NUREG/CR-2868SAND82-0485RVPrinted August 1982

Aging Effects on Fire-RetardantAdditives in Organic Materials forNuclear Plant Applications

Roger L. Clough

This report documents part of the Qualification Testing Evaluation (OTE)Program being conducted by Sandia National Laboratories

Prepared bySandia National LaboratoriesAlbuquerque, New Mexico 87185 and &vermore, California 94550for the United States Department of Energyunder Contract DE-ACO4-76DP00789

oI

Prepared forU. S, NU 'LEAR REGULATORY COMMISSIONSF 2900-Q(6-82)

NOTICEThis report wasprepared as an account of work sponsored by anagency of the United States Government. Neiter the UnitedStates Government nor any agency thereof, or any of their employ.ees, makes any warranty, expressed or implied, or assumes anylegal liability or responsibility for any third party's use, or theresults of such use, of any information, apparatus product orprocess disclosed in this report, or represents that its use by suchthird party would not infringe privately owned right.

Available fromGPO Sales ProgramDivision of Technical Information and Document ControlU.S. Nuclear Regulator CommissionWashington, D.C. 20555andNational Technical Information ServiceSpringfield, Virginia 22161

NUREG/CR-2868SAND82-0485

RV

Printed August 1982

Aging Effects on Fire-Retardant Additives inOrganic Materials for Nuclear Plant Applications

Roger L. Clough

Sandia National LaboratoriesAlbuquerque, New Mexico 87185

operated bySandia National Laboratories

for theU. S. Department of Energy

Prepared forElectrical Engineering Branch

Division of Engineering TechnologyOffice of Water Reactor Safety Research

U. S. Nuclear Regulatory CommissionWashington, DC 20555

Under Interagency Agreement DOE 40-550-75NRC FIN No. A-1051

i-ii

,.

ABSTRACT

Inhibiting fire is a major concern of nuclear safety. Oneof the most widely used commercial fire-retardant additivesincorporated into cable insulation and other organic materialsto reduce their flammability has been the halocarbon (usually achlorinated hydrocarbon),typically in combination with antimonyoxide. Such materials may be installed for the design lifetimeof a nuclear plant; this report describes an investigation ofthe long-term aging behavior of these fire-retardant additivesin polymeric materials.

Extensive aging experiments on fire-retarded formulationsof ethylene propylene r,'-er (EPR) and of chlorosulfonated poly-ethylene (CSPE) have been carried out, with chemical analysis ofhalogen and antimony content performed as a function of agingtime and conditions. Oxygen index flammability measurements werealso performed on selected samples. Significant fire-retardantlosses (both chlorine (Cl) and antimony (Sb)) were found to occurin certain of the fire-retardant materials but not in others, de-pending on the molecular structure of the particular halogen-containing component. The Cl:Sb loss ratios indicate that achemical reaction takes place under the aging conditions toform the volatile compound, antimony trichloride (SbC1 3 ). TheEPR formulations showed a modestly increased flammability withfire-retardant loss on aging. CSPE materials exhibited asignificant decrease in flammability on aging despite theloss of flame retardants. This appears to be correlatedwith the loss of flammable, volatile components from theformulation.

Using the activation energy of 34 kcal/mol derived fromArrhenius treatment of the antimony loss data for the EPRformulation having the most rapid loss rate, it is predictedthat fire-retardant loss should become appreciable for thismaterial only at substantially elevated temperatures or ex-ceedingly long times. The data indicate that the loss ofhalogen- and antimony-based fire retardants appears to beinsignificant under ambient conditions expected for nuclearplants.

iii

ACKN4OWL1EDGMEMNTS

The author wishes to acknowledge the assistance of C. A. Quintana#who carried out the aging experiments, of R. W. Bild, who performed theneutron activation analysis, and of E. A. Salazar, who was responsiblefor the polymer formulation.

iv

CONTENTS

INTRODUCTION ........................ . . . . . . . . . . . . .

EXPERIMENTAL .. . ....... o .......... o ... ...* ...... .. .. ......... 3

RESULTS AND DISCUSSION ..................................... 7

Fire-Retardant Loss from EPR ...... .............. ...... 7

Mechanistic Implications ... ........ ....................... 7

Loss Rates ....... ................... . .... ............. 12Formulation Differences . .......... ....... . ........... 15

Radiation-Thermal Aging ........ ................. .. ...... 16

EPR Flammability Measurements ............................. 17Fire-Retardant Loss from CSPE ................... o......... 19CSPE Flammability Measurements .............. o............. 22

CONCLUSIONS ... ............... ... ..... ..... ............. . 24

REFERENCES ..... . . .. . . . .. . ............. ............ 25

V

LIST OF TABLES

Table Page

I EPR Base Formulations ............................. ........ 3

II Fire-Retardant Components Used ............................ 4

III Chlorosulfonated Polyethylene Formulation ................. 5

IV Experimentally Determined Times for Loss of25% of Initial Antimony Content (EPR-V) ................... 14

V Extrapolated Times for Loss of 25% of InitialAntimony Content (EPR-V) . .......... -........... 14

VI Oxygen Index Data on Aged Samples of Fire-Retarded EPR Formulation EPR-V ....................... 18

VII Total Weight Loss from HYP-II Aged at 110 0C ......... 21

VIII Oxygen Index Data on Samples of ChlorosulfonatedPolyethylene Aged at II0°C ............................... 23

IX TGA Data Showing Integrated Weight Loss to 425 0 Cfor HYP-II Samples Preaged at 1100C .................... 23

vi

LIST OF FIGURES

Figure Page

1 Antimony content (weight percent) as determined byatomic absorption spectroscopy on fire-retarded EPR(formulation EPR-V) as a function of thermal aging ....... 8

2 Chlorine content (weight percent) as determined bysilver coulometry on fire-retarded EPR (formulationEPR-V) as a function of thermal aging .................... 9

3 Antimony content (weight percent) as determined by14 MeV neutron activation analysis for fire-retardedEPR (formulation EPR-V) as a function of thermal aging... 10

4 Chlorine content (weight percent) as determined by14 MeV neutron activation analysis for fire-retardedEPR (formulation EPR-V) as a function of thermalaging .................................................... 11

5 Arrhenius plot for 25% antimony loss rate [-log(.25/time in months)] from EPR-V as a function ofinverse temperature ............................... 13

6 Arrhenius plot for 25% chlorine loss rate [-log(.25/time in months)] from EPR-V as a function ofinverse temperature ............... ....... ............... 13

