< L V AFIRPL-TR-80-71
DECEMBER 1980
AIR FORCE ROCKET PROPULSION LABORATORYDirector of LaboratoriesAir Force Systems CommandEdwards AFB, Ca 93523
0 FIFTH PROGRESS REPORT
0STORABILITY INVESTIGATIONS
OF WATER STORAGE EVALUATIONAFTER SEVEN YEARS
Aerojet Liquid Rocket CompanySacramento, California
DTICE. M. VANDER WALL E,•LECTE
G. R. JANSERMA
A
APPROVED FOR PUBLIC RELEASE DISTRIBUTION UNLIMITED
A
When U.S. Government drawings, specifications, or otherdata are used for any purpose other than a definitelyrelated Government procurement operation, the Governmentthereby incurs no responsibility nor any obligation what-soever, and the fact the Government may have formulated,furnished, or in any way supplied the said drawings,specifications, or other data, is not to be regarded byimplication or otherwise, or in any manner licensing theholder or any other person or corporation, or conveyingany rights or permission to manufacture, use, or sell anypatented invention that may in any way be related thereto.
FOREWORD
This report covers the work performed under Contract F04611-72-C-0062,"Storability Investigations of Water," performed by the AeroJet Liquid RocketCompany at Sacramento, California, and conducted under Air Foice ProjectTask 305911 VD. The performance period covered from 1 October 1979 to30 September 1980.
The program manager is R. L. Friedman; the project manager isDr. E.M. Vander Wall. The experimental work was conducted by Dr. Vander Wall;R. L. Beegle, Jr., senior chemist; J. A. Cabeal, senior chemist and G. R. Janser, Ametallurgy specialist. *
The program was administered under the direction of the Air ForceRocket Propulsion Laboratory, Mr. Herman Martens, Project Engineer.
This report has been reviewed and is approved for release inaccordance with the distribution statement on the cover and on the DDForm 1473.
Herman Martens Torrest S. Forb1es, ChiefProject Engineer Propellant Systems Section
For the Commander
Edward E. Stein, Deputy ChiefLiquid Rocket Division
4
i'
UNCLASSIFIEDIRUcRITY CLASSIFCATION OF THIS5 PAG9 (W*7wn Dale Enhured) ___________________
~8. CONTREAT)ISRCTIOORAT N SME~~
S.PR(RING EORANAT DOCUNMEANDTADDREN PAG. BEROGRAM ELOMPENTN PROJETMAS
A Nro Be Liui Rocke CoCEpany AO3.REAI RKUI UMB ERS
II. COTRLLN OFIC NAME ANDE R ADRS 12R REPOR DAT
Airtorceiit RockestiPrpulions ofbWater,/K / ecme ~Stdrards Evaluatornl 93523 See66ara h:
Di t ib t o
ilitni
ed
O7 DS RIBTO STTEEN CONRAC thR GbRtANc onNUdM Bok 0BIEifeen ra ot
IS. rUPEETR NOTE
S9 KE OD Cniu nrvread fneesr n dniyb lc ubr
inWaer PERFRMct OGNZTON NMicoraEm oND ADDRer Str 0.ly FlOGd/M EEETeRiJCTalS
0. AeSrACet CeLiquide Roevre idit Companry en detfyb lokubrSacraeno oeCaifeorntis 9r5gr3 isto2he at ha wl pritte i
ArForce tocksemnth Prplson-tr storager/L chDetcembs f aer6, prtclal
14 , MONITORIN AtorgeC o wAE& atDESfdfer enor frema Coatrollngirafice) 15 SCURITY CLASSo this repot)r
17.D ISTRIBU TION STAEM N (of, nth abtrc entere In Bloc 20, It diffren from Report)
19,~~~~Icu[ KE WOLD (Continu on revrs sid IfI neesar and identify by~t bloc mu
UNCLASSIFIED . ... .. . ....
°sacUNIgTY CLASS? "'CATION OF THIS3 PA~G("n2~ Does ftn'.twa)
Abstract (cont)Inconel 718 (aged); 6AI-4V titanium (STA). Two types of water Are used in theprogram: 1) oxygen-aturated, delonized, filtered, and 2) o .. deion. .s • , , L u r l t e r e J , e l o l z e d . . . . .. o x y g e n - f r e e , d e i o n i z e dfiltered, Using the filtered, deionized waters, ten-year storage tests havebeen initiated in 304 and 17-4PH stainless steel, A-286 (aged) steel, Inconel718 (aged) and 6AI-4V titanium (STA) containers.
Evaluation of water and containers stored for seven yearb has beencompleted. The data show that both oxygen-saturated and oxygen-free watercan be stored in appropriate metal containers for the selected time periodswithout detrimental particulate matter formation or sienfiFcant ch~ugs inthe quality of the water. It 4. 1:1 cxŽ:!i.ent condition for transpiracioncoolant pr-rT.es.
SECUgRIY CL ASSIFICATON OF THIS PACEC,4h,. Pats Fio~
WWWAS ag
TABLE OF CONTENTS
Page7-
I. Introduction 5 ii-3II. Experimental Results and Discussions 7
Background Information 7
A. Materials Selection 7
1. Waters 7
2. Mercls 7
B. Container Sterilization and Filling 8
C. Storage Conditions 9
Water Characterization 9
A. Procedures 9
B. Discussion of Results 10
Biological Characterization 16
A. Procedures 16
B. Discussion of Resul 17
Container Examination 19
A. Pro.zedures 19
B. Discussion of Results 19
1. General Visual Examination 19
2. Metallographic Examination 25
3. Implications of the Results of the Examination 36
III. Conclusions and Recommendations 37
A. Conclusions 37
B. Recommendations 37
Appendix A Fabrication and Treatment Procedures for Water 39Containers
Appendix B Silting Index Measurement 5"
C..
1 i t .- I't'; '
9. . . ..t+1. 4 .
TABLE LIST
Table a
I Data Indicative of the Storability of Water in 1]304 Stainless Steel Containers
2 Data Indicative of the Storability of Water in 12A-286 Containers
3 Data Indicative of the Storability o' Water in 136AI-4V Titanium Containers
4 Data Indicative of the Storability of Water in 14Inconel 718 Containers
5 Data Irdiccirive of the Storability of Water in 1517-4PH Stainless Steel Containers
6 Summary of Container Analyses 30
2i
4
:i4, • . .... 1 .. . .I • " . . .... . ..
LIST OF FIGURES
Figure No. age
1 304 Stainless Steel Container3, Magnification 1/3X 21
2 A-286 Containers, Magnification 1/3X 21
3 17-4PH H-1025 Stainless Steel Containers, 22Magnification 1/3X
4 Inconel 718 Containers, Magnification 1/3X 22
5 6A1-4V Titanium Containers, Magnification 1/3X 23
6 Interior of 304 Stainless Steel Containers, 24Magnification 3/4X
7 Interior of A-286 Containers, Magnification 3/4X 25
8 Interior of 17-4PH H-1025 Stainless Steel 26Containers, Magnification 3/4X
Interior of Inconel 718 Containers, Magnification 3/4X 27
10 Interior of 6Al-4V Titanium Alloy Containers, 28Magnification 3/4X
11 Weld Crack in A-286 Container, Magnification 14X 32
12 Adherent, Agglomerated 17-4PH Stainless Steel Particles 32Found in the 17-4PH Stainless Steel Containers,Magnification 14X
13 Weld Crack in Inconel 718 Container, Magnification 14X 33
14 Isolated Pickling Attach Around Areas of Contamination 33in Titanium 6A1-4V Container, Magnification 14X
15 Photomicrograph of Weld Crack in A-286 Container, 34Magnification 10OX
16 Photomicrograph of Localized Pickling Attach at Edge of 34Inconel 718 Weld, Magnification lO0X
17 Photomicrograph of Weld Crack and Shrink Porosity in 35Inconel 718 Weld, The Weld Surface (Top) ShowsInterdendritic Attach from Pickling, Magnification 10OX
3 1
A
SECTION I
INTRODUCTION
Inherent in the concept of transpiration cooling is the requirementthat the coolant remain free of particulate matter which may clog the pas-sages of the cooling surface. The object of the "Storability Investigationsof Water" program is to gather data that will permit the Air Force to assessthe long-term storage characteristics of water, particularly with regard to
formation of particulate matter. This report is the fifth progress reportto document the experimental results from the eighty-four month storage testsof water in selected metal containers for the ten-year program conductedunder Contract F04611-72-C-0062.
