XA04NO755

RESULTS OF THE SCHOONER EXCAVATION EXPERIMENT*'

Howard A. TewesLawrence Radiation Laboratory, University of California

Livermore, California 94550

ABSTRACT

Project Schooner, a nuclear detonation in interlayered hard and soft,partially saturated volcanic rock, was executed as a part of the PlowshareProgram for development of nuclear excavation techniques. The primary ob-jectives of this experiment were: (a) to obtain experimental data on craterdevelopment and size in a new medium to further verify existing rock mechan-ics computer codes and calculational techniques; and (b) to determine thefractional release of radioactivity from a nuclear detonation in wet rock.

As was noted in the case of the Sedan experiment, appreciable (thoughrelatively small) amounts of radioactivity were released to the environmentfrom this detonation in hard, partially saturated rock. Although the thermo-nuclear explosive used in this experiment gave a yield of approximately 31kilotons, only the equivalent of the fission products from about 370 tons offission were distributed in both fallout and cloud. Data which have been re-duced to date indicate that this released radioactivity underwent only a mod-erate amount of chemical fractionation, being much more similar in this re-spect to Sedan than to Danny Boy.

EXPERIMENTAL PROCEDURE

The Schooner thermonuclear explosive, with a nominal yield of 3 ±4 kt,was detonated at 0800 PST on December 8, 1968, at a depth of 108 m. Theexperiment was carried out at the Nevada Test Site at the northern edge of thePahute Mesa area, shown in Fig. 1. The region surrounding the mesa ismountainous and extremely rugged, but the topography at the site is relativelylevel with less than 10 m of relief within a 350-m radius. The surface rockexposed in the vicinity of the site is a dense, strong, dry volcanic rock(welded tuff) extending over several square iles and estimated to be 30 to50 m thick. This rock is underlain by other tuffaceous members of varyingdensity and porosity, as can be seen in Fig. 2 which shows the lithology ofthe site. All the tuff between the bottom of the Trail Ridge Member and thetop of the Grouse Canyon Member (from 37 to 102 m) is low-density, high-porosity, weak rock. The Grouse Canyon Member (in which the nuclear ex-plosive was detonated) is a dense, strong, welded tuff, similar to the surfacerock.

Figure 3 is a summary of the porosity of the Schooner site rock obtainedfrom samples recovered from the emplacement hole, as well as from one ex-ploratory hole. Figure 4 shows the results of free-water determinationsmade on the same samples used for estimating medium porosity. It should be,noted that the water content of the Grouse Canyon Member (around the Schooner

Work performed under the auspices of the U. S. Atomic Energy Commis -sion.

306

Schooner U20u I I 6101 1160151 1 1 6`00' N

N

*Elko

37'1 5'tReno R�iher

NEVADA Mesa\%

\% evada oarTest t e

\N Ls Vegas co 'Clot100 0 100 I % c

Min� yucca S 37cOO'Scale in miles Mt. I UJ o' Lake

Xz

J/ Lincoln0 I "I I County

U_ If / French man5 0 5 10 f�oks Lo ke. <'I Clark

ack".ass County3 .0 iScale in miles /iSkull Mt

/ / 36045'Nevada

Test Site Boundary

th ro p Z I I s ercuryI

Fig. 1. Location of the Schooner nuclear-crater experimen .

N Roughly to scale, inch = 00 ft S

Ue2Ou-I Surface Ue2Ou-30

Trail Ridge Member, Thirsty Canyon Tuffdensely welded ash-flow tuff, partly welded at base

100-119 - 120

Spearhead Member, Thirsty Canyon Tuff

200 -207 - partly welded ash-flow tuff 207-z-

-239 Rocket Wash Member, Thirsty Canyon Tuff, non-welded ash flow tuff - 245

300 Reworked tuff with minor ash-flow tuff337

-352

400 Grouse CanyonMember, Belted Range Tuffmoderately to densely welded,

-460 devitrified ash-flow tuff486

500 Reworked tuff and ash-fall tuff

Approx. 100 ft

Fig. 2 Stratigraphic section of Ue2Ou -1 and Ue2Ou-3.

307

0 0

40 0 Core from Ue2Ou-3

Cuttings taken from 20u

25 - 80

120

1400

50 - 160

180E

200-C

0

220 0

24075 -

0260 -

280 -

300 -0

320 -

100 - 00

340 - 0 01

360 -00

380 -

400 1 q

125 - 0 10 20 30 40 50 60 70 80 90 100

Porosity percentage of bulk volume

Fig. 3 Porosity of rock at the Schooner site.

308

0 0

50 =5X 0.5 range I to 16range 0 2 to 0. 8

25 -10 1-

150 0 1 0

5 -

200

E a.

75 - 2500 0

300 -0 0

100 0 00 0 0 0

350 - 0 0

0 00 0 Values determined from core 011 samples, Ue2Ou-3

125 - 400 0 0

10 010 Values determined from cuttings, 0

450 Ue2Ou 3 and 20u

15 - 500 0 1 1 1 1 '� I I

0 5 10 15 20 25 30 0 20 40 60 80 100

Free water by weight - percent Saturation - percent

Fig. 4 Water content of rock samplings from Ue2Ou-3 and U20u.

detonation point) is about 3% while in the reworked tuff layer above a depthof 102 m (only about 6 m above the detonation point) the water content averages20-2 5%.

