sodium coolant: activation, species production coolant ... · sodium pollution 1/2 this coolant...
TRANSCRIPT
1ST IAEA WORKSHOP ON CHALLENGES FOR
COOLANTS IN FAST NEUTRON SPECTRUM SYSTEMS
IAEA VIENNA INTERNATIONAL CENTER, VIENNA, AUSTRIA
5TH -7TH JULY 2017
CHRISTIAN LATGÉ, L. BRISSONNEAU, TH. GILARDI
CEA-DEN
CEA Cadarache Nuclear Technology Department
(with contributions of Th. Gilardi, L. Brissonneau)
The data on this CD-ROM belong exclusively to the CEA : associated
intellectual property is CEA own property. Copies of this
presentation, or of any part of it, is forbidden without former written
CEA acceptance. CEA will not be responsible of the utilization of any
data of this presentation
“Sodium coolant: Activation, Species production
Coolant processing and handling procedures.”
INTRODUCTION TO SODIUM :
Na in the alkali metal family : Name coming
from arabic : al kaja meaning : ashes coming
from sea
PRIMARY CIRCUIT OF SFR (POOL CONCEPT) 1/2
Slab
Ar
Na
Heat
Hot plenum
Cold plenum Cold plenum
Primary pump
Intermediate
Heat
Exchanger
Steam
Or
Gas
(ASTRID)
Steam Generator Unit
Or
Heat Exchanger
Control plug
SODIUM ACTIVATION
a coolant which does not slow down the neutrons, and does not change fast spectrum
properties
a very limited activation* with short decay periods (22Na: 2.6 y, 24Na: 15 h),
* But must be of "nuclear grade” (see next slide)
low capturing power (small cross section)
Doesn’t produce any a contamination (ie 210Po)
NUCLEAR GRADE SODIUM (MSSA): SPECIFICATIONS
Activation
Clogging
Nuclear reactions
Clogging
Mechanical properties
Corrosion
Tritium
Corrosion
Nuclear reactions
………….
Gas blanket activity
Silver
Lead
Boron
Calcium
Carbon (total)
Chlorine + bromine
Lithium
Sulphur
Uranium
Chromium
Copper
Tin
Magnesium
Manganese
Molybdenum
Nickel
Barium
Potassium
Titanium
Vanadium
Zinc
Aluminium
MASS TRANSFER IN PRIMARY NA
| PAGE 6
Is due to solubility difference between hot parts and cold parts of species in the sodium
Steel solution in hot regions (bulk corrosion)
Precipitation in cold regions (bulk deposition)
| PAGE 6
2) Transfer in the flowing sodium
(parameters : T, velocity, [O])
Radioactive corrosion product transfer (54Mn, 60Co, 58Co, …)
3) Contamination of out-of-flux surfaces
(IHX, primary pumps, …)
• Diffusion in the steel
• Precipitation on cold surfaces
1) Release from the activated cladding
• Bulk corrosion of cladding steel
• Preferential release of highly
soluble elements
1
3 3 Industrial issues of
contamination
• Personnel exposure
to radiation during
maintenance & repair
• Maintenance equipment
design (reactor building
size)
• Waste management
• Decommissionning
Mass transfer (Fe, Ni, Cr, …)
Modeling with mass transfer codes (CEA, JAEA,
Russian Federation, India, USA...)
