ORNL-TM-3863.txt

 

  
  
   
   
    

ORNL-TM-3863

 

DESIGN AND OPERATION OF A
FORCED-CIRCULATION CORROSION TEST
FACILITY { MSR-FCL-1) EMPLOYING HASTELLOY N
ALLOY AND SODIUM FLUOROBORATE SALT

W. R. Huntley
P. A. Gnadt

MASTER

QISTRIBUTION OF THIS DOCOWENT 1S ORLMIT

 

 
 

 

 

This report was prepared as an account of work sponsored by the United
States Government. Neither the United States nor the United States Atomic
Energy Commission, nor any of their employees, nor any of their contractors,
subcontractors, or their employees, makes any warranty, express or implied, or
assumes any legal liability or responsibility for the accuracy, completeness or
usefulness of any information, apparatus, product or process disclosed, or
represents that its use would not infringe privately owned rights.

 

 

 

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ORNL-TM- 3863

Contract No. W-Th05-eng-26 -

Reactor Division

DESIGN AND OPERATION ”
| OF A FORCED-CIRCULA
TEST FACILITY (MSR-FCL-1) EMPLOYING Hfzstgglgggxz 128 o
ATIOY AND SODIUM FLUOROBORATE SALT

W. R. Huntley P. A. Gnadt
W

 
 
  

——————me— N O T | CE
This report was prepared as snt account of work |
sponsored by the United States Government, Neither
the United States nor the United States Atomic Energy
Commission, nor any of their employees, nor any of
their contractors, subcontractors, of their employees,
makes any warranty, express or implied, or assumes any
legal lisbility of responsibility for the accuracy, com-
pleteness or usefulness of any information, apparatus,
product or process disclosed, or represents that its use
would not infringe privately owned rights,

 

JANUARY 1973

OAK RIDGE NATIONAL LABORATORY
Oak Ridge, Tennessee 37830
operated by

UNION CARBIDE CORPORATION | | |
for the i

U.S. ATOMIC ENERGY COMMISSION

DISTRIEUTION OF THIS DOCUMENT 1S UNLIMITE
 

 

 

 

 

 

 

 

 
 

 

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CONTENTS

ABSTRACT veveeevvovaceassassssssossasssosasvasssassssnacsassassas
1. INTRODUCTION ...... s sesseassaseasscssarnanse ceeescerssesnas
2. DESIGN AND FABRICATION ..cvvecevascssccssccacccaasnses ceeenas
2.1 Design Criteria .....ccec0vcee resesstesastnsesensnans .

2.2 General Design Information ............ e eeeen
2.3 Detalled Design and Fabrication ..........ccccceeneee
2.3.1 Heater ...ccecevcececscsnccsnccoass Coeteraacae

2.3.2 COO0ler ...iieevscocrorsassonsncsonns trreevnane .

2.3.3 Salt pump «csvevcceness ceseesseavesscasessarsnce

2.3.4 Salt sampler ....... Cereereceneseatacttareaana

2.3.5 BF; system .......000000e ceeenereanaa ceeaese .o

2.3.6 Fill and drain ta8nK ...cevererertvccnnnccannes

2.3.7 ‘Corrosion specimen design ..... ceseseasssenene

2.3.8 Electrical system ......... ceeeens ceeseeiraans

2.3.9 Instrumentation and control ..........cc00cue

2.4 Quality ASsSUTance .......oeeeeeeees R Ceeeeionenans

3. OPERATING EXPERIENCE s veuvuvencnsensnnensnnrnennenrenenes
3.1 Heat Transfer Performance of Sodium Fluoroborate ....

3.2 BFy Handling ........ ceesecernas ceceessaccsorassereans

3.3 Salt PUmp OPETBtLON we.eeneenenenenennenenencnsenenns

3.4 Corrosion Specimen Removal ......ccveeeveennn. ceeeeas

3.5 Salt Sampling ..veeeeeseccrenseroonaessanasnnonsonnns
3.6 Summary of Corrosion RESULLE ...ceeeessvnsessasosnnns
CONCLUSIONS e v evenennnsnncncnsnsnnenenenennses
RECOMMENDATTONS s ¢« e e eeeseaensocanencnensassosnensesancnsnsns

) APPEND]X A- MSR-FCL-l FIIOWSHEE.P oaco.-co-oooo--oo-coccoooco.ocov
APPENDIX B. MSR-FCL-1 CONTROL SYSTEM DESCRIPTION AND OPERATING

PROCEDURES_FOR‘UNATTENDED OPERATION .ecvececscnes
APPENDIX C. MSR-FCL-1 SALT SAMPLING FROCEDURE .,.}............

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ACKNOWLEDGMENT

The fabrication end operation of the test loop were the joint
responsibility of the ORNL Metals and‘Ceramics Division and the ORNL
Reactor Division. The authors wish to thank the many personnel who
alded in the design, installation, operation, and posteoperational
examination of this test.

Special thanks are extended to the following personnel who were
instrumental in the success of the experifient.

H. E. MCCoy, Metals and Céramics Division, and R. E. MacPherson,
Reactor Division, for thelr guidance of the test program.

J. W. Koger, Metals and Ceramics Division, for metallurgical analy-
sis throughout the program.

H. C. Savage, Reactor Chemistry Division, for guidance of loop
operation during the latter portion of the test period and for the
Control System Description of Appendix B.

E. J. Breeding, R. D. Stulting, and L. C. Fuller, Reactor Division,
for their contribution to the detailed design of the system.
 

 

 

 
 

 

 
 

 

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DESTIGN AND OPERATION OF A FORCED-CIRCULATION CORROSION
TEST FACILITY (MSR-FCL-1) EMPLOYING HASTELLOY N
ALLOY AND SODIUM FLUOROBORATE SALT

W. R. Huntley P. A, Gnadt

- ABSTRACT

A forced-circulstion loop (MSR-FCL-1) was assembled and
operated to evaluate the compatibility of standard Hastelloy N
with sodium fluoroborate—sodium fluoride eutectic (NaBF,-8
mole % NaF) coolant salt at operating conditions expected in
the Molten-Salt Reactor Experiment coolant circuit. The salt
velocity in 1/2-in.-0D, 0.042-in.-wall tubing was nominally
10 fps. Hastelloy N corrosion specimens were exposed to the
circulating salt at temperatures of 950, 1030, and 1090°F.

The test has operated more than 10 000 hr at these conditions
and tests are continuing. This report is mainly concerned
with the design, fabrication, and operation of the facility.
Special problems related to accommodating the BFs vapor pres-
sure of the salt were resolved, and the sodium fluoroborate
demonstrated heat transfer characteristics that could be
approximated by conventional correlations such as the Dittus-
Boelter equation. Corrosion rates generally decreased with
opergting time; for example, the lowest coérrosion rate ob-
served for the 1090°F corrosion specimens during a 2900-hr
test interval was equivalent to 0.0003 in. of uniform materisal
removal per year. :

Kezgprds: molten salt, corrosioh, sodium fluoroborate,
Hastelloy N, design, operation, centrifugsl pump, mass trans-
fer, heat transfer, MSRE, unattended operation.

1. INTRODUCTION

The sodium fluorcborate (NEBF;—S mole % NaF) salt mixture is of
interest as a coolant for the secondary circuit of molten salt reactors
because of its low cost (~$0. 50/Ib) and relatively low melting point
(725 F) Screening tests in thermal-convection loops® indicate no seri-
ous problems due to reactions between the salt and the proposed reactor

containment material, Hastelloy N.

 

3. W. Koger and A. P. Litman, MSR Program Semiannu. Progr. Rep.
Feb. 28, 1969, ORNL-4396, p. 2L6.
 

The forced-circulation.loop'described here (MSR-FCL-1) represents a
more sophisticated test of the compatibility of the candidate salt and
Hastelloy N. High coolant velocities were used, and the design thermsl
gradient was applied to the system. The results from this test will
assist in the evaluation of the corrosion resistance of the Hastelloy N
containment material and the mass transfer interactions of the contain-
ment material and salt. Detailed metallurgical results will be presented
separately._ '

2. DESIGN AND FABRICATION

 

2.1 Design Criteria

The MSR-FCL-1 test was designed to evaluate the use of sodium fluoro-
-boratez salt in contact with Hastelloy N alloy containment material at
conditions simulating the secondary-coolant (high-temperature side of the
~ steam generator) circuit of molten-salt reactors.' One objective of the
test was to develop the technology associated with the new salt by using
it in a relatively complex operating system. -

‘The BFy vapor pressure of the sodium fluordborate salt is higher
(e.g., 1h1 mm Hg at the maximum loop temperature of 1090°F) then the
vapor pressure of other salts developed for use in molten—salt reactors.
Accommodating the BFy vapor pressure of the salt at elevated temperature
in MSR-FCL-~1 was a major design prdblem, since BF; is a noxious gas and'
s design to provide adequate ventilation for personnel protection was
required.

An existing system desigr® was used as a basis for MSR-FCL-1. Cen-
tringal pumps, air blowers, electrical transformers, and miscellaneous
_control equipment used in previous corrosion tests of this type were

 

®Unless otherwise indicated the term sodium fluorcborate will be
used in this report to designate the NaBF,—8 mole % NaF eutectic mixture.

8J. L. Crowley, W. B. McDonald, and D. L. Clark, Design and Opera-
tion of Forced-Circulation Testing Loops with Molten Salt, ORNL-TM-SQB
(May 1963).

 
 

 

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availsble. The reuse of the availsble instrument and conmtrol design and
the existing equipment resulted in a system of limited flexibility; how-
ever, these design features had been previously tested and funds were
only available for minimum redesign and fabrication of new equipment.

The hydraulic characteristics of the ekisting pump were g specific limit-
ing factor on loop performance. '

The facility was originally designed to operate for 10,000 hr and
to provide a maximm bulk fluid salt temperature of 1125°F, a bulk fluid
AT of 275°F at a velocity of T 1/4 fps (3 gpm), and a total heat input
‘of 94 kW. However, the ioop was not operated st these conditions. After
the originél design was completed and before the loop fabrication was
complete, the test conditions were changed to more nearly match the tem-
perature profile of the coolant circuit of the Molten-Salt Reactor Experi-
ment (MSRE), which was then operating. This modificetion to program plans
was a prelude to the proposed introduction of sodium fluorcborate into the
secondary-coolant circuit of the MSRE; The test facility was operated at
a maximum bulk fluid temperature of 1090°F, a bulk fluid AT of LLO°F at a
velocity of 10 fps (4 gpm), and a total heat input of 53 kW.

 Corrosion specimens were introducéd into the system at appropriate
" locations to obtaln accurate weight change, chemistry change, and metal-
lographic data. Periodic removal and reinsertion of the specimens were
specified at approximately 2000-hr intervals. Salt sampling at approxi-
mately 500-hr intervals was specified to permit chemical analyses nec-
essary for chargcterization of corrosion processes occurring during
operation. |

Protective instrumentation end an auxiliary power supply were pro-
vided in an attempt to prevent sccidental freezing of the'salt.due to
lose of normal electricai supply or & pump stoppage. Originally this
proteétive system was to be continuously monitored by facility operators;
however, evening and night shift operator coverage’fias discontinued
during the latter part of the operating period and the facility had to
be modified for unattended operation.
 