7 Antimony content (weight percent) as determined byatomic absorption spectroscopy on fire-retarded EPR(EPR-V) as a function of thermal aging with simultaneousy-irradiation at 5 krad/hr ............................... 16

8 Chlorine content (weight percent) as determined bysilver coulometry on fire-retarded EPR (EPR-V) as afunction of thermal aging with simultaneous y-irradiationat 5 krad/hr ............................................. 17

9 Chlorine content (weight percent) as determined bysilver coulometry on HYP-II as a function of thermalaging .................................................... 19

10 Antimony content (weight percent) as determined byatomic absorption spectroscopy on HYP-II as a functionof thermal aging ......................................... 20

11 Chlorine content (weight percent) as determined bysilver coulometry on HYP-I as a function of thermalaging ............................................. 21

vii

INTRODUCTION

Fire protection is a major concern in nuclear safety.Awareness in this area was much heightened following the firein the nuclear plant at Brown's Ferry in March of 1975.1-3The NRC issued a Regulatory Guide on Fire Protection in Juneof 1976,4 and has been funding research in the area of firetesting,:5 including an extensive series of cable tray firetests performed by Klamerus at Sandia. 6

Flammable materials in nuclear plants include a varietyof organic polymers used in various applications, most notablyas cable insulation materials. The flammability of organicpolymers, many of which consist chiefly of carbon and hydrogen,is a problem of general concern to the polymer industry. Con-sequently, much work has been done on the study of polymercombustion properties. Reduction of the flammability oforganic materials is achieved by the incorporation of fire-retardant additives into the polymer formulations. One ofthe most widely used types of fire-retardant additive hasbeen the halogenated hyqrocarbon, usually in combination withantimony oxide (Sb20 3 ). This halogen-antimony combinationhas been employed in conjunction with many different genericpolymer types, and is used today in a variety of applicationsincluding (along with cable insulation materials) a host ofcommercial products made with rubbers, plastics, paints andtextiles.

The halogenated hydrocarbon (the halogen is usuallychlorine, but may be bromine) by itself can have a fire-retardant effect,:? while antimony oxide alone acts essen-tially as an inert filler and has little effect on the flam-mability properties of polymer materials. 1 0- 1 2 In combination,the two additives work in a synergistic fashion. This isbelieved to occur by reaction under the high temperaturesof the fire environment to give a volatile antimony halide.The overall chemical reaction is outlined in equations 1and 2.7,8

Chlorinated hydrocarbon -- HC1 (1)

HC1 + Sb 2 0 3 - SbCl 3 (2)

The antimony halide and/or its secondary breakdown productsapparently serve as efficient free radical scavengers in theflame region above the burning material. 7 ,8, 1 0 , 1 3 The fire-retardant effect of these two additives has been seen in avariety of small-scale flammability tests which reflect thesusceptibility of materials t? combustion in the environmentof a small ignition source.",

I

Some types of polymers are intrinsically less flammablethan others. For example, polymers containing chlorine sub-stituents along the chain backbone such as polyvinyl chloride(PVC), chlorosulfonated polyethylene (Hypalon)8*, and chloro-prene (neoprene), have inherently reduced flammability. 1 0

Depending on the degree of flame retardancy desired, thesematerials may be used either with or without added antimonyoxide. 1 4 , 1 5 The three chlorinated materials named above areused extensively as cable jacketing materials in the nuclearindustry. Non-chlorinated polymer types can be fire retardedby inclusion of Sb 20 3 along with a low molecular weighthalogenated-hydrocarbon in the formulation.

Materials used in nuclear plant applications areexpected to last for the design lifetime (typically 40 years).Recently there has been increased concern over qualifyingcritical components with respect to their ability to functionafter ambient aging. Because of this concern, extensive NRC-funded research has been carried out on orga'nic polymers toinvestigate the effects of ._ing on their mechanical properties. 1 6

The results have shown that dramatic differences can exist betweenaged and unaged materials, indicating that aging must be a majorconsideration in qualification testing with respect to mechanicaland electrical performance.

Because of the concern for understanding the performanceof aged materials, the question was raised of the long-termaging behavior of cable insulation materials with respect topotential loss of the fire-retardant additives and resultingloss of flammability-inhibiting properties. A literaturesearch failed to bring to light any study on fire-retardantaging of halogen or halogen-antimony flame-retarded materials,despite the fact that this retardant system has had widespreaduse during the past several decades. 7

This report describes the results of an extensive series offire-retardant aging experiments on formulations of two materialtypes of importance in present-day nuclear plant applications.One of these, Hypalons, is a chlorinated material; the other,ethylene-propylene rubber (EPR) is a nonchlnrinated material.

*Hypalon is a registered trademark of E. I. duPont de Nemoursand Company.

2

EXPERIMENTAL

Samples made from two different EPR types (mable I) wereused in the aging experiments. One of these (A) is typical offormulations currently used in certain cable material.17,18The other (W) is similar to formulations used for certain struc-tural applications. Five different variations with respect tofire-retardant additives were prepared. Four of these containedantimony oxide (Sb 2 03 ) in combination with one of three differentcommercial halogenated-hydrocarbon flame-retarding agents. Thehalogenated-hydrocarbon additives are representative of com-pounds used as flame-retardant additives in recent years. 8 ,9, 1 9

One formulation prepared for the aging studies (EPR III) wasintended as a control sample and not a realistic flame-retardantsystem; it contained only Sb 2 03 in the absence of any chlorinatedcompound. The five flame retardant EPR formulations are summarizedin Table II.

TABLE I

EPR BASE FORMULATIONS

EPR A (parts) EPR B (parts)

Nordel 2722Low Density PEZinc OxideParaffin WaxLithargeZn Salt (ZMB)AminoxTreated Calcined ClayVinyl SilaneSRF BlackDi*-cup R

(90)(20)

(5)(5)(5)(2)(1)

(60)(1)(2)(3)

Vistalon 4608Zinc OxideStearic Acid•AF Black

SRF BlackMT BlackSunpar 2280Ethyl TelluracMBTSulfur

(100)(5)(1)

(50)(50)(50)(40)

(0.5)(1.0)(1.5)

3

Table II

FIRE RETARDANT COMPONENTS USED

'DESIGNATION BASE COMPOUND* FIRE RETARDANTS (parts)

a 0cEPR A (33)

CI J C CI I a(3a ci

Sb,0 (10)

EPR1 A 120(

a~ €!