Figure is a summary of densities obtained from in-situ density logs,core and cutting samples from the emplacement hole, and from an exploratoryhole. Figure 6 shows the seismic-velocity data obtained from a downhole-velocity survey taken in the exploratory hole (located about 20 m from theemplacement hole). The welded tuff-ash flow tuff interfaces can be clearlyseen in the presentations of both the density and velocity as a function of depth.

309

0 0

10

20

30 -

40 - 10 .......

5 -

60 -

70 -

80 -25 -

90 -

100 -

110 -

E120 -

Q. CLQ) 130 -

140 -

150 -

160 -5 -

170 -

180 -

190 -

200 -

210 -

1.0220 -

230

240 .1kI

75 -250

1.00 1.10 1.20 1.30 1.40 1.50 1.60 1.70 1.80 1.90 200 210 2.20 2.30 2.40 2.50 2.60

Density g/cm3

Fig. 5. Density plot of Ue2Ou-3.

370

75 -

250

260-

-----------270-

280-

290-

300-

310- .0

320x

1100 - 330 - Contact'-O O--* x a -

x O 340-0 O'

0350-0

360- I O.:E 0

0 0 x

370- �__�O _...x OO

380- 0

390- I�X--.-� IX

x 0 x400-

P"

125 -410- -1 'O I

60 x420- O... I0 O x

430 -

440- o In-situ density from LRL clamp-in

450- density tool - Ue2Ou -3

0 x Bulk dry, as recovered, and bulk saturated

density measured on core from Ue2Ou -3

460-0 1 Bulk dry, as recovered, and bulk saturated density

470- measured on cuttings from 20u

,(height of line is collection interval) 0

480-Contact

0 ----------

150 - 490-

500,

1.00 1.10 1.20 130 1.40 1.50 1.60 1.70 1.80 190 2.00 210 2.20 230 240 2.50 2.60

Density - g /cm3

Fig. 5. (Continued).

311

0 0

25

50 Vertical geophone

25 - 75-100 - V = 7274.3 1175.85 fsec

125 -X Velocity break at 140.0 ft

150 -5 -

175 -

200 -

E 225 - V 4493.5 223.22 ft/sec

75 - 250 -

275 -

300 -

325 -100 - Velocity break at 340.0 ft

350 -

375 -

400 -125

425 -

450 V 6662.9 916.82 ft/sec X

475

15 - 5000 5 10 15 20 25 0 35 40 45 50 55 60 65 70 75 80 85 90 95 100

Time - msec

Fig. 6 Downhole velocity plot for Ue2Ou-3.

Figure 7a gives a summary 1 of the geologic data shown in the precedingfive figures: Figure 7b indicates how the data were averaged and used asinput to the cratering computations.

RESULTS

Detonation Description

Upon detonation, the ground surface appeared to mound (Fig. 8) in anormal manner, until escape of high-temperature gases occurred near thecenter of the mound at about 17 sec (Figs. 9 and 1 0). At this time, the domewas - 90 m above ground-surface elevation. Upon general mound disassemblymaterial was ejected on ballistic trajectories with maximum altitudes as highas 900 m above the original surface and with impact points as far as 1800 mfrom ground zero (for missiles of appreciable size and weight). Figure 1shows the early stages of mound development.

312

Crater Dimensions

Average dimensions of the Schooner crater are as follows:

Dimension Measurement

Apparent average crater radius, Ra 129.9 mApparent average crater depth, Da 6 34 mLip-crest radius, Ra� 147.2 mLip-crest height, Hae 13.4 mRadius of ejecta boundary, Reb 538.9 m 3Apparent crater volume, Va 1,74 5,000 m 3Apparent lip volume, Va� 2,099,000 m

H2 0 MEASUREMENT PROJECT SCHOONER0 0

20 - 20

60 - 600 - 117 ft DENSELY WELDED TUFF

POROSITY

100 100

-117 - 137 ff OXIDIZED, WEATHEREDSUB-FLOW ZONE

140 - 140

137 - 199 f MODERATELY WELDED TUFF ATER

18 - 180199 - 207 ft OXIDIZED, WEATHERED,SUB-FLOW ZONE

220 - 207 - 238 ft SLIGHTLY WELDED TUFF 220W U-1Uj U-1238 - 259 ft OXIDIZED, WEATHERED U_Z 260 SUB-FLOW ZONE 260 Z

259 - 275 ft PUMICE - RICH TUFF I

W U-1300 -275 - 335 ft BEDDED TUFFACEOUS 300 0

SANDSTONE AND TUFF

340 - 340

380 - 380

-335 - 486 ft DENSELY WELDED TUFF

420 - 420

460 - 460486 - 490 ft BEDDED TUFFACEOUSSANDSTONE AND TUFF

500 500WATER TABLE APPROXIMATELY 885 FEET

0 0.2 0.4 0 6VOLUME FRACTION

Fig. 7a. Summary of geological data for the Schooner site.