 

 

2.2 General Design Information

A simplified schematic drawing of the test loop is shown in Fig. 1,
and an isometric drawing of the equipment is shown in Fig. 2. A complete
flowsheet is included as Appendix A. Sodium fluoroborate is discharged
downward from the salt pump (model LFB) at a_temperatfire of 950°F and at
a flow rate of 4 gpm. The salt enters the first of two heat input sections
and is heated to 1030°F; flows over three Hastelloy N metallurgical speci-
mens; continues through the second heat input section, where the bulk
fluid temperature is increased to 1090°F; and:flows.over three additional
metallurgical specimens before being cooled‘in 8 hesat exchanger to 950°F.
The cooled salt then flows over two more metallurgical specimens before
returning to the inlet of the pump. S | ‘

The sglt inventory is stored in a sump tank located below the primary
piping system. A high-purity helium gas blanket is maintained above the
salt surfaces in this tank and in the pump to minimize salt.contamination.
A dip leg in the sump tank allows the liquid salt to be forced by helium
overpressure into the circulating system. The sump tank is designed to
contain approximately twice the salt volume to be circulasted. A freeze
valve serves to isolate the salt in the circulating system from the sump”’
tank inventory. This valve consists of a cooling air line installed
around the 1/h+in.-0D, 0.035-in.-wall tubing connecting the sump tank to
the circulating system. Piping of the circulating system is principally
1/2-in.-0D by 0.042-in.-wall Hastelloy N tubing.

No direct flow measuring equipment is provided in the circulating-
salt system; provisions are made to measure the flow calorimetrically.
Three calibrated Chromel-Alumel thermocouples are installed at both the
inlet and exit of one of the heater sections. By determining the thermal
losses from this section at several temperature levels with no salt in
the system, it is possible to obtain the net electrical heat input during
operation. Flow rates can then be calculated from the net electrical n
power input and the ohserved temperasture rise in the salt as it passed
through the hesgter. '

Engineering parsmeters of the system are shown in Teble 1, and com-
position and physical properties of sodium fluoroborate'are shown in
Table 2. | |
 

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SALT
SAMPLE
LINE AJUSTO SPEDE
5 hp MOTOR
— _ QIL LINES
[[ TO PUMP
GAS
LINES 050 *F
TO _
PUMP / METALLURGICAL
OPERATING "/ SPECIMEN
PRESSURE 7 psig 1030 *F
LFB PUMP RESISTANCE HEATED SECTION
1090 °F

 

    

METALLURGICAL
SPECIMEN

 

 

FINNED
COOLER

BLOWER

METALLURGICAL
SPECIMEN /HEATER LUG (TYPICAL)

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/‘-' RESISTANCE HEATED SECTION
950 °F

FREEZE

VALVE
E)—— AIR

VELOCITY 10 fps

FLOW RATE - 4 gpm
! SUMP I
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Fig. 1. Simplified schematic of molten-salt corrosion test loop.

 

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ORNL-LR-OWG 64T40RA

METALLURGY
SAMPLE

10 kva POWER SUPPLY - {DETAIL A)

{MAIN POWER)

 
 
  

1600-amp BREAKER

   
  

  

DETAIL A

   

 
 

METALLURGY
SAMPLE

LFB PUMP

    
 
 
  
 

 
   

OUTLET

 

DETAIL B

| 10kva POWER SUPPLY
lll (COOLER PREHEAT)

7~ DUMP TANK

 

Fig. 2. Molten-salt corrosion testing loop and power supplies.

 
 

 

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Table 1. Selected engineering data for MSR-FCL-l
Based on actual operéting conditions

 

Materials, temperatures, and velocities

 

Tubing and specimens Standard Hastelloy N
Nominal tubing size 1/2 in. OD, 0.042 in. wall
Total tubing length 57 £t

Bulk fluid tempersture (max) 1090°F

Bulk fluid temperature (min) 950°F

Bulk fluid AT 140°F

Flow rate ' Lk gpm

Iiquid velocity A 10 fps

Cooler heat transfer

 

Heat load at finned cooler 180,900 Btu/hr (~53 kW)
Iiquid Reynolds number B 45,000

Iiquid film heat transfer coefficient ~2000 Btu hr-t ££22 (°F)-?
Iength of finned 1/2-in.-OD cooler coil . 26 fit

Coolant gir flow 995§cfm

Coolant air AT 185 °F

~ Pumping requirements

System AP at 4 gpm 57.5 psi (65 ft)
Required pump speed 5000 rpm

 

Salt inventory being circulated

Volume in pump bowl 85 in.®
Volume in tubing 46 in.®
Total volume ‘ ) 131 in.%®
Total weight 8.81 1b
- Miscellaneous
Surface to volume ratio for circulating 7 in.2/in.3
salt ' : :
Volume of dump tank - - . 274 in.8

 

The possibility of leakage of BF, gas through the rotating mechani-
cal face seal of the pump or from the valvés:and'fittings in the pump
seal oil lines exists. To protect pefSonnel from this noxious gas, &
ventilated cabinet is provided to enclose the LFB pump and the‘gas sys- 1
tem. An induced draft blower exhausts the air from the cabinet through
ducts to the roof of the building.
 

 

 

Table 2. Composition and physical properties
of sodium fluoroborate

 

Composition (mole %)

NeBF, ; 92
NaF . | 8
Approximate molecular weight 10k
Approximate melting point (°F) 125
8 10,656
Vepor pressure; log,, P (mm Hg) = 9.02h4 — -—ffi
At 1090°F 140

At 950°F . , ’ | 29
Densityt’ (1b/ft3)'= 141.4 — 0.0247t ( °F) | |

At 1090°F o 11h.)

At 1020°F -~ 116.2

At 950°F 117.9
Viscosity P (1b £t hrl) = 0.2121 exp —E%QET

At 1090°F 2.86

At 1020°F 3,23

At 950°F 3.7
Heat capacity © [Btu 1v1(°F)"!] 0.360
Thermal conductivity & [Btu hrlft1(°F)~1]

At 1090°F 0.23

At 1020°F 0.235

At 950°F | - 0.2k

 

83. Cantor et al., Physical Properties of Molten-Salt
Reactor Fuel, Coolant, and Flush Salt, ORNL-TM-2316, p. 33
(Egust 1960).

: S Cantor, MSR Program Semignnu. Progr. Rep. Aug. 31,
_._2J2 ORNL-4449, pp. 1547,

®A. S. Dworkin s MSR Program Semiannu Progr. Rep Feb. 29,

J . W. Cooke, MSR Program Semiannu. Progr Rep. Aug. 31,
1969, ORNL-LL4Lg, p. 92. |
 

 

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In addition, a sheet~metal enclosure 1s provided around the salt

,plplng and hegt exchanger to protect operating personnel from gross
- liquid leakage. The system piplng is considered sufficiently reliable
to preclude the need for special exhaust ventllatlon from this enclosure
for protectlon against BF, leakage.. Favorable ventilation conditions

exist in the test areas, which has a 50 ft-high ceiling and continuous

exhaust ventllation
The test loop is shown in Fig. 3 durlng installation of the heaters

and thermocouples. Figure 4 shows the. completed 1nstallatlon

| 2.3_'DEtailed Design and-Fabrication

'2 3 1 Heater

The heat input into the salt is accompllshed by resistance ‘heating

‘two sections of the system piping, each approximastely 105 In. long.

Voltage is applied between two lugs attached to the ends of each heated

- length of pipe. Control is_common to both of the heat input sections

f2.3.2_'Cooler'

Heat is removed from the system by a heat exchanger composed of an

air-cooled, 26-ft-long, 19-in.-diam coil of 1/2-in.-0D by 0.0k2-in.-wall

tubing to which 1/16-in.-thick circular nickel fins are attached (see
Fig. 3). These fins are brazed to the tubing with Coast Metals 52 fur-

nace braze alloy. The finned coil is 1n31de a, sheet-metal housing which

‘ serves as the coollng alr duct.

The salt side pressure drop, as. llmited by the capacity of the salt

'rpump, prohiblts the use of & longer heat exchanger c01l Variations in
fin dlameter and spacing are. used to provide a hlgher heat flux at the

'dhot end of the,oooler. This.geometry creates a flattened salt wall tem-

perature:profile whichlmakesapOSSible'maximum heat-removal‘without cooling
the wall at,the cold end of‘the unit below the 725°F melting point of the
salt. [This feature was importafit during the design stages, when the
expected drop in the bulk fluid temperature was from 1125 to 850°F. It
 

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Test loop assembly during

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-mocouples.

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Fig. 4. Corrosion test loop installed in test stand.

 
 

 

12

became less important when the proposed operating conditions were changed
to simulate the Molten-Salt Reactor Experiment coolant circuit tempersture
profile (1090-950°F).] |

The cooler is resistance heated during preheating of the loop. This
resistance heat system is alSo used to keep the salt above the melting
point during loss of normal Building power. ,Hastelloy N lugs are installed
at the inlet, midpoint, and exit of the coil for attachment of three
electrical leads. The lugs project through holes in the air duét to give
access to the electrical connections. During a loss of normal power the
voltage is supplied to the central lug of the coil from a diesel-generstor
unit used for emergency electrical supply. o

A hinged door, provided on the air exit side of the cooler housing,
is closed to reduce the heat losses during preheating and is equipped to
close autdmatically during & power outage. The top side of this door
and the four sides of the air plenum are insulated with Johns Manville
Kaowool thermal insulation to further reduce the heat losses.  This insu-
lation is also used to plug the holes where the electrical lugs penetrate
the air duct.

Air to the cooler 1s supplied through appropriate‘ducting'by a
model 200-A-1 Americen blower with a 3-hp 1725-rpm motor which provides
& maximum air flow of 3200 efm air through the ductwork; However, in
normal operation the alr flow required is about 1000 c¢fm. A throttling
damper is provided to regulate the flow.

Selected engineering data on the actual performance of the cooler
are shown in Tgble 1, along with other engineering parameters of the

system.

2.3.3 Salt pump

The salt pump, model LFB, used in this corrosion test is shown in
Fig. 5. It is a centrifugal sump pump desighed et ORNL and features a
downward discharge. The pump has an overhung vertical shaft, two greése-
sealed ball besrings, and an oil-lubricated mechanical face seal above
the salt liquid level and just below the lower ball bearing. Shaft and
seal cooling are provided by oil which flows downward through the hollow
 

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ORNL—LR—DOWG 30958
" 3=—oIL IN
N1l
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23'/2in.
SPARK PLUG
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FACE SEAL - AN
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OIL OUTLET — 1 ‘
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== A

LIQUID LEVEL— l
eve 4 U]

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SALT INLET——EZ2 “, [\ l.

IMPELLER VANE +—— ey, i
- lDISCHARGE
9Y/5 in.——

 

Fig. 5. Molten-salt pump (model IFB).
 