The five metallic materials used for container material in the programare: J
304 stainless steelA-286 (aged) steel17-4PH (aged) stainless steelInconel 718 (aged)6A1-4V Titanium (STA)
Two types of water are considered in the program:
oxygen-saturated, deionized, filtered water andoxygen-free, deionized, filtered water
Three categories of tests are used for obtaining the data necessaryfor assessment of the storability of water. They are:
Water Characterization
Biological CharacterizationContainer Examination
SThe investigations which led to the selection of the candidate metallicmaterials for tankage for use in the ten-year storage of waters are reportedin AFRPI.-TR-73-94 "S:ORABILITY INVESTIGATIONS OF WATER," VOLUME I: EXPERI-
MENTAL STUDIES, FINAL REPORT, Aerojet Liquid Rocket Company, Sacramento,California, December 1973. The results from the first year of storage arereported in AFRPL-TR-74-76 "STORABILITY INVESTIGATIONS OF WATER, LONG TERM
STORAGE EVALUATION," FIRST ANNUAL REPORT, Aerojet Liquid Rocket Company,Sacramento, California, December 1974. The results from the second year ofstorage are reported in AFRPL-TR-75-62 "STORABILITY INVESTIGATIONS OF WATER,LONG TERM STORAGE EVALUATION," SECOND ANNUAL REPORT, Aerojet Liquid RocketCompany, Sacramento, California, December 1975. The results from the thirdyear of storage are reported in AFRPL-TR-76-95 "STORABILITY INVESTIGATIONSOF WATER, LONG TERM STORAGE EVALUATION," THIRD ANNUAL REPORT, Aerojet LiquidRocket Company, Sacramento, California, December 1976. The results from the
S.1
i-
Introduction (cont.)
fourth year of storage are reported in AFRPL-TR-77-74 "STORABILITY INVESTI-GATIONS OF WATKR, LONG-TERM STORAGE EVALUATION," FOURTH ANNUAL REPORT,Aerojet Liquid Rocket Company, Sacramento, California, December 1977.
This annual repprt is presented in three sections: (1) Introduction,(2) Experimental Results and Discussions, and (3) Conclusions and Recommen-dations. In addition, there are two appendices provided for the convenienceof the reader: Appendix A, Fabrication and Treatment Procedures for WaterContainers, which documents the history of the tanks, and Appendix B,Silting Index Measurement, which describes a clogging tendency test.
6
SECTION II
EXPERIMENTAL RESULTS AND DISCUSSIONS
BACKGROUND INFORMATION
The purpose of the long-term storage tests is to demonstrate thatwater can be stored without formation of significant quantities of particu-late matter and with insignificant corroaion of appropriate metal containersfor time periods of at least ten years in a controlled envi-onment. Thebackground information is presented for the convenience of the reader and
documents the initial conditions of the selected containers and waters priorto the storage periods. The discussion is presented under the followingheadings: (1) Materials Selection, (2) Container Sterilization and Fillirig,and (3) Storage Conditions.
A. MATERIALS SELECTION
I. Waters
Based on the data derived from the preceding experimentalwork (Reference 1), it was apparent that both oxygen-saturated and oxygen-freewater were acceptable candidates for long-term storage tests. Further, thefiltration of the water through a 0.22 micron pore size absolute filter wasdemonstrated to remove microorganisms effectively. Thus, the water used tofill the containers was passed through an activated charcoal bed to removeorganic compounds and through two mixed-bed ion exchangers to obtain waterthat had an electrical resistance value of 1 megohm/cm or greater. The waterwas transferred through 0.22 micron filters into a 5-gallon stainless steelsupply tank. To ensure the saturation of the water with oxygen, filteredoxygen was putger through the water in the supply tank for a minimum of15 minutes. To obtain oxygen-free water, the water in the supply tank washeated to the boiling point of water for one hour while being purged withfiltered nitrogen obtained from the boil-off of liquid nitrogen. The tankwas then pressurized with the filtered r.1trogen, Allowed to cool to ambienttemperatures, and then repressurized with the filtered nitrogen. The outletof the supply tank was fitted with a Twin 90 Filter* unit to assure thesterile characteristics of -he water used to fill the storage containers.
2. Metals
The selection of the materials of construction for the long-term storage test containers was based on the results of the laboratoryinvestigations (Raference 1). The aluminum alloys were eliminated from
Ref. 1 E. M. Vander Wall, R. E. Anderson, G. R. Janser, StorabilityInvestigations of Water, Volume I, Experimental Studies,AFRPL-TR-73-94, Contract F04611-72-C-0062 (December 1973).
* A 0.22 micron pore size, absolute filter pack availablc from MilliporECorioration, Bedfuod, MA.
7
Sf"•.
A. Materials Selection (cont.)
consideration due to their introduction of insoluble corrosion products whichare a source of particulate matter in the water. Because test results on thvremainder of the seven candidate materials were rot discriminatory, choicewas made on the basis of selecting not more than one alloy from each class ofmaterial. The one class of material with more that one representative was the18% chromium - 8% nickel austenitic stainless steels, i.e., 304L, 347 andArde-form 301. Hence two of these materials were eliminated to provide thufive materials required for containe, fabrication. The 304L stainless steelwas selected due to its attractiveness as an expulsion bladder material. hence,the selected materials are: 304L stainless steel, A-286 (aged), 17-4P11 stain-less stoel, Inconnel 718 (aged), and 6A1-4V titanium (STA). Duilno fabri-cation, some 304 stainless steel parts were incorporated into the 3041.stainless steel containers, consequently identified as 304 stainless stevcontainers. The fabrication procedures, the heat treatment cycles, th-cleaning orocedures, and the passivation procedures to which the container'were subjected are presented in Appendix A of this report.
13. CONTAINER STERILIZATION AND FILLINC
Following the final rinsing with filtered, deionized water and thesubsequent drying of the containers in a vacuum chamber, the containpr, werewrapped with reusable sterilization paper. The wrapped containers were thensterilized in an autoclave at 2500F witl. 15 psig steam for 30 minutes, fol-lowed by a 30-minute drying period. The containers were then stored in thepaper to maintain their sterile condition.
