ML20148T483

Review of Recent Studies of Radiation Induced Behavior of Ion Exchange Media, Preliminary Rept

ML20148T483
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Site:	Three Mile Island
Issue date:	11/30/1980
From:	Barletta R, Robert Davis, Swyler K BROOKHAVEN NATIONAL LABORATORY
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ML20148T481	List: ML20148T477 ML20148T483
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CON-FIN-A-3162 BNL-NUREG-28682, NUDOCS 8102270016
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( Bht.NUREG-28632 INFORMAL REPORT l

. LIMITED DISTRIBUTION l

REVIEW OF RECENT STUDIES OF THE RADIATION INDUCED BEHAVIOR OF. ION EXCHANGE MEDIA K. SWYLER, R. E. BARLETTAs ANr R. E. DAVIS NOVEMBER 1980 PREPARED BY THE DIVISION OF NUCLEAR WASTE MANAGEMENT DONALD G. SCHWEITIER, DIVISION HEAD DEPARTMENT OF NUCLEAR ENERGY BROOKHAVEN NATIONAL LABORATORY ASSOCIATED UNIVERSITIES, INC.

UPTON, NEW YORK 11973 l

r Prepared for the U.S. Nuclear Regulatory Comi Sion

! Office of Nuclear Materials Safety and Safeguards l Contract No. DE-ACO2-76CH00016 b

8102270Ol(0- -

BNL-NI, REG- 28682 INFORMAL REPORT LIMITED DISTRIBUTION

. 1 REVIEW OF RECENT STUDIES OF THE RADIATION INDUCED BEHAVIOR OF ION EXCHANGE MEDIA X. Swyler, R. E. Baric;ta, and R. E. Davis Manuscript Completed: Novemoer 1980 Prepared by the Division of Nuclear Waste Management Donald G. Schweit:er, Division Head Department of Nuclear Energy Brookhaven National Laboratory Associated Universities, Inc.

Upton, New York 11973 NOTICE: This document contains preliminary infornation and was preoared primarily for interim use. $1nce it may be subject to revision or correction and does not represent a final report, it should not De cited as reference without the expressed consent of the ,

author ( s) . l l

l Prepared for the U.S. Nuclear Regulatory Counission Office of Nuclear Materials Safety and Safeguards l Contract No. DE-ACO2-76CH00016 l Fin No. A-3162 j

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NOTICE This report was prepared as an account of work sponsored by the United States Government. l4either the United States nor the

'Jnited States Muclear Regulatory Canurission, nor any of their employees, nor any of their contractors, subcontractors, or their ecoloyees, makes any warranty, express or isolied, or assumes any legal lianility or responsibility Sr the accuracy, completeness or usefulness or any infomation, apparatus, product or process dis-closed, or represents that its use would not infringe privately owned r1gnts.

4 ABS 7 ACT A review of the results of recent experiments on the effects of radiation on ion exchange media is presented. The results described include pH changes, gas generation, agglomeration of organic ion exchange resins and corrosion of mild steel in contact with ion exchange nedia.

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CONTENTS ABSTRACT. . . . . . . . . . ................... iii CONTENTS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . y FIGURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vi TABLES. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vi ACXNOWLED GEMENTS. . . . . . . . . . . . . . . . . . . . . . . . . . vii

1. INTRODUCTION. . . . . . . . . . . . . . . . . . . . . . . . . . 1

2. EXPERIMENTS PERFORMED AT GTT ................. 3 2.1 Pressurization Experiments . . . . . . . . . . . . . . . . 3 2.2 Ga s Co n tent Expe ri me nts . . . . . . . . . . . . . . . . . . 4 2.3 Aggl omerati on. . . . . . . . . . . . . . . . . . . . . . 5

3. EXPERIMENTS PERFORNED AT PSU. . . . . . . . . . . . . . . . . . 7 3.1 pH Changes . . . . . . . . . . . . . . . . . . . . . . . . 7 3.2 Aggl ome ra t i on. . . . . . . . . . . . . . . . . . . . . . . 10 3.3 Gas Generation in Inorganic Ion Exchangers . . . . . . . . 11 3.4 Corrosion Studiese .................... 12

4. EXPERIMENTS PERFORMED AT BNL. . . . . . . . . . . . . . . . . . 15 4.1 Formation of Acid (s) . ............-..... 15 4.2 Ag gl omerati on. . . . . . . . . . . . . . . . . . . . . . . 16 4.3 Co rro s i on . . . . . . . . . . . . . . . . . . . . . . , . 16 4.4 Fast Electron Irradiations . . . . . . . . . . . . . . . . 17

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SUMMARY

OF RE SULTS. . . . . . . . . . . . . . . . . . . . . . . 19 5.1 pn Changes . . . . . . . . . . . . . . . . . . . . . . . . 19 5.2 Ga s Generati on . . . . . . . . . . . . . . . . . . . . . . 20 5.3 Ag gi ame r a ti o n . . . . . . . . . . . . . . . . . . . . . . . 20 5.4 Corrosion. . . . . . . . . . . . . . . . . . . . . . . . . 20

6. REFERENCES. . . . . . . . , . . . . . . . . . . . . . . . . . . 23 l

AP P E ND I X A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 i

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FIGURES 1.1 Estimated Cumulative Dose to Epicor-II Ion Exchange Media as Used in TMI-2 AFHB Flean-up vs Ti Based on Calcu a-40 Ci ft-5; b- 30 Ci ft ; c- 160 Ci ft-}ations of Appendix A.