313

Topography of the crater is shown in Fig. 12. The isopach contour pro-files of the crater along orthogonal axes are given in Fig. 13. Figure 14 in-dicates the application of the above dimensions, and Fig. 15 is an aerial viewof the crater.

It may be seen from an inspection of both Figs. 13 and 15 that this crateris somewhat atypical when compared with those resulting from previous nu-clear detonations. Especially in the western quadrant of the crater, the pres-ence of the strong, hard 30-m-thick surface layer of welded tuff resulted in aslope of approximately 7 ', much steeper than the normally observed - 3 5400.

Surface Motion

The velocity of mound rise as a function of time has been found to be anextremely useful parameter in cratering physics studies. Not only does itprovide critical data for verifying computerized cratering calculations, but italso has been employed in the formulation of a semi-empirical approach which

(97

STATlONL2C)u-PORTION OF AREA 20IES T0.RA-

Fig. 12a. Project Schooner postshot topography.

317

enables an appropriate scaled depth of burst to be selected for a nuclear cra-tering detonation.

Two experimental techniques were employed in the Schooner Event todetermine mound velocities: (1) Flares were emplaced 40 ft apart on a linecrossing surface ground zero. The motion of these flares was recorded photo-graphically subsequent to the detonation, and the resulting record of flarelocation as a function of time was analyzed to determine mound velocity.(2) Accelerometers were located at a number of the flare stations; data fromthese instruments were displayed on oscilloscopes, photographed, and theresulting record was analyzed to determine both accelerations and velocities.Data from the two techniques were found to be in good agreement.

Figures 16 and 17 represent plots of the Schooner surface motion overa period of time prior to mound disassembly. At times of the order of200 msec, peak vertical velocities of about 50-55 m/sec due to surface spallwere observed in the vicinity of surface ground zero. In the time period

77--

CiED

STATONU20u-PORT15470F AREA 20Z

I C 1-1. I-P

Fig. l2b. Project Schooner isopach map.

318

South North5700 -

5600 -

5500 -

5400 - -

5300 11000 Soo 600 400 200 0 200 400 600 8DO 1000

West G. Z. East5700 - -

5600 - / ------ - -

550 - -

5400 - -

530&0 Boo 600 400 200 0 200 400 600 800 1000

G. Z.

Fig. 13. Schooner crater orthogonal profiles.

-WIDTH BETWEEN LIP CRESTS

WIDTH OF APPARENTCRATER

DEPTH OF APPARENTEJECTA CRATER

ORIGINAL R NDSURFACE DEPTH OF

\ FALL BURST�_._RLJPTURE '-, .11

ZONE

TRUE RATER -OUTER LIMITBOLJNDARY_�R OF BLAST

FRACTURING

Fig. 14. Idealized cross section of asingle-charge nuclear craterin basalt.

between 300 and 600 msec, the surface velocity remained relatively constant;however, after 600 msec, another distinct acceleration of the material becameapparent. This phase of the mound growth is attributed to the continuingexpansion of the vaporized material around the detonation site which, at thisrelatively late time has recompacted the debris above the shot point and thenimparts additional energy to the rising mass. As can be seen from the recordshown in Fig. 17, the flare target 24 m to the west of ground zero attained amaximum velocity of 65 msec before its motion could no longer be measured.

The surface velocities measured on Schooner are compared with thoseobserved from other nuclear cratering detonations in dry or partially satu-

319

7 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1

msec

60 - x< 200o 200-600

-13\0 600-1000

5 - o 1000-1400A 1400-1800E

40 -Z-0> 30 -

U\0\

> 20 jdge of crater Edge of crater

X-X-X-X

X/ X\

10 - xxX-.X -

0 N I I I - 1-160 -120 -80 -40 0 40 80 120 160

Distance from G. Z. - m

Fig.. 16. Schooner surface motion.

70 1

60 -

5 -

40 -E

Z.

'Z; 30 -0

20-

10-

0 0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8Tin* sec

Fig. 17. Schooner vertical velocity (Target 10).

321

rated rock, shown in Fig. 18. It can be seen that the spall velocity lies on theline delineated by the Danny Boy and Sulky Events. It is of interest to notethat, although the data shown in Fig. �,� were obtained from detonations inrock, the Sedan2 mound spall velocity"' lies very close to the line drawn totypify such nuclear cratering detonations.

On the basis of this mound velocity scaling analysis, it would appearthat the Schooner detonation could have yield6 a crater even if it had beenemplaced at a significantly greater depth, perhaps as much as 135 m. Suchan analysis should be approached with caution, however, for current experi-ence does not allow a definitive evaluation to be made on the possible effectsof such variables as geologic layering, moisture content of the environment,or fracture density of the rock.