All the steps required to fill the containers with water wereconducted in a sterile, laminar-flow bench. The tanks were removed from t'ewrapping paper in the laminar-flow bench. The tanks were weighed empty, tnenweighed when filled completely with sterile water to determine the totalvolume of the tank. The water was drained out and the tank was rinsed oncemore with the sterile water. A sample of the rinse water was checked for ph,conductivity, and Silting Index (see Appendix B). If the values indicatedthat particulate matter and dissolved species were not present, the tank wasconsidered ready for filling; if the values indicated that contaminants werepresent, the tank was rinsed until there was no evidence of contamination.A Silting Index value of 1 or less for the rinse water when using the filterwith a cross-sectional area of 1.0 mm2 was used as the criterion that nosignificant quantity of loose particulate matter remained in the containers.
Before the final filling with oxygen-saturated deionized water,the tank was purged with oxygen from a filtered, supply. The tank was thenfilled with the water and a sample was withdrawn for pH conductivity, andSilting Index measurements. The ullage was adjusted to the ten percent valueby weighing the container and Its contents; the ullage space was purged withthe filtered oxygen, and the container was capped with a sterile, taperedplug made from the same material as the container. The plug was seated in
L 8
B. Container Sterilization and Filling (cont.)
the fill-tube by use of a hammer. The containers were filled with the oxygen-free, deionized water in a analogous manner, except that filtered nitrogenInstead of oxygen was used for purging and blanketing tae container.
The final sealing of the containers was acLompI)lished by GTA-weldingthe fill-tube/plug interface. The welds were inspected visually for anyapparent anomalies. None were found. Then the containers were labeled forthe long-term storage test and placed in plastic bags.
The sampling plaii for the long-term storage tests is to I) removeone container of each material with the two types of water for inspectionand evaluation every six months for a period of four years, 2) evaluate oneset of containers after seven years, and 3) evaluate the remaining set ofcontainers after ten years. The contents will be characterized with respectto pH, conductivity, particulate content, and biological activity, and thecontainers themselves will be subjected to metallurgical examination if th,other test data indicate that this is required.
C. STORAGE CONDITIONS
The storage area for the wa1l.r contain.frs is an air-conditlonedroom which is monitored continuously to document thdt the temperature Is mclin-taj!aed at 70 + 100F and that the relative humidity is maintained at 50 + 25percent. The containers are stored in a closed metal cabinet to protect themfrom an accumulation of dust, and the couitainers themselves are covered withplastic bags to prevent direct contact with foreign metal surfaces. Thecontainers are visually examined on a weekly basis.
WATER CHARACTERIZATION
"After six-month intervals of storage at the conditions definedabove, ten containers are removed for evaluation. They consist of two con-tainers of each selected material, one containing oxygen-free water and theother containing oxygen-saturated water.
A. PROCEDURES
After the initial six-month storage period, the water containerswere washed with deionized water and then placed in a sterile, lami-iar-flowbench for further handling to remove the stored water. The outlet of the con-tainer was rinsed repeatedly with filtered, deionized water to remove any con-taminants and then briefly subjected to a torch flrine to sterilize the exteriorof the metal. In the subsequent six-month storage periods, the water cnn-tainers were immersed in a 95% ethanol bath prior to placement in the sterile,laminar-flow bench. Subsequent to their removal from the bath and placementin the laminar-flow bench, the residual alcohol on the tank surface was
,• • ::,l • ''i-•I|" rr ,
A. Procedures (cont.)
removed by burning. The outlet of the container was repeatedly exposed toa torch flame to assure a sterile condition. All the containers were openedin an identical manner. A sterile tubing cutter was used to sever the fill-tube. Foc the six-month, twelve-month, and eighteen-month storage periods,the water was expelled from the containers by inserting a sterile stainlesssteel capillary tube into the fill-tube of the container. Filtered, gaseousnitrogen was passed through the capillary tube while the container itselfwas kept inverted. The first several ml of water were used to flush thetr-be, then discarded. Subsequent samples of water were collected for measure-ment of pH, electrical conductivity, dissolved solids, particulate matter,flow behavior, and for characterization with regard to possible biologicalcontamination. Foc the twenty-four month and subsequent storage periods,special cannula were fabricated so that the water could be expelled fromthe container while it was maintained in its normal upright position. Thecyclic insertion and withdrawal of the cannula for the various samples wasavoided by controlling the nitrogen flowrate used to pressurize the con-tainer during the water expulsion.
The measurement of the pH was made by using a standard pH meterwith a calomel reference electrode and a glass indicator electrode. Theelectrical conductiviLty of the water was measured by using a LalsbaughConductivity Meter (Model No. 900-.01T) with a standard dip cell. Thecontent of dissolved solids in the water was determined by evaporating 200-300 ml samples of the water to dryness and then weighing the residue. Inaddition, any particulate matter which collected on the 0.8w filter of theflow behavior device was examined microscopically and sized. The flow be-havior of the water was evaluated by using a Silting Index Apparatus (seeAppendix B for description), which permits filtration of the liquid througha known area (1.0 mm2 ) at a constant pressure to allow recording of the flowdecay due to the presence of particulate matter as a function of time. Thestandard method of the test is described in ASTM F52-69. The data arereported as Silting Index values, i.e., the greater the value, the greaterthe degree of contamination by small particulate matter.
B. DISCUSSION OF RESULTS
The data obtained from the tests are presented in Tables I to 5.The data obtained during the initial loading of the containers, as well asthe Jata for the preceding storage intervals, are included in the tabula-tion to facilitate comparison and identification of trends. The baselinedata are labeled as initial, and the data obtained after the sturage periodsare labeled as final.
I0
4J,4.I 4.' .L u
CE co A VIR, Ci - zU "6-- 4-1 4, G CL
LI Uv L. 41 41 -41 U go L. '
C, 0, 4.i - .
L. w U CE GO r ' L. alU0 0
-o xE x 00 aL a.j o.UL~~ 0. g. m L . .. L0 i I. C-q~~ ~ W . LL ~
0 L v ( Q '
' c l 7C,*
L Ii 0-LnU ~ ~ E UU '
Z( c 7 7 7 7 77 - ++
M1 -, as -n A 'D VoCI-Y : i C m c ý 0 n1
'-5 D, C ý ý 6 C= ý C
CO mCUaM. n MS
5.. - -0 -
.~ 1 . C'.ý S' 7'. 0 0C
4' 41. 01 ('w 41CJ ( A 1 0 1LiL
-C~ Ciý 14 '~0) Cý (D (D C ) 0 C >0f
CD5 C5 0 CDi C
200
Go 0, (A 0' 0o 000
-C- - - - .-. --
00 ~ '
L J 4) 4)J ~ .
IV -i a, 4) 4j1.2
d) 4J 5
a9 CL L. I- L L.
LLL 4) 0.. -
' 0 C-1 S.. LIJ kI 41c4l4'
0.~~ + .2 22 1. L . S. 2'
cctcy. 5 ' - ~ a
2c 2 -j0. 0
K %O x ~ r- xVI 0' ~ I ~7,a7 X . ' 7C c
CD C> - <m Q5 0c r C:.) 0' ('D (' r,~ -ý C, C) 0 C, C
4a
'n -a I I , , , - CD v en .7 C> -- aD I
D 4 CD P.. 'mI C" CD* C". C, C; C; 0 -. u c u
31 In- 0 0 CD -D -n Q 3 C
r- C9 C9. - 0ý 09 Qc a' 0ý 9 lý
--'. -- -a -- cc - - 0 0- -
M L m Lu m I- I
'0 'D ('4 C C al C 0 0C D C CD 90
,A~.