14

shaf% through a rotary seal. The oil leaves through holes in the shaft
located Jjust above the top side of the mechanical face seal. The pump
requires a gas purge as described in Section 2.3.5. Pump performance
data taken with water are shown in Fig. 6. The model LFB salt pump was
 selected for this particular test since several pumps were available and
over 400,000 cumulgtive hours of successful operation had been experi-
enced in many previous applications at Oak Ridge National Laboratory.
The head capability of the pump is somewhat lower than desired, and the
acceptance of this limitation.resulted in 8 maximum liquid velocity of
10 fps.

The pump tank contains the only free liquid surface in the circu-
lating system during normal operation with the dump tank isolated by =
freeze valve. The pump is located at the highest point in the flow cir-
cult, and the pump tank acts as a liquid expansion volume. The liquid
level in the tank is indicated by two spark plug probes which have
Hastelloy N extensions welded to the center electrodes to make contact
with the liquid salt at preset elevations. A salt sampling apparatus
is provided at the pump tank, as described in Section 2.3.4.

2.3.4 Salt sampler

A cross section of the moltén-salt sampler is shown in Fig. 7. It
is used to remove salt samples from the pump tank at approximately 500-
hr intervals during the test program. (The test loop operation is not
interrupted during sampling.) The sampler consists of a dip tube with a
small copper bucket attached on the lower end which is lowered into the
molten salt in the pump tank. Vacuum and inert-gas back-filling con-
nections are provided so that the sampler assembly can be attached to
or removed from the pump tank-without contaminating the salt inventory.
A Swagelok fitting with Teflon ferrules acts as the packing giand on the
1/4-in.-0D dip tube. The Swagelok nut is loosened, as required, to per-
mit raising or lowering of the dip tube. The original bucket design had
a cépacity of about 2 g of sodium fluoroborste. A second separate com-
partment which holds about 0.5 g was added later to provide a separate

 sample for an oxygen analysis.
 

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Performance characteristics of the LFB salt pump in water.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

FLOW (gpm)

 
 

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SWAGELOK
FITTING

  
 
     
     
  

BUCKET:

VACUUM
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SAMPLE
REMOVAL SECTION

 

CORNECTION

PERMANENT
LOOP ASSEMBLY

BALL VALVE

  
 

      

LFB PUMP
AN B
§|§ __ MAXIMUM LIQUID LEVEL
o *L§ TTTMINIMUM LIQUID LEVEL
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Fig. T. Cross section of a molten-salt sampling device.
 

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17

2.3.5 BFa system

A relastively complex tubing system is provided to supply He-BF,
mixtures for use in purging shaft seal oil leskage from the salt pump.
A simplified schematic of the system is shown in Fig. 8, and the com-
plete system is shown in the flowsheet of Appendix A. Special pressure
regulators from Matheson Company with chemically coated nickel bodies
and Monel diaphragms are used on gas cylinders containing BFy . These
materials are used to resist attack by HF 1in case of moisture contami-
nation of the BFa gas. All gaskets, valve packings, or soft valve seats
were of Teflon or Kel-F, which are also resistant to attack by HF. A
standard 200-f‘t.3 capacity gas cylindér supplies a gas flow of about
80 cc/min to the reference side of a thermal conductivity cell; the gas
flow then continues on to the pump. The gas flow to the pump is used
to purge seal oil leakage from a catch basin and carry it to an oil
trap, from which the o0il can be drained manually as required. The gas
flow then returns to the thermal conductivity cell, where a comparative
meagsurement is made to detect any change of BF; concentration in the
helium.

It was originally thought that a 3% mixture of BF; and helium (for
a 950°F pump bowl temperature) would be necessary for the purge flow
through the seal oil leakage catch basin of the salt pump. This require-
ment was brought sbout by the fact that the seal oll leakage catch basin
and the gas space above .the salt level in the pump are interconnected,
and thus s possible path for loss of BFg'from the salt is creagted. The
use of a purge-gas mixture having the same composition as the gas in
the pump bowl would preclude removal of BF; and a resultant change in
salt composition. However, it was found in actual operation, as discussed .
in Section 3.2, that the use of He-BF; mixture was unnecessary. Since
the loss of BF; from the pump in a pure helium purge was too low to
Justify the COm?lications attending BF, addition, a pure helium purge
was used throughofit most of the tesf.

Most of the seal purge system is fabricated of 1/k-in.-OD by
0.035-in.-wall copper tubing. DBrass compression fittings are used exten-
sively. Check valves are used to preclude BFé.backflow into helium supply

lines or backflow of atmospheric moisture into the BF; -He vent lines.
 

Fig. 8.

18

ORNL-DWG 68-2795

 

 

 

 

 

 

 

 

 

 

    

 

  

FLOW Ha0
L .
INDICATOR CONDENSER
e I l/ ) |
~ THROTTLE oIL SALT
VALVE TRAP
Y
~\ SEAL PURGE
TO PUMP
\ GAS AND
THERMAL OIL FROM
CONDUCTIVITY CELL PUMP SEAL *

    
   
  

FLOW INDICATOR

THROTTLE VALVE

PRESSURE GAGE

PRESSURE REGULATOR

HELIUM-BF3 MIXTURE SUPPLY

Molten-salt forced-circulation corrosion loop — simplified
schematic — LFB pump seal purge systemn.

 
 

w

»

19

2.3.6 Fill and drain tank

 

The fill and drain tank is fabricated from a 23 3/16-in. length of
Hastelloy N, 5-in., sched-40 pipe with 1/2-in.-thick flat heads. The
five pipe risers located on the cylindrical surface of the tank provide
for salt addition and removal, spark plug level indication, and gas
pressurization. A drain line is provided at the bottom of the tank as
an additiohal path for salt removal. 'The tank is electrically insulated
from ground to prevent the flow of electrical current from the main loop
tubing, which is resistance heated during certain periods of off-normal

operation.

2.3.7 Corrosion specimen design

 

Corrosion specimens (see Fig. 1) are used to monitor corrosion rates
at the points of maximum, minimum, and intermediate bulk fluid tempera-
tures. The Hastelloy N specimens are approximately 2 5/8 in. long,

0.250 in. wide, and 0.030 in. thick. A total of eight specimens are
mounted in the three locations. Details of the corrosion specimens
design and mounting arrangement are shown in Fig. 9. The specimens are
mounted on the Hastelloy N stringers, inserted into the l/2—in. tubing,
and tack welded into position. The section of 1/2-in. tubing containing

the specimens is then butt welded into the system piping.

2,3.8 Electrical system

The electrical power system is shown schematically in Fig. 10.

Power is- supplied to the test facility from a 460-V, thrée-phase, delta-
connected building supply. A separate connection from a diesel-generator
provides emergency power to some of the equipment in the event of &
failure to the normal building supply.

Upon'failure of the normal supply voltage, the diegel-generator is
automatically started, and an automatic transfer switch connects the
emergency power éupply to thé facility. When normal pofier becomes avail-
able, the automatic switch returns the system load to this supply.

The heat input for normal operation is provided by two resistance-

heated sections. Voltage is supplied to these sections through a
 

 

 

 

INSERT TAB
AND THEN

TACK WELD STRINGER

20

ORNL-DWG 68-4294R

   
 
  
 
   
   

TACK WELD

CORROSION
SPECIMEN

TO INNER SURFACE

OF TUBE

Fig' 9.

Molten-salt test loop corrosion specimens.
 

21

LU

13.8kV/460V
200, 1000 kVA
3¢ TRANSFORMER

o

NORMAL POWER BUS

 

 
 
   
 
 
  

DISCONNECT
SWITCH

I
|

-

110 kVA
SATURABLE
REACTOR

110 kVA
4 20/40-76V

{600A AUTOMATIC
OPERATED CIRCUIT
BREAKER

)

1 MAIN LOOP
! HEATER

H

——————

_—

ORNL-DWG 72-9802
DIESEL

? GENERATOR
T EMERGENCY
- POWER BUS

1H

K—I-\UTOMI&TIC TRANSFER
SWITCH

 

 

)

o—+
N

CIRCUIT

N/
\—/

 

'BREAKER
3kVA 3kVA 25kVA
460/115V 460/115V - 460/230-115V
) S5hp 3hp 3hp LUBRICATION
LIGHTING INSTRUMENT AUXILIARY PUMP COOLER EXHAUST PUMP
AND POWER HEATERS MOTOR BLOWER BLOWER
MISCELLANEOUS MOTOR  MOTOR

"

 

N

. Fig. 10. Schematic of electrical power system.
 

22

saturable reactor, which in turn supplies g 110-kVA high-current trans-
former. Temperature is controlled on these sections by a variation in
the impedance of the saturable reactor.

During normal operation the circuit breaker, shown in Fig. 2, is
closed and the electrical potential is applied between the two sets of
lugs (A&B, C&D). This circuit bresker is opened manually to permit pre-
heating of the piping system (except cooler) and is sutomatically opened
to provide heat to all the system piping (except cooler) under emergency
conditions. When the circuit bresker is open, the electrical potential
is applied between lugs A and C, and the resulting two parallel electri-
cal resistance heating circuits keep the system temperature above the
freezing point of the salt. Power measuring instrumentation is provided
to determine the heat input to the system.

A separately controlled resistance-heated circuit is provided for
preheating the cooler. When normal power is lost, autométicrcontrols
also apply electric potential to this section of piping to prevent freez-
ing of the salt.

| Additional electric supply sources are provided for the salt pump
motor, lube oil pumps, the cooler blower motor, the BFg cubicie exhaust

blower, instrument power, and miscellaneous lighting and auxiliaries.

2.3.9 Instrumentgtion and control

 

The salt pump is driven by a 5-hp 440-V motor connected to a
variable-speed magnetic clutch. The clutch output torque is delivered

to the pump by V-belts. The speed of the coupled units is regulated by

varying the supply voltage to the magnetic coupling. The normal supply

is from an electronic unit furnished with the magnetic clutch. In the
event of the loss of the normal clutch control voltage, the loop is
automatically placed in a standby (preheat) condition.

Pump speed is measured by a tachometer built into the magnetic
clutch, and alarms are provided for low and high speed. The pump speed
is checked with a "Strobe" light at the beginning of each test run to
insure that the desired speed is obtained.

~ The loop temperatures are controlled by a Leeds and Northrup

"Speedomax-H" controller, which senses changes in loop temperature and
 

 

i

N

L 1]

23

transmits a signal to the saturable reactor to increase or decrease voltage
applied to the two resistance-hegted sections of the piping.

Controls are also provided to close the outlet dsmper on the radiator
air duct, stop the blower motor and the salt pump, and transfer the main
heat input to the preheat mode in the event of any of the following off-
normal conditions:

1. low clutch speed,

2. 8alt high tempergture,

3. salt low temperature, -

h. loss of normal power to the facility,

5. low lube oil flow to the salt pump.

