UBNRDL-TR-899IV VUI4'4 IV'U'

S'?PHYSICAL AND RADIOCHEMICAL PROPERTIE8SOF FALLOUT PARTICLES

by0. R. Crocker va fw•"• s W

J. 0. O*Connor "TfNCL 1 ~~LTOE. C. Frelling

DDCNnv 171% 1 16,i[l

U.S. NAVAL RADIOLOGICALDEFENSE LABORATORY

SAN FRANCISCO CALIFORNIA , 14135

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The work reported. va part of a projecotsyponeed. ty the Space Nucl~ear PropulsionOffice undur Contract N~mbew AK (AT-49).R505 (~4).

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ABGTRACT

A survey has been made of the very large body of literature now

existing on thr characteristics of fallout particles. An attempt is

made to suamwize in concise form the ranges of plsical and radio-

chemical properties of particles of the debris produced by devices

detonated under various conditions. The results of studies of the

leaching action of various solvents on fallout particles are also

summarized.

-e.

SUMM4ARY

The p1wuical and radiochemlcal properties of fallout particles

from nuclear weapons do not fall into narrowly defined ranges. Deto-

nations at altitudes sufficient to prevent incorporation of soil into

the fireball tend to produce small, spherical) highly active particles

with the activity distributed throughout. If soil and other on-site

material is incorporated into the fireball, one observes increased fre-

q•,ency of particles with lower specific activity, irregular shape,

larger size, evidence of partial melting and agglomeration, and acti-

vity concentrated on the surface of the particle. The leaching action

of various solvents on fallovt particles depends upon the nature of

the particles themselves as well as that of the solvent.

ii

4

IRWJC1ISON

As the application of nuclear power expands, the nature of radio-

active debris becomes a subject of ever increasing interest. In addi-

tion to concern with world-wide radioactive fallout from atmospheric

testing, consideration must be given now to venting underground eCplo-

sions and reactor accidents, and perhaps in the not too distant future

to contaminating events produced by the peaceful applications of nuclear

explosives and to the safety aspects of space vehicles and satellites

powered by nuclear reactors and radioisotope sources.

In the twenty years since the testing of nuclear devices began, an

enormous amount of attention has been directed toward characterizing

fallout particles. These studies have involved many different observers

at many different installations, and a large literature on the subject

has accumulated. By far the greatest portion of this literature is in

the form of classified and unclassified technical reports to the Armed

Services of the United States, although important contributions have

been made in the open literature. The diffuseness, classification, and

general unavailability of this material make it difficult for the non-

specialist to form a clear idea of the general charateristics of fall-

out.

Nuclear debris resulting from various 'ission processes will natur-

ally have many similar radiochernical properties. Nuclear debris formed

at high temperatures in explosions or excursions and thus consisting

primarily of oxides of uranium, plutonium, and structural metals will

have many physical properties in common. Recognition of this has led

to an interest in the properties of fallout particles for tre purpose

of permitting valid comparisons with radioactive debris from other

sources and also, equally important, to avoid the pitfalls of unwarranted

comparisons. This report is the result of a survey of the fallout iiý-

erature and it attempts to summarize in a concise form the ranges of

physical and radiochemical properties that have been observed.

LITERA'-RE SOURCES

In 1960 the Defense Atomic Support Agency initiated a project to

collect, critically select, summarize, and publish the then existing

test data relevant to the physical and radiochemical properties of fall-

out. More than two hundred source documents were consulted, as were

pertinent documents covering the testing since 1960 and numerous other

sources of information. This investigation has provided the background

for the present report.

The characteristics of fallout particles depend to a certain extent

on such factors as weapon yield, height of burst relative to ground

surface, the nature of the materials in the device, the presence or

2

absence of a tower or other on-site materials for testing Rnd inetr=-en-

tation and how much and what kind of soil is drawn into the fireball.