10--4 U
0 - ~~ 0 ra ~ co ' 2 I'
12
ot
~~~~~e VI ~ 1-U ~ 0 4-' U L 41 4. i (v c U u
4) U. , Z. m ) 1 4
-2 'Co A, - C'a '
'.+ + +; + + +a + u 0 ~ - 0 ~0 - ~ -
exa ~ . LI 4-I LV V%-'. u ~ ~ 4' L 0 I 4. 04 0) 04 0) L 1. V .
01 VI IC IC 01 LO 0%L - 10 ~ 0 1 0-0 0 : 0 a -- : - - ~ - :
06 q
IA. 0 ) -n Cl CD 0 Q C I 0 II C: I
U. j-J - ;AW t
U.1 0 - -0 CD - I C> - -Q - - -
44 4
0600
C) 0) CI v 0 C, 0 0 0 - - 0 0 0
w rI 0 -' 0 %0 0b CQ co1 00 "
1.cm 0 M~ en l 0
rQ k1 fnV V0 CO -,Q a,9 0 N N
001 0 N - LIe - -13
'V -0LT 41 !ý TVU a G )
*-' 'A In~ cna
'u Z Mu au m 'u!I <- m. co -M Cc0.
06 a accQ~-~~ -~~~ af*l~u ~ u 0 - V '
CD0 0. 0-1 R G 0 G D r0 000 fn a1 0C, N 0 Na 4. Lc.- *i L.-41 44 41 al m0% CJL C SJ a, ZC ;, ;. 7& & -a -a -a D.
cm~ ~ ~ -W 49 4E 4c - C c
0*-cm 34
w. 'A o > 'n
Za) 4C ~ ' -a- -
41 41~ - 4 0 an - 0 al 03~~~C C3a C, N D 0o, UZ 0! o- o 0D 0, 0, C) Cý 0ý 0> C 0
La 0> a41 Q
en ,- Lo en N a a ,
05 0; C C;o C:;
0- 0 - 0, 0m
0: C) C, C: 0 m a
$4 - -
* z
CD Q- C.... ..... 0 0 0 0 CD C
a. a I.. ~ 14 L.14
Ih 4)0I
0 4 U
41 LI m 41 0 .
IQ4 CN -ý m 4 m-~t 41 414 r-CC L 1
L) cu 1S* .2- c4 M4
Le I. . w- 4 41 a) cm (1 41 41 ICA, U 4) 4
,Z Z4 Z. 6flU a4 fa1 4 42.t -. , -.. 4 4
.- LJ.-.-C \J c' U -. a -l-.) 4.1 .-L S ' 0c, -S .1w, C1 ~ 1 ~ 1 ~ .1 0
.La Za7 ul 7~v
C.- " IC 1. a, C I n C, I I
CD ~~~~4 -ý CDJ Qn CDI 0 Qn 4)0 0D
C5 0 0 a CD CD0
51 C4J 09 -: 9
a 0 eý c- n CD o
~ui ~ - 0 0- - -0 0 0 - .- 0 - - 0 0
9A o 9 0 09 (Z' 0ý In Cn 0ý I n I
qu I-. w I
m4 - a I n, 14, 0" Ic. 1ý a' N I a I , 0 'N
0 C C) C) rD 0 CD CD Cý 0, C C3 0 Cý ) C
10-1 &AL O 6 1
(' C. n C..aL c - I- 1' -L In L -L . L -L L
B. Discussion of Results (cont.)
The significant items to be noted from the data are as follows:
First, the pH values of the waters change slightly during the storageperiods. If the values are averaged, the following pH values are obtainedfor the various containers used:
For storage in 304 stainless steel containers, thepH value increased 0.2 for the oxygen-free water and0.3 for the oxygen-saturated water.
For storage in A-286 containers, the pH value did notchange for oxygen-free water but did increase 0.2 foroxygen-saturated water.
For storage in 6AI-4V titanium containers, the averagepH value is unchanged for oxygen-free water and increased0.2 for oxygen-saturated water.
For storage in Inconel 718 containers, the pH valueincreased 0.4 for oxygen-free water and 0.2 for oxygen-saturated water.
For storage in 17-4PH containers, the pH value increased0.3 for oxygen-free water and 0.3 for oxygen-saturated water.
Secondly, the resistance values of the waters have stabilizedafter the initial decrease in values due to an increase in concentration ofionic species, and the final resistance values still correspond to concen-tration levels which contain less than one part per million of dissolvedmetallic ions.
Third, the Silting Index values indicate the presence of aslight amount of particulate matter in the size range of less than 5 micronsIn the water, but the concentration levels are insignificant with regard tothe quantities of particulate matter that are required to cause cloggingin flow passages. In addition, the concentration level of particles inthe less than 5 micron size is not increasing with increased periods ofwater storage.
Fourth, there is apparently no increase in the total solidscontent of the waters as the period of storage increases; the valuesobserved are sufficiently low so that the quality of the water is notimparied. The level of detection in the method used corresponds to amg/lI.
16
A _ __ - - - - = - -- - - - - - - - .
B. Discussion of Results (cont.)
Fifth, the pH values, the resistance values, and the SiltingIndex values are not significantly different between the various storageperiods.
The particulate matter collecting on the filters appeared to hethat which adhered to the container walls during the cleaning, pickling,passivation, and flushing procedures prior to filling. In summation, thewaters were all suitable for use in transpiration coolant devices afterwater storage periods of up to eighty-four months.
BIOLOGICAL CHARACTERIZATION
A. PROCEDURES
200 ml samples of the water taken from the storage containerswere filtered through pre-sterilized filter pads which were transferreddirectly to sterilized Petri dishes contiining suitable nutrients for directcolony counting after a suitable culturing period. The procedures aredescribed in Standard Methods of Analysis of Water and Waste Water, AmericanPublic Health Association, 13th Edition (1971) and Biological Analysis ofWater and Waste Water, AM 302, Millipore Corporation, Bedford, Mass. (1973).In addition, any biological organisms present were washed from the filtersurfaces with a sterile buffer solution and placed directly in sterile nutrientsolutions for culturing. This Is to assure that adequate samples areavailable for identifying the genus and the specific species of micro-organisms that might be present in the stored water. Based on the lag-period,prior to growth, of microorganisms which has been observed earlier in theprogram (Reference 1), the tubes containing the nutrient solutions were Lincubated for periods of up to one month.
B. DISCUSSION OF RESULTS
The results obtained by culturing samples from the water contain-ers are presented in Tables 1 to 5 under the heading "Biological Activity."The lack of any indications of microorganisms being present is denoted by a,minus sign. If growth was indicated in either the culture tubes or on thefilter pad, but not on both, an "X" is used. If growth was found in boththe culture tubes and on the filter pad, a plus sign is used as an indicationof the positive result.
After a month of incubation of the samples from the six-monthstorage tests, there was no indication of microorganism growth on the pre-sterilized filter pads. Slight growth was observed in the culture tubescontaining washings from the 304 stainless steel and one of the A-286
17
I
B. Discussion of Results (cont.)
containers. The number of microorganisms present was extremely small, asindicated by the negative results with the filter pads and the slight amountof growth in the culture tubes. There was no evidence that any biologicalgrowth occurred during the six-month storage period. The microorganismsfound were identified as an Aeromonas species.
After a month of incubation of the samples from the Lweive-monthstorage period, one of the culture tubes containing the washings from anInconel 718 container exhibited growth, but the filter pad was negative. Themicroorganisms present were identified as most likely being Pseudomonasaeruginosa. The filter pad used for culturing the contents of both of the17-4PH, one of the 304 stainless steel and one of the A-286 containers exhibitedgrowth, but the corresponding culture tubes were all negative. The micro-organisms were identified as a Pseudomonas species. Again there was noevidence that bioloRical growth occurred during the twelve-month storage period
in any of the containers.