Bypass switches are provided around most of these instruments to facili-
tate startup and to provide a means of testing the workability of the

control system during normal operation.
2.4 Quality Assursance

~Although the desgign of the salt circulating system was essentially
the same as had been used on a previous program, it was reviewed by the
_ORNL‘Pressure Vessel Review Committee.

Complete histories of the Hastelloy N used in the pressure-containing
portion of the loop were documented, except for the salt pump, which had
been febricated and assembled in accordance with ORNL Reactor Division
Standard Procedures in force at the time. Although records of the mate-
rials or welding were not available, the administrative procedures in
effect at the time of fabrication providéd assurance .of the integrity of
the pump. Since many of these pumps had been operated and hundreds of
thousands of hours of experience with this type of equipment had been
accumlated, it was felt that the reliability of the units was suffi-
ciently established to warrant their use without complete documentdtion.

The inspection of the materials used to fabricate the salt-containing

- portions of the system other than the pump included ultrasonic tests and

dye-penetrant checks in accordance with ORNL Metals and Ceramics Division
specifications MET-NDT 1 through L.
 

 

2L

WEIding of components and assembly into the system were conducted
in accordance with Metals and Ceramics Division specification PS-23, =
-25, and -35, which include welder qualification procedures, weld joint
design, and welding parameter limitations. Welds were inspected by x-
ray examination and dye-penetrant methods stated in Metals and Ceramics
Division specification MET-WR 200 and 201.

Material and cleaning requirements invoked during fabrication in-
cluded degreasing with perchloroethylene vapor, followed by water and
alcohol rinses. Before each part fias welded into the system, it was
agaln wiped with an alcohol-sosked cloth. Both the part and the cleaning
cloth were visually exsmined for evidence of foreign materisal.

All cleanliness, material, and weld inspections were made by person-
nel other than those having the responsibility for febrication and assem-
bly. Weld reports, which included the inspections and materials certifi-
cations, are on file with the Inspection Engineering Department.

Helium lesk tests were made on the completed piping assenbly prior
to installation of the pump rotary assembly into the pump bowl. Lesk
testing was done in accordance with ORNL Inspection Engineering Quality
Assurance Procedure T. No detectable lesks were observed.

All wiring was given a terminal-to-terminal check prior to energizing.
Each control function was checked manually to insure that the protective
schemes were operating properly prior to filling of the system.

Operational procedures, including sbnormal condition procedures,
were prepared to assist the operators. A complete description of the
operation of the control system was prepared (see Appendix B), and train-

ing sessions were conducted for the personnel
3. OPERATING EXPERIENCE

The test loop has been operated for 10,335 hrjat design conditions

~ for an additionsl 1135 hr at off-design temperature. A chart of the
operating history is shown in Fig. 11. For most of this time the system
was operated at 1090°F meximum bulk fluid temperature and 950°F minimum
bulk fluid temperasture. Figure 12 is & typlcal temperature profile of
the system. The inner wall temperatures are estimsted from heat transfer

calculgtion.
 

-

25

_ ORNL-DWG 72- 9803
Il OPERATION AT DESIGN CONDITIONS

| CONSTRUCTION OR REPAIR
[ ] sHAKEDOWN

 

DESIGN
STARTED

 

I | I | I !

ADDED SALT
TO DUMP TANK

660 hr ,
ISOTHERMAL
" OPERATION

REMOVED METALLURGICAL

    
 

10,335 hr TOTAL TIME
AT DESIGN CONDITIONS

1135hr TOTAL TIME AT

 

 

 

 

 

       
 

 

 

U/ /S ISOTHERMAL CONDITIONS
s l
CONSTRUCTION LOOP REACHED PUMP OIL SALT LEAK DUE
STARTED DESIGN BEARING FIRE TO OVERHEATING
~ CONDITIONS FAILURE
351 hr AUTOMATION
ISOTHERMAL OF LOOP
OPERATION
I l [ l i [ [
JULY JAN JuLy JAN JULY JAN JULY JAN
1967 1968 '

1969 : 1970 1971

Fig. 1l. Operating history of test loop.
 

26

ORNL-DWG 69-2535

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

| FRST | | SECOND | [ FINNED
IHEATER | | HEATER | COOLING COIL ']
[ | m m TO
go? s — @ P—H+H+H|—I—H—|+I—H—1-P+H-H—®-——pump
s
T 1 | @ METAL COUPON LOCATION
i | —— LIQUID TEMPERATURE
l | ——— INNER WALL TEMPERATURE
1300 |—i | ;
[ | ] i
| | i !
1200 i — E
| b _
1 ' | - 1
— 1100 e
& 1ot T
r” !
@ 1000 ———+ | —+- ~=——]
E ! | ] TS eI e
§ 900 ' t i |
= | | I
- 800 —1 | |
! | |
.
700 — L |
| | |
600 L | | |
0 10 20 20 40 50 60

LENGTH (ff)

Fig. 12. Temperature profile of molten-salt forced-circulation cor-
rosion loop, MSR-FCL-1, at typical operating conditions.

Y ]
 

w)

a

")

27

After raising the sodium fluoroborate from the sump tank into the
salt piping proper and establishing the freeze valve, the system is
started. The salt pump is started and the speed is adjusted to approxi-
mately 5000 rpm. The main power is transferred to the two resistance-
heated piping sectioné by closing the circult bresker, and the loop tem-
perature is increased by adjusting the temperature controller. The sys-
tem differential temperature is established by starting the blower and
adjusting the damper in the air system duct. For the initial startup a
flushing charge of salt was run in the salt piping for 478 hr, after
which it was discarded and the working charge of salt was installed.

The reliability of the system during the initial 10,000 hr of op-
eration was very good, but after this time seversl difficulties were

encountered. A pump bearing failure occurred, resulting in damage to

‘the pump impeller. Chips were rubbed from the impeller and deposited in

the sglt piping. Extensive repairs to remove these chips from the loop
piping were necessary. In addition, fatigue failuré of an oil line
resulted in an oil fire, requiring extensive repairs. Subsequently, the
loop piping was ruptured during an inadvertent overheating transient
cagused by a defective control thermocouple and ah operator error during
the replacement of the thermocouple. Table 3 lists the interruptions
that occurred during the operation period, over half of which (15) were
due to problems with component auxiliaries such as the pump rotary oil
seal and drive motor and the blower shaft bearings. Replacement bearings
in the blower and blower drive motor were reguired about every six months.

3.1 Heat Transfer Performance of Sodium Fluorcborsate

| Since no published heat transfer dsta were available for the sodium
fluoroborate salt, the heat transfer characteristics of sodium fluoroborate
were measured in the MSR-FCL-1. Provisions for these heat transfer mea-
surements were not part of the originsl design criteria, and the tests
were made with existing instrumentation which was not highly sophisticated.
Also considerable uncerfiainty'ekisted in available physical property data,
particularly on viscosity and thermal conductivity; so the sbsolute acéu-

racy of results obtained is questionable.
 

 

28

Teble 3. MSR-FCL-1 operational interruptions

 

 

Number
Item of

| failures
Rotary oil seal (Deublin) leskage 5
Salt pump bearing failures 3
Drive motor and clutch problems 6
'Air blower.besrings 2
Instrfifient mal functions 6
Electrical system difficulties L
0il line fatigue failure at pump rotary seal 1
- Other mechanical problems 2
Total 29

 

The heat transfer dats were obtained in one -of the resistance-heated:
sections of the loop piping. This section was 105 1n. in length and
O.hlo in. in inside dismeter. The tubing inside diameter was determined
by micrometers, and wall thickness measurements were made with a model 1L
Bronson Vidi-gage. The flow rate through the tubing was measured calori-
metrically by observing the power input and the temperature rise of the
salt. Heat losses at various temperatuie levels had bheen determinéd pre-
viously. The specific heat data for thé salt presented in Table 2 was
among the better defined physical property data and had an uncertainty of
29, The flow velocity was calculated using salt density data with an
uncertainty df 5%. Powei input meaéurémenté were madé fiith instruments
of iO.S% accuracy. | |

- The temperature measurements were made with 1/16-in.-OD stainless-
steel-sheathed,'insulated-Junction, Chromel-Alumel thermocouples. Bulk
fluid,temperatures at the heater inlet and exit were each measured by

three calibrated thermocouples. Ten thermocouples located along the

105-1in. length were used to obtain the wall temperature in the heated
region.
 

 

 

 

")

n

*y

1)

29

All thermocouples were electrically insulated from the tubing wall
to preclude an electrical path along the stainless steel sheaths, since
all portions of the plping were above ground potential during resistance
heating. Two layers of quartz tape provided electrical isolation from
the piping and also served to thermally insulate the thermocouples from
the pipe wall. The ends of the thermocouples were installed in a 180°
arc around the quartz-tape-covered tube and held in place with a band of
shimstock spot welded to itself. Two inches of "Hi-Temp" diatomaceous
egarth formed the thermal insulation for the piping. The detail on ther-
mocouple installation is presented to emphasize that the configuration
was not ideal for accurate temperature measurehent. The error between
insulated thermocouples and thermocouples installed directly on the pipe
wall was later determined to be less than 10°F. The overall AT from
pipe wall to bulk fluid ranged up to 100°F, so the thermocouple error of
10°F represents about a 10% uncertainty.

Performance data were obtained at heater inlet temperatures from
974 to 1060°F and heater exit temperatures from 1038 to 1170°F. The
Reynolds modulus ranged from 5500 t0751,h00, and heat fluxes ranges from
15,750 to 160,000 Btu hr ' ft™2. The measured heat transfer coefficients
ranged from 267 to 2130 Btu hr 1 £ft72 (°F)™'. The data obtained correlated
well with the Dittus-Boelter equation as shown in Fig. 13 (using recently
determined physical prOperty values from Teble 2). Although no statisti-
cal anslysis has been made, it is estimated that the error in the mea-
surements is less than 20%. These heat transfer data constituted the
first demonstration that sodium fluoroborate performs as an ordinary heat

transfer fluid.

3.2 BF; Handling

The LFB salt pump was designed to operate with approximately 80 ce/
min of helium purge through the pump shaft seai region to remove traces
of oil leaking through the rotating face seal (see Fig. 5). The vapor
pressure of the NaBF, component of the salt mikture, as shown in Fig. 1k,
produces a BFy partial pressure above the salt level in the pump bowl.

Since the helium purge tends to carry some of the BF; out of the system,
 

 

 

30

3 ORNL-DWG 68-13483R

HEATED SECTION Z/D RATIO=256
© EXPERIMENTAL DATA

)0.8

Mo
(T',,O'T =0, 023(~Rl

 

o' ' ;
103 2 5 104 2 5 i0°
REYNOLDS NUMBER

Fig. 13. Heat transfer characteristics of NaBF,-NaF (92-8 mole %)

flowing in 0.410-in.-ID tube.
 