COMPARISON OF SCALED CRATER DIMENSIONS ANDCODE PREDICTIONS

Cratering experience to date in all media for both nuclear and chemicalexplosives is summarized in the cratering curves hown in Figs. 19 and 20.Previous studies reported by Nordyke3 ai Toman have indicated that crater

3.4dimensions (radius and depth) scale as . for the yield ranges withinexisting experience. From Fig. 19, it can be seen that the Schooner scaledcrater radius is about what would be expected, considering the Danny Boy

160 - 500 1140 -120 - 400 -E

100 300 -80 - Sch( 0011- Delta (gas)

Bravo (gas vent)0 Z_ AI

Pre-schoonerff (G)60 - 0 200 Delta

? Danny boy (G)12 01ASch( Bravo

Cab Alfa40 \jj�'PS II _BB13 _Lqraters

a \ICharl le.2 100 _77f.. CobA r RetarcsL. - (S) F

a %Sulky

a gy N� HE data2OL- 0-

NE data501 1 ___-L I I

100 200 400 600 800 1000

Depth of burst ft/kt 1/3

30 40 60 80 100 200 230300

Depth of burst -m/kt 1/3

Fig. 18. Hard rock surface motion.

Sedan, with a nominal yield of 100 kt, was fired at a depth of 193 m andgave a maximum spall velocity of 35 m/sec.

322

24070 - Bear Pow, shale (HE)

Pre-schoonerff ,-Dugout, hard rock row60 - '1� 200 Buckboard

1Z Alluvium (HE)CZ Sch Cab

15 - 160 Sedan

E

40 --a 1202 Pre-Gondola I (NM) - 9 uvium N

30 20-ton.2 A Buckboard (TNT) - 20 -ton \,&- Dry, hard rock

so v Pre-schooner I (NM - 2 t (HE)* Nuclear, alluvium

20 Pa 0 Nuclear, hard rocka M Dry hard rockQ. Q. Sch Schooner - 31 kta- Cab Cabriolet - 23 kt< 10 40 DB Danny Boy - 042 kt (NE)

Bug Buggy - Ca 1 I kt Sulky -Sulky - 009 kt

0 0 ____L_ I I I I . I I I I

0 40 80 120 160 200 240 280

Depth of burst - ft/kt 1/3.4

0 10 20 30 40 50 60 70 so

Depth of burst - m/kt 1/3.4

Fig. 19. Cratering data, scaled apparent crater radius versus

scaled depth of burst.

and Cabriolet experience - (The Buggy crater may well be relatively small dueto the complex geologic layering5 which prevailed in the detonation site.)

Figure 20 indicates that both Schooner and Buggy gave scaled crater

depths somewhat less than would be predicted by the curves shown in thefigure. Again, the probable reason for the shallowness of the Buggy crater

is the geologic variability of the emplacement medium; however, in the case

of Schooner, it should be recalled that the scaled mound velocity curve

(Fig. 18) suggested that this detonation was carried out at somewhat less than

the "optimum" cratering depth. However, due to the layered geologic struc-

ture at the detonation site, emplacement of the explosive at the normal "opti-mum it cratering depth could have jeopardized the formation of a normal

crater.

Figure 21 is a comparison between the observed Schooner cvter (aver-

age dimensions) and that pedicted using the SOC-TENSOR Codes. It may be

seen that while the computed crater radius is significantly smaller than that of

the actual crater (by about 12-20%), the estimated depth agrees well with that

observed.

However, it is of interest to note that the predicted peak surface spall

velocity 34 mec) is almost 40% less than the 55 m/sec actually observed.

Should the spall velocity have been as calculated, it can be seen from Fig.

that the Schooner velocity would have been only slightly higher than those

observed on the Cabriolet and Buggy experiments, and hence, would have rep-

resented a case where crater formation was only marginal if spall were to be

the only mechanism by which the overburden would be accelerated.

32 3

I I I I I I

V Pre-Gondola I (NM) - 20-ton

5 - A Buckboard (TNT) - 20-tonv Pre-Schooner I NM) - 20-ton* Nuclear-alluviumco

40 - 0 Nuclear-hard rock4..S, 120 - ....- Pre-Schooner E Buckboard 12--,-,

Cab Dugout-hard rock row30 Sch V-C Sedan

80 - Alluvium-a (NE and HE)

20 - Bug

U Bear Paw sh HE)

40V10 - Dry, hard ro k (HE)U

SulkyDry, hard rock (NE)

0L__ a-a- 0

< 0 40 80 120 160 200 240

Depth of burst ft/kt 1 3.4

0 10 20 30 40 50 60 70

Depth of burst - m/kt 1 3.4

Fig. 20. Cratering data, scaled apparent crater depth versusscaled depth of burst.

More recent (postshot) calculations have been performed with the SOC-TENSOR codes in which the effect of the water in the Schooner environmenthas been weighted more heavily; the results of these computations agree moreclosely with the observed values for the crater dimensions and spall velocity.It should be noted that in all Schooner calculations, it was assumed that about10% by weight of the cavity vapor consisted of water, since this is approxi.-mately the amount which should be present when the involvement of both theash fall tuff and the welded tuff is considered.