Sb:oa (10)

EPE III ASb20 8 (10)

EPR IV B cI 1 l1 (20)

ci ci

SbROg (10)

EPR V B XJC--'CXe--n CX8 (20)

X - H, Cl

Id - 70%, by weight,

of the cpd.]Sb,01 (10)

*Refers to base formulations in Table I.

4

A chlorosulfonated polyethylene (Hypalons) formulation,similar to that used in cable material applications 1 8 (shownin Table III), was used in the aging experiments. Two hypalonvariations were studied, namely with and without added Sb 2 03(HYP-I = no added Sb 2 03; HYP-II = 7 parts added Sb 2 0 3 ).

Samples of the compression-molded polymers were prepared byBurke Rubber Corporation; specimens having dimensions of 15.2cm x .6 cm x .2 cm (6" x .22" x .07") were utilized in theaging experiments.

Thermal aging of polymer samples was carried out in chamberswhich were placed inside ovens. The chambers had carefullycontrolled air flow (giving the equivalent of two changes ofatmosphere per hour) and temperature control to within + 1C.

TABLE III

CHLOROSULFONATED POLYETHYLENE FORMULATION*

HYP I (parts)

Hypalon 40 (100)LGB Clay (75)Philblack A (15)NBC (2)Kenaflex A (10)Sunolite 240 (2)Sundex 790 (30)Litharge Paste (20)MBT (Captex) (1)Tetrone A (2)

*HYP II is identical to HYP I except thatit contains an additional 7 parts Sb2 03

5

The wet chemical analysis for antimony (Sb) and chlorine(Cl) was carried out by Spang Microanalytical Laboratories ofEagle Harbor, Michigan. Chlorine was determined using astandard silver coulometric technique. 2 0 , 2 1 Antimony wasdetermined using atomic absorption spectroscopy. 2 2 Wetchemical analytical data given throughout this report representthe average of at least two different determinations. Themean error in the data given for Cl is approximately + 0.15absolute percent in the case of the EPR samples. In the caseof the Hypalon samples, it ranged from + 0.2 to + 0.5 absolutepercent. The mean error for the antimoiiy determTnations wasapproximately + 0.07 absolute percent in both materials.

Neutron activation analysis for Cl and Sb was performedon intact polymer specimens using 14 MeV neutrons. 2 3 Theactivation reactions used were: 3 7 C1 (fn,p) 3 7 S and1 2 3 Sb (fn, 2n) 1 2 2 Sb. The activation reaction generallyused for Sb analysis t 1 2 1 Sb(fn, 2n) 1 2 0 Sb) was impracticalwith these polymer samples due to interference by otherelements in the formulation including silicon and chlorine.Reference standards were established with NaCl-Sb 2 03 - benzoinoxime mixtures. Activated samples were counted on a Ge(Li)detector coupled to a 4096-channel multichannel analyzer. Theprecision of the analysis for both Cl and Sb was on the orderof + 10% relative.

Oxygen index flammability measurements were carried outby US Testing Corporation of Los Angeles, California, accordingto the ASTM standard. 2 4

6

RESULTS AND DISCUSSION

Fire-Retardant Loss From EPR Formulations

Of the EPR formulations studied, four of the five (EPRnumbers I through IV) did not show appreciable changes in fire-retardant content after either 6 months at 1200C or 8 months atl10"C. In contrast to this are the results obtained with theformulation designated as EPR-V. Initial scoping experimentsrevealed significant fire-retardant losses in this material, andextensive aging tests were undertaken at a series of differenttemperatures. The temperature range (120"C-80*C) was chosen toinclude the lowest temperatures (based on the scoping experi-ments) expected to be practical for use in thermal agingexperiments on a reasonable timescale. This experimentaldesign was chosen to provide the optimum data to allow forextrapolation of the results on the most rapidly changingformulation examined (i.e., EPR-V) to lower temperatureconditions which would be typical of ambient environmentsof interest.

Aging at 80'C gave rise to no measurable changes in thefire-retardant content during the timescale of the experiment(two years). Figs. 1 and 2 present the data for antimonycontent (as derived by atomic absorption) and for chlorinecontent (as derived by coulometry) as a function of agingtime at the temperaturess 120*, 110, 100* and 90"C. Inorder to provide independent verification of the aging-induced disappearance of thesE elements from the polymermatrix, a portion of the samples were analyzed by the neutro.Onactivation technique. This data is presented in Figs. 3 and4. The trends seen with the two techniques are in agreement;significant losses of both chlorine and antimony are clearlyseen.

Mechanistic Implications

Chlorine loss can conceivably occur by two mechanisms:1) simple migration and evaporation of the chlorinated hydro-carbon out of the polymer matrix, and 2) degradation involvingdehydrochlorination. Antimony oxide has a volatilizationtemperature of 1550*C, 2 5 so that any significant antimony lossat low temperatures must be preceled by chemical reaction toyield a more volatile species.

7

Two antimony species, SbOCI and SbCl 3 , have been discussedin the past as playing key roles in the synergistic Oire retar-dancy of the antimony oxide - halocarbon combination. 2 6 , 2 7

Evidence that the principle species in the vapor phase inthe flame environment was SbCl 3 has been previously obtainedby mass spectrometry. 7 However, it had been thought that HC1reacted with Sb 2 0 3 to generate SbOC1, and that the productionof SbC1 3 depended upon a series of endothermic disproportion-ation reactions of SbOCl which have been shown by differentialthermal analysis to take place only at very high temperatures. 7 ' 2 8

The fact that the antimony oxide - halocarbon combination makessuch a good flame-retardant agent had been discussed in termsof the fact that the decomposition temperature of SbOCl matched

3.0 ,, , ....

2.0

p1.0

0 1200 CA 1108Ca 100 0 C

goo C

0.00 2 4 8 a 10 12 14 14 18 20 22 24

AGING TIME (MONTHS)

Figure 1. Antimony content (weight percent) as determined byatomic absorption spectroscopy on fire-retarded EPR(formulation EPR-V) as a function of thermal aging.

8

very well with the decomposition temperatures of typicalpolymeric materials with which it is used1 (the so-called"right place at the right time" theory of flame retardancy).

Recently, a laser pyrolysis - mass spectrometry study hasdemonstrated that, in fact, when either the pyrolysis productsof a PVC formulation or HCl from a cylinder were passed overunheated Sb 2 0 3 , evidence coul be obtained for the introductionof SbCl 3 into the gas phase. These results indicated thatSbC1 3 production was possible by reaction of HC1 with Sb 2 03without involving the high temperature disproportionationreactions of intermediate SbOCl. Subsequent mass spectralstudies in which mixtures containing Sb 2 0 3 and polyvinylidenechloride were pyrolyzed together similarly revealed SbCl 3volatilization at temperatures around 170*C, and also revealedSb 4 06 volatilization at temperatures around 300*C. 3I Thespecies Sb 4 was also detected, and its appearance was closelycorrelated to the appearance of SbC1 3 and of Sb 4 0 6 .