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TABLES

?. 1 Threshold Doses Observed During GIT Pressurization Experiments. . . 4 2.2 Maximum Gas Production Observed During Gas Generation Experiments at GIT. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 3.1 Moisture Content and Initial pH of Resins Utsd in PSU pH Study. . . 8 3.2 Loading Patterns of Ion Exchange Columns for Buffering Action Ex pe ri me nts . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 -

3.3 pH Yalues of Solutions Formed From Irradiated Resins. . . . . . . . 9 3.4 pH Yalues of Solutions Formed From Irradiation Ion Exchange Media . 9 3.5 Flow Rates Through Ion Exchange Colunos Before and After 60Co I rra di ati o ns . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 3.6 Gas Generetien in Ieolite (10NSIV-II-95) During Irradiation . . . . 11 3.7 Corro si on S tu dy Experi ments . . . . . . . . . . . . . . . . . . . . 13 4.1 Hydrogen Ion Concentrations (as pH) of Water in Contact With I rradi a te d I on Exen an ge Re si ns . . . . . . . . . . . . . . . . . . . 16' l

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ACXNOWLEDGEE NTS The authors would like to thank Ors. Donald G. Schweitzer, Thomas Gangwer, and Allen J. Weiss for many valuable discussions on aspects of the material reviewed. They also express their appreciation to Nancy Yerry for her. skillful preparation in typing the manuscript.

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REVIEW OF RECENT STUDIES OF THE RACIATION INDUCED BEHAVIOR OF ION EXCHANGE MEDIA

1. INTRODUCTION Ion exenange materials are conventionally used to decontaminate water con-taining radiorcelides. However, in total absorbed dose (in excess of 10ghe o'*esence rao), these organic of ioni:ing radiationresins ion exchange at high are known to undergo radiation damage. The previous work and some issues of the concerns for the 'short tem storage of organic ion exchange resins containing high loadings of radionuclides based upon earlier literature were discussed in

" Status Report on the Leachability Structural Integrity, and Radiation Stability of Or Additives."(1) ganic lon concluded It was Exchange Resins Solidified in this repore thatinthe Cament and Cement fundamental Witn processes causing resin degradation are not understood and that the extent of radiation damage is specific to resin type. ~

Detailed infomation regarding radiation damage to ion exchange media per-tint.nt to the conditions expected curing the storage of ion exchange media waste generated in the auxiliary building (AFHB) cleanup activities at TMI-II is un-available. Consequently, several scoping studies have been performed *w esti-mate the magnitude of these problems. This work was condugted by R. C. Mc Farland at Georgia Institut.g of Technology (GIT),l2) K.X.S. Pillay at Pennsylvania State University (P:U)l4,41, and by the Division of Nucleer Waste Management at Brookhaven National Laboratory (BNL). Much of this work was per-Nrmed using material typical of fon exchange media used in the nuclear industry since the identity of the actual ion exchange materials used in the EPICOR-II dominerali:ing system is not available at this time due to t..e vendor's concern over its proprietary nature. In the studies reviewed here, the investigators used external irradiation to simulate the radiation dose that is received oy ion exchange media internally 1oaded with radionuclides. Differences in the radia-tion damage to ion exchange media h4ve been observed in some cases for external i as opoosed to internal irradiation.(8) While external irradiation simulates the most significant radiation effects, external irradiation does not simulate the actual radiation processes that occcur with internal loaoing. This recort is a review of the results of these scoping studies. We have arranged the body of the report, sections 2, 3, and 4, by the laboratory perfoming the work, rather than by the category of experiments even though similar or related ex-J periments have been performed by more than one institution. The sununary of re- j sults, section 5, groups the data by categories of experiments.  ;

Figure 1.1 shows several estimated cumulative absorced dose curves for Epicor-II ion exchange madia as used in the TMI-II AFHB cleanup versus time.

The bases of this figure are the results of the dose rate calculations outlined in the appendix of this report. These calculations assume that a total of 1200 curies of activity are unifomly distributed throughout the entire ion exchange bed volurae (case a), one-half the bed volume (case b), and one-fourth the bed volume (case c). Within the considered volume, all of the beta particle energy is assumed to be deposited, while tissue equivalency is assumed for gansna ray 1

9 attenuation. If the more conservative approach of total gamma ray absorption was assumed, the total cumulative absorbed dose would increase by approximately a factor of two in comparison with the results given in Figure 1.1. Al so, re-giens of high localized activity would result in a substantial increase in the cumulative cose oelivered to these regions. The figure is included to allow the i reader to make qualitative comparisons of delivered dose in the experimental work to a time frame.

p . .

....ij . . 7' ....j , ..6

c 2 ,

d

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- a.

3 10 ~ 7 7

3 10' _

! d

/

~

~

/

', , ,,..I . , , . ....I , , . , ,,

, 1 10 time (years)

Figure 1.1 Estimated cumulative dose to Epicor-II ion exchange media waste as generated in the TMI-II AFMS cleanup vs time based on calculations of Appendix A.

a 10 Ci f t-3; d- 80 Ci ft-3; c- 160 Ci ft ,.

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2. EXPERIENTS PERFORMED AT GAi The purpose of the experiments performed at GIT was to "detennine the pres-sure buildup and gas compcsition as a function of gamma dose in burial canis-ters" of i I cleanup.Pgn exchange 3 This media task was planned divided to be into two used in sets separate the TMI-II reactor building of experiments:

pressurization and gas content. It should be noted that for the data in these  :

experiments, experimental errors were not given, and these experiments were not '

orginally planned in connection with the TMI-II AFriB cleanup.