It is felt that the present computational approach to cratering prediction,as modified by the Schooner experience, will allow the adequate prediction ofevents carried out in partially or completely saturated rock.

Radioactivity Studies

One of the primary objectives of the Schooner experiment was the studyof the release and distribution of radioactivity resulting from this detonationin partially saturated rock. extensive sampling program, both for thecollection of fallout and cloud samples, was fielded. Data obtained are stillin the process of being correlated and interpreted; however, some preliminaryresults can be reported at this time.

324

150 1 1 1 1 1 1 1 1

rowout distribution

100

Material 54;Preshot estimatesof apparent crater Po.= 2 35

bserved apparent crater

Fallback bulked 30%E50

Material 60;a-166PO

0 Material 51;0 2.3

Estimated c vity radius in material 1

Calculated cavity radius in material 60

50 100 150 200

Range - meters

Fig. 21. Estimated and observed profiles of Schooner crater.

Cloud Size

The Schooner cloud at time of stabilization 4 min after detonation) rep-

resented a typical main cloud-base surge configuration, although the relative

sizes of these two cloud components were notably different from those observed

on the Sedan Event:

Schooner Sedan

Main Cloud

Cloud diameter (m) 2420 2300

Cloud height (m above terrain) 3990 3600Cloud volume (m3) 1.5 X 1010 1.0 10 10

Base Surge

Cloud diameter (m) 4220 6800

Cloud height (m above terrain) 670 1200Cloud volume (m3) 9 10 9 4.3 X 1 0 10

325

At the time of the Schooner detonation, ground-level winds were south-erly at about 5-10 knots, while the winds aloft were from the west-southwestat an average speed of 30 knots. These meteorological conditions are re-flected in the observed fallout pattern as shown in Fig. 22, where the pre-dominant contribution of the main cloud fallout is apparent.

S-31 N

(.01

N

e S-45 Fallout tray

1

5 0 5 10 15 20

Statute miles

16

Fig. 22. Schooner fallout. field (R/hr at H+1 hr).

RELEASED RADIOACTIVITY RESULTS

Fallout

As has been done for past events, the amount of radioactivity releasedas ''close-in" fallout was defined as that which fell outside the limit of directthrowout. The pattern shown in Fig. 22 was integrated in the usual way; theareal distribution of the radioactivity in the observed pattern was integratedover the'range from 0.36 to 604 square miles and then extrapolated to an"infinite area. Using an intensity of 3380 R r (at H+1 hr) as the exposurerate resulting from the fission products from 1 kt of fission being uniformlydistributed over a 1-square-mile plane surface and a "terrain shielding factor''of 0.75, the observed fallout integral of 850 (R/hr)H+l hr X mi2 can be seento be equivalent to the radiation from the fission products resulting from- 340 tons of fission. Figure 23 gives the observed values for the gamma ex-posure rate (corrected to H+l hr) along the '."hot line" of the fallout field; aswould be expected, this "hot line" represented a trace of the path of theSchooner main cloud. Also shown in Fig. 23 are the gamma exposure rates

326

calculated using the KFOC computer program7 (using as input the observeddetonation time meteorology and measured total amount of radioactivity de-posited in the fallout pattern). It can be seen that the calculated values agreewith observed exposure rates within a factor of 3 at all distances, which,considering effects of terrain and other random variables, is considered to beadequate confirmation of the fallout model.

10

1.0

0 I

0.01 A KFOC-calc results

Observed data

0.00110 100 1000

Statute mi downwind

Fig. 23. Schooner main cloud hot line (H+l hr) exposure rate.

Radiochernical results obtained from a number of fallout collectors areshown in Table 1. The approximate locations of the six "close-in" trays areshown in Fig. 22; the other two collectors were too far from ground zero to beshown in the reference figure. It can be seen from the data given in Table Ithat there was a moderate amount of chemical fractionation within the falloutpattern, ranging from factors of 40 for some radionuclides to factors of onlyabout for the tungsten isotopes. Since the major contributor to the H+1-hrgamma exposure rate among the listed radioisotopes is obviously W87, andsince the correlation between radionuclide deposition and gross gamma fieldreadings has not been found to be much better than about a factor of 2 thedata given in Table I do not appear to be inconsistent. Obviously, there issome relative fractionation between the more 11 volatile'' elements (such astungsten) and those which display refractory behavior uch as manganese oryttrium).

327

Table 1. Results of radiochemical analyses of samples from allout traysand vaseline-coated tarpaulins, expressed; as pCi/m at zero time,divided by the gross gamma radiation field reading in R/hr (cor-rected to Hl hr). Multiplying each number in a particular columnby the factor shown at the head of the column will give the value of(pCi/m2)0, divided by the gamma field reading.