I.-2tu

0

0_j

10 12 14AGING TIME (MONTHS)

Figure 2. Chlorine content (weight percent) as determined bysilver coulometry on fire-retarded EPR (formulationEPR-V) as a function of thermal aging.

9

From the data on the loss rates at the various agingtemperatures and time periods obtained by us (Figs. I and 2),it can be calculated that the average molar ratio for the lossof these two elements is approximately 3:1 Cl:Sb. (There isa fair amount of experimental scatter in the data, along withindications of somewhat higher Cl:Sb ratios at the lowesttemperature of 90*C). The data are consistent with a pictureof the aging-induced antimony volatilization proceedingthrough the same chemical reactions (Eqs. 1 and 2) by which

Z2.0

0

4 o

0.0 -0 2 4 6 8 10

Figure 3.

AGING TIME (MONTHS)Antimony content (weight percent) as determined by14 MeV neutron activation analysis for fire-retardedEPR (formulation EPR-V) as a function of thermal aging.

10

the two additives are believed to react in the fire environ-ment to produce the flame-retarding effect. The stoichiometryindicates that the principle species through which the antimonyvolatilized from the polymer on aging is SbC1 3 (which has aboiling point of 283*C).25 The antimony loss found in thiswork is consistent with the recent mass spectral evidencethat SbCl 3 can be generated at low temperatures. Moreover,it demonstrates that very significant amounts of antimonyvolatilization (indeed, apparently total antimony loss) canoccur from Sb 2 03 -halocarbon fire-retarded polymer formulationsat temperatures far below those required for thermal degrada-tion and volatilization of the polymer itself. A large partof the chlorine lost on aging apparently involves decomposi-tion of the chlorinated hydrocarbon, with evolution of HCl(which then reacts with the Sb 2 0 3 ).

4.0

ZU

3.00

o 2.0-

2 4 6 8 10 12

AGING TIME (MONTHS)

Figure 4. Chlorine content (weight percent) as determined by14 MeV neutron activation analysis for fire-retardelEPR (formulation EPR-V) as a function of thermalaging.

11

Loss Rates

Figure 5 shows a plot of the log of the time required fordisappearance of 25% of the antimony initially present, as afunction of inverse aging temperature. The antimony loss isseen to exhibit linear Arrhenius behavior over this temperaturerange. Similar plots for 12.5% loss and for 50% loss alsoexhibit relatively linear Arrhenius behavior. The chlorinedata covers a more limited range of relative total loss, andalso has a larger relative error. Arrhenius plots exhibit morescatter, but also appear reasonably linear; Figure 6 is a plotof the log of the time required for disappearance of 25% of theinitial chlorine content as a function of inverse temperature.

From the data in Figures 5 and 6, it is possible toestimate an apparent activation energy (Ea) for loss of thetwo fire-retardant components. The antimony loss gives anEa of 34 + 3 kcal/mole; chlorine loss has an Ea of about31 + 4 kcal/mole. The activation energies obtained forchlorine and antimony are very similar, and may in fact bethe same within experimental error. The halogen-bearingcomponent used in this formulation (EPR-V, Table I) is achlorinated paraffin wax. The Ea values are similar tothe apparent activation energies reported by Madorsky 3 2

for the thermal dehydrochlorination of three different poly-vinyl chloride specimens (26, 30 and 32 kcal/mol) obtainedat higher temperatures (235-260*C).

Using the activation energy calculated for antimonyloss, it is possible to extrapolate the loss rate to lowertemperatures. The accuracy of such extrapolation depends,of course, on the overall process retaining linear Arrheniusbehavior at the lower temperatures. Table IV presents datafor the observed time for loss of 25% of the initial antimonycontent, while Table V shows calculated values of time forloss of 25% of initial antimony content at lower temperatures.The extrapolated data indicate that for EPR formulation V,antimony loss in sufficient amount to cause an appreciableeffect on flammability properties during timescales ofpractical importance would only occur for material applica-tions at significantly elevated temperatures (i.e., above70°C).

The temperature of an operating high voltage cable willbe below 50*C, and in most cases will fall in the range of30-40OC; 3 3 low and medium voltage cables generate less heatthan the high voltage cables. The ambient temperature of

12

I-.

00j

2.8 2.7 2.6 2.5

Il/T (x 103)

Figure 5. Arrhenius plot for 25% antimony loss rate [-log(.25/time in months)) from EPR-V as a function ofinverse temperature.

4

030_j

2.6

1/T (x103)

Figure 6. Arrhenius plot for 25% chlorine loss rate [-log(.25/time in months)] from EPR-V as a function ofinverse temperature.

13

TABLE IV

EXPERIMENTALLY DETERMINED TIMES FOR LOSS OF 25%OF INITIAL ANTIMONY CONTENT

(EPR-V)

TEMP.

120*C

1106C

1000C

900C

TIME

2 wk

1.4 mo

4.8 mo

21 mO

TABLF V

EXTRAPOLATED TIMES FOR LOSS OF 25%OF INITIAL ANTIMONY CONTENT

(EPR-V)

TEMP.

800C

700C

60*C

50 0 C

400C

300C

TIME

7 yr

28 yr

120 yr

600 yr

3 x 103 yr

2 x 104 yr

14

- nuclear plant may contribute to raising the absolute_emperature of the cable somewhat, depending on specificplant location. It appears that even for the material(EPR-V) which has the most rapid loss rate of the formula-tions tested, the fire-retardant loss should not be signifi-cant in the temperature range and timescale important fornuclear plants.

The data would, however, indicate the volatilizationof fractional percentages of antimony at temperatures nearambient. The generation of antimony trichloride (SbCl 3 ) inapplications having large quantities of fire-retardant mate-rials in confined areas could have significant implisations,since SbC1 3 has both corrosive and toxic properties.

Formulation nifferences

The EPR formulations examined showed major differences infire-retardant aging characteristics; only one formulationshowed appreciable loss of fire-retardant additives under thethermal aging conditions studied. A major factor behind thedifferences between the EPR formulations examined is mostlikely the ease with which the particular halogenated hydro-carbon can break down to yield HCl (or HBr), which serves asthe first step leading to the eventual loss of SbC1 3 (orSbBr 3 ).