31

L2

ORNL-DWG 72-9804
{000

500

200 |-

8

o
o

n
o

.}

BFy VAPOR PRESSURE (mm Hg)

10

n

10,656
r{*r)

. loqio P=9024-

 

1
800 900 1000 1100 1200 1300

TEMPERATURE (°F)

. Fig. 1k, Vapor pressure of NaBF,-NaF (92-8 mole %). (From ORNL-
T™™-2316. ) | |

&
 

32

it is possible to change the salt composition by gradual depletion of
the volatile constituent. As indicated by the NaBF,~NaF phase diagram
(Fig. 15), the freezing point of the salt mixture changes drastically
with a change in composition néar the eutectic. Therefore this problem
needed further consideration.

The helium purge, as originally installed, was through the seal re-
gion of the pump, which was loosely coupled through an annulus around
the pump shaft to the helium gas space above the salt level in the pump
bowl. It was assumed that BFs; vapors from the salt mixture would diffuse
up the shaft annulus into the seal region and be carried gway by the purge
gas. To avoid the problem of BF; depletion in the salt mixture, a system
was installed to permit blending BFs; into the helium purge to produce a
BF; concentration in the purge gas equivalent to the concentration in the
pump bowl. Thus, no net loss of BFs in the system would occur.

The possibility of chemical interaction of the BFy in the purge gas
with the oil in the seal region also had to be considéred, and preliminary
tests were run to see if a problem existed. The amount of BFy in helium

~ required to sustain the 92-8% salt mixture was calculated to be 1%, with

a pump bowl temperature of 850°F, or 3% with the pump at 950°F. Mixtures
of these two gases were prepared by adding the proper asmount of BF; to
bottles containing helium; however, confirmstory analyses for the concen-
tration of BFy in helium were unsuccessful. Checks with commercisl sup-
pliers of mixed gases revegled that there were no economical methods for
determining the BF; concentrations in helium in the 1 to 3% range. The
BF; gas adsorbs on the walls of analytical equipment, resulting in gross
inaccuracies in analytical results. Attempts at confirmatory analysis
were abandoned, and the concentrations were assumed to be those predicted
by the mixing calculations based on volume, temperatures, and pressures.
Tests were conducted to examine the effect of mixtures of 1 and 3%
BF; in helium of the Gulifspin 35 pump oil under conditions which would
simulate its use in the pump seal-oil purge system. The results for the
1% BF; mixture indicated that the seal leakage o0il would not be affected
deleteriously by contact with the mixture. Some discoloration and an
increase in acidity were noted in the oil after only a few hours of

exposure to the gas mixture; however, viscosity changes over a long
 

 

L1}

)

TEMPERATURE (°C}

33

ORNL-DWG 67-9423A

 

1000

g

 

8

 

 

3

 

8

 

500

 

H
3

 

 

300

 

 

 

 

 

 

 

 

 

 

 

 

 

200
NaoF

20 - 40 60 80 NGBF4
NaBF, (mole %)

Fig. 15. The system NaF-NaBF,.
 

 

3L

period gave no reason to suspect that the small passages of the pump seal
purge system would become plugged with degraded oil.

Results of two separate room-tempersture tests of approximately one
week's duration using the 3% BF; mixture with an oil leskage flow rate of
10 cc/day and a gas flow rate of 80 cc/min indicated that the seal oil
purge line would probably become plugged during loop operation; thus use
of this 3% mixture for purging was abandoned. A black sludge,lformed in
the test setup which simulated the pump catch basin, eventually plugged
a 1/8-in.-diam port (see Fig. 16). In these tests the oil removed from
the test gpparatus was extremely acidic, with g pH from 1.0 to 1.5.

Attempts to determine the composition of the oil sludge were unsuc-
cessful. Infrared spectrophotometrié exafiination indicated that traces
of water were probsgbly removed from the piping system by the sparging
gas and that the acid formed by the BF; -water reasction had attacked one
or more of the ingredients of the oil to form the sludge. Thé BFs also
produced, either as products of degradation or by direct addition to some
component or components, new materials not found in unexposed oil. No
further effort was made to characterize the degraded oil.

To eliminste BF; in the seal purge stream and the resulting oil deg-
radation, the purge route through the pfimp bowl was changed to provide a
pure helium purge gas flow down the pump shaft. It was thought that by
providing this purge, helium could be used to remove the legkage oil from
the oil catch basin in the pump and the helium flow down the shaft would
deter (except for back diffusion) the BFy vapor from reaching the oil.
This purge path required the addition of a new outlet gas 1line from the
pump bowl and a new line for BFy addition into the pump bowl. The BF
addition was required since the helium flow down the shaft and across
the BF; vapor space in the pump would carry off BF vapors in even greater
quantities than had been anticipated with the purge only through the face
séal region. After one day of operation the outlet line from the pump

'vapof space plugged with reaction products from the salt, oil, and BFj.

As’ an expedient, a decision was made to return to the original design

for purging the pump seal with no BF; addition to the purge stream. The

helium was connected to the pump seal purge line, and the effluent was
carefully monitored for BF; contaminstion. Measurements from the thermal
 

 

 

35

      

 

 

 

 

 

 

 

 

- | - - - PHOTO 7590
, o {
| I 1
| INCHES
| Fig. 16. Sludge formation from polymerization of Gulfspin 35 oil
after one week's exposure of 3% BFj;—He mixture at room temperature.

 

 

 

 
 

 

36

conductivity cell indicated that the helium gas (80 cr? /min) leaving the
pump oil cgtch basin was contaminated with approximately 0.08% BFy . This
indicated that the amount of BF; removed from the NaBF, salt during the
scheduled 10,000-hr operation would not significantly alter the salt com-
positidn. Had the BF; depletion been significantly high, plans were to
replenish the BF; by intermittent gas additions to the salt.

During calibration of a thermal conductivity cell which was to be
used to measure the concentration of BFy in the effluent line from the
seal purge line, a 1/h-in.-OD copper tubing vent line plugged. A 3%
mixture of BE, in helium had been purged through the conductivity cell
and vented to atmosphere in a ventilastion system. Reaction products of
‘moist alr and BF; completely sealed the end of the tube and stopped the
seal purge (see Fig. 17). An scidic solution was found in the vertical
line immediately adjacent to the discharge end of the tube, evidently
formed when the BFy gas came in contact with moisture in the air. Acid
was also formed on the ventilation hood in the vicinity of the BF-He
vent. Enough acid was present to form droplets on the lower edge of the
hood, which demonstrated that a suitable BF; "serubber" is required for
future systems where long-term, reliable venting of significant BF; con-
centrations must be maintained.

The low BFa concentration in the helium purge from the final con-
figuration of the shaft seal purge system resulted in little acid accu-
mulation at the gas purge line outlet. Inversion of the purge line out-
let port and the addition of a bucket-type catch basin helped to reduce
the plugging problem at the end of the purge line. No accumulation of
acid on the air exhsgust ducts was visible, but acid reaction products
were noted at the end of the purge line. As the buildup of these products

was noted, the open end of the copper tubing was either cleaned or cut off.
3.3 Salt Pump Operation

The major problems to be resolved by the use of the model LFB pump
in this test program involved (1) the effect of the BFy partial pressure
on the oil in the seal leakage catch basin and (2) the bearing and oil

seal performance at 5000 rpm for sustained periods of operation. The
 

 

 

 

 

 

 

i
i
i

 

 

 

 

 

 

 

 

 

 

*

"

.

 

37

i PHOTO 76078

 

, Fig. 1T. | Typical plugging formation where BFj3—He mixtures are vented
to atmosphere. R ) B B
 

 

38

problems relating to BF; reactions with the Gulfspin 35 oil in the pump
are described in Section 3.2. In addition the bearing and seal lifetime
was a point of concérn.since a pump of this type had not been used in
applications requiring thouSahds of hofirs of operation at the relatively
high speed of 5000 rpm. A series of idéntical pumps had been operated
at speeds around 3000 rpm and had demonstrated adequate reliasbility dur-
ing about 450,000 hr of operation.®

Normal operstion conditions for the pump were as follows:

Salt inlet temperature, °F 950

Salt flow rate, gpm | 4

Pump speed, rpm _ 5000
Coolant oil  Gulfspin-35
Coolant oil temperature, °F 110

Pump tank pressure, psig - 7.0

Pump tank cover:gas | Helium
Purge gas for seal leaksge Helium
Purge gas flow rate, ce/min 80

The pump was removed for routine maintenance at approximately 2000«
hr intervals to install new bearings. These bearings have a relatively
short lifetime expectancy of about 4000 hr at 5000 rpm. Normally this
maintenance period coincided with removal of the corrosion specimens from
the loop piping. However, three bearing failures occurred during opera-
tion despite the bearing replacement schedule.

The polymerizgtion of oil in the catch basin by reaction with BF;
was no problem during the 2000-hr operating periods. The leaking seal
0il was darkened by contact with the BF; and & black coating formed on
the bottom of the catch basin, but no significant plugging occurred.

This could be s problem, however, in a-systém where”periodic removal and
cleaning are not possible or perhaps where higher BF; concentrations are:
present. The seal oll catch basin at the conclusion of g typical 2000-hr

run is shown in Fig. 18.

 

4J. L. Crowley, W. B. McDonald, and D. L. Clark, Design and Operation

 

of Forced-Circulation Testing Loops with Molten Salt, ORNL-TM-523, p. 9
(May 1963).
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

*

3y

39

Fig. 18. Typical appearance of the seal 0il catch basin of the salt

pump after 2000 hr operation (model LFB pump).

 
 

 

 

40

The seal oil leakage rate has averaged approximately 1 ce/day (see
‘Pgble L4). The leakage rates were higher than average during short periods

neéar the end of the test, for reasons that were not discernible.

‘Teble 4. Seal oil leakage rates in

 

 

salt pump
removed operation - (cc/day)
12-9-68 13 3.5
10-18-68 9 2.
o-14-69 58 - 0.3k
3-25-69 39 10.51
T-22-69 - 1ok - 0.17
10-22-69 . 80 0.27
12-17-69 38 1.05
1-29-70 43 0.81
h-2h-T0 66 10.58
10-16-T0 . sl 0.90 -
10-19-710 3 20.0
1-11-71 L ol.0
1-12-T1 1 30.0

 

aAverage leak rate = 1 cc/day.

The seal leakage 0il is highly acidic due to its contact with BFj;
tests with litmus paper showed a pH of 1 to 1.5. Analytical results of
oll samples revesgled small amounts of dissolved boron. |

The mechanical faée seal appeared in good condition upon disassembly
at the end of each operating period. Although there were no indications
of impending trouble, the seal was changed as a precsutionary measure
during each pump maintenance cycle. The upper bearing normally showed

evidence of loss of most of its internal lubricant (grease); the lower

S L]
 

k1

bearing usually appeared in excellent condition, but both bearings were
replaced routinely. The upper bearing is affected by the drive belt
tension and operates under s heavier radial load then the lower bearing.
The condition of the upper bearing was ample evidence that when the salt
pump 1s belt driven, operation at 5000 rpm for 2000-hr periods was a
maximum practical service limit. -

' The sodium fluorcborate drained easily from the rather complex ge-
ometry of the salt pump. Normal draining procedure consisted in circu-
,'lating the salt at 1000°F and turning the pump at about 1000 rpm as the
‘1iquid level was lowered. Typical appearance of the salt-wetted portions
‘of the pump after a 2000-hr test period is shown in Figs. 19 and 20.