After a month of incubation of the samples from the eighteen-monthstorage period, there was indication of microorganism growth on the filter'pads and in culture tubes containing samples from one of the 304 stainlesssteel, one of the A-286, and one of the 17-4PH containers. The microorganismswere identified as a Pseudomonag species. The number of organisms present
was extremely small, and there was no evidence that growth occurred during the
eighteen-month storage period.
After a month of incubation of the samples from the twenty-four
month storage period, there were indications of microorganism growth on thefilter pads and in the culture tubes containing samples from one of the 304stainless steel, both of the A-286, both of the 6A1-4V titanium, and one of"the 17-4PH containers. The microorganisms were all of the same species and,based on the classifications used in the 8th edition of Bergey's '"anual ofDeterminative Bacteriology," were identified as most likely being Pseudomonasteslosteroni. In this edition, much of the former genus Aeromonas is nowincluded in the genus Pseudomonas, and therefore the microorganisms observedin the two samples (f the six-month storage period may be the same speciesas those identified in samples from the twenty-four month storage period.
The number of organisms present in the samples from the twenty-four month storage period waq extremely low, less than 100 per ml of water,and there was no evidence that growth occurred during the storage period.The fact that all the organisms are of the same species indicates that theywere probably introduced during the fill procedure and that the improvedwater removal procedure reduces the possibility of contamination during thesampling procedure.
8
I.N
B. Discussion of Results (cont.)
After a month of incubation of the samples from the thirty-monthstorage period, there were indications of microorganisms present on thefilter pads and in culture tubes containing samples from both of the 304stainless steel, one of the A-286, one of the 17-4PH and both of the6AI-4V titanium containers. The number of microorganisms present was small,and there was no evidence that any growth occurrea during the thirty-monthstorage period. The microorganisms present were identified as a Pseudomonasspecies.
After a month of incubation of the samples from the thirty-sixmonth storage period, there were indications of microorganisms present onthe filter pads and in the Lulture tubes containing samples from one of the304 stainless steel, one of the A-286, one of the 6AI-4V titanium and one ofthe 17-4PH containers. The number of microorganisms present was extremelysmall, less than 2 per ml, and they were identified as a Pseudomonas species.
After a month of incubation of the samples from the forty-twomonth storage period, there were indications of microorganisms present onthe filter pads and in culture tubes containing samples from one of the 304stainless steel, both of the A-286, one of the 6A1-4V titanium, and one ofthe 17-4PH containers. The number of microorganisms present was small, andthere was no evidence that any growth occurred during the forty-two monthstorage period. The micororganiams present were identified as a Pseudomonasspecies.
After a month of incubation of the samples from the forly-eightmonth storage period, there were indications of microorganisms present onthe filter pads and in the culture tubes containing samples from one of the304 stainless steel, both of the A-286, one of the 6AI-4V titanium, and oneof the 17-4PH containers. The number of microorganisms present was small,and they were identified as a Pseudomonas species.
After a month of incubation of the samples from the eighty-fourmonth storage period, there were indications of microorganisms present onthe filter pads and in the culture tubes containing samples from one ofthe 304 stainless steel containers, one of the A-286, one of the 6A1-4Vtitanium, and one of the 17-4PH containers. The number of microorganismspresent was small, and they were identified as the Pseudomonas specieswhich had been identified in the previous storage periods. From the slightgrowth which was observed in the culture media, it can be inferred that themicroorganisms are in a weakened condition.
In summation, the biological testing has shown that there is noevidence for any bioligical growth during the storage periods even thougha slight number of microorganisms were introduced duriiig the fillingprocedures.
19 1
CONTAINMR EXAMINATION
A. PROCEDURES
After removal of the water from the containers by draining, theywere vacuum-dried for a day to insure sectioning in a dry condition. Thecontainers were then photographed to docwnent their general appearance.Sectioning of the containers to expose the internal surfaces was accomplishedby sawing without coolant to prevent contamination other than from sawingdebris. Subsequent handling of the container halves was carefully per-formed to avoid touching the interior surfaces. After removal of the debrisgenerated by sawing, the internal surfaces were then eamined with topunaided eye and photographed to document their general appearance.
Visual examination of the interior surfaces at magnifications from5 to lOX were conducted to define conditions found in the aforementionedvisual examination and to reveal areas requiring additional examination atmagnifications to 40X. All welds were examined at 40X magnification.Representative discrepancies were photographed at magnifications adequatefor defect definition. Those defects requiring further definition wereexamined metailographically to establish their cause and extent. Sectionstaken either through or immediately adjacent to the affected areas weremounted, polished, and examined. Photomicrographs were taken to documentthe condition. All interior surfaces were dye-penetrant inspected todeLue•ine whether any defects were undetected during the visual examination.
B. DISCUSSION OF RESULTS
The results of the container examinations are discussed underthree headings: (1) General Visual Examination, (2) MetallographicExamination, and (3) Implications of the Results of the Examinations.
1. General Visual Examination
The external appearance of the containers is documentedphotographically in Figures 1 through 5. The internal appearance of thernntainers is documented photographically in Figures 6 through 10.Examination of these surfaces without visual aids showed full penetrationfor the full length of all weldments. Other conditions resulting fromfabrication and cleaning procedures were as follows: (1) Pickling smut onthe interiors of the 17-4PH stainless steel and Inconel 718 containers;(2) an adherent agglomeration of 17-4PH stainless steel particles in the17-4PH stainless steel containers; (3) knifeline attach at the edge of theInconel 718 welds as a result of pickling; (4) etching of the parent metaland welds in Inconel 718 containers and of the welds in the 17-4PH containersas a result of pickling; (5) residual oxides from heat treatment in theA-286 and titanium 6A1-4V containers; (6) rough surface of the 17-4PHstainless steel containers as a result of scale removal during pickling; and
(7) stains and localized pickling attacks around areas of pre-heat-treatmentcontamination.
20
!,- , --Ii - i l i i ! | i i i i ! i ! i i -[ i --
-Lae
No. 15 No. 18
Figure 1. 304 Stainless Steel Containers,Magnification 113X
No. 16 No. 17
Figure 2. A-286 Containers, Magnification 1/3X
r[
:.1
No. P9 No. P19
Fiq,'re 3. 17-'1 I 10H Staitile.s Steel,Cnriraine rs, Mdgn ification 1/3X'
3I
r ,
No. 16 No. 18
Figure 4. Iru,(o1 7P1. Contai lor;,'arn i c La t ifr 1,.3):
ohm-
- =
No. 16 No. 18
Figure 5. 6AI-4V Titanium Containers,Magnification 1/3X
23
21 _ ____ ____ _ __ ____ __ _ ______ _ 1
ii
, N
ý0O. -It No. 18
FIr~tericr cf 3!;' "tdjinless Steel Cont-anc, aifctn3.X
24
No 6N .17. Itju i -3 u tanr ,Mgiia in34
)f25
0o P9 N D
'J';ri c of '-lPil[A - 1025 St a in I L- St~eel Cu to nerMa cin if jit i ,n 3/ 1X
26
0
* 4-
LC)w
vKC
O 4-.
.1 r
CD
lost- -0
B. Discussion of Results (cont.)
No significant differences were apparent between the six,twelve, twenty-four, thirty, thirty-six, forty-two, forty-eight, and eighty-four month exposure containers, or between those holding the oxygen-free andoxygen-saturated water.