2.1 Pressurization Exoeriments The pressuri:ation experiments were conducted on a cation ion exchange res-in, an anion ion exchange resin, and activated charcoal irradiated in separate stainless steel capsules. The cation resin used was Dow HRC-S, and the anion resin used was Dow SBR-ON. These resins were converted to the sodium and berate forms respectively using a sodium berate solution (concentration and velume un-speci fi ed) . The activated charcoal was also treated with the sodium borate so-lution. After this pretreatment, the samples were dewatered by pulling air

hrougn tne, column for two minutes. The samples were then placed in the irradi-ation caosules. A maximum of 66.79 cm3 of samcle was olaced in each capsule.

This gave a void volume acove the resin of aoout 10.35 cW (13.4t).

~he capsules were then irradiated using a 60 oC gamma-ray source having a flux of approximate 1v 5 x 100 rad /hr. The maximum cumulative doses were ao-proximately 2.5 x 109 rad for the cation resin, 8 x 108 rad for the anion resin, and 5 x 109 rad for the activated charcoal . During the irradiation, air cecling was supplied to maintain the samole temocrature between 30 *C to 45 *C.

In all cases, an apparent threshold for the onset ef pressuri:stion could ce coserved. Threshold values are given in Taole 2.1. Both the cation and anion resins showed a linear increase in pressure with increasing dose aoove tne threshold dose. The sloce of this dose dependence was 0.083 psi /M rad for the cation resin (maximum dose of approximately 3 x 109 rad) 8and 0.27 psi /h rad for the anion resin (maximum dose of approximately 8 x 10 rad). The acti-vated enarcoal showed a rather different dose dependence. Above the threshold dose, *he pressure rose rather rapidly to a maximum of aoout 5 psi at 1 x 10I rad. Above 1 x 109 rads, the pressure remained slign:ly below nis peak value.

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Table 2.1 Threshold Doses Observed Dur n GIT Pressurization Experiments l2g Material Cumulative Dose (rad)

Dow HRC-S 8 x 107 Dow SBR-ON 4.7 x 107 Ac*ivated charcoal 1.5 x 108 2.2 Gas Content Experiments The composition of radiolytically generated gas as a function of dose was determined for the Dow HRC-5 and the Dow SBR-ON resin. The resins were again pretreated with sodium borate. The samples were loaded into stainless steel capsules (The dose with a total rate was volume approximately of 18.9 cc. 4.86A x 10 single rad sample wasirradiation,

/hr.) Af ter run at eachthe dose.

samole tubes were attached to an evacuated volume whien contained a septum througn which samples were withdrawn for gas chromatographic analysis.

A total of five gases were identified as cation resin degradation products:

hydrogen, methane, ethane, propane, and butane. For the anion resin, hydrogen, methane, ethane, and propane were observed. In addition, traces of an un-identified hydrocarbon gas were detected in the hign dose anion capsule. It was speculated by Mc Farland that this gas was a brancned chain and/or unsaturated compound. Significant amounts of amines were not detected in either the cation or anion resin experiments.

The production of hydrogen, methane, ethane, propane, and butane (cation resin) was plotted versus total g.uuna dose. For H2 and CH -

4 , the proeucticn wita dose appeared to be roughly linear for both cation and arion resins. While for the other gases, the dependence was more complex. The maximum volumes of gas generated per gram of resin estimated from Figures 10 througn 14 of refer-ence 2 are given in Table 2.2.

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Table 2.2 Maximum Gas Generation Gas Production Experiments Observed at GITDyrjng 2

Gas ResinA Amount of Gas Dose (rad) at./g H2 cation 2.0 x 10-1 3 x 109 anion 2.2 x 10-1 5 x 108 CH4 cation 2.1 x 10-2 3 x 109 anion 7.4 x 10 8 x 108 CH26 cation 2.8 x 10-3 3 x 109 anion 1.3 x 10-3 8 x 108 C3Hg cation 6.4 x 10-5 1 x 109 anion 3.8 x 10-5 8 x 108 CH4 10 cation 1.5 x 10-5 1 x 109 aCation resin Dow HRC-S and anion resin Dow 58R-ON.

2.3 Agglomeration Although experiments were not specifically designed to provide any infonna-tion on agglomeration, the following observations were reported:

e In the high dose samples, a liquid phase fomed. The liquid pnase had a volume approaching 50% of the original resin sample.

e Trapped gases in this jguid phase caused it to froth wnen the pressure was released. *)

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3. EXPERIMENTS PERFORMED AT PSU l

The ocjective of the experiments perfonned at PSU was to initiate a prelim-inary scoping study eimed primarily at demonstrating speculated radiation in-duced behavier of ion exchange media and mild steel in contact with these media.

In this regard, four areas were selected for this investigation: pH changes as a result of irradiation, agglaneration of ion exchangers, generation of gas from the radiolysis of an inorganic ton exchanger, and the corrosion of mild carbon steel in contacted with ion exchangers in a radiation field.

