UNCLASSIFIED
ORNL



.
:
*


hindi
makatakan
diantaran

1065
URNL
- 1065
/711
ONI - AEC-OFFICIAL
2
637
OINI - ATC-OITICIAC
1.1
MAR 23 1965
SUMMARY OF EXPERIENCE WITH HIGH-TEMPERATURE WOORMOCOUPLES
USED IN THE ORNL-GCR PROGRAM PUS RRADIATION EXPERIMENTS
N. 8. Briggs
Instrumentation and Controls
Division
E. L. Long, Jr.
Metals and Ceramics
Division
F. R. McQuilkin
Reactor Division
1C8
INTRODUCTION
This preliminary report summarizes a portion of the experiences
with 46 high-temperature thermocouples used in about 40 irradiation tests
of encapsulated fuel materials for the EGCR and advanced GCR programs.
These tests were conducted in the ORR Poolside Facility, the ORR Gas-
Cooled Loop No. 1, and the ORR F-1 Core Facility. ?

privately owned bus; or
with the Comm 301., or hla e oployment wib such contractor.
diune minaw, or froides kce.. to, any Information pursuedi lo ve employmeal or contract
such eaployvt or cont' xhur ol the Commission, or employee of such contriclor preparos.
ployee or contractor of Use Commission, or omploys of such contractor, to the enent wat
Ao used in the whore, "perma actos on beball of the Commission" includes any on-
ure of any information, apparitus, method. or procos, disclosed in this report,
8. Ainae, may liabilidos mu respect to the wool, or for das fes retuung from the
of ray talormaron, apparatus, polkod, or proces diacioned in to report may not lofringe
racy, completeness, or wefuser, oltre information coaulnod la
A. Makes any warranty or representation, expressed or implied, with respect to the accu.
Sules, sur the Commission, nor wy Domu nching on behalf of the Commission:
The report was prepared us as sccount of Gover meat sponsored work. Neither the United
--LEGAL NOTICE
o report, or that the war
We are presenting information on the design of thermocouple assem-
blies and their compatibility with several types of fuel materials. In
general, we cannot draw any conclusions as to the emf drift of high-
temperature thermocouples due to transmutation effects on the wires,
because of changing neutron flux patterns during an experiment irradiation
period and the uncertainty of possible changes in the thermal conductivity
of the fuel material. Many times in such tests our primary objective 18
to obtain only initial data from these thermocouples to check our heat
transfer analysis and to provide a measure of fuel thermal conductivity.
Our philosophy on thermocouple design has been to protect the ther-
mocouple wires from direct contact with the fuel materials and to provide
an inert gas (usually helium) environment for them independent of the
fuel gas environment. We are also leapfrogging our thermocouple designs:
because of the long lead time between design of experiments and results
from postirradiation examination, we find ourselves reusing designs that
later prove to be wholly inadequate.
Fuel specimens in the experimental assemblies include VO2 bushings;
UO2 dispersions in BeO; vibratorily compacted ThO 2-102, pyrolytic carbon
(PC) coated particles of UC2 or (U, Th) C2, either loose or in graphite
matrices of several geometries, including 0.6-in.-OD bushings, 1 1/2-13.-
OD spheres, and 6-cm-OD spheres; and Beo-graphite materials for compati-
bility studies. Fuel-element center temperatures measured varied from
1700 to 3700°F, with the majority being in the range of 2000 to 2500°F
(Table 1.1). Frequently, the high-temperature thermocouple assemblies
were designed for temperature capabilities higher than that experienced,
because of uncertainties in thermal conductivity of fuel specimens.
ORNI - AIC - OFFICIAL
D. B. Trauger, Some Major Fuel-Irradiation Tests Facilities of the
Oak Ridge National Laboratory, ORNL-3574, (April 1964). Note: The F-1
Facility is described on page 28 under "Eight-Ball Experiment."
OINT - AIC - OFFICIAL
PATENT CLEARANCE OBTAINED. REISTO
THE PUBLIC IS APPRI : ED. PRODUKT
ARE ON FILE IN THE RECOVING SOCJON.
17121Q_V - INBO
OINI - ACC - Official