For this reason it is convenient to summarize the physical and radio-

chemical characteristics of the particles according to the type of

burst which produces the fallout. However, there is some unavoidable

overlap in the classification by this method. For instance, the parti-

cles produced by low air and by tower bursts may resemble either those

produced in high air bursts or those from ground-surface bursts. Fur-

thermore, the classification, are not completely unambiguous, since a

burst altitude that is high relative to a low-yield device might be low

relative to a high-yield device. The interesting concept of a scaled

height of burst, which vould properly weight the parameters in such a

way as to provide an unam iguous classification, does not yet seem to

have acquired a formulation which applies to all device weights.

This summary does not attempt to include the properties (other than

leaching behavior) of fallout particles resulting from bursts on and

under the surface of the ocean. Many tests of this kind have been con-

ducted, but those properties of the particles which have not been re-

ported elsewhere(1$2) remain too poorly defined to merit inclusion here.

Similarly, no information is included on the particles formed in com-

pletely contained underground bursts.

The observations which form the basis of this report were made by

many workers and involved a variety of objectives, methods, and instru-

mental biases. In particular, the sampling methods used differed greatly

3 4

and often are described in weapons test reports only loosely or not at

all. In fact., it is not always clear whether a description refers to a

complete sample or to some selected portion of it. Where obscurities,

contradictions, and omissions have been encountered, no attempt has been

made to incorporate the data.

PHYSICAL PROPERTIES

Table 1 summarizes size, shape, color, density, location of activity,

and ferromagnetic properties of fallout particles for three different

types of burst. High air bursts are those which involve no appreciable

amount of soil, while ground-surface bursts involve large amounts of

soil. Low air and tower bursts form an intermediate classification

which sometimes involves soil interaction with the fireball and some-

times does not.

Only rough limits are shown for particle size. There has been much

speculation about the distribution of particle sizes. Unfortunately the

test data available do not permit any definitive statements. Very little

information is available with regard to particles in the submicron size

group. Particles in this size range certainly exist in fallout, but

apparently account for only a small fraction of total mass and activity

in local fallout and for ground surface bursts. In high air bursts,

however, they may be the largest contribution to world wide fallout.

'4

High Air Burst Low Air and 'ower Ground SurfaceBursts Bursts

Size Seldom greater Range from a few microns Same as 1o airthan 20 microns to several hundred or a and towerdiameter. Dist- few thousand microns. bursts.ribution unknown. Upper limit dependsSize varies in- upon nature and amountversely with of interacting soil, etc.yield.a

Shape Almost all spher- Both spheroidal and irre- Irregular parti -ical. Occasion- gular. Proportions de- cles predominate.ally two spheres pend on shot conditions. Some spheroidsare stuck to- Small spheres stuck to observed. Vari-gether.a larger particles some- ous kinds of

times reported. agglomeratesand partiallymelted parti-cles.

Color Colorles, gold- Colorless, gold-yeflow, Soil color pre-yefloiw orange, orange, red, brown, dominates, butred, brown, green, black# other colorsgreen, black. also noted.

Density 3 to 4.-3 g/cc 1 to 3 gfcc 1 to 3 gicc

Activity Particles are Scm particles active Activity com-Location active through- throughout. Some have centrated on

out. activity mainly on sur- relatively smallface or outer zones. proportion of

particles, mainlythose that appearto have been par-tiaelly melted.

Ferro- No " ata. Fartic.es may or m•y not Sma'L. proporon'magnetism be magnetic. Magnetism of particles

may be associated with sometimes mag-dark color. In some netic. Depends,tower bursts most par- on soil and ma-ticles may be magnetic. terials on site

of detonation.

aSome large non-spherical particles were reported from a sub-megaton air

burst 1480 feet above coral reef. Some large particles were also re-ported from a high yield air burst 43 50 feet over water.