3.1 oH Changes It is generally recognized (5) that the radiation effects on ion exchange resins, as well as radiolysis of water within the resin matrix, produce a vari-ety of products that significantly change the pH of the overall matrix. It was speculated that sixtsres of cation exchangers in the hydrogen (H+) form in combination with the anmonium (NH 4 +) form might produce a buffering action, due to the possible availability of NH3 gas from the NH4 + form of the resin. The cation exchanger At;eerlite IR-120 in the H' form was used as the primary material. A large batch of the NH4 + form of this resin was prepared by mixing a cuantity of Amoerlite IR-120 wi th NHaOH. Layered combinations of these two forms of the cation exchanger with stratification ratios ranging from 1:10 to 1:1 to 10:1 by weignt were used to examine this potential buffering acti on.

The initial pH and noisture content of the unirradiated resins are given in Table 3.1. Table 3.2 gives the column leading patterns used in the buffering experiment specimens. Specimen containers were ma All specimens Mrs irrt.diated to a total absorbed dose of 7 x 10prad of quart:.

in the gamma flux of a nuCo source (at approximately 1.2 x 10: R/hr). Af ter irradiation, columns were sectioned into approximately 2 gm samples. A 10 mL volume of deionized water was adoed to eacn sample, and the pH of the supernate was measured. The values of tne pH are given in Table 3.3. A significant lowering of the pH was ob!erved in all cases. For samples 25 and 27, a slignt variation of pH along the neight of column was seen.

The results of some additional pH measurements of irradiated ion exchange media are presented in Table 3.4 These specimen were gamma-irradiated to a total cose of 4.4 x 108 rad. Specimen containers for these experiments were made of aluminum. Since aluminum is reactive in either acid or alkaline envi-romnents, the observed pH values do not represent an accurate measure of the irradiated specimens acidity or alkalinity.

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Table 3.1 Moisture Content and Initial pH(3igf Resins Used in PSU pH Study Resin (fom) Moisture pHA Content (5)

Amerlite IR-120 (H+)b 39.7 3.4 Anmerlite IR-120 (NHa+) 39.4 8.5 Amer 11te IRA-400 (Cl gb 42.0 4.6 Ieolite (IONSIV-IE-95) 0.0 8.0 aihe pH was measured in the supernata of of resin and 10 mL of a sixture of deionized water 2 g(pH 6.8). '

bA s received % vendor.

Table 3.2 i

Loading Patterns ofAction CationExperiments Exchange Cgmns for Buffering Sample No. H+ Fom NH4 + Fom 21 20 guts (bottom) 2 gas (top) 22 20 gas (botton) 2 gas (top) 23 2 gas (top) 20 gas (botam) 24 2 gas (top) 20 gms (botton) 25 10 gas (bottom) 10 gas (top) 27 10 gas (top) 10 guts (bot *am)

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Table 3.3 pH Values of Solutions Formed From Irradiated Resins (3)

Section Sample No.

21 22 23 24 25 27 Top 1 1.6 1.6 2.2 2.1 2.1 1.5 2 1.6 1.6 2.1 2.1 2.0 1.5 3 1.5 1.5 2.1 2.1 1.9 1.5 4 1.5 1.5 2.2 2.1 1.8 1.6 5 1.5 1.5 2.2 2.2 1.7 1.6 6 1.5 1.5 2.3 2.3 1.6 1.7 7 - 1.5 2.3 2.3 1.6 1.8 8 1.5 1.5 2.3 2.3 1.6 1.9 9 1.5 1.5 2.4 2.4 1.5 2.0 10 1.5 1.6 2.3 2.5 1.5 2.1 Bottom aihe pH was measured in the supernatant of a mixture of 2 g of resin and 10 mL of deionized water (pH 6.8).

Table 3.4

1. Values of Solutions Fonned Fr

. Irradiation Ion Exchange Median Ion Exchange pHa Asterlite IR-1200 3.5 Amber 11ta IRA-400b 4.6 10NSIY-IE-95C 9.0 IONSIY-!E-95 +

Aseerlite-IR-120 + 4.0 I Amoerlite IRA-440d I aThe pH was measured in the supernate of a sixture of 2 g ion exchanger and 10 W bA s re.ceived of deionized water (pH = 6.8).

from vendor.

C0 rip-drf.

dEqual weights.

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e 3.2 Agglomeration j Several columns containing single exchanger or layered beds of IONSIV-IE-95, Amerlite IR-120, and Amoerlite IRA-400 were prepared in 2 cm diam x 20 cm long aluminium tubes. These ion exchange colums were then attached to a flow measurement sys*em, and the flow rate of deionized water through the beds was measured. After allowing the exces's water to drain out, the columns were capped with end fittings (not air-tignt). These columns were then exposed to the gamma-flux in a 60 C o facility (4.5 x 106 R/hr) until the total dose re-ceived was approximately 2.2 x 109 rad.

After irradiation, the columns were again attached to the flow measurement device in the same way as before, and an attempt was made to measure the f!ow rate througn the columns. Only the column filled with zeolite showed a flow.

All of the colums containing organic exchanger showed no flow at all. These plugged columns were submerged in a large tank of water. In subsequent test dng of the soaked colums flow was initiated in all but one casa URA-400). The  !

results of the flow testing are shown in Table 3.5.

l Table 3.5 l

Before and At'ter 00Co Flow Rates Through Ion Exchange Cg3yms Irradiations Column Weight Pre-i rradiation Post-i rradiation No. Ion Exchangers Ratio flow rate (mL/ min) flow rated (mL/ min) 1 10NSIV-IE-95 1 18 19 (without pre-treat-ment) see footnote 2 IONSIV-IE-95 & 1:1 16 13 I Amerlite IRA-120 3 10NSIV-IE-95 & 1:1 19 22 Anoerlite IRA-400 4 ICNSIV-IE-95 & 1:1:1 12 11 Amerlite IR-120 &

Anoerlite IRA-400 5 Amer 11te IR-120 1 23 25 6 Amoerlite IRA 400 1 7 could not initiate flow alnnediatel'er v after irradia*

in1tial conof ion tion,s.it was system und Flownotwas possible initiatedtobyget any flow flooding thethrougn columnthe and possibly creating flow channels.