1.2
Table 1.1. Ranges of Temperatures Measured
..
Average Temperature
Range
(°F)
Number of
Thermocouples
ه
ي
<2000
2000-2500
2500-3000
>3000
بیا
یہ
Maximum Temperature
(°F)
Number of
Thermocouples
<2000
2000–2500
2500-3000
>3000
I wio o
All thermocouples which gave questionable indications were
· excluded.
IVIDU10-DIV-INIO
OINI - AC - OFFICIAL
ONAIC - OFFICIAL
ORNI - 10-orriCIAC
1.3
DISCUSSION
The 4 thermocouples were classified into six types with appro-
priate subtypes. The different types which are described below represent
major geometrical and material variations, and the subtypes provide for
minor variations. The thermocouple wires were Pt/PtgoRhin, W/Re, or
WogRes/W74Re 26.
Type 1 thermocouples (Figs. 1.1A, 1.1B, and 1.10)" have stainless
steel- or Inconel-sheathed thermocouple wires insulated with crushed Mgo
in the low-temperature region of the experimental assembly. The sheath
is brazed to a stainless steel capsule bulkhead. A portion of the sheath
is removed from the wires that will be in a high-temperature region, and
high-fired ceramic insulation is placed over them. The wires and the
insulators are contained within a refractory-metal thermocouple well which
16 also brazed to the stainless steel capsule bulkhead. The measuring
junction is of a coil design, discussed later.
Type 2 thermocouples (Figs. 1.2A and 1.2B) are the same as type 1
ther couples except that the measuring junction is the more common butt-
weld design. To form this junction, the wire that melts at a lower tem-
perature is melted first and allowed to braze to the wire that melts at
& higher temperature.
Type 3 thermocouples (Fig. 1.3) are the same as type 2 thermocoup.l.es
with the addition of a protective sleeve or coating over the thermocouple
well.
Type 4 thermocouples (Fig. 1.4) have tantalum-sheathed thermocouple
wires with crushed ceramic insulation. The sheath 18 inside an open-end
refractory-metal tube. The tube and sheath are brazed to the capsule
bulkhead.
Type 5 thermocouples (Fig. 1.5) are tantalum-sheathed with crushed
ceramic insulation. A protective sleeve or coating is placed over the
tantalum sheath. The sleeve is not brazed to the capsule bulkhead.
Type 6 thermocouples (Fig. 1.6) are tantalum-sheathed with crushed
ceramic insulation inside a refractory-metal thermowell that has a pro-
tective sleeve or coating. The sheath and the thermocouple well are
independently brazed to the stainless steel capsule bulkhead.
OINT - AEC - OFFICIAL
The figures referred to include a brief case history for each
thermocouple. The experiment numbers, such as 08-5, -13 , and BOGRAC
Mark I listed on the figures, are code identifications for tests con-
ducted in the Poolside, Loop 1, and F-l facilities, respectively. The
dut numbers enumerated under the heading "Sheathed Material" are from an
internal coding system and are ueed for identification of each material
purchase item which allows classification of the thermocouple inventory
according to vendors' and purchase specifications.
OINI - AC - ORFICIAL
WI91510 - DIV-INIO
IVIDID10 - DIV-INTO

---4
---------------
.
MAZE
MARE
· HIGH TEMPERATURE THERMOCOUPLE TYPE 1
TYPC CAMMINENT
ruct
NOTES
SERVICC
POST: IRRAQ CIAM
WINCS SWEATMEO MITENT
MAA. NANOL (HOST
marion
KATEMIAL INSULATION
TIM AVERACC, TINC
TEMPT
MIS
| КТК Lug BUSHINGS
I MOSTic VIACS I JUNCTION IN TAXI
romaus' aal
IMANC INDICATO. FROM I T WWUL COMPLETELY FILLO
imrc
1/C, osvay D TO Mark ; WITH Mas aue TO LEM IN
Caruc. meu com ww mere
AN
I.
.
YTO
OTTO
OTTO
OTTO
OTTO
Mons
ino
TUMCSTEN WELL IN GOOD CON.
DITION. NO INFORMATION AVAIL
U ON THERMOCOUPLE.
1.4
-
C
C
OTTO
Rio
DITTO
DUTTO
T
U ITULO. .
* WIRL MOME Aroma
STUCK IN Suth. 1/0 INCT
Wannes MEAN COW na ACAMO IN TACT
O a u MAMICATION
wp.com! 04 ss!
majad
2010 Dia, leo Insu
DUTTO
CS
w MOMEN CONTAINCO
I NAK MO (
MMC OF
Tie sarco INITIAL STARTUP : CORROSIVE ATTACK
GROUrt to em DAY WAL
PAUNC ON STARTUP
ACF ORNL 3302.
24 21 s mods was MUMCN Ma Me
Toe RRATU to neup of INSIQ CAPSULE.
245 rok DAYS THE
TAILU
OTTO OTTO
OTTO
lonxa
SI TA
OITYO
"
1
0
.00
DA
Mo Qiaran MMATONT-
MOLY wu tuTE MOLD 1700 1023
MOS
. Ondort! COWICO LINCTM TMC | iAC FAILCO AFTER WOS. DAIRY.
na, v
c us. IRC AT (D WMWA TO 2950 2.5
MO LANE
MOS (MMATIC O'MO
NO INORMATION AMALANG
ON TNCRMOCOUPLE
0 0o aut
1 on To
.
Opis
OTTO
OTTO
OUTTO
OITTO
2700
DITTO
Fig. 1.1A. High-Temperature Thermocouple, Type 1.
ORNI - AIC - OMSICIAL
OINT - AC - OFFICIAL
WIDT10 - 33V - INDO
IVIISIO- DIV-INIO