Fi-M P-d A"i-ti.. P-d-l�

(pCj,,.2)�

Di�t- 'T H h,

S,11 S,90 Z,95 A1.99 R�103 T� 132 1131 C�137 .140 C,141 C,51 �54 C.57 C.58 Y88 T. 168 �M T�l 83 W181 185 187 lb 203Mi- G. Z. (It

SWi.. .. lb M.) /h�H.Ih, O 0) (10') (10') O A (10') (101) (j05) (102) (101) 01) (101) (105) (101) (I A n 0) a O') ao') (101) (I A (1 A (109) (I

S-16 050. 3 1.3 - - 3 420 4 92 3 6 - 4 9 - 38 1 9 2 9.4 1 270 3.8 1 1 1 8 330

S-30 040- 1 0 3 - - - 350 - 1 30 4 - 52 1 - - - - 27 - - - - - 24 -

S-45 030- 27 0.37 - - 1.3 � 6 5.9 59 2 2 - 8.8 3.4 - 4.8 2.1 4 2.6 1.0 2.2 3 3 2.4 7.4 0 -

S-72 055. 4 0.3 - - 3.9 1 50 2 300 100 - 3 9.8 - 1.2 2 3 2 7.3 2.8 5.4 - 7.8 22 7 4 90

FFOCC-S-91 063- 270 0.009 1.2 a 0.8 - 7 - 3 4 1.2 2 7 2 0.8 6 1.3 0.4 1.0 - 2.2 6 - -

FFOCC-3-53 0 59- 4 3 0.002 0.3 34 1.8 - 2 - 4 6 3 20 1 1 4 1.7 1 2.5 1.1 - - 3.2 1 0 - -

B...-g.)

S. 2 000. I 3 - - 0.58 2 4 .0 50 1 - 6.5 1.8 - 1.7 0.86 5.2 0.87 0.36 0.83 4 1.6 4.7 7.1 8 6

S-43 010. 27 0.17 - - 0.74 2 4 3 58 7 - 6.4 2.1 - 2.3 1.4 6.6 1.3 - 1.2 7 1.8 5.3 8.5 -

A- .p 2.3 X 10" 2 - "' 3.5 1 4.9 1.8 2.9 3 2.9 8.5 1 5 240

When the geometric averages of the values given in Table I are taken(with the "far-out'' collections given somewhat less statistical weight than theother data), the results shown in the bottom line are obtained; all fission pro-duct data have been averaged to obtain an estimate of the fissions/m2 per(R/hr)H+l hr- When the average results are multiplied by the previouslynoted fallout integral, 850 (R/hr),H+1 hr X mi2, the total amounts of the variousradionuclides in the Schooner fallout pattern are obtained; these are given inTable II. For purposes of comparison, results are also given in terms ofequivalent tons of fission yield (expressed as dose rates at Hl hr). It can beseen that the Schooner fallout field contained only about 2.57o as much fissiondebris as was observed for Sedan.8 Although the amounts of induced radio-activities in the fallout are quite similar, the total radioactivity in theSchooner pattern is less than 25% of that measured in the case of Sedan.

Cloud

A number of aircraft samples were taken from both the Schooner maincloud and base surge at 12.5 min after the detonation. Radiochemical analyticalresults obtained from these samples are given in Table III. It can be seenthat the three regions of the main cloud represented by the samples were re-markably similar with regard to the radionuclide concentrations detected.The two base surge samples showed somewhat less correspondence to achother, with the first having only about 407o as much radioactivity per m asdid the second.

Schooner main cloud and base surge volumes measured at time of sta-bilization (H+4 min) have been noted previously; using photographically docu-mented rates of cloud growth as well as dimensional data obtained in thecourse of aircraft sampling, it has been estimated that at H12.5 min, themain cloud volume was about 4 X 1010 m3. Similarl , the base surge wasalmost a factor of 2 larger at H12.5 min (1.5 X Olffm3) than at H4 min.Applying these corrected cloud volumes and using the geometric average ofthe measured cloud concentrations given in Table III, approximate total cloudburdens have been calculatedly and are shown in Table IV.

Additional datall reported on Schooner cloud concentrations, as deter-mined for times later than H12.5 min, indicate that the relative radionuclidecompositions of both the'main cloud and the base surge changed only slightlywith time; this is in marked contrast to the observations made on the basesurge cloud from the Danny Boy experimental

328

Table IL Total amounts of several radionuclides deposited inSchooner fallout; comparison with Sedan fallout.

Schooner Sedan

Total Ci in Equivalent tons Equivalent tons ofNuclide Fallouta of fissionb fission in falloutb

Total fission 21Cproducts 5.1 X 10 35 1400

24Na - 3

SC 44m - - 0.3

Mn 54 850 0.002 -

Mn 56 - - 3

Co 57 770 0.0003 -

Co 58 3700 0.01 -

Y 88 1080 0.007 0.03

Tm 168 400 0.002 -

Ta 182 640 0.002 -

Ta i83 8300 O..O1 -

W 181 640,000 0.1 -

W 185 1.9 10 6 - -

W 187 3.3 X IO 7 55 50

Pb 203 53,000 0.0 5 -

Other - 250 d -

Total: -340 -1460

aCorrected to tb 01

Exposure rate at HI hr.