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1 3.3 Gas Generation in Inorganic Ion Exchancers Zeolite (IONSIV-IE-95) spples of varying moisture content, some loaded with cesium, were exposed to o0C o gama radiation. These samples were placed in pyrex containers specially desiped to allow subsequent study of gases pro-cuced within the matrix du-ing irradiation.

The irradiation containers, with a volume of about 8 nL, were fitted with a

' break-seal" and glass attachment to allow incorporation into a vacuum line for gas analysis. Known weignts of zeolite samples were placed inside these glass containers, and thr/ were heat-sealed at atmospheric pressure. The ratio of zeolite column volume to the tetal container volume was about 0.5. The samples to 60 werethenexnosegradwasreached.Co dose of 1.4 x 10 gama radiation Following (at 3.9 x 108 the irradiation, theR/hr) until a total pressure was deternined and the gas present in the samoles was analyzed. The results are given in Taole 3.6. The variations in gas comoositions were attributed to ne following reasons. "The well known ability of molecular sieves to adsoro signi-ficant amount of gases and the unique ability of Zeolites to relatively retain large quantities of hy gen in the gas phase."ggen account for the obsarted ratio of hydrogen and oxy-Table 3.6 Gas Generation During in Ieolite (IgY-IE-95)

Irradiation Samole Pressure Gases (volume 5)

No. Pretreatmento (psi abs.) n2 U2 N2 310 Orip-dry 20.3 4.5 0.6 90.7 32 Orip-cry 18.0 1.3 32.5 66.2 33b Orip-dry 20.3 3.1 1.8 32.2 (Cs-loaded)c 34 Ori p-dry 20.0 1.0 36.9 62.1 (Cs-loaded)C 35 Air-dry 13.9 0.9 29.2 69.9 36 Ai r-dry --- 0.6 24.1 75.4 37 Ai r-dry 13.0 1.0 33.1 66.0 (Cs-loaded) 38 Air-dry 11.6 0.6 33.4 66.1 (Cs-loaded)

Blank Ai r-dry 13.9 --- 20.2 79.8 (non-irradiated) aMoisture cantents for air-cry and drip-dry zeolites were 21.0% and 33.3%

(byweighti, respectively.

bNthane (3 to 4t) was identifiec in addition to H2 , 0, and N2 . The source of methat:a is not uncerstood. -

Othe Cs loacing on tnese sanples was 0.6 meq/g of dry zeolite.

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3.4 Corrosion Studies In order to ascertain the extent of radiation induced corrosion in ion ex-cnanger systems, metal coupon studies were conducted. The ion exchange mate-rial s used were Ameerlite IR-120, Amoer11te IRA-400, and 10NSIV-IE-95.

Two different types of irradiation facilities were employed for the corro-sion experiments. One was a o0C o gamma-irradiation facility. The other, a researen rtactor (TRIGA-Mart III) in the shutdown mode was used as the irradia-tion source having the fission produc* spectrum. Both single exchanger / coupon and layered bed exchanger / coupon systens we e studied.

Mild steel coupons made frt:m steel plates identified as ASTM-1018 crade were used in all the corrosion study experiments. This mild steel grade is s%

ilar in composition to other types of common steel such as ASTM-1020 and ASTM-A-36. All have a carbon content in the range of 0.20% to 0.25t. Finely polished coupons wert prepared from one large piece of stock material . Irradi a-tion experiments at o0C o f acflity used coupons of size 12 m x 50 m x 3 mm.

Another set of 12 mm x 30 nm x 3 na coupons were used in irradiation experiments using the TRIGA Reseach Reactor. Blank samples (unirradiated) were prepared and preserved u.toer identical conditions. The results of the corrosion experiment are sumarized in Table 3.7.

The coupons from the blank samples showed little or no trace of rust or corrosion effects. The irradiated mild steel coupons were removed from the ion exe.1 anger beds and were rinsed with water to remove the weakly attached resin beads adhering to the surf aces. These were then photographed (see reference 3) for the purpose of having a risual record. The corrosion layers on the specimen were then carefully removed using a nylon brush, and the weignt losses of the mild steel coupons were determined. Some brief qualitative descriptions of the mild steel coupons, as they appeared before removing the crust formations on their surfaces, are also given in Table 3.7.

As is evident from the description in Table 3.7, all of the irradiated met.

al coupons showed significant corrosion. Pitting and cor*osion were enhanced wnere the exchanger was di.*ectly in contact wi th the metal surf ace.

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Taele 3.7 Corrosion Stuey Exoeriments 54 sele Ion Exon 4 agers Irradiation weignt less Qualitative Features of Carroced no. used Fac111ty 5 ints 46 wt. og/ce2 netal coupon Surfaces 7 10mSIV.!E.95 Woe 0.9 6.4 Scotty rusted areas vita zeelite means strongly aenering.

8 10u5IV.1E.95/ 60 coa 2.5 IS One half coered with rust only. The Aseerlite IA-120 other half had rust and resin Deads.