-----
--
--
BRAZE
MAZE
HIGH TEMPERATURE THERMOCOUPLE TYPE I
TYPE C (RIMMT !
Puth
NOTES
SLAVICC
OSTIRNAQ CIAM.
NO NO.( WIRTS WEATHCO MI TOM WELL
NPROX (osure
Insation
MATERIAL INSULATION
AVCTACL TIME
LAIT
| TEME i
023 W. Me 04 SST.
TUNCITINUO, IUSMINCS
2350L 2150 į I MOS. NO INFORMATION AVAILABLE ON!
|vs ainaa
azos' aüd
TMC AMOCOUPLE
WA, NO in
aix la
azodia LOT 10
ish LONG.
01.9 DITTO DITTO Dil To DITTO
OITTO
2150
OIT TO
1
S MOS.
1.5
OIT TO
QITIO
DITTO
04.6
12W
304 SST.!
0125 aa
My ASUL
M. QisTaal
6220 w. 1.1
8920 2440 ! MOS.
T* QSCILLATED KETWEEN TWO WCLL APPEARED NORMAL.
OCATTO TIMP, LEVELS. TEMPS
GIVN ron UMR UML WHICH
RIMONCAFTD ron FINAL MONTM.
YAC MAILCO AT I WEEKS NO INORMATION AVAILAOLL OM
SIMTUP
IMCAMOCOUME
11.90 TOITTO DITTO TOITTO
vonta
LI:
OIT TO IOIT TO
DITTO
MO
OITTO
DITTO 1
DIT TO
DITTO
OUT TO INCO
0123'aa
1 WENS MOTO OF T/C WELL SHOWS
· MO REACTION WITX PUCL.
เor เหe
.lOITTO
DITTO, DITTO
DITTO
20
owns
LCAMS AMOUNO TOP OF T/C
WELL ASSMILY.
V
VO, SUSHINGS Ima i
Yje SST, TUIG:
VIIM. NO
IMNSVERSI FINS I
CLAD.
DIT TO
LIOS
| DITTO
DITTO 1 DITTO
DITTO
TRE TAILLD AT
STMTU
14 WEEKS SMALL LOAN AMOUNO TOP or
IRC WELL ASSEMBLY.
L1.nom
DITTO
DITTO
DITTO
DITTO
No.
220AY
wo Quaraa)
- 2020 w. r. I
MO 1/C INFORMATION AVAIL.
CLAD OF FUEL CLEMENT
CRENCA
Fig. 1.1B. Hich-Temperature Thermocouple, Type 1.
ORNI - AIC - OFFICIAL
OIMI-AIC - OINICIAL
IVI1110 - ) 3V - INTO
WIDT10 - IV - INTO

:::
:::od
BAAZE
MAZC
HIGH TEMPERATURE THERMOCOUPLE TYPE i.
ruti
MOTOS
SERVICE
SCAIMO . TEMA
PNOL 1 noun
MATERIAL INSULATION
AVENAGE TIME
NOST IRRAD CIAM.
TYPC (XPERIMENT
MQ
Wincs
INSERTION
DATE
LI.on W. R
I vs
I
9.0
INCONEL
anas'aa
fuLL CLIMENT TAILCO AT
STARTUP
|aaoou LOT 124
Toitto Dirio
Mhe aiur'aavo, IUSWINGS IN
2020 W .304 S37 Tuki;
WIAL WRAPPED
TRANSVERSE Finns
IN SLAD
OIT TO ADVANCED CCA
VO, AUSHINGS
MACMINCO SHIRAL'
FINS
DIT TO
1.1.11M
VIA
T/C TAI O AT
STMINE
CONS NO INFORMATION AVAILABLE ON
THERMOCOUPLE
1.6
11:1)
DIT TO
DIT TO
T 2550 Ta
2400
19 WEEKS
OITTO
01 Tio! OITTO
EXCEPT
LOT 131
Jo, IUSMINGS.
VENICO FULL
(LEMENT.
1
-
-
-
-
į
Fig. 1.10. High-Temperature Thermocouple, Type 1.
--
ORNI - AIC - OFFICIAL
ORNI - AC - OMRCIAL
-
IVO - DIVINIO
WIJN10 - 91V - INDO