2. Metallographic Examination
A summary of the analyses performed on the containers ispresented in Table 6. The results of the macro- and micro-examinationsare shown in Figures 11 and 17. The results of the analyses are discussedbelow for each container material.
a. 304 Stainless Steel
The interiors of the containers were in excellentcondition, exhibiting no significant defects.
b. A-286
One weld shrinkage crack was found in the two con-tainers. This crack, which is similar to those found in previously examinedcontainers, is shown in Figure 11. A photomicrograph of the crack is shownin Figure 15. Light residual oxide remains at the top of the containersafter pickling. The oxide appears as the dark area on the left side of the
container in Figure 7. No evidence of corrosion resulting from the storageof water could be found.
c. 17-4PH Stainless Steel
These containers exhibited the same conditions found inthe previously examined containers, i.e., smut, roughening of the interiorsurfaces due to scale removal during pickling, and tightly adherent agglo-merated 17-4PH stainless steel particles which are deposited in isolated areasof corrosive attack by pickling. These particles have been previouslyidentified as 17-4PH stainless steel; like smut, they are considered to bereaction products of the pickling operation. This condition is shown inFigure 12. No evidence of corrosion from the storage of water could befound.
d. Inconel 718
As with the previously examined containers, examinationof the interior surfaces at modernte magnification revealed knifelinecorrosive attack at the edge of all closure weldments. ThIs condition,which is attributed to pick'ing, is shown in Figure 13 as the dark line atthe bottom edge of the weld. A ph-tomicrograph of a section taken through
29
U 0
fO4-'1
4-)n
00 E 00 0 0
c1 u . r . -. .. . . . . . *.jI 0 0000 0 0 0.:.-' Z*- * . , .
o4-)cn-
ccU(- 1
L) 0 - >>4- > 1 4
U- 4)- S aJ * )LA.)v V) a) U-V .- 0. 0. .
IM Z()a ) (/10V)0 L 0 C ) )J 4- A-- vvC4 4V-) 01 ) 4Z 'Z Z - .- -~ - : 00 : L) M~ 0)M -O J U 10) CA M - g
LL. c C C C: 0 M 4J- (1) 0 M4JS-() 0 10 -j S- ) 0 M 4ý- 4-)OLL . - U0.( - UL L ui cu. 0-
< 4-41 + L.O 0 A Li.. LL- e) E U LoEU E/ aA uLn D C -_A:LA 0 .- EL0Ar ES.A A 0
4-'-
C: CIC
c03
U
41 V) U)U)
Z 4J ~0 4-1
c 4)4 - 4-J
a ) u 'U- - V
0 -~ w ~C
g C 0
c 4-'
v xU
4C Q)~ 41)
uC. C 4 ) 4J .CC
U If)i CV0C 4-CJ
GJ -0
L-*.-4 4a v - Q)M
5~~+J ý - 4-.' -C 4J 4 C *--
0 ' C .C . i .4U 4-' 4 -'0
0' . 0 -ccU 0- 0 600) V U ~ 4
C ~ ~ ~ ~ ~ 1 'UU U
doV cu- ea~~ 4~~ 's~-- ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ a 0.. . 0.- . . U E.. - U.-) %- (D o0 41 ~ - C: 41 =C
0.) ) C 4) - (- ~CL 0 Ia. E fa... 4- 4-' 1 t-'VEw
=C Sc
*0 "0C) 0J cn) >
P-~1 c*- <U
W LAJ t w .0V..-'o in) U)II0 -4) 1t 5- 4' 1CL0 -- -
- () O
4)~~~~~.1). a) Wt -M.
I :C E c -4'-) i)
E 4) 4.9,a
o0 -MC -- a m + o4Cz C 0- L-C._= o =
IE ~~~~~~ ~ . 4'c
4-)%- 4 ox I t 1 L
(U 0.CU
C 441 .-
C O0c>
CV00)
) 00
31
inr-4
Figure 11. Weld Crack in A-286 Container,Magnification 14X
Figure 12. Adherent, Agglomerated 17-4PHStainless Steel Particles Foundin the 17-4PH Stainless SteelContainers, Magnification 14X
32
Figure 13. Weld Crack in In(ýorel 718 Container,Maqnif ication 14~X
Figure 14. Isolated Picklinq Attack Around
6A1-4i Contariner, Maqriifmdion 14X
33
IVI
A-9
Figure 5. Photomicrograph Of Weld Crack iA-286 Containerý Magnification 100X
Figure 16. Photorn)cropraph Of LocalizedckMirý MttaCK at Edge ofInconel 718 Weld, Manification 700X
34
Ipp
XF
u ~.1 L
Figure 17. Photomicrograph of Weld Crackand Shrink Porosity in Inconel718 Weld. The Weld Surface (Top)
Shows Interdentritic Attack from
Pickling. Magnification IOOX
35
H=
B. Discussion of Results (cont.)
this area is shown in Figure 16. The one weld crack found during the exam-ination is shown in Figure 13. A photomicrograph of the crack is shown inFigure 17. The photomicrograph also reveals interdendritic attack frompickling at the weld surface and shrink porosity in the weld interior. Thecontainers displayed a tightly adherent smut as a result of pickling. Noanomalies attributable to water storage were found.
e. Titanium 6A1-4V
The container interior surfaces exhibited small Isolatedareas of light-blue oxide and stains and corrosive attack from pickling aroundareas of contamination present during heat treatment. The residual oxidesformed during heat treatment (aging) in air and were not removed duringpickling. It appears that the presence of contamination during heat treatmentcontributed to oxide resistance to removal by pickling. As shown in Figure 14,some contaminated areas produced corrosion attack on their periphy duringpickling. All defects found in the containers are due to inadequate cleaningprior to heat treatment. No effects attributable to the storage of water werefound.
3. Implications of the Results of the Examination
Discrepancies found in the internal surfaces of the con-tainers were due to fabrication and cleaning procedures rather than thequality of the stored water. The discrepancies were the same as thosefound In previously examined storage containers. The most serious of thesediscrepancies, with regard to influencing the function of the containersfor storing transpiration coolant water, is the generation of a smut onthe Inconel 718 and 17-4PHstainless steel during pickling. However, noneof these irregularities have produced particles of sufficient size andquantity to degrade the functional quality of the water. The primary causeof these conditions is attributed to poor inert gas coverage on the container
interiors during heat treatment and to the resulting excessive oxidation.
The presence of contaminants in the titanium alloy con-tainers prior to heat treatment and in tho geld cracks found in the A-286and Inconel 718 containers is attributable to inadequate process control onthe part of the container supplier. In spite of the presence of the con-taminants, the functional quality of this water was not impaired.
36
A5.1r
SECTIO TI1
CONCLUSIONS AND RECOMMENDATIONS
A. CONCLUSIONS
The following conclusions are drawn from the eighty-four monthstorage evaluation program.
1I. All five container materials, 304 and 17-4PH stainless steels,
A-286, Inconel 718, and 6AI-4V titanium, are suitable for the storage ofwater for transpiration cooling purposes.
2. Both the oxygen-free and oxygen-saturated waters demonstratedfavorable storability characteristics with regard to pH changes, ioniccontamination as evidenced by electrical resistance measurements, and particu-late formation as evidenced by Silting Index values and microscopic inspectionof filters.
2. Xed on the biological tests, there is no Lvidence thatbiologi..al growth has occurred in the containers during storage periods upto eighty-four months.