Of the three halocarbon fire-retardant additives examinedin this study (see Table II), the partially chlorinated paraf-fin used in EPR-V stands alone as being able to readily undergoan intramolecular dehydrohalogenation. (The bromine substitu-ents i-nthe halocarbon of EPR-II have no adjacent hydrogensubstituent. The loss of adjacent H and Cl atoms from thehalocarbon of EPR-I and EPR-IV would result in the formationof a double bond connecting two bridgehead positions - asituation of extremely unfavorable geometry [Bredt's rule). 3 5 )It has been pointed out before 9 that thermal degradation ofhalogenated flame-retardant additives during polymer processingcan be a concern and that substantial differences exist inthe thermal stability of various halogenated flame retardantsat polyolefin processing temperatures (which can typicallyfall in the approximate range of 235*C - 250 C). 9 Otherdifferences in individual formulations could conceivablyplay a contributing role in determining rates of fire-retardantloss on aging.

15

Radiation-Thermal Aging

For. the majority of cable insulation in a nuclear plant,probably only thermal aging will be important. Some of thecable, however, which is in the containment area may experiencea significant amount of radiation. Figs. 7 and 8 show datafor samples of EPR-V aged at 100' and at ll0*C under conditionsof simultaneous y-irradiation at approximately 5 krad/hr.Comparison with Figs. 1 and 2 leads to the conclusion thatthe added radiation did not appreciably affect the fireretardant loss rate. Other irradiation experiments wereperformed on EPR-I at 110C and 1000C, using a dose rateof approximately 5 krad/hr to a total dose of about 30 Mrad.As with the oven-aging experiments, no measurable change inchlorine-or antimony content was detected. These resultswould tend to indicate that unlike aging-induced changes intensile properties, where radiation exerts a predominantinfluence, the radiation aging of EPR with respect to theloss of fire-retardant additives is relatively less signifi-cant compared with-the effects of thermal aging.

DOSE (Mrad)

t2.0

20

10X

1.

4 8AGING TIME (MONTHS)

Figure 7. Antimony content (weight percent) as determined byatomic absorption spectroscopy on fire-retarded EPR(EPR-V) as a function of thermal aging with simultaneousy-irradiation at 5 krad/hr.

16

This conclusion is consistent with a related observationreported previously. A value for the radiation yield of HC1loss from y-irradiated PVC near room temperature was deter-mined as G(-HC1) = 13.36 A similar radiation yield for thechlorinated hydrocarbon in EPR-V would lead to the expecta-tion that only a small fraction of the total chlorine presentwould be lost after exposure to the radiation doses used inthis study. By way of contrast, radiation effects show upstrongly in terms of tensile property changes because onlyvery small changes in chain scission or crosslinking areneeded to produce noticeable macroscopic effects.

EPR Flammability Measurements

Material flammability can be discussed in terms of twogeneral testing categories. The most commonly used type ofcombustion test evaluates flammability in the presence ofa small-scale ignition source, and gives information on thepropensity of materials to ignite and burn under low-levelfire-initiating conditions (as was the case with the Brown's

DOSE (Mrad)10 20

6.0 1

5.0-

I 4.0z,J

0

,U 3.0-

0

S2.0

Figure 8.

AGING TIME (MONTHS)

Chlorine content (weight percent) as determined bysilver coulometry on fire-retarded EPR (EPR-V) as afunction of thermal aging with simultaneous y-irradiationat 5 krad/hr.

17

Ferry fire, which was set off by a candle used by an employee).1, 3

There are numerous ASTM tests designed to fulfill this function.Such small-scale combustion results are strongly dependent onfire-retardant additives. 8 , 9 A second type of fire test focuseson material flammability characteristics in the environmentof an already existing, large-scale fire. 3 7

For the purposes of this study, we employed one of themost widely used of the small-scale ASTM flammability tests,the Limiting Oxygen Index Method, 2 4 for testing of selectedsamples from the aging experiments for comparison with thefire retardant loss data. The limiting oxygen index isdefined as the minimum concentration of oxygen, in volumepercent of a mixture of nitrogen and oxygen, that willsupport combustion.

(02)LOI

(02) + (N2 )

Data from Oxygen Index Flammability Tests performed onseveral aged EPR samples having substantial fire retardant lossare given in Table VI. Changes in oxygen index are not large;the aged samples exhibit moderately increased flammability.

TABLE VI

OXYGEN INDEX DATA ON AGED SAMPLES OFFIRE RETARDED EPR FORMULATION EPR-V

AGING CONDITION OXYGEN INDEX

Unaged 28.0

12 months at 100*C 27.0

8 months at 110*C 26.5

4 months at 120*C 26.0

18

a

Fire-Retardant Loss From Chlorosulfonated Polyethylene

The second polymer type included in this work was chloro-sulfonated polyethylene (Hypalons). The formulation studied ischaracteristic of that used in cable jacketing material. 1 8

Hypalon contains chlorine substituents distributed along thebackbone of the polymer chain. Chlorination in the range of35% is typical. 3 8 (Chlorosulphonyl groups initially presentin low concentration in the resin react during curing as apart of the crosslinking process.)

Figs. 9 and 10 present data for chlorine and antimony contentas determined by coulometry and atomic absorption, respectively,for HYP-II as a function of aging. Significant losses of bothelements are found. Fig. 11 presents data for chlorine content(determined by coulometry) for CSPE formulation HYP-I whichcontains no Sb 2 0 3 . Again, significant aging-induced chlorineloss is seen.

15

U * 12O0Ce 5. ..

6 8 10

AGING TIME (MONTHS)

Figure 9. Chlorine content (weight percent) as determined bysilver coulometry on HYP-II as a function of thermalaging.

19

Interestingly, the curves for antimony and chlorine lossexhibit a level phase or even an upward trend during the earlystages. This behavior can be explained in terms of the lossof other volatile components from the formulations: Table VIIshows weight loss for HYP-II as a function of aging time at1100C.

Arrhenius treatment of the data is complicated by the rapidloss of volatile components proceeding simultaneously withthe fire-retardant loss (the two processes could be expected tohave different activation energies). A straightforwardtreatment of the data does not appear to yield suitably linearArrhenius behavior, so that activation energies for the fire-retardant loss were not obtained. However, the chlorine andantimony losses are of the same general magnitude as thoseobserved with the EPR-V over this temperature range. Thefact that the hypalon formulations lose antimony and chlorineon aging must result from the fact that chlorosulfonatedpolyethylene, with its random distribution of chlorine sub-stituents along the polymer backbone, can readily undergointramolecular dehydrochlorination (as was the case withthe chlorinated additive used in EPR-V).

i $ i I i i

~*12o0c

2.0 ei 120C

* iorc

zw

I-0z

0

4

0.0I0 2 4 6 8 10 12

AGING TIME (MONTHS)

Figure 10. Antimony content (weight percent) as determined byatomic absorption spectroscopy on HYP-II as a functionof thermal aging.