O
W
ORAZE
ORAZE
BRAZC
HIGH TEMPERATURE THERMOCOUPLE TYPE 2
TPC CIMRIMENTI ! 2
Full
NOTES
Schvice
POST IMRAO CIAM
NO NO O WINCS WATHIO MI: TOMA WELL
TYPC
NOL CROWN
.INSERTIOM
WATCHIALNSULATION
ANRAGE TINC
DATE
TOMY
11:9 nitono 100
.0
N
VO, AU SHINC (GCA INSTRUMENICO 1940 i 160 WICKS NOCHEMICAL ACACTIONS AC
1177/01 Vs no STRICS
TrueL ASSMILY POST
IWCCM WILL COUL
SST.
NU. ORAL 3302
UI
O ITTO, DITTO
DITTO
OUT TO
OITTO
OITTO
TELAS
DIPTO
--.-..
Liisa
oirro
dirvo. Oirro
Outro : orto *-OUTRO
DITTO ------1960
1.7
1.7
OITTO
DITTO
DIT I
LO:IA
1273201
OIT TO
DITTO
LOW ICONS NO INFORMATION AVAILABLE
on TMCAMOCOUL.
VERY (AMATIC
-
--
*** IM
11.76
Dirro
durio
OITTO
OTTO *
DITTO
DIT TO
OIT TO
2700
-
2100 '14 MINS (NO CAP ON CAN LEANCO.
FAILUAC IN CLADOINC NOIN
FORMATION AVAILASLC ON
THE OCCULE
31680 Weens
NO INFORMATION AVAILABLE
yor.21
1 on IMCAVOCOUPL.
11.90 .airpo' DITTO
DITTO
DITTO
DITTO
2100
VENTCO rutu
CLEMENT
1/1/6)
20
XCHCOULCD DISCruce J18
SOCRAC
MAAM I
10:1
W.SA. INCONCL 0.0 0.0.3' MO 0125" NON VILCO
w.na no ve' oo 00.0.022' 00100169 10. CRASHTC
1020'a VOINSA IQITOLO WA PWM COMAATIOILTU
LOT 15)
LONG TEST
Quero : DITTO DITTO DIPTO
OITTO
(ACCPT
JO LONG
WELL IN CONTACT IN PILL AS ON 122070
WITH GRANITl. Oor, cord. TIONS TO CATC ARC.
TON 6.0 PLUG IN
1923 2 WCS
wtιι Οι για
DITTO
DIT TO
!
!
OITTO CICIPI
000
1910
WEEKS
(ACEPT
TC.)
WELL IN CONTACT
WITM I.a SOTTOM
1.0 PLUG IN WELL
OMIITTA
۲۲
و۲۲:
و ۵۱۲
DITTO
OITTO
OI I TO
DITIO
CACCPT
16:9
۵۱۲۲۵
Схсат
LONG
OITTO CACCP
2160 2050 2 WEEKS
Fig. 1.2A. High-Temperature Thermocouple, Type 2.
ORNI - AC - OFFICIAL
OANI - AIC - OSSICIAL
IVIDIO-
V-INUO
NVIDI110 - IV - INTO

Y:::
::::
:
::::::::
::
:
::
::
::::}
P
ouze
ĶI
MAZCO
HIGH TEMPERATURE THERMOCOUPLE TYPE 2
TPC CIRNIMINTI I
full
MOTIS
SAVICE
Na mai Wincs WEATHCO! MINCMO
TVAC
Anonimos
HINSOLUTION
MATCHIAL INSULATION
ny AVCHAGL PIMC
OST INAAQ (NAM
I am
!
SC COUCO DISCHARGE TW
IN PILC AS OF 1//65
COMOITIONS TO APC AAC
2033 2 WEEKS
20 | MOCRAC WS AN INCONEL 1.0 aousº Mo 0.125 NON FULLCOWELL IN CONTACT
Me 1 XR 10 aa aa .2022° 02.0.016° 1.0.GAAMITE WITH S.a sorrow
n.o Qataa MOINSA LA MTO SLG WALL TWM coume PIBILIT I PLUG IN
Or 193
14h Lance CST.
ONIT TLA
OIT TO Carro DITTO DITTO
DITTO
DITTO
(YCEPT
TO?
wa tu.
E LONG •
1.8
DITTO
!
I
DITTO (1CCO
i 21% OWOCKS
Fig. 1.2B. High-Temperature Thermocouple, Type 2.
ONNI - ALC - ONNICIAL
OINT - AC - OFFICIAL
-----------
.: W21110 - ) IV - INIO
IVI91510 - DIY - INYO