The white deposits are traces of frozen sodium fluoroborate salt.

3.4 Corrosion Specimen Removal

Corrosion specimens,are‘normally-xemoved for examination at approxi-
'metely 2000-hr intervals, but when operating problems were encountered
- they were removed more frequently. TneZSalt inventory was drained into
the sump tank, and the piping was cooled to room temperature prior to
specimen removal. An argon purge flow was maintained through the loop

during specimen removal to mlnimize air contamination of the inner sur-

~ faces of the remaining piping Tubing cutters were used to remove the

tubing that contained the specimens. Immediately after the specimens
were removed the open ends of the piping -rere sealed to allow slight
argonflpreSsurization;of the system while the specimens were cleaned and
inspected; o "_ |

The specimen stringers were retrieved from the tubing after grinding
the tack weld which joined them to the inner tubing surface. The grinding
was done carefully so that the specimens could be reinstalled in the same
tubing from which'they'were recovered, _The specimens were cleaned of
residusl salt droplets by placing them in warm distilled water for sbout
1 hr followed by ethyl alcohol washings and air drying. Specimen weights
were then measured and weight changes calculated.
 

 

|
1
i

 

 

 

 

 

 

 

42

Fig. 19. Appearance of the salt pump bowl after draining
1000°F at conclusion of 2000-hr run (model LFB pump).

PHOTO 96313

 

salt st

 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

0

 

43

   

PHOTO 9631tA

 

Fig. 20. Typical salt deposits remaining on support structure and
heat baffles of LFB pump after draining salt at 1000°F at conclusion of
2000-hr run.

 
 

 

L

3.5 Salt Sampling

Salt samples were taken at the start of the test and at about 500~-hr
intervals thereafter. The salt was analyzed prior to operation in MSR-
FCL-1 (Teble 5); the original salt charge contained high concentrations
of metallic impurities (Fe, Ni, Cr, Mo). The changes in concentration
of these impurities have been rather erratic with time, probably due to
inadvertent moisture contamination of the salt inventory. Some general
trends were observed in the salt analyses after several thousand hours
of operation. For eiample,‘the chromium concentration increased from
66 to ~250 ppm and thereafter remained at that generai level, the iron
concentration dropped from LOT7 ppm and remained at sbout 70 ppm, and the

nickel and molybdenum concentrations were reduced to less than 10 ppm.

Table 5. Analysis of sodium fluoroborate salt
prior to operation in MSR-FCL-1

 

Na - 21.8%‘

B 9.14%

F 67.9%

Cr 66 ppm
Fe 407 ppm
Ni 53 ppm
Mo 41 ppm
H,0 ~400 ppm®
0 ~400 ppm

 

aAnalysis questionable.

A cross-sectional view of the salt sampler is shown in Fig., 7. A
copper bucket is attached to the lower end of the sampler assembly, and
the assembly is then attached to a hydrogen furnace so the bucket is in
the heated zone, and the bucket is fired in hydrogen at 1100°F for 30 min.
After firing, the bucket is protected at gll times by an argon-atmosphere

while being moved to the test stand. The sampler container and holder is

C.
 

hs

attached to a Swagelok coupling on the pump tank riser. The volume be-
tween the two closed ball valves is evacugted and back filled with helium
at least four times before the ball valves are opened to lower the sample
bucket into the pump tank. The bucket is held below the liquid surface
for several minutes to insure filling, after which it is raised above the
lower ball valve and allowed to cool for 30 min. Tt is then withdrawn to
a position above the upper ball valve, and the valve is closed. The top
portion of the assembly, including the upper ball valve, is disengaged,
and the sample is removed from this assembly within a dry box. The de-

tailed sampling procedure is given in Appendix C.

 

3.6 Summary of Corrosion Results

The weight changes of the corrosion specimens in MSR-FCL-1 are
plotted in Fig. 21 for the entire operating period. The corrorion rate
gradually decreased during the first 9500 hr of operation.

The specimens operating at the highest temperature (1090°F) showed
the greatest weight loss, which was equivalent to a uniform metal removal
rate of 0.001 in./year after 9500 hr. The lowest corrosion rate occurred
during a 2900-hr period (6700 to 9600 hr), when the weight loss rate was
equivalent to 0.0003 in./year; Corrosion rates would probably be reduced
if more highly purified salt wére used.,

Operation difficulties after 9600 hr resulted in an undetermined
amount of air and moisture inleakage to the salt system. The drastic
effects of this inleakage are shown by the sharp increase in the weight
change at a salt exposure time of 10,000 hr. This behavior is similar
to that experienced in a £hermal convection test loop' when wet air came

in contact with the salt due to a defective cover gas line.

CONCLUSIONS

A materials compatibility loop was assembled and operated for
10,000 hr to investigate corrosion of Hastelloy N by sodium fluoroborate.
Automatic controls adequate to prevent damasge to the system due to

upsets during unattended periods of operation were developed and applied.
 

WEIGHT CHANGES (mg/cm?)

20

L6

ORNL-DWG T7i-4938R -

10

    
   

950*F
I
{030°F

-20

=30

-40 1090°F

0 2000 4000 6000 8000 10,000 12,000

Fig. 21. Weight changes of removable standard Hastelloy N speéimens
in flowing sodium fluoroborate (MSR-FCL-1).
 

 

»

b7

Corrosion specimens and salt samples were routinely removed for
analysis. ,

An existing salt pump design and available components were success-
fully adapted for salt cificulation, Operation of the salt pump, model
LFB, at 5000 rpm for 2000-hr periods is a maximum practical servicé con-
dition for the grease-lubricated bearings when the pump is belt driven.

Degradation of the salt pump seal leakage oil due to contact with
low concentrétions of BF; has not been a problem at a salt temperature
of 950°F during 2000-hr operating periods. In the LFB pump geometry,
diffusion of BFs vapors from the pump bowl gas space to the seal region
is sufficiently restricted that the BF, concentration does not become
critical. Thus purge flows to prevent this diffusipn are not necessary.
This results in a greatly simplified purge gas systém.

Heat transfer performance of the sodium fluorcborate agrees well
with standard heat transfer correlations.

Sodium fluorcborate exhibits good drainability at about 1000°F.

In well-ventilated areas relatively simple ventilation and shielding
enclosures may be used for low-temperature BF; tubing and gas panels
because of the visual warning provided by the "white smoke" which forms
from the reaction of BF; with molst air.

Sodium fluoroborate is easlly contaminated by air when in the molten
state, and great care to prevent air inleskage is required in all phases
of operation. |

The corrosion rate of Hastelloy N specimens at 1090°F averaged sbout
0.001 in./year during 9500 hr of operation and was reduced to sbout
0.0003 in./year during the last uninterrupted 2900 hr of operation. The
corrosion rate increased sharply with air inleskage. |

- RECOMMENDATIONS

:A new system design should be provided for future tests to achieve

~ improved pump capsbility and relisbility, higher salt flow velocity,

and a more flexible, rapid specimen removal technique.
Future tests should be designed to allow corrosion specimen re-
moval without dumping the salt inventory. This would prevent dilution
 

 

L8

of the circulating sslt inventory with the salt remailning in the dump
tank an& simplify interpretation of the corrosion processes. '

The design of future salt corrosion test loops should provide an
emergency heating system which will allow the pump to be stopped with-
out subsequent free21ng of the salt.

A sultable BF; "scrubber" must be developed for future sodium
fluoroborate pump systems, so that BFy vent lines cen be operated for
long periods without plugging, acid formation, or back diffusion of
vater vapor into the salt system.

The effect of sodium fluoroborate purity on corrosion rate should

be determined in future pumped corrosion test facilities. Techniques

for conbtrolled purification of the salt will be required.
 

+

k9

Appendix A

MSR-FCL-1 FLOWSHEET
 

w

dnm ngv 19 ag
MAIN DL

TO ANNULUS

SPECImIN

LI

NEATER Lve ~nEATER U8 'C”

" EQUIPMENT  |DENTIFICATION

EQUIPMENT LOCATION

RI& MOUNTED

oK GASCONTROL PANEL

AT REAR OF & Ab-CoNTAOL PANEL
N VENTILATED CUBICLE

fa PANEL MOUNTED

!O NOT PANEL MOUNTED
'

EXAMME OF RAUVIAMENT DEMANKTION

§ S EQUISMENT LOCATION
By —RQUIPMENT IOENTIECATION
VEA RQUIRMENT MUMBEA

SUMTER b
Suen Caromt Convoranen

FLOW SHEET

 

 

0%

 
 

e+ e

 

51

-Appendix B

MSR-FCL-1 CONTROL SYSTEM DESCRIPTION:AND OPERATING
PROCEDURES FOR UNATTENDED OPERATION

CONTROL SYSTEM DESCRIPTION

The control system of MSR-FCL-1 was revised during July and August
1970 to permit unattended operation of the loop during evening and night
:Shift'periods. ‘This deseription-is intended to assist in the operation
of the loop and to provide guidance in the event of any difficulties en-
countered during operation. ‘

The automatic control system is designed to transfer the loop opera-

tion from "design,"

or normal, conditions to "isothermal," or standby,
conditions in the event design limits are exceeded or a malfunction of
equipment occurs. |

‘The principal changes in the control system are (1) the circulating
pump is shut off in the event of an alarm condition, (2) loss of pump
iube and cooling oil flow is included as an alarm condition that will
transfer the loop to "isothermal," or standby, condition, and (3) a con-
trol was added to automatieally provide the proper amount of heat to

‘maintain the salt inventory molten with the pump off.
-Normal Operation

In the normai (design) mode of opefation; tfio-seotions of‘piping
between the pump dlscharge and cooler 1n1et ‘are heated by direct re51s-
.tance_heat. This heat is removed in the finned cooler to prov1de a
temperature dlfference in the circuit. An -LFB pump circulates the molten
salt, and a constant speed blower W1th a manually adjusted damper provides
~ air flow for heat removal from the flnned cooler. During normal operation
7;the follOW1ng conditions exist: L R ) |

1. _salt is. carculatlng in the lOOp and the pump is on-
’ 2."the pump 1Ubr1cat1ng and cooling 011 is flow1ng,
3. the two d1rect-res1stance-heated sections are supplled with- sufflclent

power to provide the desired temperature rise in the salt;
 

o2

. the air blower is on and the cooler housing door (top of cooler
housing) is open to provide sufficient cooling to reduce salt tem-
peratures to desired level; |

5. the cooler direct resistance heater is off.