20

z10

0

zU 0

2 120T0•

I0 I I I f

0 2 4 6 8 10 12

AGING TIME (MONTHS)

Figure 11. Chlorine content (weight percent) as determined bysilver coulometry on HYP-I as a function of thermalaging.

TABLE VII

TOTAL WEIGHT LOSS FROM HYP - IIAGED AT 1100C

AGING TIME

2 wk

4 wk

8 wk

12 wk

% WEIGHT LOSS

2.4%

4.3%

5.4%

6.5%

21

Chlorosulfonated Polyethylene Flammability Measurements

Oxygen index measurements indicated very large changes betweenaged and unaged CSPE samples, with the material becoming lessflammable after aging. The effect is seen with both HYP-Iand with HYP-II (see Table VIII). This decreased flammabilityresults despite the loss of both chlorine and antimony on aging.

The principle explanation for this observation most likelyresults from the loss of low molecular weight organic componentsfrom the formulation. These low molecular weight additivesare relatively volatile and are nonchlorinated, and henceshould be substantially more flammable than the highly chlorinatedbase polymer resin. Thermogravimetric analysis confirms a pro-gressive decrease in the amount of weight loss during theearly stages of the thermolysis of the CSPE samples, as afunction of the extent of aging: Integrated weight loss datafor samples heated from ambient to 425*C at 10/min is tabulatedin Table IX. Even assuming that a part of the speciesvolatilized in the TGA experiment represents chlorine andantimony, the TGA differences between aged and unaged samplesare substantially larger than can be accounted for by thedifferences in Cl and Sb content of the samples. The TGAanalysis is probably a good indication of the relative amountsof volatile components released from these samples undercombustion-initiating conditions of small-scale flammabilitytests.

Large changes in the flammability of chlorinated polymersas a function of additives has been noted before. For exampleplasticized PVC has much reduced flame retardancy comparedwith the unplasticized material. 1 5 Apparently, in the caseunder consideration in the present study, the effect of theloss of chlorine and antimony on the oxygen index value isoverridden by the effect of the loss of volatile organicadditives.

22

TABLE VIII

OXYGEN INDEX DATA ONSAMPLES OF CHLOROSULFONATED POLYETHYLENE

AGED AT 110*C

FORMULATION

HYP-I

AGING TIME

Unaged

4 mo

8 mo

OXYGEN INDEX

35

46

46

39

43

HYP-II Unaged

4 mo

8 mo 50

TABLE IX

TGA* DATA SHOWING INTEGRATED WEIGHT LOSSTO 4250C FOR Uiz - II SAMPLES

PREAGED AT 1100C

PREAGING TIME % VOLATILIZEDON HEATING TO 4250C

Unaged

2 mo

4 mo

8 mo

25%

22.4%

16.5%

15.1%

*TGA performed at 10*C/min heatingrate in air.

23

CONCLUSIONS

Polymers containing halocarbon or halocarbon-antimony oxidebased fire retardants can lose appreciable amounts of bothhalogen and antimony through volatilization during thermal aging.This is seen to hold where the halogen is contained in a lowmolecular weight additive in the formulation (as with EPR)as well as for the case where the halogen is a part of the basepolymer resin (as with hypalon). Fire-retardant loss appears tobe strongly dependent upon the molecular structure of the halo-carbon in terms of its ability to undergo intramolecular loss ofHCl. The HCl generated can react readily with Sb 2 03 to producethe volatile SbCl 3 .

Oxygen index flammability tests indicated modest increasesin flammability of ETR with fire-retardant loss on aging. Hypalonformulations actually became markedly less flammable on aging;this behavior appeared % be associated with the loss of flam-mable, volatile additives from the polymer on aging.

Using the loss-rate data on the EPR formulation whichlost fire retardants most rapidly, Arrhenius extrapolationindicated that the fire-retardant loss from this formulationshould be important only at very significantly elevatedtemperatures; for example, loss of 25% of the initial antimonycontent should require some 120 years at 60*C and some 3,000years at 40*C. The hypalon aging data was not amenable toan Arrhenius treatment, though fire-retardant loss ratesunder the accelerated laboratory conditions employed in thisstudy were on the same order as those of the EPR formulationmentioned above.

The data generated-in this work indicate that the loss ofantimony-halocarbon fire retardants due to aging under the am-bient conditions expected in nuclear plants should not be sig-nificant over the timescales of interest. There is nothing inthe results that would be inconsistent with a supposition thatthe specification and testing of flammability and fire-retardantproperties in terms of the unaged polymer materials is appropriatefor indicating behavior throughout an estimated 4G year nuclearplant lifetime.

24

REFERENCES

1. Jack E. Gilliland, "Testimony before the Joint Commissionon Atomic Energy, Hearings on the Browns Ferry Fire," Sept.16, 1975.

2. U. S. Nuclear Regulatory Commission, Recommendations Relatedto Browns Ferry Fire, NUREG-0050, Washington, DC, February,1976.

3. G. Kaplan, "The Brown's Ferry Incident," IEEE Spectrum,Oct., 1976, p. 55.

4. U. S. Nuclear Regulatory Guide 1.120, "Fire Protection Guide-lines for Nuclear Power Plants," Washington, DC, June, 1976.

5. G. L. Bennett, Summary of Fire Protection Research Sponsoredby the US Nuclear Regulatory Commission, Joint Power GenerationConference, Charlotte, NC, Oct., 1979.

6. L. J. Klamerus, Cable Tray Fire Tests, SAND 78-1810C, PES-IEEE Winter Power Meeting, New York, Feb., 1979.

7. J. Pitts, in ?lame Retardancy of Polymeric Materials, Vol. 1,W. Kuryla and J. Papa, Eds., Marcel Dekker, New York, 1973,p. 133.

8. J. Lyons, The Chemistry and Uses of Flame Retardants, WileyNew York, 1970.

9. R. Schwartz, in Flame Retardancy of Polymeric Materials, Vol. 2,W. Kuryla and A. Papa, Eds., Marcel Dekker, New York, 1973, p. 83.

10. P. Warren, in Polymer Stabilization, L. Hawkins, Ed., Wiley,

New York, 1971, p. 313.