CONTAMINATION OF IHX
| PAGE 7 7
Evolution des activités le long de l'EI B
0.1
1
10
100
1000
-9500-8500-7500-6500-5500-4500-3500
Côtes (mm)
Ac
tiv
ités
(kB
q/c
m3)
54Mn
58Co
60Co
Higher contamination at low temperature but less in depth
550°C 400°C
Activity for main radionuclides along PHENIX IHX B
RESULTS OF SIMULATION WITH OSCAR-NA CODE
| PAGE 8
| PAGE 8
Measurements
°C 550 390
OSCAR-Na calculation 480 °C
Deposition Corrosion
(β D / uc).C’
(β ud / λ).C’
(K / λ).C’
The global amount of contamination as well as the contamination profiles on PHENIX IHX
are correctly simulated with OSCAR-Na
(K / λ).C’
480 °C
(β D / uc).C’
(β ud / λ).C’
Corrosion Deposition
IHX temperature
MAIN RADIO-CONTAMINANTS
| PAGE 9
54Mn 5426Fe (n,p) 54
25Mn g emitter 835 keV 55
25Mn (n,2n) 5425Mn period: 312 d
51Cr 5024Cr (n,g) 51
24Cr g emitter
5224Cr (n,2n) 51
24Cr period : 27,7 d
5426Fe (n,a) 51
24Cr
58Co 5828Ni (n,p) 58
27Co g emitter
5927Co (n,2n) 58
27Co period: 70,8 d
60Co 5927Co (n,g) 60
27Co g emitter
6028Ni (n,p) 60
27Co period : 5,27 a
1, 17 et 1,33 MeV
10
FISSION PRODUCTS IN SODIUM
(If pin rupture)
Radiocesiums 134Cs 136Cs 137Cs
Période : 2 y 13 d 30 y ; g ; 0,66MeV
Importance : Quantities and period
Might be trapped in carbon trap (and NaCrO2 deposits ?)
Enrichment in gas phase
Radioiodes 131 I 133 I 135 I
Period : 8 d 21 h 6,6 h Short, can be trapped in cold trap
Strontium 90 Insoluble in sodium, in oxide form (originates from 90Rb, 90Kr, 90Br solubles) b emitter, period 29 a, 2,2 MeV Found in primary pumps (EBR II)
11
FISSION PRODUCTS IN COVER GAS
Xénons
135Xe 131 Xe 133Xe Period : 12 d 5 d 9 h
Kryptons 85Kr 87Kr 88Kr
Period : 10,8 y 76,3 m 2,8 h
Rapid release if pin rupture, no dilution in Na
Xe : very short period
Kr : easily vented during shutdown.
SFR’S PROCESSES DEDICATED TO NA & NA CIRCUITS
- Purification with cold traps, filters, hot
trap (getter)
- Na aerosols condensers
- Cleaning in « cleaning pits »
- Structural material decontamination
- Na treatment (conversion into NaOH
with « Noah » process)
- Residual Na carbonation
- Cold trap regeneration/treatment
- Na wastes conditioning | PAGE 12
Sodium pollution 1/2
This coolant needs to be purified because of a potential accumulation of
impurities such as oxygen and hydrogen and their deleterious consequences.
These pollutants can be introduced during the operation of an SFR.
In the primary circuit:
- main discontinuous source of contamination due to O & H:
adsorbed gasses & metallic oxides less stable than Na2O,
- contribution of O to steel corrosion in core,
- activated corrosion products transported towards the
components: Intermediate Heat Exchangers (IHX)…
- contamination (60Co, 54Mn…) & dosimetry during
handling and/or repair.
generally considered that an SFR must be operated
with [O]< 3 ppm in normal operation in order to control the generalized corrosion.
nuclear reactions in fuel and boron carbide : a very small continuous source of
tritium in the primary vessel which permeates through the IHX towards the
intermediate loops.
Some fission products if fuel cladding failure (137Cs…)
| PAGE 13
Sodium pollution 2/2
In the intermediate loops:
- main continuous source: hydrogen due to hydrogen diffusion in steam generators (SGU)
through tube walls, due to aqueous corrosion on the water side and also to the thermal
decomposition of hydrazine, used to control the oxygen content in the water.
- main potential discontinuous sources:
- sodium water reaction event: H2, NaOH and potentially
Na2O and NaH crystallized products.
strongly exothermic & extremely fast and may be inducing
cracks in the neighboring pipes.