4. Discrepancies in the containers, such as cracks, smut andetched surfaces, were produced during fabrication, cleaning, and passivationof the containers. Yet with adequate flushing prior to storage, the storedwater is suitable for use as a transpiration coolant.
B. RECOMMENDATIONS
i. Long-term storage tests should be conducted with the selectedwaters in contain 's in which dissimilar metals are present to demonstratewhich combinations of metallic macerials can be used as suitable componentsin a transpiration coolant system.
2. The ease of fabrication, cleaning, and passivation of con-tainers should be given proper priority in the selection and design of
container materials for transpiration coolant devices.
3. Long-term storage tests should be conducted with the selectedwaters in containers which contain non-metallic materials which may be ofuse in the fabrication of transpiration coolant systems.
371
i.
L -
APPENDIX A
FABRICATION AND TREATMENT PROCEDURESFOR WATER CONTAINERS
39
39
?A~iB~AlIK~~arTI 1J~.
FABRICATION AND TREATMENT PROCEDURESFOR WATER CONTAINERS
The fabrication procedures, the heat treatment cycles, the cleaningprocedures, and the passivation procedures for the water containers prior tofilling are presented below.
A. CONTAINER FABRICATION
Drawings of the long-term storage container and its associatedweld tooling are shown in Figures A-1, A-2, and A-3. The sequence of opera-tions in the container fabrication is as follows:
1. Cylindrical Tube, -1
a. Fabricate -1 cylinder tube by rolling the sheared sheetstock into the desired diameter.
b. Weld the lingitudinal joint using the automatic GTA*welding process. Full weld penetration must be obtained using gas backupfor the welds.
C. Dye-penetrant inspect welds, then trim tubes to requiredlength. No cracks allowed.
d. Machine tube ends for weld joint preparation.
e. Clean tubes and store in appropriate container whileavtiting next assembly.
2. Fill-Tube, -2
a. Section fill-tubes to 6 + 0.12 in. lengths.
b. Deburr fill-tube ends and inspect.
c. Clean fill-tubes and then package individually andstore for next assembly. V
3. Tank Head, -3
a. Blank tank heads to the desired diameter by punching orsawing and then machining.
b. Machine weld joint preparation at cuter edge asrequired.
c. Drill the fill-tube hole to mate with the fill tube.
*Gas Tungsten Arc
41
FMOID.UI PAGE BLANX-IiOT FI li-LD
J •Y
-_l
0 4
00S +1
CD
< 0
C)C+10tn-
o4
InI
I-
LLL
43J
Cu EXPANDING FILL-TUBEHEAT SINK FIXTURE
Cu
TANK HEAD
TANK HEAD TOFILL-TUBE HEATSINK FIXTURE
GAS PURGE TUBE
Figure A-3. Weld Tooling for Fill-Tube to Tank Head Joint
44
A, Container Fabrication (cont.)
d. Counter bore the tank head on one side at the fill-tube
hole for weld joint preparation.
e. Inspect tank heads, clean and package.
4. Tank Endt -4
a. Perform operations 3,a, 3,b, and 3,e as above.
5. Assembly Sequence
a. Assemble -2 fill-tube into -3 tank head using appropri-ate weld fixture and tooling.
b. Weld root pass on grooves side without weld filler wireby the automatic GTA welding process.
c. Clean root pass by rotary wire brushing using a cleanstainless steel wire brush.
d. Weld the cover pass using the appropriate weld fillerwire.
e. Reposition the part in the weld fixture and then place
a filler weld at the fill-tube to tank head junction.
f. Inspect welds and clean part.
g. Fixture tank head assembly ulth -1 tube for weldingand purge tank with Ar or He.
h. Weld root pass without the use of weld filler wire.Full penetration must be obtained at the ID of the joint.
i. Dye-penetrant inspect and clean root pass. No cracksallowed.
J. Fill weld groove uaing the appropriate weld filler wire.
k. Inspect and clean the inner tank surfaces.
1. Locate the tank end to the tank for welding, then purgethe closed tank with Ar or He.
45
A, Container Fabrication (cont.)
M. Make the root pass without the use of weld filler wiretc insure full penetration.
n. Clean root pass surface.
o. Inspect the internal weld penetration using a bore-scope. Full weld penetration is required.
p. Run weld cover pass using the appropriate weld fillerwire.
q. Clean, inspect, and package unit for shipment.
Heat treatment of the containers was performed in an argon Aatmosphere, and with one exception, as noted below, utilizing the thermalcycles listed in Table A-I.
Upon receipt of the tanks, the certifications were examined,and it was found that some of the material used to fabricate the 304L stain-less steel containers was actually 304 stainless steel. With the concurrenceof the Air Force, the containers were subjected to a heat-treatment at 1925*Fin hydrogen, followed by rapid cooling to preclude sensitization in the weldheat-affected zone.
B. PREPARATIVE PROCEDURES
1. Container Cleaning and Passivation
All the containers were degreascd by submerging and agitatingthe tanks three times in fresh isopropyl alcohol. The containers were thenpurged with dry, filtered nitrogen and placed in a vacuum chamber for finaldrying. The A-286, 17-4PH stainless steel, and Inconel 718 containers were Athen subjected to an alkaline descaling treatment for 60 minutes with KeliteNo. 235 at a concentration level of 32 oz per gal at 190'F. The containerswere then rinsed with water at 150OF for 2 tc 5 minutes, followed by a rinseat ambient temperatures with deionized water for 2 to 5 minutes, then purgedwith dry, filtered nitrogen, and finally dried in a vacuum chamber.
A
The 304, A-286, and 17-4PH stainless steels and Inconel 718were descaled in a pickling solution of 20% HNO 3 , 5% HF, and 75% H20O at 130*Ffor 30 minutes per immersion until the last traces of scale were removed, asconfirmed by examination with a borescope. Following the acid treatment, thetanks were flushed with tap water for 2 to 5 minutes, then flushed withdeionized water for 2 to 5 minutes, then subjected to ultrasonic vibrationin a water bath for 15 minutes, flushed with deionized water for 5 minutes,purged with dry, filtered nitrogen, and finally dried in a vacuum chamber.
46
L I
u 0 u EuE
0C 0 0 06 0
C . C; C; it;
CL). 04-) QJ- 04-) (1)4-) W4-3 d)4-) 0)~
> > > > > 0)'
OA &A' tO 0 O CA eU 0 tVn Otf to ~ %A tv -
.en .in -19 0 .ld A .1 ) d _wE . vE ý.~en U
v-u eE to .- V -E to0 fa 6- to
LA)
-cc0 0 0 0LL.
0 O ýa Ln
-~~ ~ LL. s- . O~ >
C CL CI C- 0 >- 0'
4- 4s4J) Cý J 41 4 00
EU U LL V) OC e- 00 *
n 0' 0n C' (0
oý r- Lo r, C). a) I .r. 1 -U co U i- IC co 0 - Ui I-- C) C)s
i-i4-) C) 4-) LACJC C o -
o ~ ~0o 0 00o.) o z 'c V4)L
CQ)4-)= 4:L- 4-J I Z4 -
i-.. i.-. 04 f- M4 ( -V 0
0A *i- M~ S *--S t
C
00
cu- V). -
w0 0
4-' /+ E
fo &A C
L1- 0 .v- o 00
4.) r_ . 4) i ~ .
co co 0
CD) ClC -
""n mnC
47
B, Preparative Procedures (cont.)