9 Ameerlite IR.120 60goa 3.3 24 Covered witn rust througneut. One end nad unite soots in addition to rust.

10 Amerlite 1AA-400 60cea 1.3 13 Unifers tain layer of rest. No crust .

formatten.

11 10msIV.!E.M/ 60cea 4.4 32 me significant cmst, but significant Asnerlite IRA-400 pitting en surfaces.

12 10msiv.lE.95/ 80Ca* 4.1 30 Cavered fully vita blact beses and rust.

Aamerlite 12 120/

Aseerlite IAM 74 10msIV.!E.95 none 0 0 trignt surfacas. Barely visible rust soots at *ne edges.

94 Asser11te IR-120 none 0.3 2.0 Almost all of the surface of the couson was emeree with a very tnin layer of correston preeuCt.

10 4 Amerlite IAA 400 none 0 0 Brignt surfaces like tne eristnal saaele.

No visible corrosien preesets or rust spots.

41 10mSIT.!E.95 TR!ge 0.3 3.1 Distinct, but saetty crust fometton vita

selite particles amering to tne :orrosion predact.

42 Asserlite IRA.!,20 TRIEAa 3.5 27 Significant carmten preeuct butle.us.

uniform tnrougneut the surface.

43 Aseerlite IAA 400 TRIM 8 0.7 5.2 Scotty corrosion eroeuct build.up.

escocially around seges of the coupon.

44 10mSIV.!E.95/ TRIE8 0.4 6.2 Untformly distributed surface layers of Asserlite.!R 120/ corresten premacts.

Asserlite=lAA 400 800se a 2 x 10 9 ese; flus = 4.4 s 10' g/hr.

30csa a 4.4 2 108 red; flua a 7.4 z 10 R/hr.

. 13 l

1

. - _ - - - . . . , . , - . . . - , - . . . _ _ . _ , , _ _ ~ . . _ - . _ _

4. EXPERIENTS PERFORMED AT BNL Radiation damage studies on organic ion exchange resins are currently under-way at BNL. Using techniques simile to those discussed above, investigations of acid product femation (pH change), radiation induced corrosion, radiolytic gas formation, and P cilities include a 6'tsin Coagglomeration gamma flux andare a 3being out. Irradiation carried accelerator.

MeV electron f a-The ob-jectives of these experiments are first to confim and extend the results of scoping studies described above, and, second, to detemine the dependence of potentially significant radiation effects on key parameters such as radiation dose, dose rate, type of radiation and resin loading. To date, measurements have centered almost entirely on two resin types: the cation exchanger Anmerlite IRN-77 and the "C-665" resin supplied to BNL by the NRC. With the exception that C-66% is a cation exchanger, no written documentation is avail-able.

The functional group on the IRN-77 resin is sulfonic acid (-503H). This material is supplied in the hydrogen fom. To investigate the sensitivity of radiation induced effects to resin loading, measurements were carried out on

!RN-77 in the hydrogen fora (IRN-77(H+)) and on samples of IRN-77 which had been converted to sodium form (IRN-77 (Na+)).

Certain preliminary results of tne BNL investigations are described briefly in sections 4.1 through 4.4. It must be enchasized that these results are pre-liminary, and, in several cases, surt be considered subject to confimation.

The objective here is to display early trends.

4.1 Fomation of Acid (s)

A series of sangles was gamma irradiated to various doses at a dose rate of approximately 4 x 100 R/hr. The irradiation were carried out in vented pyrex tubes. Following irradiation, the samples were throughly mix 3d with deioni:ed water in the ratio 2 g resin to 10 mL water. The pH of the resulting solution was then measured and recordec. Initial results are shown in Table 4.1.

Several observations are noteworthy:

o Without exception, for the resin studied, the pH steadily decreased for increasing gamma dese. This radiation incuced generation of hignly acidic conditions is in accord with previous measurements cited acove.

e The acidity produced is sensitive to resin chemical loading. The sodium form of IRN-77 is much less acidic than the hydngen fem prior to irra-diation, and this trend continues in irradiated samples. One samole of C-66% resin was titrated to pH 7 with NaOH prior to irradiation, wnich converted the resin to the sodium form. Following irradiation, the pH of the titrated C-66% resin solution us substantially higher than that of an untreated C-665 resin exposed to the same gamma dose.

e In the pH experiment, the water mixed with the irradiated resins becomes colored. The coloring danens steadily from pale yellow to deep ameer with increasing absorDed dose. For equal raciation coses, the coloring 15 1

1 i

was always more pronounced for IRN-77 (H+) than for IRN-77 (Na+).

inus, the coloring following *.he same qualitative trends shown in the pH measurements.

Table 4.1 Hydrogen Ion Concentrations (as pH) of Vater in Contact With Irradiated Ion Exchange Rasins oHa j Dose (rad) C465 C-66% (Na+)b Udi-77 (H+) IRN-77 (Na+)

0 4.4 7.0 3.5 0.8 107 (Y) 2.6 --

2.5 4.7 1.25 x 107 (e-) -- ~- 2.5 --

3x107 (Y) 2.0 --

2.0 3.6 ,

4.6 x 107 (e-) --- -

2.0 --

108 (Y) 1.6 3.0 1.5 2.9 3 x 108 (Y) 1.1 --- 1.0 2.1 109 (Y) 0.9 -- 0.6 1.3 aMeasured in supernate of a mixture of 2 g of resin and 10 mL of deionized water.

bTitrated to pH 7 with WaOH prior to irradiation.