Standby Operation

The loop is preheated by direct resistance heating during standby
operation except in the pump bowl section and the dump tank region, which
are heated by Calrod electric heaters. Direct resistance heat for normal
and standby operation is applied through three separaste control systems.
The two main heater sections (used for normal operation) are supplied
from one control system, and resistance heating of the entire loop (used
for standby operation) is controlled by a second control system. The
cooler is preheated by the third separate resistance hea#-control_system.
During normal (design) operation this heat will not be applied. With a
loss of salt circulation, the cooler hester circuit and loop resistance
heater circuit along with the pump bowl heat will maintain the salt in-
ventory sbove the freezing point. During standby operation the following
conditions exist: , - : ! - o
1. salt is not circulating; the pump is off (Note: <the pump may be op-

ergted, if desired, if the alarm interlock relay is manuslly bypassed);
2. the pump lubricating and cooling oil is flowing;
3. the loop direct resistance heater is energized with the circuit ar-
ranged to heat the entire loop except the cooler;
L. the cooler direct resistance heater is on;

5. the air blower is off and the cooler housing door is closed.

Automatic Transfer from Normal to Standby Conditions

A 1600-A circuit breasker installed in the main resistance heat supply
transformer secondary provides g means of transferring from high power
(normal) operation to standby operation. The following alarms will trans-
fer the loop from normsl to standby conditions- '

1. high loop temperature,
 

 

 

4

23

2. low loop temperature, .
3. low pump speed,
4., low lube oil flow (10 sec delay before transfer).

Emergency Power System

An automatic transfer is made to the diesel-generator bus in the
event of a bullding power outage. The design includes a time delay, §0
that for an outage of less than 2 sec, the loop will continue on AT op-
eration. For an outage of over 2 sec, the dilesel generator 1in the base-
ment (which will have started immediately upon a power failure) will be
timed in to provide control power, resistance heat to the loop, resis-
tance heat to the cooler, pump power, lube oil motor power, pump bowl
heat, dump tank heat, and drain line hest.

OPERATING PROCEDURES
Initial'Startup‘and Preheat

Refer to :flowsheet, Dwg. 10h86-R-001, Rev. 3, for valve locations
and functions.

1. Caution: Start oil pumps before applying heat to the system.to
prevent accldental overheating of the bearing and seals within the LFB

pump . . o . :
The two lubricating and cooling oil pumps are started by start

switches (lsbeled Nos. 1 end 2) in the magnetic emplifier cebinet. The
'pfimbs are in parallel in,the'oil circfiit;'ahd eithEr or‘both\pumps can
be turned on. With the control switch in the "off" or "preheat" position,
_ the pumps can be started or stopped by the "start" switches.‘ With the

control switch in the "on or "gutomatic" positiOn, operation of the lube

doil pumps is controlled by the lube oil flow switch. Onlloss of oil flow

the standby pump will be automatically started
2. Preheat the main loop by manually closing the 400-A fused safety

switch supplying the main resistance heater. The 1600-A circuit breaker

is open. Set bypass switches 13, 1k, 15, 16, 17, 18, and 22 in the
 

 

54
"preheat" position. The dc supply to the saturable reactor is "on"
through the magnetic amplifier. Set the potentiometer supplying power -
to the saturable reactor at ~10 on the potentiometer dial.
3. Preheat the cooler by closing the 30 A fused safety switch
supplying the cooler resistance heater circuit Automatic closing of
the contactor "CR" in this circuit is permitted through NC contact R8-6.

Bypass switch 16 (cabinet 2) should be closed ("down" position) manually

to prevent shutdown of cooler heater vhen reley R8 is energized.

., 'Close the 60-A fused safety switch supplying variable trans-
formers through the 15-kVA transformer. This energizes all auxiliary
heating circuits. i :

‘a. Close the fused safety switch labeled "Emergency Power Supply
to complete the circuit for diesel power if & building power failure -
occurs., | :

b. Heat dump tank to ~900°F. ('The dump tank heat should be turned
on ~12 hr before startup, as the tank heats very slowly.)

c. Heat the drain line (except the‘freeze_valve) to ~800°F.

5. Pressurize the loop with helium to ~3 psig.

a. Close the_30-A fused safety switch to the normal clutch supply
excitation. . - ) |

b. Close contaet push—button, closing the pump starter and also
feeding the clutch. Selector switch "Ss" is set at "ofg. " Relay R5 is
closed. o " -

c. Adjust the pump speed to ~500 rpm (cabinet 1).

d. et the low pump speed alarm at 400 rpm.

6. The pump seal purge ‘should be flow1ng through the thermal con-
duct1V1ty cell at ~80 cc/min. L
| 7. After all loop temperatures are at 850 to 1200 °F, position
valves for the loop filling operation as follows. Be sure all heater

'lug temperatures are at least 900°F. The valve position shown will ‘
sllow pressurizing the dump tank from one of the helium cylinders, Whlle

the second cylinder is used to maintain loop purge gas flow and pressure.
 

 

25

e ; Closed

Lf?

HV 19 HV 30
HV 20 HV 46
HV 21 HV 81
HV 22 -HV 83
HV 26 HV 84
HV 27 HV 117
HV 28 HV 139

i i i

8. Adjust the flow through FI 17 by opening HV 21 to ~0.2 fta/hr
9. Close HV 21. | _
~lO. Thaw the freeze‘plug*by closing HCV 110 and turning up the heat
on the fill line (Variac 8, panel 3). :
11. Open HV 22 and HV 81 to pressurize the dump tank slowly to push
salt into loop. Dump tank pressure of ~5 psi above loop 1s required for
loop fill. (PI 116 is located in pump enclosure. ).
12. Slow the gas flow to sump by closing HCV 16 when the lower pump
probe 1ight comes on.
13. Close HCV 16 when the top pump prdbe 1light comes on.
1k. Close HV 2kh. |
'15. Open HV 26 slightly to drop the salt level until the top probe
light goes off.
16. Close HV 26. | | |
17. TUrn off Variac 8 and start air flow through the freeze valve
by opening HCV 110. | |
18. When the freeze velve is frozen, open HV 26 to vent the dump
tank to ~h4 psig. |
- 19. Close HV 81, 26 and 82 |
20,“ Check the pump seal purge and the thermal conductivity cell
recorder | _
| 21; Blower and damper control.permissive relay R8 is noW'energized
by manually closing switch 15 ("down position) When the relay is
closed, it seals itself in through contact 38-3, paralleling switch 15
In order to permit shutdown of the blower and damper on long-time 1oss
of power, switch 15 is now opened manually ("up" or normsl operating
position). The cooler blover main control power (switchland bresker on

'~ the bresker rack) should be off to prevent blower startup until needed.
 

s s 1 s i\ v e e m e e ot s e e n o

 

 

56

22. Increase the pump speed to the desired level. For 4 gpm (~l0
fps) a speed of LBOO to 5000 is adequate. Check pump for excessive op-
erational noise, vibration,‘or.arpossible oll leak in the rotary union.

'23. With the loop temperatures sbove 950°F, manuslly close the
1600-A bresker (located on the east side of the loop enclosure) and
slowly increase the main resistance heat potentiometer to ~80% and turn
off the cooler heater by placing switch 16 in the operate (up) position.

24, When loop temperstures start increasing, turn on the cooler
blower using the start switch and the breaker on the breaker rack. The
sliding damper on the blower intake should be closed. |

25. Open the door on the top of the cooler hou31ng and engage the
) solenoid which will hold the door open.

 26. Open the sliding damper a little at a time as required to adjust
the loop temperature to the desired level. Lock the damper in the final
position for long-term operation. " | '

27. Flace all bypass switches (1 through 18, and 22) in the operate
or automatic p031t10n

28. Place the building alarm switch (No. 23) in the "up" position
to actlvate the building alarm and signal to the plent shift supervisor
(Pss). » |
29. Make final adjustments on the temperature controller (TIC-1,
cabinet 2) and the blower damper, as required, to obtain the desired

temperastures on the metallurgical specimens
Main Transformer — How to Control

The power to the main power subplyxis controlled by direct current
on a saturable reactor. With the potentiometer adjustment knob (Mag
Amp. Cab ) at zero, there is still some dc current in +the reactor which
gives what is called "dc’ leakage current" to the heater section.  If the
Pyr-o-vane controller cuts off de | completely, as ev1denced by the maln |
power supply alarm light comlng on, there is still available vhat is |
termed "minimum leskage current" to the heater ‘section.

Should the temperature reach the set p01nt)of the Pyr-o-vane, the
dec will be cut off and the loop transferred to isothermal conditions.

o/
 

 

¥

 

o7

Resistance heat will be reapplied as soon as temperature'has dropped .
below the set point. .Therefore, the Pyr-o-vane gives "on-off" control
of temperature should a high-temperature alarm condition occur.

When an alarm condition has occurred and the loop has been trans-
ferred to the standby conditioh, power for resistance heating of the
entire 1oop is controlled through the second potentiometer (Mag. Amp.
Cab.), which must be preset to deliver the correct amount of power to
keep loop temperatures gbove the salt liduidus'temperature (725°F) but
below ~1200°F. The correct setting for the isothermal heat is deter-
mined during startup and 1s indicated on the potentiometer scale,

Position of Control Switches During Normal OperatiOn

The following list of switches and controls includes a brief expla-
nation of each as to its function and position during normal operation.
| Note: The "up" position is the proper position for all switches
during normal operation with a AT, except switch 22, which is down or
in the "automatic" position.

1. Control Cabinet No._l

a. Switches 1 through 12 are alarm silence switches associated with
each of the 12 alarm lights. These_switchec'are'for acknowledging the
alarm condition and will‘silence the bell only. Whenever any of these
switches are in the "down" (acknowledge)'position, the blinker light
will be on.

. b. Clutch supply selector switch ("SB") will be 1in the "off" po-
sition to give normal power supply to the clutch. The auxiliary clutch
supply is disconnected , H

c. Switch 20, the building and plant shift supervisor (PSS) alarm

bypass, ghould be in the "up" position to allow building and PSS signal.

d. Switch 21, the loop containment eir flow alarm, has been re-

moved. This alarm now 1s located on,the_"Tigerman"_annunciator, and

this switch is no longer needed.=

Switch 22, during normal operation, should be in automatic"

'(down) position to allow pump shutoff for high and low temperature and
 

 

 

58

low pump speed. On "test" position the switch prevents stopping of the

pump automatically except on loss of oil flow:

2. Control Cabinet No. 2.

 

. " Switch 13, the low-temperature automatic-operation bypass, will
be left in open or "operate" position. When closed, it prevents automstic
operations -due to low tempersture. -Egtg: This does not bypass the sudi-
ble and visible alarms. T | o

Switch 1k, the automatic operation bypass switch, will be left
"operate" position. In "test" position it will prevent any of- the
automatic actlons from taking place and is to be placed in "test" position
only when testing the various alarm circults and during actual "preheating"

or "thawing" of the loop. |

c. Switch 15, the automatic operation relay reset, will be left in
the closed or “operate" position to allow sutomatic operation in the .
event of an alarm condition. The switech is placed in‘"operate"uposition
soon after startup of & loop to allow seal-in of relsy 8, whichrdirectly
performs the automstic operation. Thereafter, it will be used only to -
"reget" the automatic operation circuits (after the cause for same has
been cleared and the loop is ready to go back on.AT) | o
d. Switch 16 the cooler héater control switch, will be left in

open or operate position. ‘This allows’ relsy action to supply resistance
heat to the cooler in the vent of an alarm condition requiring it. On
"preheat” position it will allow heat to be applied to the cooler without

. an alarm condition.

e. Switch 17, the ‘main resistance hester switch, will be left in
the "operate" or closed position. This will allow the 1600-A breaker

to trip during an alarm condition. In "prehea " position it will prevent

trlpping of the breaker automatically. .

f. Switch 18, the low-speed and low-temperature reset, will be left
on closed or operate position. This serves as ‘a reset for either the
low-temperature or the low-clutch-speed slarm. ‘When the switch is reset
after a low-clutch-speed alarm, it will automatically place the clutch
supply back on the normal supply, provided it is available. When reset
after lov-temperature slarm, it will reset the alarm relay only.
 