5

Statements about the shape and color of the particles are essentially

qualitative and are based on subjective judgments. The small spherical

particles, which ara characteristic of high air bursts, become scarcer

as more soil interacts with the fireball, but they are observed occa~iion-

ally even in deeply buried cratering shots. The colors observed in

fallout particles sometimes have been ascribed to the presence of speci-

fic chemical elements. Such assignments are not very strongly supported

by chemical analysis. Figures 1 through 4 show some typical shapes ob.-

served in s"-.race and tower shots.

The density values given are for single particles; that is, they

are true densities rather than bulk or tap densities. The location of

radioactivity within the particles has been studied mainly by autoradio-

graphic methods applied to thin sections or mounted particles. Figures

3 and 4 illustrate this technique. The ferromagnetic properties of fall-

out particles have not been studied much.

RADIOCHaaCAL PROPERTIES

Table 2 summarizes specific activity, decay, fractionation, induced

activity, and deposition and partition of fallout particles. These pro-

perties are strongly dependent on whether or not soil interacts with the

fireball. The first two classifications of bursts in the table are based

mainly on this distinction. A third classification, sub-surface crater-

ing: bursts, has been added since some of the radlochemical properties

of deeply-buried bursts are. distinctive.

NPiAL 334 -45

Fia. 1. A typical radioactive fallout particle from a towershot in Nevada. The particle has a dul.l, metallic luster andshows numierous adhering small particles.

1/2 mm

Fig. 2. An~ active fallout particle from a tower shot inNevada. The particle is spherical with a brillant, glossysurface.

NROL. 534-611

"7"

..~' :) . ... 1/2 m m1/2 mm

Fig. 3. Photograph (left) and autoradiograph (right) of a thin

section of a spherical particle from a ground surfacc shot atEniwetok. The radioactivity is uniformly distributed throughout

the particle.

8

WROL. 14-6B

I z•

1mm ISO

Fig. 4. Photograph (left) and autoradiograph (right) of a thin

section of an irregular particle from a ground-surface shot atBikini. The radioactivity is concentrated on the surface of the

9

TABMZ 2. RADIOCRECAL PHD)ER'M

Nigh Air Brts 5-w Alior Surf ace Mu-Surface(No soil enters Bursts (Soil _ntua r.-+÷-* ."4fireball) fireball) Bursts

specifiC Volm specific acti- Lover than that of Mots InvolvingAt.ivitY V1 iY (dpa at 25 days high air burstsp very large amounts

per cubic micron) 2 depending on of soil may notto 750, depending on mount of tower, produce more thanyield. The number of soil, etc., inter- 1010 equivalentZr 9 5 equivalent is- acting in fallout fissions of Zr 9 5siona* per gam can formation. Typi- per gram.be estimated from: cal surface shots(.4xo3reAk~ produce falloutDevice, weight(g) wivth activity anbut this gii-s high high as 1015 zr 9 5

values. EUperimental equivalent fissionsvalues range as high per gram.as 1018 to 1021 fis-sions per gram.

Dicsyr Beta decAy exponent WM- decay expo- aM-0 am law- airranges from 0.5 to nent approximately bursts.1.7 vith Modal value 1.2.of about 1.1 for large(greater than I Microndiameter) particles.

I~ction- Larger particls Cos-e-in fallout Crateuizi sho-ts mayation (greater than 1 Micron is usua,3. deple- trap large amounts

dimeter) depleted in ted in volatilely of refractory massvolatilely bebaving behaving mass chains in fall-omws chains. Submi- chains, vhile back. In theseoron particles rela- vorld-wide fallout cases, local fall-tivey representative. is enriched, out is enriched in

volatilely behav-Continued ing mass chains.

'Ibis is the number of atom of fissioning material resuired to producethe Zr95 found in the semple. For exmple, suppose 1000 atoms of Zr95are found in a sample of debris from u05 thermal neutron fission.Since in this fission process the fissioning of 100 u2 35 atoms produces6.26 atoms of zr95# the sample of debris contained 1000/.o626 or 15,9Oeq•ivalent fissions of Zr95.