4.2 Agglomeration l Only qualitative results (visual observations) are presently available.

l For IRN-77 (Na+), IRN-77 (H+), and C-665 resins, irradiation to doses of an-l proximately 108 rad did not produce any severe agglomeration. The major visi-ble effect was that the resins became progressively more colored. At 3 x 108 rad, a definite stickiness was obgervable in all three resin types. 7he IRN-77 (H') seemed most affected. . At 10 rad, the IRN 77 (H+1 had a guimpy ap-pearance. The IRN-77 (Ma+) was similarly agglomerated. The C-665 resin al-though quite sticky, was somewhat less agglomerated than IRS-77 (H+). When water was added to all these resins (10:2 by weignt), the samples "deagglom-ersted". The IRN-77 (H+) forned a gel-like solution. Again, the C-565 resin l seemd are durable.

4.3 Corrosion Corrosion behavior of mild steel and stainless steel (304) in irradiated 1 IRN-77 (H+), IRN-77 (Na+) and C-665 resins has been studied. Coupons were l

. 16 t

l t

l incecded in resin samples prior to gamma irradiation. The samoles were then irradiated to various doses. Subsequently, the coupons were removed and com-pared with similar coupons which had been emoedoeo in resins, but which received no irradiation. Again, at this point, only qualitative results are availaole.

These are described below:

e For mild steel, corrosion was increased by irradiation. IRN-77 (H')

and C-66% resins appear more corrosive than IRN-77 (Na*).

e Corrosica is greater fgr samples irradiated to 3 x 108 rad than for those irradiated to 100 rad. The corrosion time for dose of 108 rad is approximately one day and three days at 3 x 108 rad dose, e Thus far, (3 days corrosion time, 3 x 108 rad) radiation enhanced cor-rosion has not been observed for stainless steel .

4.4 Fast Electron Irradiations Several samples of IRN-77 (H+) were irradiated with 2.2 MeV electrons.

Both pH measurements in vented containers and gas evolution measurements in closed containers have been carried out. In the gas evolution measurements, the pressure was monitored while the irradiation progressed. The calculated dose based on beam current and energy loss data was appegximately 1 x 108 rad oer hour in the pressuri:stion measurements and 5 x 10/ rad per hour in the pH s tudies. Results to date indicate:

e The measured pH in the electron irradiation measurements so far agree reasonably well with the expected gamma irradiation at the same total dose (c.f. , Table 4.1). This suggests tnat the pH change is not par-ticularly sensitive to dose rate, anc that electrons and gamma rays are sensibly equivalent on a per rad basis.

e At an absaroed dose of aaproximately 3 x 108 rad, an overpressure of about 3 psi was produced in the closed container experiment. We are presently determining the plenum volume; it i; estimated at least 50%.

The slope of the pressure versus dose curve appears so far to be closely proportional to radiation dose rate. This was determined oy changing tne beam current during irradiation, while monitoring One overpressure. This appears to be an extremely useful technioue.

Hydrogen and methane were identified as gaseous radiolysis products, w

17

i 1

5.

SUMMARY

OF RESULTS The woric performed at GIT, PSU, and BNL described previously within this ,

report fall into four categories: pH change, gas generation, agglomeration, and j corrosion of metals in contact with irradiated ion exchange media. The results by category are summarized below.

No attamot was made to interpret the results of these experiments. This review is not intended to imply agreement with, or rejection of, the integre- ,

tations and conclusions given in the documents reviewed. l 1

5.1 oH Changes e For radiation doses of abcut 107 rad and above, all pH

.hanges were observed by PSU and BNL to be substantial with respect to the pH of the unirradiated starting materials with the exception of IRA-400.

e The water added to irradiated resins to perfom pH measure-ments at BNL was observed at to become colored. The coloring daricans steadily (from pale yellow to onep amoer) with increasing dose.

e Layered concinations of the H' and NH4 + forms of the IR-120 cation resins with stratification ratios ranging frcrn 1:10 to 1:1 .,

to 10:1 by weight were examined at PSU. All samoles received 7 x 10' rad total absorbed dose. After irradiation all layered specimens had low pH values (1.5 to 2.5). Some specimens showed a modest variation of pH along the bed length. Based upon this experieent, the hydrogen form of IR-120 is estimated to have a final pH of 1.5, wnile the annoniated fom is estimatad to have a final pH of 2 4.

e At PSU, the IRA-400 anion resin was irradiated to 4.4 x 108 rad, and had a measured final 'pH identical to that of tne unirradiated starting material .

e Similar pH changes were observed at BNL for the IRN-77 H+ form cation exchange resins to those changes observed at PSU for the IR-120 H+ fom at similar total accumulated total dgge of acout 108 rad. These irradiations were carried out in a ou Co gamma flux. Several samples of resins irradiated at BNL to 109 rad showed pH values of about 1.0. Samples of the IRN-77 Na* form exenanger examined at BNL showed pH values consistently higher (less acidic) than the IRN-77 H+ form.

e at SNL, which were about ten The timeselectron irradiations higher in of resins,0 dose rate than the oCo irradiations, showed similar pH changes in tne resins to those pH changes observed for gamma irradiated resin.

19 l

l

.- . . . .. ,~ - . . = . - -

4 Recent work at SNL on corrosion of stainless steel imedded in resins indicated no corrosion at the end of a three day enerient used to obtain a 3 x.105 rad dose.

l l

1 21

6. REFERENCES

1. R. E. Barletta, R. E. Davis, T. E. Gangwer, N. Morcos, D. G. Schweit::er. and A. J. Weiss, " Status Report on Leachability, Structural Integrity and Radiation Stability of Organic Ion Exchange Resins Solidified in Cerrcnt With Additives," BNL-NUREG-28286 (1980).