:26
be
:=====
===
CLO TIM SMEROS
BRAXE
ΜΑΖΕ
HIGH TEMPERATURE THERMOCOUPLE TYPE 3
Punc CIMMINENT
1 1 ruel
NOTES
SCAVICE
OI IRRAD (XAM
Na
WINCS SCATMO MI POMO. WELL Alive on tuleve
NOK Owosund
INSATION
WATCHIAL INSULATION
COA PIIK MALCOI
Tom AVCHAGE | TIMC
DATC
01.1 wg av TIMCONCL Toonraa. no wao. n.MX 20. nsinalPC COATCO VCA
TRC LOST MEM B NOSI/C ( WCLL (MMITTUD.
vi noluraamploops'io loro ut laoci w.T. I Vacuum MAPICLES IN
CASURING
comTION OF
MO (NO MAO ALLORCDI
AKATION O CAR.
2010'ual insul mous us''LOMC 121 come with MIL CRAMITE
"LATNIT 6. aa!
JUNCTION
ure
su. Tuvun
LOT 120
.(STI)
o .1 OITTO 1 DIPTO DIT TO OIT TOOIT TO DITIO DITTO
OITTO
293
2000 VNOS NO (VIOCNICE OF ANY AC.
(ACEM
2 Tos nuso
ACTIONS a IAC ASSEMBLY
LOT 131
JMS MM
COWOMENTS WITH Ime
rom W IN IN
sumamoinC CANire
sa sana''
MATRIN.
DITTO TOITTOLOITTO DITIO
OIT TO
Tom 1 [ 21401 2240 lova MOS
DITTO
CICEPT
MEASURING
IR QUE O CANATIC ) T/C NUNCTION ONONEN
LOT 124
JUNCTION
TU SU QAY. OIMCHISC locron MOT CCLL CY:
STATE (W OSTRVCO ALTAMINATION.
I MOLY IN CRROR
IOITTO DITTO DITI
DITT
DIT TO DITTO DITTO z rumus ar ) NPILL AS OP 1721
SCHOUCO DI CHANCE
(ACEPT
MLS The Moon CONDITIONS TO CATC AAC
LOT 144
2323 2050 ANOS.
VLOAT
то ам.
1.10 DIT I DITTO 10.0 2005 in aan PTAOLITIC
1COost pe WENTED FULL TINDILC AS Or T72016! DISCUCE NOT SCMEOULCD
aa. 2027" on 1. ow COATING
COATU wca CLIMENT corations TO OATC ARC
La mous
13% LONG laoos' T.
ARTICLES IN
2500 2450 , INOS.
CIL. www.
int maacn
1.9
DITTO
و۲۱يه
w
i
sunca m
er
Fig. 1.3. High-Temperature Thermocouple, Type 3,
ORMI - AIC-OISICIAL
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Sinn
Nierman *4rum
tenemoudronwardowana
ORAZC
MAIL
HIGH TEMPERATURE THERMOCOUPLE TYPE 4
FUEL
MOTES
SLAVICE
SWEATMCO WITOUR. WILL
MAX. APPROX trosune
MATERIAL INSULATION
ARCRACCPIMC
POSTIAKAD (XAM.
WINCS
Punt ( APCMIMENT
NO NO.(
INSTATION
PARE
2005
.
Hooa. No ca
1.
2405 1
245
) NOS
000
OMM MOP COATED WO
twee
ATCLIS IN
Camill MIMIY
TUOMING
SWEEP TYM CNsu.
CO., (HITS VIA
WILL SMC ATM
ANNULUS
NO INFORMATIUN AVAILABLE ON
TMAVOCOUAC
PVC FAILLO APTEN UZ OYS
OTTO
OTTO
۲۲۵
OTTO
OUTTO
1985
I MOS
OTTO
Οτι
.
Home O
DIT TO
DIPTO
--.
OTTO
Burro
oirro
OOO.
2//2 Ogo' ao LOT 70
! 1600
1723
mas
.
I DIT TO
oo WAMOWW!
Wa MRTKLES
IM ho WAMIL
DITTO
OTTO
2166
2180
sqmos
OIT TO
INC saker on on CNY
.
......
Fig. 1.4. High-Temperature Thermocouple, Type 4.
ORMI - AIC - OINICIAL
*****O'RNI - AIC - OINICIAL.-.-.-
IVIDU10-DIN- INTO
IVIO
-DIV-INIO

pretirinh
Vacrita.orma
wath
2
. WAAN ANTAKT
HYV I N TXANO
WARE
mor IANA (KAM
HIGH TEMPERATURE THERMOCOUPLE TYPE 5
ime launchini
KAVICE
| WNU INCATO wi.Nu
м XIV
NOTES
w ororost?
Orion
MANTNIAL RULATION
AVOWCE TIME
Mr
PC Courove
Moonaal
NIK
en | 113 Imos
w a o'a a LOT Ne
Nem m .
2. a. la MARII communur
WITH The WMAINITE
ACT. ONNL: 301
in
| OTTO
OTTO
I WITO
mnauik
NO
WITO UM IN
tren THAI
CMQ ADOCO TON XAL
MONS
LOT 1X
maty Louc
on 1.
MEACTOR STARTUP
WA MACKCO AMOUNO
1/C WOLL NO OTHER INFO.
MWAIL. CAP marro IN
WOT CRLL
1.11
1.11
QITO
Kin
LOT
OTTO
SOME
WITO
II ALE AJ Nava
IAOMON QURING con TIONS TO MCM
TAMMICATION
awo w MA
XCHLOULIO disce
:
M
WITO
mauti
LLAN IN UPRA
BRAZE-SS. SLEK
ADIO ON SOM
✓ CANCRU. Von Ko WC WLS
* SOU ANLASMA MANO.
ronMO 01104 WIRQ an.
LOT NO
10.
01.
TW
OTTO
| OTTO
ITO
I slots
WC min A a no
raw WCIO MLS OCCP OUTER
мм. Тамо от.
TAI INACTM MOUALLY
Minu
.
...
Fig. 1.5. High-Temperature Thermocouple, Type 5.
OINI-AC- OISICIAL
...OIN- AIC -OISICIAL
WID1810 - DIV-INIO
IVINTOOV.INIO