* exponent referred to is the quantity x in the equation A1/A2 = (t 2 /t 1 )where A1 is the activity at time tl.

10

f

TABIZ 2. RADIWaOOBDCAL RoPW.IM (Continued)

]Mgh Air Bursts Low Air or Surface S(No soil enters Bursts (Soil enters Cratering46J.& VNMJ"J. Burets~J. DW

Induced Vumerous induced acti- Remerks on bih Rmarks on high airActivity vities observed, air bursts apply, bursts apply, ex-

Those of mass less except thet at cept that at earlythan mnei 2D3 do not early time acti- time activityappreciael"y increase vity frox )n56 from NA24 my be-the activ!ty at early (particularly in co appreciable.times. Cwntribut~on steel tower bursts)of u237 u239, u2 4.o and Nae& mWy be

and Np4 9 are variable appreciable.a__ sometimes appreci-

Deposition- Virtually all ebri Close-in rdiation CMZi;arhap•e all--and goes Into vorld-wide fields of high in- out fields ofPartition fallout. If height tensity, extending high intensity,

of burst is low dovuvind in cigar- like surfaceenogh, ground-radi- shaped pattern, bursts exceptStion patterns result Deposits as high mum depositedfroM induced activity, as a few gro of my be MichThe radiation contour. fallout per sqare greater. largeof these patterns are foot for typical peart of activitycircular and can reach surface shots. my be broughta-hr doese rates of 25 Partition betwsen dmn in fall-backr/hr at the center close-in and vorld- and local fall-then groMd material wide fallout iniri- out. We variesis not dram into the ously estimted at Vith nuelide, duefire-ball. Relatively 25%-to-75% close-in, to fractionation.little ground material depends on device in oevent 12%raises this dose rate yield, moil condi- of and 0.2%to 1000 r/hr by scar- tions, etc. of Zr 9 5 reportedenging radioactive to hlve escapedmterial from the into world -widecloud. f t.

1...1

In the literature many differcnt units have been used for reporting

. . - •, ,., +, ,+a- P,-a mdAums, n? an't•vitv for fin-

sion products is eMtdvalent fissions based on Zr95. This is the number

of atom of the fissioning material required to produce the Zr 9 5 found

in the sample.

The decor of fission product activity vith time has been widely

studied.'4'5) The early expectation that this wciuld prove to be a

valuable method of characterizing fallut samples has met with some

disappointment. It is true that the decay curves exhibit considerable

variation in overall slope and slight differences in shape, yet it is

impossible to draw my7 reliable conclusions about the radiochemical

composition of a sample from the study of its decor curve alone. It

is not even possible to explain differences in two or more samples from

the sam event by copring their decay arves. The decay masurement

is eseential3y too insensitive to shed nuch light on the very complicated

compositional variables that are of interest. or purposes of predict.

ing dose rates and making shielding calculationss, the early prediction

of Way and Wignsrr) that gross fission product ctivity should vary

roghly as the -1.2 pmvre of tiw remain* the neat uAeful gneral rule.

The phenomenon knon', a fractionation of the fissioni-product radio-

nuelides is coonly observed in fallout and has been widely discus-

e*,(6P7s8P9P1,l0') Fission processes are known to produce the fission

products In fixed proportions, yet the proportions observed in fallout

samples are often very far from the expected values and may even differ

12

greatly from sample to sample. It is genera.Uy believed that this

densability of the elements conposing the mass chains durn the very

raplu 'l;u•nching of the fireball. Thus, mass chains which contain Br,

I, Kr, ard Xe at earliy times (vo3Atile chains, such as mass-89 and

=as-137) may condense at a different time and in a different way from

chains which do not contain these elements (retructory chsair such as

mans-95 and mass-144). A method for the systematic analysis of radio-

chemical data on fractionated nuclear debris has been developed by

fteiling.0(9

Both fission and fusion processes result in the production of

activity other then fission-product activity. These activities, called

induced activities, &rise from the inter, * 4an of neutrons with the

atmosphere, the unburned core material, the device cuing and sIle3Aizig

and the tower materials and other on-site materials including the moll.