CTotal fissions.

dT6 stimated, including mainly short-lived radionuclides such as Na 24 andMn

Table III. Results of radiochemical analyses of samples taken from boththe main cloud and the base surge cloud at 12.5 min after detona-tion. These results are expressed in pCi/m3 at zero time.Multiplying each number in a particular column by the factorshown at the head of the column will give the value of (pCi/m3)O.

(PCi 3)0,

Fission Products A�tivation Pr.d.cts

Sample ientification MO 99 Ru' 03 Tel 32 131 Cs, 37 B.' 40 ce, 41 Ndl 47 Na 24 Mn 54 Co 57 Co 58 Y 88 Ta' 83 W181 W185 W187 pb 203

(105) (104) (105) (104) (101) (104) (103) (103) (106) (103) (10 3) (104) (103 ) (10 4) (10 6) (10 7) (108) (105)

Scboone, main l..d 01 1.25 3.06 3.15 10.3 8.7 4.24 7.51 4.60 1.6B 9.63 3.93 2.57 5.09 5.44 8.33 2.42 4.35 4.86

S.h ..... main 1..d 42 0.93 2.24 2.74 8.7 8.8 3.64 6.27 7 34 1.32 7.23 3.14 2.00 4.7 4.7 3 6.58 1.83 3.68 4.08

Sch..n.r main .1o.d N3 1.33 2.49 2.95 9.53 8.4 4.25 9.41 7.35 1.92 10.6 5.03 3.08 6.29 7.07 9.37 2.80 3.76 5.22

Scho.... base surge �1 0.1 5 0.34 0.4 2 1.33 7.7 1.06 1.10 0.58 0.19 0.99 0.62 0.32 0.50 0.77 1.38 0.4 0.66 0.68

Schoone bse urge R2 0.35 0.85 1.05 3.29 9.1 1.99 2.38 1.42 1 0.55 2.56 2.04 0.91 1.23 1.99 3.61 1.02 1.69 1.82

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Table IV. Total amounts of several radionuclides inthe Schooner clouds at H12.5 min.

Nuclide Main clouda Base surgeb

c Equi-\�. tons c Equiv. tonsTotal Ci of fissiond Total Ci of fissiond

Totalfission 21e 20eproducts 22 X 10 15 2.8 X 0 2

Na 24 64,000 0.6 5000 0.05

Mn 54 360 0.0009 24 0.00006

Co 57 160 0.00006 17 0.000006

Co 58 1000 0.003 81 0.0002

Y 88 210 0.001 5 12 0.00008

Ta 1 3 2300 0.003 1 90 0.0002

W 181 3.2 X 1 0 5 0.0 5 3.3 X 10 4 0.005

W 18 5 9.2 X 10 5 - 1.0 10 5 -

W 187 1.6 X 1 7 25 1.6 X 10 6 3

Pb 203 9000 0.02 17 00 0.001 5

Otherf -9 -0.6

Totals: -50 -6

a 10 3The estimated clbud volume is 4 X 10 M

bThe estimated cloud volume is -1.5 X 10 10 M3cCorrected to t 1

dExposure rate at H1 hr.

eTotal fissions.

fEstimated; mainly short-lived radionuclides, such as Mn 56

It is of interest to compare relative Schooner main cloud radionuclideburdens as determined by different sampling methods. In addition to theH+12.5-min aircraft sampling of the cloud, a number of other penetrationswere made at later times; the data from these samples and cloud radiationlevel determinatins ave been correlated, using the large cloud dispersionmodel, 213PUFF. Pi Also, at about H1 hr, some 150 small particulatesamplers were dropped through the cloud to obtain an.estimate of the aerosol"lumpiness" (see Fig. 24), as well as to ascertain the total radionuclide in-ventory.14 Results obtained from these different approaches are:

Sampling method W 181 cloud burden (corrected to t0

Aircraft, H12.5 min 3.2 X 1 05 CiCorrelated late-time aircraft data 1.5 X 105 CiDrop packages, H1 hr (2.5-10) X 105 Ci

The only one of those three methods that may be said to give a goodestimate of the "non-falling" cloud burden is the second. The H12.5-min samples apparently contain in about equal amounts both the "non-falling"material, as well as radioactivity which was deposited as local fallout (though

330

.010103 -

0000 00� 5.2B

.000

102 - 2.71 7 54

70 8.07 10 ��i �3

I 01 1.69 4.262.72

1.12

0.048 0.80 2.10 .54 a. 3.04

100 - 0.021 0. 52 0.61

0.480.

0. 23 0.12 20.53

028 0.9499 - 1.10, 0.3

0 .75 0 039 0.0-310

"as0 1 0.

0.

z 98 0 124 kO 1357 .030 is 3

0. 150 05 -0 0

00, 0.059

97 -

0.067

96 - e4o

95 - 10 milesGZ

94 1 1 1 1 1 1 1 1 1 1 1 1 1 1530 540 550 560 570 580 590 600 610 620 630 640 650 660 670

East

Fig. 24. The Schooner cloud contour based on measurements made at H1 hr. The isopleths are based on the con-centration of gross activity at H50 hr integrated from 18,500 ft MSL to the terrain surface. The coordi-nates are based on the Central Nevada Grid Coor�inate system and the unit is 10,000 ft. The dashed-linecontours are based on extrapolated data. = background reading.

perhaps at distances of 100 or more km from ground zero)-. The drop packagesamplers obviously collect a large amount of falling debris since they samplenot only the visible cloud, but also all of the material beneath the cloud downto the surface of the ground.

