampling in air streams of varied velocity and direction (Fig. 11).
The shrouded probe exhibits near-constant sampling efficiency over a wide range of wind
speeds and for particle AD range spanning <I 1m to 20 pm (Huebert er ai., 1990).
Interna! wall losses are very low, which eliminates the need to recover significant
portions of the sample after each run. The shrouded probe operates at a single design
sample flow rate, unlike isokinetic probes, and therefore there is no need for contro} and

monitoring of sampling rate.

Figure 11, Cross-section and physical realization of a shrouded probe (McFarland et al. 1989)
connected to quick-change filter cartridge (center) and critical orifice (left).

Shrouded probes were extensively tested (McFarland et al., 1989; Huebert er al., 1990)
for their performance under extreme conditions showing excellent sampling efficiency.
For this project five special shrouded probe-quick-change filter cartridge-critical orifice

. assemblies were constructed and used to collect reference (free air stream) samples in the
wind tunnel experiment. The built-in critical flow venturi sets the nominal flow rate to

57L min’,

22


APPENDIX C
CORRECTIONS TO PREVIOUS REPORTS

Report 3
In Table 5 on p. 21, the inventory of “Sr in Region BA-2 (Baneberry) was given

incorrectly as 0.4 Ci. The correct value is 4.0 Ci. me

Report4 - aoe

a. The labelson the Johnie Boy results in Table 7, p. 43, were switched. Table C-1 belowisa
corrected version of Table 7,

b. In Appendix A, the Nevada Grid Coordinates of the soil samples at the Little Feller
site are wrong. The right values, as obtained from the NAEG database, are given below.

Point East North

43 606117 862204
44 606342 862329 ©
45 606167 862509
46 606042 862664
47 605941 862581

48 605852 862769
49 605867 862819
50 605667 862939
51 605797 863169

Earlier results for these samples were reported in Essington (1985).

Figure C-1 shows the true locations of the soil samples and the in situ measurements at
Little Feller IL. This figure is a revision of part of Figure 33 in Report 4.

Use of incorrect locations for the soil profiles resulted in inappropriate values of the
inverse relaxation length being chosen for the-GAMANAL analysis of the in situ
measurements. Figure C-1 shows that seven of the nine profiles were from inside the GZ
region and two were from outside. The averages of the calculated inverse relaxation lengths
(from Table 5, Report 4) for the two most important radionuclides in each region are as
follows:

Alam Y's
inside GZ region 0.51/am 0.55/em
outside GZ region 0.11/em 0.05/cm

41



TABLE C-1, INVENTORY ESTIMATES FOR AREA 18

Radionuclide Inventory + Sampling S.D. (CI

Region (ntti) lam 238Py 9,240Py Co
Little Feller I .
GZ area 5.76 52 +19 S742 BD 41 2 + 16°
Nof GZ 10. 8B 091 46 p11
Little Feller I 9.36 47 +14 56+ 17 2 + 81 034 + .0027*
Johnie Boy
GZ area 32. 35+ 05" 67+ M8 39+ 2 50 + 0%
NofGZ nr. Sit 09° 12 + 055 674 32 6 + O15"
Danny Boy A 66 +13 D+ 2% + 52 2 + 07
Total 160.76 18. + 27 39 + 32 97. +15 13 = be
TABLE C-1. INVENTORY ESTIMATES FOR AREA 18-Continued
: Radionoelide Inventory + Sampling S.D. (Ci)
Region BCs Sr ~ _ Wy ISM4Ey 1S3By
Little Feller I
GZ area 12+ 018 2+ 032 039+ .0041° 024+ 0026" 058 + 0066"
Nof GZ Br) a. 046* 033" 079"
Little Feller 29+ 000-584 060 10 + 0078 10 +0088" = 11 + 0077"
Johnie Boy
-GZ area 10 + 10 52 452 78 +.091 414.0277. 35 +00
Nof GZ 11 + 071 57 + 37) OO +036" 864 + 5" 58 + 024"
Danny Boy 23 + 2 14 + .18 53 + 073 B+ 00 27 + 019°
‘Total 50 + 32 3. + 67 21 +.12 13 £06 14 + 038

“These estimates are based largely on upper limit values.

3



U.S. Environmental Protection Agency (1999b). Ambient Air Monitoring Reference And
Equivalent Methods. 40 CFR Part 53.

U.S. Environmental Protection Agency (2000). Sampling and Analysis Methods for
Particulate Matter and Acid Deposition. Draft: 4.14: 4-38. Retrieved June 29, 2000 from
the World Wide Web: http://www.epa.gov/nceawww 1/pdfs/partmatt/vol 1/067 1ch04.pdf

Zebel G. (1978). Some problems in the sampling of aerosols. In Recent Developments
in Aerosol Science (Edited by D.T. Shaw) pp. 167-185, John Wiley, New York.

38


N

t

Approximate Scale:
inch = 7 miles

Figure 1. Portions of the NTS surveyed by the RIDP.