The range of nuclides observed in fallout vwich are attributed to neu-

tron activation is large and includes, for ecmple: Be*7 Na24p A12p

1454f 0 n5 , F55, 70590 06 0 Od135 , *w 185, 0V 38, Uj2 37 , U23 9, U2W and

Np2 3 9 . The niber of neutrons from a fission event that are avaUiable

for inducing activity is of the isame order of magnitude as the nvber

of fissions,, and this number mut be distributed wong al Uinduced

activities. It is therefore unlikely that more than one or two of the

induced activities will be present in fission-event falla• t .n suffici-

ent pntity to account for an apeciable fraction of the total activity

13

at reasonably ear:ly ties after detonation. Sj.nce woet fisuion-product

indce activiitie.~. m"u'as o6 ; owy hoermp 1. ?e i tively important. in

old fallout.

LACH•G PROPDITI&

The effects of leachig nuclear debris are: of particular interest

became of their relation to the biological availabilti• of the radio-

amtive species, aid considerable effort has been devotod to docatenting

these effects. Of the numrous solvents studied, by far the moist ex-

tensively Investigated are distilled water (including rainvater), sea.-

water, and 0.31N CI. Distilled water and reinvater are of interest

become of their relation to weathering and soil transport. Sewater

Is of importance in the uptake of radionuclides in the marine biosphere.

The O.11 W1 is genes•ally considered to be a simulant for stomach fluids.

The leaching properties of nuclear debris have ususally been reported

in term of the fraction of gross beta or goss gem activity found in

a solid, soluble or colloidal state. In these term the behavior is very

calex. Besides depending upon the matrix material of the fallout, its

par-ticle also and type) its previous history; the duration of leaching

action and the solvent employed, it also depends upon the time after

detonation at which leachin begins, Results In term of individual

nuclildes are inh awe significeant, but these are relatively scawce.

The wet desirable d&aa of all, the rates of dissolution of individual

nuclidem, ae virtualxy non-existent, doubtless because of the effort

" 'l owili• • i I lll ". I | i:' I . ,i . i

required. Most workers report some "equilibrium value" of the solubil-

ity, which usually corresponds to a levelling off of the curve for

leached activity vs. time.

Results in terms of gross beta activity suffer the additional dis-

advantage of requiring great care for reliable determination and it is

seldom clear that this care has bern taken. It does appear to have been

established, hovever., that gross beta activity is more easily leached

in going from tower-shot debris to silicate-burst debris to air-burst

debris. As expected, 0#.3 11I is more effective than water: Water

dissolves at most a few percent of the gross beta activity from tower

debris; 0.11N HCI dissolves mset of the gross beta activity in air-burst

debris. Same authors report that the solubility increases as the size

decreases. The debris fran coral-amrface bursts is reported to be highly

soluble in water, not only the gross beta activity but the particles

themselves. fresh coral-burst debris is largely CaO and Ca(0H) 2 and

hence raises the pH considerably when it dissolves (to 10-n1).

Measurements of eross gamsa activity in samples of debris from

coral surface shots show that at 4-8 daOrs only about 8 % of the activity

dissolves, but at 20 days some 23% dissolves. These results are con-

siderably lover than those reported for gross beta activity. FPr our-

face-water barge shots, at 2-3 days, 60-70% dissolves. In both the

island and barge cases the colloidal fraction was relatively negligible.

Radlochmical measurements of the leached material from silicate-

surface and subsurface bursts indicate that iodine, cesium, strontium

and barium radionuclides Are among the principal contributors to the

leached activity. In the case of silicate-surface bursts, the increase

in so±unoiiiy vitn aecreasing particle size rias been clearly established.

--. J. t''-lahn oe f0A!..%. vrUJAw

appears for particles less than 44 microns in diameter.