2. R. C. Mc Farland, "The Effects of Gama Radic.i:1on on Ion Exchange Resins and Activated Charcoal," TMI-II-RR-6 (1980).

3. K.X.S. Pillay, " Radiation Effects on Ion Exchangers Used in Radioactive Waste Manageinent," NE/RWM-80-3 (1980).

4. T. Gangwar and X.X.S. Pillay, " Radioactive Loading of Ion Exchange Mate-rial s: Radiation Related Areas of Concern," BNL-NUREG-28647 (1980).

5. T. E. Gangwer, M. Goldstein, and K.K.S. Pillay, " Radiation Effects on Ion Exchange Materials, BNL-50781 (1977).

23 l

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I e o, I

ACPENIDX A i l

This appendix outlines the method used to calculate the cumulative absorted dose as a function of time. The results of these calculations were displayed in Figure 1.1.

Table A.1 lists the radionuclides wnich were considered, as well as rele-vant quantities of activity and pertinent decay properties. The selection of these radionuclides and of the relative amounts was based upon an analysis of the influent to a particular TMI/EPICOR-II prefilter (#16). This information was obtained at a meeting held at the TMI site on October 20, 1980. The curies of an isotope were scaled such that a hypothetical liner would contain approxi-mately 1300 total curies.

Table A.1 Nuclides and Relevant Decay Data Used in Calculation of Dose Rates Radionuclidea Tota 1b y [c g Curies (yr-1) ggj$

(yr MeV (rad /cm2h r-lmCi-1) 895 r 65 5.0 0.138 0.583 noY d 90 r 25 0.025 28 0.200 noY (95) (.0073) (0.931) (noY)

{CsY)e 200 0.33 2.1 0.152 8.7 137Cs '700 0.023 30 0.195 3.3 aThese radiois t  : counted for approximately 99". of the total racioactivity bN ormali:ed tc, . ,,roximately 1300 total curies.

CReference 6.

dL ess than 0.01*. o 39 r decays with the rele se of a gama ray; for tne purpose or ca cui tion this mooe was neg ected.

eDaugcay ter ofcoinc15 90  ; for the ourcose of calculation, 90Y was assumed to ent witn parent cecay The remaining information (geometry, activity densities, etc.) used in the calculations is given in Table A.2. Three cases ere considered. In each case, the total activity is assumed to be uniformly distributed throughout the volume of a cylinder. The radius of all cylinders is 50 cm, wnile the heights are 30, 40, and 20 cm. For these assumed geometries, the bulk activity densities are 30, 80, and ISO C1/ft3 , respectively.

The dose delivered by beta decay was calculated frcm the following equa-tions. The initial beta dose rate of the itn radionuclide, D , is:

.s 01 = A Cjij 25

~,- . - - - . - . - - ,

e e;

Table A.2 Assumed Geometry, Geometric Correcticn, and Activity Densities Used in Calculation Case a b c radius (cm) 60 60 60 80 40 20 iheight(cm)1)

(cm- 216 206 180 volume (ft3) 32.5 16.3 8.13 (cm3) 9.2x105 4.6x105 2.3x105 activity density, (mCf /cm3) l 69se 0,07 0,14 0,23 90S r 0.0 27 0.054 0.11 134Cs 0.22 0.44 0.88 137Cs 1.1 2.2 4.4 l

C1 is the activity density of the ith radionuclide, T iis the average beta  ;'

energy and A is a proportionality ccnstant. When Cj is in Ci/c9 andIj is in MeV, A equals 2.1 x 103 red cm3 MeV hr-lmCi-1 and Dj is obtained in rad per hr. The total absorbed beta dose due to the decay of tr.e ith radio-nuclide, 0 (=), is b8 x 8.75 x 103 hr.yr~1 l D s (,) ,

i

.wher0 11 is the cecay constant of the ith radionuclide in yatrs-1. The beta dose absorced at any time may then be calculated by l-O!(t)=D{(=)(1-e~At), i The dose delivered by gama decay was estimated from the fol'1owing equa-tions. The gamma dose ra*a is 7

Di = CijTi where Ti is the gama ray constant of the ith radionuclido and T is a geomet-ric factor, which assumes tissue ecudvalency. T j has the units rad cm2 mci-l b r-1; y has the unit c:n-A.

The values of i given in Table A.2 were estimated fnm the values of I given in Reference 2. E.xtrapolation of i for a cylinder of radius, r, of 60 cm was accomplished by least square fitting the published data to the form g2 = mr + b.

25

4 een .

The total gamma absorbed dose, 0[(=), is d[x8.76x103 nr yr*I 0[(=)= -

A j  :

and the cumulative gamma dose was obtained from 0[(t)=0{(=)(1-e-St).

The total cumulative absorbed dose for all nuclei and 'octh d? cay types was >

obtained from the following equation, O(t) = (Of( =) + 0[( =))(1 - e-4t),

This equation is plotted in Figure 1.1 as a function of time for each of the three loadings.

References '

1. Bureau of Radiological Health and the Training Institute Environmental Control Administration, Radiological Health Handbook, U.S. Government Printing Office, Washington, D.C. U970).

2. G. J. Hine and G. L. Brownell, Radiation Dosimetry, Academic Press. Inc.

New York (1956).

i 4

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.. ._. -- - . - . - . . . -