ZZZZZZZZZ
Beach
Sot
May
-
-
MAZE
MAZC
HIGH TEMPERATURE THERMOCOUPLE TYPE 6
NOTES
MOST IMRAO CIAN
lull
TYPC
WELL
MAI.
irn CIMERIMENTI
No
WIACS Stamco WI TEMO
INSTATION
MATERIAL ROLLATION
PALE
suive an HILVE
COM TING MARD
LAVICA
NPROXI was
AVENACKI TIME
MOTO IS MAICO
WW Cu.
PC COATLO V
MATICUL
CM UTC
MATRIX OC OA
Winnelaous' aa
0010° aa lor
2000
| WHQLTK
QwaQ COATING
OON' W 0.010 TK
.) om
TAMOS NO I/C Iwo CAPSULE
WAALO AY MIMARY
CONTAINMENT
06.
1.12
OTTO
OTTO
OTTO
OTTO
OTTO
OTTO
ORTO
Crime LCALD
PC MATONMANCE
(XCELLENT
| TIC WOW KINO ( KAMOINED
TOOTM T/C ASSEMBLY
MAAL JOINTS LLAMCO.
-
-
-
-
-
Fig. 1.6. High-Temperature Thermocouple, Type 5.
ORMI -NIC - OMSICIAL
ORNL - ATC - OFFICIAL ******
TOOTJO- J
DINI - AIC - OFFICIAL

1.13
-1N10
The thermocouple data in some instances are incomplete or inclu-
sive, because the tests were conducted primarily for the fuel studies,
and operational control was based on requirements for neutron flux,
exposure time, and surface temperature conditions. Unfortunately, some
potentially valuable postirradiation examination information on thermo-
couples was not obtained due to limiting schedules and/or costs.
As can be noted in Figs. 1.1-1.6 (ref. 3, 4), thermocouple types
1, 2, and 3 have þare wires beaded with Beo insulation and are inserted
into protective wells (called bare-wire thermocouples), while the types
4, 5, and 6 are tantalum-sheathed thermocouples inserted into wells.
Types 3 and 6 have sacrificial sleeves that are intended to react with
the surrounding fuel materials. The schematic views in the figures are
purposely out of proportion to make certain details clearer. More
realistic schematic views of four thermocouple types, as incorporated in
their experimental assemblies, are shown in Figs. 1.7-1.10.
Among the bare wire thermocouples, type I was the earliest design
in this series and reflects several development steps. The coiled
junction was thought to be desirable to offset differential thermal expan-
sion between tungsten and rhenium, and between 95% W-59 Re and 74%
W-26% Re. The rhenium or the 740 W-26% Re wire was coiled. Experience
with types 2 and 3 thermocouples (which were smaller assemblies with the
same size wires as used in larger assemblies) indicates that expansion
apparently is not a significant problem with tungsten-rhenium alloy
wires and that they can be successfully butt-welded. Use of tungsten
and FS-82 well materials was discontinued in favor of the fairly success-
ful and less expensive molybdenum tube well. The Pt/Pt 9 Rhio wires were
replaced by tungsten-rhenium wires, because we expected to encounter
higher temperatures and because platinum-rhodium wires are fragile.
The rhenium sleeve used in the type 3 thermocouple design was used
to structurally support the molybdernim in the event that it became car-
burized and tended to disintegrate. Indications are that carburization
of the molybdenum tube was not a problem. Major penalties for this
relatively rugged design, as used in types 3A and 3B thermocouples, were
the large hole in the fuel specimen and the costly rhenium sleeve.
The highest temperature measured with a bare-wire, coil-junction
thermocouple was 3700°F (a type 1D thermocouple la experiment 03-5).
Because of the nature of the fuel specimen, the experiment was conducted
80 as to achieve the maximum temperature during the second month of
irradiation. Subsequently, under steady operational conditions, the emf
output or the thermocouple drifted downward uniformly to 2950°F over a
3-month period, erratically drifted to 2340'F in two weeks, and then
failed two weeks later.
ORNI - AIC - OFFICIAL
ORNI - AIC - OFFICIAL
3GCPR Quart. Progr. Rept. Mar. 31, 1962, ORNL-3302.
"GCPR Semiann. Progr. Rept. Mar. 31, 1964, ORML-3619.
1.14
OINI - AIC - OSSICIAL
UNCLASSIFIED
ORN L-LA-OWO TO267R