Of particular interest is a study on weathering effects which con-

eludes that tae effect of rainwater in leaching silicate p•mticles is

minor. The plysical movement of the soil, caused by rain, is more

effective in transporting the activity.

The physical state distributions of individual radionuclides for

water surface and underwater bursts have recently been disucased at

length elsewhere. (2)

DISCLESION

The physical and radiochemical properties of fallout particles

fron nuclear weapons do not fall into narrowly defined ranges. Depend-

ing on the characteristics of the device and the shot conditions, par-

ticle sizes ma range from sub-micron to centimeter dimensions. A.Mout

all colors common to minerals may be observed at least occasionally;

specific activity may vary over maxr orders of magnitude; active par-

ticles may have either irregular or spheroidal shapes and be either

magnetic or non-magnetic. Activity may be concentrated on the particle

surface or uniformly distributed throughout the particle and all degrees

of fractionation may be observed.

16

If the components of the device, the height or depth of the detona-

tion and the nature of the soil and other on-site materials are speci-

fied, the range of properties to be expected in the fallout particles

can usually be narrowed considerably. Detonations at altitudes suf-

ficient to prevent incorporation of soil into the fireball tend to

produce small, spherical, highly active pcrticles with the activity

distributed throughout. If soil and other on-site material is incor-

porated into the fireball, one observes increased frequency 'f particles

Vith lower specific activity, irregular shape, larger size, evidence

of partial malting and aggloerationj, ard activity concentrated on the

surface of the particle.

The leaching action of various solvents on fallout particles is

quite complex and depends rather strongly upon the nature of the par-

ticles themselves as vell as naet of the solvent and the experimental

conditions.

17

--

vI,

-'

REFEENCES

1. C. E. Adams, N. H. Farlow and W. R. Schell, "The Compositions,Structures and Origins of Radioactive Fall-out Particles," Geochim.Cosmochim. Acta 18:42, 1960.

2. E. C. l'reiling and N. E. Ballou, "Nature of Paclear Debris in Sea-Water," Nature M9:1283, 1962.

3. K. Way and E. P. Wigner, "The Rate of Decay of Fission Products,"Pi s. Rev. U:1318, 1948.

4. P. Zigman and J. Macki.n, "Early Time Decay of Fission ProductMixtures IIP" Health Physics 2:79, 1961.

5. J. E. Watson, Jr., "An Analysis of Calculated and Measured FissionProduct Activities," Ballistic Research Laboratories, AberdeenProving Ground, BRL-1239, February 1964.

6. J. L. Magee, 'Vorldwide Effects of Debris from the Atomic Bomb,Appendix II, Project Sunshine," U. S. Atomic Energy Conmission,AECU-3488, 6 August 1963.

7. K. Edvarson, K. Low and J. Sisefsk1I, "Fractionation Phenomena inNuclear Weapon Debris," Nature 184:1771, 1959.

8. C. F. Miller, Fallout and Radiological Countermeasures, StanfordResearch Institute, 1963.

9. E. C. Preiling, "Radionuclide Fractionation in Bomb Debris,"Science M:1991, 1961.

10. R. P. Shields, W. E. Browning, Jr., C. E. Miller, Jr., and B. F.Roberts, "Release of Fission Products on the In-Pile Melting orBurning of Reactor Fuels," in Eighth AEC Air Cleaning Conference(O.k Ridge), TID-7677, 1963.