Consequently, the main cloud radionuclide burdens summarized inTable IV should be divided by a factor of 2 to be representative of the non-falling" cloud which contributes to long-range fallout.

Although the data relating to the base surge cloud burden are consider-ably less extensive than tho e obtained for the main cloud, the similar particlesize distribution observed'T in the H12.5-min samples from both cloudswould lead to the conclusion that about half of the radioactivity measured inbase surge samples.should be attributed to the "non-falling" debris.

On the basis of the foregoing discussion, the total released radioactiv ityfrom the Schooner Event may be summarized as:

Equivalent tons of fission

Fallout 340Main cloud 25Base surge 3

Total: -37 0

ADDITIONAL RESULTS

A number of other experimental programs were also conducted on theSchooner Event; some of the data from these programs have already beenreported, but have not been discussed in this paper.

Extensive studies of the impact of the Schooner radioactive debris on thebiosphere have been conducted by the Bio-Medical Division of-the LawrenceRadiation Laboratory, and by the U. S. Public Health Service (SouthwesternRadiological Health Laboratory), and. preliminary reports14,15 summarizingthe results are available.

Air blast easurements were ade (both at short and long range) bySandia Laboratories (Albuquerque). Reports are not as yet published. A studyof ejecta characteristics has been completed; a report on the data obtained isbeing published. 16

ACKNOWLEDGMENTS

The author wishes to thank those scientists, both at LRL and elsewhere,whose data have been summarized in this report. In addition to those includedin the references, the cooperation and help of a number of individuals wereinstrumental in the formulation of this paper; among these are:

J. B. Andrews, U. S. Army Corps of Engineers, Nuclear CrateringGroup (long-range fallout collection);

T. A. Gibson, LRL (fallout field assessment);J. R. Hearst, LRL (site geophysics);W. R. Hurdlow, LRL (accelerometer program);A. L. Prindle, LRL (radiochemical analysis);L. D. Ramspott, LRL (site geology);B. B. Redpath, U. S. Army Corps of Engineers, Nuclear Cratering

Group (crater configuration);R. F. Rohrer LL (surface motion analysis, cloud size assessment);

332

L. L. Schwartz, LRL (radiochemical analysis);R. W. Terhune, LL (cratering computations);

REFERENCES

1. A. E. Lewis and L. D. Ramspott, Trans. Am. Geophys. Union, 50,155 1969).

2. M. D. Nordyke and M. M. Williamson, "Project Sedan," PNE-242F,Lawrence Radiation Laboratory, Livermore, 1965.

3. M. D. Nordyke and W. Wray, "Cratering and Radioactivity Results froma Nuclear Cratering Detonation in Basalt," UCRL-6999, Rev. II,Lawrence Radiation Laboratory, Livermore, 1963.

4. J. Toman, "Summary of Results of Cratering Experiments," UCRL-71456,Lawrence Radiation Laboratory, Livermore, 1969.

5. J. Toman, Nucl. Appl. Tech. 7 243 1969).6. J. T. Cherry, Intern. J. Rock Ydech. Min. Sci 4 1 1967).7. J. B. Knox, "Prediction of Fallout from Subsurface Nuclear Detonations, If

5th U. S. AEC Symp. Radioactive Fallout from Nuclear Weapons Tests,1965, pp. 331-353.

8. J. A. Miskel, "Project Sedan: Radiochemical Studies," PNE-231,Lawrence Radiation Laboratory, Livermore, 1967.

9. J. J. Cohen, T. V. Crawford, and R. F. Rohrer, private communication.10. R. W. Taylor, ed., "Plowshare Program Quarterly Report of the

Chemistry Department, January through March 1969," UCRL-50015-69-1,Lawrence Radiation Laboratory, Livermore, 1969.

11. T. V. Crawford, "Diffusion and Deposition of the Schooner Clouds," to bepublished.

12. N. A. Bonner and J. A. Miskel, Science, 150, 489 1965).13. T. V. Crawford, "A Computer Program f6-rCalculating the Atmospheric

Dispersion of Large Clodds," UCRL-50179, Lawrence RadiationLaboratory, Livermore, 1966.

14. L. R. Ans Raugh et al., "Bio-Medical Preliminary Report for ProjectSchooner, UCA-L-750718, Lawrence Radiation Laboratory, Livermore,1969.

15. "Preliminary Report of Off-Site Surveillance for Project Schooner,"Southwestern Radiological Health Laboratory, Department of Health,Education, and Welfare,. Public Health Service, Bureau of RadiologicalHealth, January 1969.

16. R. W. Henny, ''Schooner Ejecta Studies,'' to be published.

333