11. H. Elias, Macromolecules, Vol. 2, Plenum, New York, 1977, p. 854.

12. R. F. Lindemann in Flame Retardancy of Polymeric Materials,Vol. 2, W. Kuryla and J. Papa, Ed., Marcel-Dekker, New York,1973, p. 1.

13. C. Fenimore and G. Jones, Combust. Flame, 10, 295 (1966).

14. Reference 8, p. 300.

15. M. O'Mara, W. Ward, D. Knectges and R. J. Meyer, in FlameRetardancy of Polymeric Materials, Vol. 1, W. Kuryla andJ. Papa, Eds., Marcel-Dekker, New York, 1973, p. 195.

16. R. L. Clough and K. T. Gillen, J. Polym. Sci., Polym. Chem.Ed., 19, 2041 (1981).

25

b. R. L. Clough and K. T. Gillen, Radiat. Phys. Chem., 18661 (1981).

c. K. T. Gillen and R. L. Clough, Radiat. Phys. Chem., 18679 (1981).

17. D. R. Luh, Ethylene Propylene Terpol.mer in Wire and CableConstruction, 18th International Wire and Cable SymposiumAtlantic City, Dec. 1969.

18. M. Brown, Elastomers Laboratory, E. I. DuPont, Wilmington,Delaware, Private Communication, Oct. 1980.

19. W. Kuryla, in Flame Retardance of-Polymeric Materials,Vol. 1, W. Kuryla and J. Papa, Eds., Marcel-Dekker, NewYork, 1973, p. 1.

20. N. Linnet, American Laboratory, Oct., 1973, p. 74.

21. D. Skoog and D. West, Principles of Instrumental Analysis,Holt, Rinehart and Winston, New York (1971), p. 537.

22. J. Van Loon, Analytical Atomic Absorption Spectroscopy,Academic Press, New York (1980).

23. R. W. Bild, J. Radioanal. Chem., 1982 (in press).

24. Standard Method For Measuring the Minimum Oxygen Concentrationto Support Candle-Like Combustion of Plastics (Oxygen Index),ASTM D 2863-76, American National Standards Institute, 1976.

25. Handbook of Chemistry and Physics, 46th Edition, Section B,Chemical Rubber Company, Cleveland, Ohio, 1965.

26. R. W. Little, Flameproofing Textile Fabrics, ACS MonographySeries 104, Reinhold, New York, 1947.

27. J. W. Hastie, J. Res. Nat. Bur. Stand., A, Vol. 77A, 733 (1973).

28. J. Pitts, P. Scott and D. Powell, J. Cellular Plastics,35, (1970).

29. R. M. Lum, J. Polym. Sci., Polym. Chem. Ed., 15, .489 (1977).

30. A. Ballistreri, S. Foti, G. Montaudo, S. Pappalardo and E.Scamporrino, J. Polym. Sci., Polym. Chem. Ed., 17, 2469(1979).

31. A. Ballistreri, S. Foti, G. Montaudo, S. Pappalardo and E.Scamporrino, Polymer, 20, 783 (1979).

32. S. L. Madorsky, Thermal Degradation of Organic Polymers,Krieger, New York, 1975, p. 163.

26

33. T. Ling, The Anaconda Wire and Cable Company, personalcommunication, Feb. 1981.

34. N. I. Sax, Dangerous Properties of Industrial Materials,2nd Ed., Reinhold, 1963, p. 457.

35. E. Eliel, Stereochemistry of Carbon Compounds, McGraw-Hill,New York, 1962, p. 300.

36. R. Salovey, in Radiation Chemistry of Macromolecules,Vol. II, M. Dole, Ed., Academic Press, New York, 1973,p. 38.

37. E. F. Smith, "An Experimental Method for Evaluating FireHazard," 4th International Fire Protection Seminar,Zurich, Switzerland, Oct., 1973.

38. J. Maynard and P. Johnson, Rubber Chem. Tech., 36, 963 (1963).

27

Distribution:

U. S. Nuclear Regulatory CommissionDistribution Contractor (CDSI) (290 copies)

265 copies for RV25 copies for NTIS

Division of Document ControlDistribution Services Branch7300 Pearl StreetBethesda, MD 20014

AERE HarwellDidcot OxfordshireOX 11 ORAEnglandAttn: D. Phillips

AMN Impianti Termici E. NucleariVia PacLnotti, 2016151 Genova SampierdarenaItalyAttn: G. Bottinelli

AMN SpaVia G. D'Annunzio 11316121 GenovaItalyAttn: P. Giordano

AMN SpaCentro Sperimentale del

BoschettoCorso F. M. Perrone, 11816161 GenovaItalyAttn: C. Bozzolo

Atomic Energy of Canada, Ltd.Chalk RiverOntarioCanadaAttn: G. F. Lynch

Atomic Energy of Canada, Ltd. (2)Power ProjectsSheridan Park Research Comm.Mississauga, Ontario L5K1B2CanadaAttn: C. Byrne

P. Gumley

Babcock Brown Boveri ReaktorHeppenheimer Strasse6800 Mannheim 31Postfoche 410323West GermanyAttn: R. Schemmel

Battelle Institute VAm Romerhof 35D6000 Frankfurt/MWest GermanyAttn: B. Holzer

Belgonucleairerue de Champ-de Mars, 25B-1050 BrusselsBelgiumAttn: J. P. Van Dievoet

Bhabha Atomic Research CenterTrombay, Bombay400 A85Ind4Attn: S. K. Mehta

ASEA-ATOM (3)EngineeringBox 53S-721 04VasterasSwedenAttn: G. Kvist

A. KjellbergB. Langser

ASEA KABEL ABP. 0. Box 42108S-126 12StockholmSwedenAttn: C. T. Jacobsen

British Nuclear Fuels, Ltd.Springfield WorksSalwick, PrestonLancsEnglandAttn: W. G. Cunliffe, Bldg 396

28

Bundesanstalt fur Material PrufungUnter den Eichen 871 Berlin 45West GermanyAttn: K. Wundrich

Centre d'Etudes Nucleaires deFontenay-aux-Roses (3)

BP No. 692260 Fontenay-aux-RosesFranceAttn: Cogne

M. LeMeurG. Ganouna-Cohen

Electricite de France (5)Service Etudes et ProjectsThermigues et NucleairesTour E.D.F. - G.D.F. Cedex No. 892080 Paris la DefenseFranceAttn: J. Roubault

M. BarbetA. JanoirY. LeLouarnJ. Delaire

Electricite de France (3)Direction des Etudes et RecherchesLes Renardiers - Route de SensEucuelles - 77250 Moret Sur LoringFranceAttn: G. Delmas

P. RoussaireV. Deglon

Electricite de France (4)DER1 Avenue du General de Gaulle92141 Clamart CedexFranceAttn: J. Clade

A. LacosteJ. RibotL. Deschamps

Centre d'Etudes NucleairesBP No. 2191190 Gif-Sur-YvetteFranceAttn: G. Gaussens

J. Chenion

de Saclay(2)

CERNLaboratorie 1CH-1211 Geneva 23SwitzerlandAttn: H. Schonbacher

Commissariat a l'Energie AtomiqueCEN CadarcheBP No. 113115 Saint Paul Lez DuranceFranceAttn: J. Campan

Conductores Monterrey, S. A.APDO Postal 2039Monterrey, N. L.MexicoAttn: Ing. Patricio G.