-PWG HEAD
(304 STAINLESS STEEL)
FOR DETAILED DIMENSIONS
SEE DRAWINGS: D-RD-10731
D-RO-10732
oran
STAINLESS STEEL
THERMOCOUPLE SHEATH
SLEEVE
1304 SS)
-THERMAL SHIELD
(304 STAINLESS STEEL)
21 in.
NEUTRON SLUG
(304 STAINLESS STEEL)
-BO INSULATOR
- TOP CAP (304 STAINLESS STEEL)
LOW DENSITY MOO SPACER
FUEL ThO2-2.9 wt% VOZ
(VIBRATORY COMPACTED)
0.250 in. OD X 0.173 m. ID
X gain. LONG
MO TE WELL
9.171 in
- BeO TE INSULATOR
skin.
W-26 % RO WIRE
-
--
-
-
-
.
-0.625 in. OD X 0.020 m. WALL
X 6.984-in. LONG TUBE
(304H STAINLESS STEEL)
.,..
.
-TE BAND
(304 STAINLESS STEEL)
Skee-in GAP
-TE (CHROMEL-PAALUMEL)
SOLID B80
-LOW DENSITY MOO SPACER
in in.
Sight.
Bygą in. DIA
- BOTTOM CAP
(304H STAINLESS STEEL)
OURT-wel-UPNICIAL
-
Fig. 1.7. Typical. Type-1 Thermocouple Installation in Experiments
03-5 and 06-5.
OINI - AIC - OFFICIAL
-
-
.
-
-
-
1.15
ORNI - AIC - OFFICIAL
ORNI - AIC - OFFICIAL
WXLIINNO
Will. I

ht:8333
ws
TOP CMO CAI
. .
.
- MERLOcount LL
.
TOP GRAPHITE WHA ATOR --
SUELLO MAMTE MELLETT
-W- No THERMOCOne
GAS OUTLET
:
.
PYROLITIC QNAPHITE SLEEVE
101 TON GRAPHITE WSULATOR
BOTTOM ENO CAP
Fig. 1.8. Typical Type
01-5, 08-5, and 082-5.
Thermocouple Installation in Experiments
ORNI - AC-OFFICIAL
ORNI - AIC - OFFICIAL

1.16
- ORSICIAL
OINI - AIC - OSSICIAL
OINI - AIC - OFFICIAL
UWCLASSIFIED
ORNL-LA-OWO OUNONG
OINI-A
NTRAL THERMOCOUPLE

MOLYBDENUM THERMOWELL
|
Woo
TE-31
BRAZE
CENTRAL THERMOCOUPLE
BOO BEADS
S221522USBIECTESSELSPIESEBLIEBEBSIEBIE

WELD
FUEL PELLETS
8.0
TUBE
TE-5
CU BRAZE
TE-12-
MAXIMUM
- B&O PLUG
STAINLESS STEEL
CLAD
- MO WELL
TE-4-
Blain.
Mg0
ORNI - AEC - OFFICIAL
Fig. 1.9. Typical Type - Thermocouple Installation in Experiments
I 1-5, -6, -7A, and ~70.
ORNI - AC - OFFICIAL
1.17
MI - AC-OFFICIAL
ORNI - AIC - OFFICIAL
UNCLASSIFIED
ORNL-DWG 63-3061

SURFACE TEMPERATURE
THERMOCOUPLES
---UJTER TUBE
INNER TUBE
C
CENTRAL TEMPERATURE
THERMOCOUPLE
- STATIC SECTION
> GRAPHITE CONTAINERS
"?
L
Am
1>POROUS CARBON
END INSULATORS
--- END CAPS
DPW
M
SWEEP GAS OUT
- GRAPHITE POWDER
- SWEEP SECTION
5220
SWEEP GAS IN
IV JIS10 - DJV - INTO
Fig. 1.10. Typical Type-3 Thermocouple Installation in Experiments
01-7, 05-7, 08-7, and O1A-8.
ORNI - AC - OFFICIAL
ORNI - AIC - OKSICIAL
quo-21-INIO