 

o9

g. Switech 19 is not in use.
h. A summary table of the switch positions is presented in Table
B.1. | |

Hegter and Gas Controls During Normal Operation

1. The cooler heat control variable transformer will be preset dur-
ing starfup to provide sufficient heat to the cooler to prevent freezing.
This setting (indicated on front diasl) should be changed only if the
cooler heater circuit is in use and an adjustment of cooler temperatures
is necessary. , _ | ‘

2. The cooler preheat voltage meter gives an indication of the
voltage across the coolerjlugs,during"application of power to the cooler
coil. It is the only positive indication of power being applied (other
than temperatures) to the coil. |

3. The loop resistance heat control (the potentiometer in the Mag.
Amp. Csb.) will be preset during startup to provide sufficient heat to
the loop piping (except cooler) to prevent freeging if the loop is auto-
matically transfefred to isothermal or standby. The proper setting is
indicated on the potentiometer disl, |

4. The catch basin flowmeter ghould have a slight bleed of helium
(~80 cc/min) as indicated'by the flow indicator, FI 91, in’ the BF,
cubicle.

5. The pump pressure should be between 6 and 8‘psig (fihe pressure
recorder is in the pressure recorder cabinet).

6. The dump tank pressure ghould be between 3 and k4 psig.

7. The equalizer and vent valves.should,be closed (uv 84 and HV

- 83).
Abnormal‘Conditions,

1. Switch Positions During Standby

During standby (preheat), switches 17, 18, and 19 are open ("down"
position), as shown by the operation of alarm light L 11. During "operate,
all three switches are closed ("up" position) and the light is off.

"
Table B.1l. Control switch list

 

 

 

. _ S Position
Number Description Tocation Normal Preheat
' operation operation
1 Shuts off loss of normal clutch supply alarm Control cab. 1 Up Down
2 No longer in use :

3 Shuts off low-clutch-speed alarm \ Control cab. 1 Up Down
L Shuts off loss of power to pump motor alarm Control cab. 1 - Up Down
5 Shuts off loss of main power alarm Control ceb. 1 Up Down
6 Shuts off blower alarm | Control cab. 1 Up Down -
T Shuts off loop high-temp. alarm Control cab. 1 Up Down
8 Shuts off loop low-temp. alarm Control ecab. 1 Up Down
9 Shuts off low lube flow alarm Control cab. 1° Up Down
10 Shuts off loss of cooler power alarm Control cab. 1 Up Down
11 Monitors switches 17, 18, 19 Control cab, 1 Up Down
12 Monitors switches 13, 1L, 15, 16 | Up Down
13 Low-tempersture control bypass Control cab. 2 Up - Down
1L - Time delay relay test switch Control cab. 2 Up Down
15 Reset for preheat transfer control Control cab. 2 - Up Down
16 Cooler preheat control circuilt Control cab. 2 Up Down
17 Trip circuit bypass for main circuit breaker Control cab. 2 Up Down

18 Permits low-temperature and low-pump-speed | |

operation - | Control cab. 2 Up Down
20 Building and PSS alarm bypass - Control cab. 1 Up Down
21 No longer in use
22 Permits pump operation at high and low o -

temperatures .Control cab. 1 Down Up

 

09

 
 

 

 

"y

61

Switch 11 must be "off" during "preheat" to shut off bell and flasher.
When closed during "operate,” switch 11 will permit the bell and flasher
to function should any of the three switches be opened menually (human
error) .
During "preheat," switches 13, 1h, 15, and 16 are closed ("down"

position), as shown by the operation of alarm light L 12. During

"operate,” all four switches are open ("up" position) and the light is
off. Switch 12 must be "ope! during "preheat" to shut off the bell and
flasher. When closed during "operate," switch 12 will permit the bell .
and flasher to function in event any of the four switches should be

closed manuelly (human error).

2. Pump Speed Low
| Low pump speed will cause the following actions automatically:

a&. The pump ac motor, and thus the circulating pump, is stopped.

b. The blower is stopped.

¢c. The door on top of cooler housing is closed.

d. The 1600-A breaker is opened, and the loop is resistance heated
around entire circuit except for the cooler coil.

e. The power supply to the main loop resistance hester is switched
from the main.loOP heat control mode to the isothermal heat control mode,
which is preset to provide the reduced heat to the loop, as required, on
loss of salt circulation.

f. The resistance heat to the cooler coil is turned on.

g. A signal is transmitted to the Plant Shift Superintendent's (PSS)
office.

. 3. Loop Temperature High

A high loop temperature will cause the same actions as described .

in 2, above.

4., Loop Temperature Low

A low-tempersture alarm will cause the same actions as in 2, above.
 

62

5. High or Low Loop Heeter Power
High or low loop hééterip6wer will give local, building, and PSS
elarms only. -

-

6. High or Low Loop Pressure

High or low loop pressure will give local, building, and PSS alerm

- only.

T. ZLoss of Pump Lube Oil Flow

. If the pump lube oil flow falls below a preset value, the second
oil pump will be started automatically. If flow is not returned within
10 sec, the ac pump drive motor (and thus the salt circulating pump) is
stopped. |
63

Appendix C

MSR-FCL-1 SALT ‘SAMPLING PROCEDURE |

1. Install the sample bucket in the sample holder (Ref Dvg.
10486RO08E. |

2. Fire sample bucket at lower end of sample tube in the Reactor
Chemistry furnace &t 600°C for 30 min under hydrogen gas. Be sure to
light the hydrogen vent on the furnace during firing.

3. Lift the sample bucket out of the furnace to just below first
ball valve; let it cool under an argon gas pufge-fbr 30 min.

L. Lift the sample bucket above top ball valve (HV 114) and close
the valve to isolate the bucket with 10 psig of argon over pressure.
Close gas valve HV 137. Remove the sample holder assembly from the fur-
nace.

5. Install the sample holder assembly on the pump sample line,

6. Set the gas valves in the following order (Ref. Flowsheet Dwg.
10486RO01E): open HV 61 (for pump purge); open HV 13; open PV 14 fully;
open HCV 16, 19; close HV 20, 21, 22, 119.

T. ©Set the vacuum valves in the following order: close HV 132,
turn on the vacuum pump, open HV 122, 124, 138, 115, 113, 136. Pump
the system down to HV 137 and ball valve 112.

8. Close HV 138 (vacuum valve).

9. Open HV 119. Pressurize the system with helium to HV 137 and
ball valve HV 112.

10. Open HV 11k and HV 137.

11. Close HV 119 (gas valve).

12. Open HV 138 (vacuum valve).

13. Alternately pressurize the system,with helium and pump the sys-
tem down with a Welch mechanical vacuum pump at least four times.

14, Close HV 138 and open HV 119. - |

15. Open HV 112 (lower ball valve) and push the sampler to the
bottom of the pump bowl; leave it in this position for 5 to 10 min.

16. Lift the sampler above HV 112 (lower ball valve) and close
velve HV 112. |
 

 

6L

17. Let the ssmple cool for about 30 min.
18. Close HV 119; open HV 138. (pump on the sample to remove BFy
- gas).

19. Close HV 138; open HV 119; 1ift the sample above HV 114 gnd
close HV 11k; close HV 136, 113, 137, 115, 119. T:Lghten the Swegelok
fitting on the push rod. |

20. Remove the sample holder at the Swagelok fitting between HV
114 and 112 and between HV 115 and 137. |

~ 21. Close HV 13. o |
22. Deliver the sample to Metals and Ceramics personnel for

analysis.
 

 

 

O o1 v Lo+

88.
89.
90.

91.

Internal Distribution

External Distribution

D. F. Cope, RDT, SSR, AEC, ORNI

ORNL-~TM-3863

J. L. Anderson ks. M. I. Lundin

C. F. Baes 46. T. S. Lundy

S. E. Beall 47. R. N. Lyon

C. E. Bettis 48. R. E. MacPherson

E. S; Bettis 49, H. E. McCoy

E. G. Bohlmann 50. H. C. McCurdy

C. J. Borkowski 51. C. K. McGlothlan

G. E. Boyd 52. L. E. McNeese

E. J. Breeding 53. J. R. McWherter

R. B. Briggs 54, H. J. Metz

D. L. Clark 55. A. S. Meyer

J. W. Cooke 56. A. J. Miller

W. B. Cottrell 57. R. L. Moore

J. L. Crovley 58. E. L. Nicholson

J. H. DeVan 59. A. M. Perry

J. R. Distefano 60. R. C. Robertson

S. J. Ditto | 61-62. M. W. Rosenthal

W. P. Eatherly 63. H. C. Savage

D. E. Ferguson 64. Dunlap Scott

L. M. Ferris 65. J. H. Shaffer

A. P. Fraas 66. M. R. Sheldon

L. C. Fuller 67. M. J. Skinner

C. H. Gabbard 68. A. M. Smith

P. A. Gnadt 69. A. N. Smith

W. R. Grimes 70. I. Spiewak

A. G. Grindell 71. R. D, Stulting

R. H. Guymon 72. D. A. Sundberg

W. O. Harms 73. R. E. Thoma

P. N. Haubenreich 4. J. R. Weir

"R. E. Helms 75. M. E. Whatley

H. W, Hoffman 76. G. D. Whitman

W. R. Huntley - T7. L. V. Wilson

W. H. Jordan 78. Gale Young

P. R. Kasten 79. H. C. Young

J. J. Keyes 80-81. Central Research Library
J. W. Koger 82. Y-12 Document Reference Section
A. I. Krakoviak 83-86. ILeboratory Records Department
- | 87. ILaboratory Records (RC)

David Elias, USAEC, Washington, D.C. 20000
Norton Haberman, USAEC, Washington, D.C. 20000
Kermit Laughon, USAEC, OSR, ORNL
 

92,
- 93.
9h-96.

- 97-98.
99-115.

116.
117-118.

66

T. W. McIntosh, USAEC, Washington, D.C. 20000

M. Shaw, USAEC, Washington, D.C. 20000

Directorate of Licensing; USAEC, Washington, D.C. 205&5

Direczorate of Regulatory St.a.nda.rds, USAEC, Washington , D C.
20545 |

Manager Technical Information Center, AEC, for ACRS

Research and Technical Support Division, AEC ORO

Technica.l Informa.tion Center, AEC