11. T. M•auro, K. Yoshikawa and N. Maki, "Radionuclide Fractionation inFallout Particles," Health Physics -1:199, 1965.

18

UjNClASSIFIEDSecuurity Classification

DOCMAENT CONTROL DATA - R&D(Secgurity classification of 1104., booty of abstract end indexkgIa nviotaflee must be uentered whoon the owsall report is cN..iesif

1. ORIOINATING ACTIVITY (Corporate author) I.. .....------- ..IU. S. Naval Radiological Defense Laboratory UNCLASSIFIEDSan~ Francisco, California 914135 16 "u

3. REPORT TIYLK

PHYSICAL AND PADIOCHD4ICAL PROPERTIES OF FALLOUT PARTICLES

4. DESCRIPTIVE N0TES (riyp. of ropoe rof in nchisive dates)

9, AUTHOR($) (Last name. Giffl.14W, Iigidal)

Crocker, G~lenni R.O'Connorp Joseph DoFreiline, Edwvard C.

a. P.KPO PT DATE 70. TOTAL.. No. OF 9*Aft b.N.OPOP

1 November 1965 28 37 -N-ap"~On. CONT14ACT OR ORANT NO. S&. ONIOINAION's RKPONT NUM.EIW8)

AEC(AT-49)-2505 (14) USN.RDL-7th.8996. PROJICtr No,

*b. *=NR~PORT NO(S) (AnY o@iqstjWbmamItW A~welailed

MO A VA IL. AIMILiTY/LIMiTATION NOTIC99

Distribution of this document is unlimited.

~If SUPPLERMENTARY NOTES It. SPONSORING WILITARY ACTIVITY

i.ANSTRACTA survey has been made of the very large body of literature nov existing

on the characteristics of fallout particles. An attemipt is made to stisarizein concise form the ranges of physica~l and radiochemical. properties of~ particle$of the debris produced by- devices detonated wnder various conditions. Theresults or studies of the leaching action of various solvents on falloutparticles are also uuimawized.

DD I JAN644 1473 _ _ _ _ _ _ _

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the departmental project office or laboratory sponsoring (pir-6. REPORT DATL_ Enter the date of the report as day, Ing for) the research and development. Include ad***&.month, year, or month, year. If more than one date appearson the report, use date of publication, 13. ABSTRACT: Enter an abstract giving a brief and factual

is. OTA NUMER F PGES.Thetotl pae cunt summary of the document indicative of the report, eves thouth'I*.TOTL NMBE OFPAGS:, he ota pae cunt it may also appear elsewhere in the body of the technical re-should follow normal pagination procedures, I.ea., enter the port, If additional apace is required, a continuation sheet sicl'number of pages containing inormation. be attached,7b, NUIM~ER OF REFERENCE&. Enter the total numnber of It lqt highly desirable that the abstract of claswilfied repcortsreferences cited ini the rsport. be unclassified. Each paragraph of the abstract shall end w~ithSo. CONTRACT OR GRANT NUMBER: If appropriate, enter an Indication of the military securlt3. classificstioja of the In.the applicable number of the contract or grant under which formation In the paregruph, represented as (78), (s), (C).) or (U).the report wee written. There is no limitation on the length of the abe tract. How.Ab, 8c, & Ild. PROJECT NUM89RA Enter the appropriate ever, the suggested length is from 10 Sto 225 w~rds.military department Identtifiestiont, such as Project number,subproject number, system numbers, task number, aet. 14. KEY WORDS: Kay words are technicalliy meaningful terms@

I ~or short phrases that charactetrize a report and oasy be used as9a. ORIGINATOR'S REPORT NUMBER(S): Enter the ORh- index entries for cataloging the report. Key words must hecial report number by which the document will be identified selected so that nho security classification Is required. ldewI.-and controlled by the originating, activity. Thise number must (iers, such as equipment model designation, trade "sam, mliUirybe unique to this rtsport. project code name, Ieog~raphic location, may he used as key

Pb, THE REPRT ~h~DR(S~ I thereprt lsa ent words but will be followed by an indication of technical con.asigned any ether report numbers (either by the orijginator test. The assignment of links, role*, and **lo*t is optlionill.

o,*by the sponsor), also enter thise number(s).10. AVAIL ABILIT Y/LIMITATION NOTICES: Entor any lim-

Mit -ations on further dissemination of the report, other than those S

DD I JAN 6 1473 (BACK) UiNCLUSIruI ___

Security Classification