1.18
The type 3A thermocouple designs were the first used in the type 3.
group. Because of unforeseen problems with the experimental rig assembly,
the tungsten-rhenium thermocouples were subjected to excessive handling
and bending. This was remedied by a subsequent minor redesign of the
experiment hardware.
For preparation of tantalum-gheathed thermocouple types, we improved
the fabrication techniques after the type 4 thermocouples had been made
and used. We believe that the failure of type 4 thermocouples may have
been related to a poor fabrication technique, and therefore, longer life
could probably be expected for a similar thermocouple fabricated today.
It is possible that the outer surface of the tantalum sheath had oxidized
(or carburized) and that this was responsible for the failure mechanism;
we do not know this to be true because we lack postirradiation examination
information.
The type 5 thermocouples were designed with a minimum diameter of
the fuel specimen center hole and of the thermocouple sheath and to obtain
as rugged a thermocouple as possible. The sleeve was included as a sac-
rificial element that was expected to form a carbide and provide
protective coating.
The type 6 thermocouple design was similar to the type 5 design,
but with the additional protection of a well at the expense of a slightly
larger hole in the fuel specimen and a larger penetration through the
first capsule bulkhead.
Although not completely successful, the type 5 thermocouple in
fueled graphite has functioned well at 2300°F (2500°F max) for 9 months
and 2900°F (3050°F max) for 2 months. In one case the performance of
the thermocouple appeared to be satisfactory at 2400°F (2800°F max) for
2 1/2 months, even though sleeve and sheath barriers failed.
SUMMARY AND OBSERVATIONS
-
-
-
-
-
-
-
A summary of the data given in Figs 1.1 to 1.6 together with the
thermal neutron exposure is presented in Table 1.2. In Table 1.2 the
types of thermocouples are grouped according to the different fuel
materials tested.
-
Bare coil-junction thermocouple assemblies in molybdemum wells per-
form reasonably satisfactorily for medium (2500 to 3000°F) temperature
service and somewhat less satisfactorily for high (3000 to 3700°F)
temperature service after the first month of exposure.
ORNI - AC - OFFICIAL
The type 3 thermocouple is considered to be the most successful
type for the graphite fuels irradiated to date.
ORNI - AIC - OFFICIAL
ORNI - AIC - OFFICIAL
ORNL-71G-OTICIAL
1.19
The type 2 thermocouple is probably the least expensive of all
six thermocouple types and the least complicated of types 1, 2, and 3.
The tantalum-sheathed thermocouples in open or unsealed wells are
probably satisfactory for low (1700 to 2500°F) and medium temperature
service for reliable initial measurements, but are probably unsatisfac-
tory for any extended service.
The tantalum-sheathed thermocouples in sealed wells have performed
well for extended periods under relatively low temperature service.
ORNI - ACC - OFFICIAL
-----ORNO-ALC - OFFICIAL
IVIDI:10 - DIV - INIC
IVIDUDJO - DIV-INIO
Table 1.2.
Types of High-Temperature Thermocouples Used with Different Types of Fuel
Type of
Fuel
Thermocouple
Type No.
Experiment
Average
Service
Temperature
(°F)
Thermal Neutron
sure
(nvt X 1020)
No.
UO2 Bushings
0.2
.
ASSASSIS
(a)
1950
(b)
(c)
2320 (a)
2150
2150
(c)
1800
1750
voouw
2.5
01-3
OLA-3
08-3
OLC-A
088-4
02-5
07-5
04-6
21-5
-6
11-7A
-70
-7B
-9
21-8
-8S
-10P1
-10P2
1.3
1.3
1.3
1.3
2.5
1.3
(a)
1.20
UO2 Bushings in 304 stainless
steel tube, wire-wrapped
transverse fins on clad
2100
(a)
2420
2350
(a)
3200
(e)
(a)
ir w
.5
(e)
1.44
-11M
999 SFA
21.80
2400
VO2 Bushings, machined
spiral fins
UO2 Bushings, ventilated
fuel element
Vibratorily-compacted
ThO2-U02
UO2 particles in Beo
matrix
2.2
3025
2700
2120 (a)
5.0
5.0
L1-70
-13
03-5
06-5
01-6
1.5
ONNI - All OFFICIAL
COANI - AIC - ONNICIAL
IVIDIDO. DIV-INO
IVISI310. DIV-INIO
Table 1.2. (continued)
Type of
Fuel
Thermocouple
Type No.
Average
Surface
Temperature
(°F)
Thermal Neutron
Exposure
(avt x 1020)
Experiment
No.
30
2450 (1)
(8)
-14
LA
2425 (a)
1725
Loose PC coated UC2
particles in cylindrical
graphite matrix
PC UC2 particles in
graphite matrix, 0.6-in.-
OD bushings
PC coated UC2 particles
lu graphite matrix-08-6
has 1 1/2 in. OD spheres.
All others, 6-cm-OD spheres
172
viv Nr.
5A
1750
ЗА
ЗА
ЗА
2600
01-5
08-5
08A-5
08-6
01-7
05-7
08-7
OLA-8
OLA-7
05-8
05B-7
08A-7
01-8
08-8
2050 (f)
1.21
2300 (f)
2400
2900 (a)
2000
2150
..oo
Non-fueled, Beo-graphite
compatibility test
2B
1825 (1)
1970 (f)
2050 (f)
2025 (f)
215
BOGRAC
Mark I:
TE-1
TE-3
TE-5
TE-9
TE-2
Thermocouple failed on initial reactor startup, or gave erratic Indications
during entire irradiation.
"The thermocouple assembly was lost near completion of the capsule assembly.
ORNI ~110-- ONNICIAL
ORNI - AEC - OSSICIAL

IV1110-DIV-INIO
IVID110 - DIVING
Table 1.2. (continued)
The thermocouple emf was unstable or gave unusual indications such that the measured
temperatures are open to question.
"Thermocouple failed during irradiation. Value given 18 average temperature to time
of failure.
Experiment failed at reactor startup.
Experimental assembly is still in the reactor.
1.22
DANI - AC - OFFICIAL
OLNLOA1C - OINCIAL
DATE FILMED
5 / 14 / 65


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- LEGAL NOTICE

.
This report was prepared as an account of Government sponsored work. Neither the United
States, nor the Commission, nor any person acting on behalf of the Commission:
A. Makes any warranty or representation, expressed or implied, with respect to the accu-
racy, completeness, or usefulness of the information contained in this report, or that the use
of any information, apparatus, method, or proces disclosed in this report may not infringe
privately owned rights; or
B. Assumes any liabilities with respect to the use of, or for damages resulting from the
use of any information, apparatus, method, or process disclosed in this report,
As used in the above, “person acting on behalf of the Commission! includes any em-
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END