The 304 and A-286 stainless steels and Inconel 718 werepassivated with a 30% HN0 3 /3% Na2Cr 2O7 aqueous solution at 130'F for 25 min-utes, rinsed with tap water for 2 to 5 minutes, rinsed with deionized waterfor 2 to 5 minutes, subjected to ultrasonic vibration in water for 5 minutes,rinsed with deionized water for 2 to 5 minutes, purged with dry, filterednitrogen, and dried in a vacuum chamber. The 17-4PH stainless steel receivedthe same treatment with the exception of a 10-minute passivation time.
The 6AI-4V titanium was degreased in isopropyl alcohol asdescribed previously for the other tankage and then descaled in a picklingsolution of 33.2% HN03, 1.6% 11F, and 65.2% water at 140*F for 3 minutes. Thetitanium containers were rinsed with 130*F tap water for 2 to 5 minutes, fol-lowed by a rinse in deionized water for 2 to 5 minutes, then subjected toultrasonic vibration in water for 5 minutes, rinsed with deionized water for2 to 5 minutes, purged with dry nitrogen, and then dried in a vacuum chamber.
2. Container Sterilization, Filling, and Scaling
Following the final rinsing with deionized water and the dry-ing of the container in a vacuum chamber, the containers were wrapped withreusable sterilization paper. The wrapped containers were then sterilized inan autoclave at 250OF with 15 psig steam for 30 minutes, followed by a 30-minutedrying period. The containers were then stored in the paper to "aintain theirsterile condition.
All the steps required to fill the containers with water wereconducted in the sterile laminar-flow bench. The tanks were removed from thewrapping paper in the laminar-flow bench. The tanks were weighed empty; thenweighed when filled completely with sterile water to determine the totalvolume of the tank. The water was drained out and the tank was rinsed oncemore with the sterile water. A sample of the rinse water was checked for pH,conductivity, and Silting Index. If the values indicated that particulatematter and dissolved species were not present, the tank was considered readyfor filling; if the values indicated that contaminants were present, the tankwas rinsed until there was no evidence of contamination.
Before the final filling with oxygen-saturatted deionizedwater, the tank was purged with oxygen from a filtered supply. The tank wasthen filled with the water and a-sample was withdrawn for pH, conductivity,and Silting Index measurements. The ullage was adjusted to the ten percentvalue by weighing the container and its contents; the ullage space was purgedwith the filtered oxygen; and the container was capped with a sterile,tapered plug made from the same material as the container. The plug wasseated in the fill-tube by use of a hammer. The containers were filled withthe oxygen-free, deionized water in an analogous manner, except that filterednitrogen was used instead of oxygen for purging and blanketing the'container.
48
i
_ . . . . .. .. ... .. .....
3, Preparative Procedures (cont.)
The final sealing of the containers was accomplished by GTA- Iwelding the fill-tube/plug interfacc. The welds were inspected visually for jany apparent anomalies. None were found. Then the containers were placed inplastic bags and labeled for the long-term storage tests.
The sampling plan for the long-term storage tests 1b toremove one container of each material with the two types of water for inspec-tion and evaluation every six months for a period of five years. The contents
vill be characterized with respect to pH, conductivity, particulate content,and biological activity, and the containers themselves will be subjected tometallurgical examination if the other test data indicate that this isrequired.
A
A
494
2
S I
II=
49
APPENDIX B
SILTING INDEX MEASUREMENT
FMIMNGb PAGE AA-I kE
51
I
SILTING INDEX MEASUREMENT
In order to obtain a measurement of the clogging tendencies of theparticulate matter which may be produced during the storage of water in thepresence of metals and non-metals for prolonged periods of time, a flow test -
of the water samples through nominal 1 micron size pores was required. Dueto the limited quantity of the water available for each sample, approximately20 ml, the ASTM Method F 52-69, "Silting Index of Fluids for Processing
Electron and Micro-electronic Devices," was selected as being appropriatefor the program.
The method determines the silting or clogging tendency of a fluid con-tamning fine particles and gelatinous materials suspended in the fluid. Thefluid is filtered through a membrane filter having a uniform pore size of 0.8micron at a constant differential pressure. Particles larger than 5 micronsform an open network above the filter and do not affect the clogging tendency;particles smaller than 5 microns tend to block the flow passages of the fil-
ter and cause a decay in the flowrate. The rate of flow decay is expressedin terms of a Silting Index value: the greater the value, the greater theclogging tendency. A schematic diagram of the apparatus in shown in
Figure B-1.
The total volume of fluid passed through the filter is 12 ml. Theflow of the last 10 ml is timed incrementally as V1 (I ml), V2 (5 ml), andV3 (10 ml), with TI, T 2 , and T 3 the times required to flow the respectivevolumes. The Silting Index value is calculated from the equation:
cT - 2TS.I. = 3 - 2T2i
T1
The tests in the program we e conducted with three silting heads, No. 1 wit•an effective area of 1.0 an , No. 2 with an effective filter area of 4.3 mm,and No. 3 with an effective filter area of 18.5 mm2 . The procedure used inthe tests was that prescribed in ASTM Method F52-69, except that samples weretested in triplicate only when sufficient sample was available. A photographof the apparatus* used is shown in Figure B-2.
Water which has passed through the 0.22 micron pore size absolute fil-ter, and which was used in preparation of the tests, always produced a SiltingIndex value of less than 1 using the No. 1 silting head which has a cross-sectional area of 1 mrs2 . The effect of particle size on the Silting Indexwas evaluated using latex spheres with a mean particle size of 1.25 micronswith a range from 0.5 to 2.0 microns and puff ball spores with a size rangefrom 3 to 4 microns. These data are presented for silting heads Nos. 1, 2,and 3 which have cross-sectional areas of 1 nm 2 , 4.3 mm2 , and 18.5 mm2 ,respectively, in Figures B-3 and B-4. The particle concentration Is givenin mg/l because the suspensicns were prepared on a weight basis; the actual
*Available from Millipore Corp., Bedfore, MA
W==at PAGE BAjJOe II
53
____
CONSTANT PRESSURE
S.O. APPARATUS 11LBS/IN.2
FLUID RESERVOIR FILL o Vo
V1 34,-SILTING HEAD ADAPTER
0.8 p MEMBRANE FILTER
A = EFFECTIVE AREA OF SUPPORT SCREENEXPOSED FILTER EFFLUENT
BEAKER
VOLUME- RATIO
Vo/V1 2/1
V /V= 5/1V3 /V1 1t0/1
Figure B-1. Schematic of Silting Index Apparatus
54
LLL
V))
C3C
LL4J
LLLL
jM i< wcoIwI(Da
55
1000
FSILTING HEAD NO. I
1 SILTING HEAD NO. 2
A SILTING HEAD NO. 3
100
-J-
x 1 0
SA
zz
10
21 1
0. 1 I I I 110I
10" 10" 1 10 10
PARTICLE CONCENTRATION, mg/i.
Figure B-3. Concentration Effect of 1.25 Micron Average Diameter Latex Particleson the Silting Index Values
"56
__ _ _._.__ _.J
- -
100
fS
Li100
A
U)
Q10
0.1 __ _
S10- 10 1 10 10
PARTICLE CONCENTRATION mg/i
Figure 8-4, Concentration Effect of 3-4 Micron Diawret•r, Puff Ball Spores onthe Silting Index Value
57
densities of the particles are comparable. The significant item to note fromthe comparison of the data is that the Silting Index values are comparable atconcentration levels that differ by at least one order of magnitude, thesmaller particle producing the higher Silting Index value.
5 i
58