G. Murga

Electra de Viesgo, S.A.Departmento NuclearMedio, 12 - SantanderSpainAttn: J. L. del Val

EURATOMC.E.C. J.R.C.Ispra (Varese)ItalyAttn: G. Mancini

EURATOMJoint Research CentrePetten EstablishmentEuropean CommunitiesPettenThe NetherlandsAttn: M. Van de Voorde

Fisher Controls, Ltd.Century WorksLewishamLondon, SE 137 LNEnglandAttn: P. A. Graves

Framatome (2)Tour FaitCedex 1692084 Paris la DefenseCedex 16FranceAttn: J. Meyer

G. Chauvin

29

Furukawa Electric Co., Ltd.Hiratsuka Wire Works1-9 Higashi Yawata 5 ChomeHiratsuka, xanagawa Pref.Japan 254Attn: z. Oda

cesellschaft fur ReaktorsicherheirGlockengasse 26000 Cologne 1West GermanyAttn: S. DluZniewski

Hitachi Cable777 Third AvenueNew York, NY 10017Attn: H. J. Amino

M. Sasson

Imatran Vioma OYPower Station Departmentulrikinkatu 27Box 13800101 Helsinki 10FinlandAttn: B. Regnell

Institute of Radiation ProtectionDepartment of Reactor SafetyP.O. Box 26800101 Helsinki 10FinlandAttn: M. Keikkila

international Atomic Energy AgencyWigramerstrasse 5P.O. Box 100A-1400 ViennaAustriaAttn: S. Machi

ITT Cannon Electric CanadaFour Cannon CourtWhitley, Ontario, LIN5V8CanadaAttn: B. Marshall

Japan Atomic Energy Research InstituteTakasaki Radiation ChemistryResearch Establish EstablishmentWatanuki-MachiTakasaki, Gunma-KenJapanAttn: N. Tamura

Japan Atomic Energy Research InstituteTokai-MuraNaka-GunIbaraki-KenJapanAttn: A. Kohsaka

Kansai Electric Power Co., Inc.1725 K Street NWSuite 810Washington, DC 20006Attn: J. Yamaguchi

Kraftwerk Union Aktiengesellschaft (2)Hammerbacherstrasse 12 + 14D-8520 ErlangenWest GermanyAttn: W. Morrell

I. Terry

Meideusha Electric Mfg. Co., Ltd.1-17, 2-Chome OsakiShinagawa-KuTokyoJapanAttn: M. Kanazashi

Motor ColumbusCH-5401Parkstrasse 27BadenSwitzerlandAttn: H. Fuchs

NOK AG BadenBeznau Nuclear StationCH-5312 DoettingenSwitzerlandAttn: 0. Tatti

Ontario Hydro700 University AvenueToronto, Ontario, M5GlX6CanadaAttn: R. Wong

Osaka Laboratory for Radiation ChemistryJapan Atomic Energy Research Institute25-1 Mii-manami Machi,Neyagawa-shiOsaka 572JapanAttn: Y. Nakase

30

Oy Stromberg Ab,Helsinki WorksBox 118SF-00101Helsinki 10FinlandAttn: P. Paloniemi

R•ein-Westf TUVStuebenstrasse 53D-43 EssenWest GermanyAttn: R. Sarturi

Studsvik Energiteknik ABS-61182NykopingSwedenAttn: E. Hellatrand

SydkraftSouthern Sweden Power Supply21701MalmoSwedenAttn: 0. Grondalen

Tokyo Electric Power Co., Inc.No. 1-3 1-Chome Uchisaiwai-ChoChiyoda-KuTokyo 100JapanAttn: 3. Ramada

Traction & ElectriciteRue de la Science 311010 BrusselsBelgiumAttn: P. A. Dozinel

Universidade Federal de Rio de JaneiroAV. N.S. Copacabana 661/120122050 Rio de JaneiroBrazilAttn: Paulo Fernando Melo

Waseda UniversityDepartment of Electrical Engineering170-4 ShinjukuTokyoJapanAttn: K. yahagi

Westinghouse Nuclear Europe (3)Rue de Stalle 731180 BuraselsBelgiumAttn: R. Minguet

R. DoesemaJ. Cremader

10001154120012141214180018101811181118131813181518152155215523419200930094009410942094409441944294439444944594459445944594459445944694469446944694469446944694469446945094529452945294529700621431413151

3.D.G.A.A.R.R.L.R.3.K.R.S.J.0.K.W.R.A.D.J.D.M.W.D.S.L.C.D.W.F.J.B.L.W.L.D.E.E.F.R.J.K.3.D.3.E.K.L.W.

K. GaitA. BouchardYonasOwyoungV. SmithS. ClaassenG. KeplerA. HarrahL. Clough (10)G. CurroT. GillenT. JohnsonR. KurtzE. GoverM. StuetzerB. MurphyC. KyreL. Peurifoy, Jr.W. Snyder3. McCloskeyV. WalkerA. DahlgrenBermanA. von RiesemannD. CarlsonL. Thompson0. CroppM. CraftT. FurgalH. McCullochJ. WyantS. YUE. BaderL. Bonzon (15)E. BuckalewD. BustardM. JeppesenE. MinorA. SalazarV. ThomeE. TrujilloA. ReuscherAkerBrysonMcKeonS. PhilbinH. BecknerA. PoundJ. Ericksen (5)L. Garner (3)

31

IF120555056755i 1 ANIRVus NRCN$KR-DIV OF -N~ikNEERINGSECTIUN4 LEAUER-iENV QmUALEQUIP QIJALIF BRAN~t1440WASHINGTON UL 20b555

MJ Sandia National Laboratories