[H] controlled at a low level (< 0.1 ppm) to detect asap a
potential event in SGU producing.
Risk of deposits on the cold walls (Na2O & NaH), plugging
of narrow sections, reduction of heat transfer coefficient in IHX.
- contamination of the residual amount of Na by air and moisture, after draining, prior to
handling and/or repair operation, inducing deleterious effects, mainly due to stress
corrosion cracking induced by aqueous soda.
In all circuits:
- Potential oil ingress (pumps)
- Metallic filling due to maintenance, etc…
| PAGE 14
SOLUBILITIES OF O AND H IN SODIUM
0,01
0,1
1
10
100
1000
10000
100
130
160
190
220
250
280
310
340
370
400
430
460
490
520
550
580
Temperature, °C
[O], ppm
[H], ppm
log [ ( )] ..
( )10 6 2502444 5
O ppmT K
log [ ( )] .( )10 6 467
3023H ppm
T K
Noden solubility law Wittingham solubility law
O and H solubilities are
negligible close to 97.8°C
Consequences: Na can be
purified by Na cooling,
leading to
crystallization of O and H
as Na2O and NaH
in a "cold trap"
Quality of Na has been always well mastered
with cold traps, in normal or transient situations
(start-up purification, large air pollution in SPX)
C. LATGE, “Sodium quality control, In International
Conference on Fast reactors”, Kyoto, Japan,
(December 2009).
14 JUILLET 2017 | PAGE 16
HOT TRAPS
COLD TRAP: PRINCIPLE
14 JUILLET 2017 | PAGE 17
14 JUILLET 2017 | PAGE 18
COLD TRAP: MODELING
14 JUILLET 2017 | PAGE 19
Purification based on cristallization of impurities (H, T and O) by cooling down the
temperature of sodium
PSICHOS (SPX,
now CHEOPS)
Concept with 2 zones
Solubility of O and H in liquid sodium
satNa
TrapCold
T HHDH
T][][
][
][
PIRAMIDE (EFR
now ASTRID)
Concept with global
modular cooling
Wittingham
Noden
New generation of cold traps
OXYGEN-METER USED IN 80’ 90’
Electrochemical cell : Thoria dopeed with Yttria,
Reference electrode : air, In/In2O3
Developed by Harwell laboratories (UK)
Currently new developments in CEA:
thoria doped Yttria and HfO2-10%Y2O3
0,5
0,525
0,55
0,575
0,6
0,625
0,65
0 0,5 1 1,5 2
E(V
)
log Co(ppm)
S
E
14 JUILLET 2017 | PAGE 21
HYDROGEN-METERS
STANDARDIZED PLUGGING-METER
air
temperature
air
Na
Na
Chamfered edge
12 grooves
PLUGGING METER : T PLUG AND T UN-PLUG MEASUREMENT
time
temperature
flowrate
initial flow rate Qn
0.5 Qn T plug
T un-plug
high T stage
low T stage
TsatO = TbO + DT
TsatH = TbH + DT
TbO and TbH = Tb, measured by the
plugging Meter, a non specific device.
Operating parameters :
- Tmax = 350°C , in order to dissolve residual NaCrO2.
- Cooling rate : 3°C/min
- Qmin = 50% of nominal flowrate (if pollution increases, possibility to increase this value up to 80%).
PRODUCTION OF TRITIUM AND
TRANSFER INTO PRIMARY SODIUM
2 main sources of tritium production in the reactor core:
14 JUILLET 2017 | PAGE 24
Fuel ternary fissions (239Pu) A source production based on 3 parameters:
yT: fission yield (atoms T / fission)
a: number of fissions / thermal energy unit (fissions / J)
Pth: thermal power of the reactor: (W)
Fission yield can be based on the raising value for 239Pu and recent measurements with
lower uncertainty: yT ≈ 1,4258.10-4 7,1.10-6 atom T/fission
O. Serot & C. Wagemans (1999) - C. Wagemans (2001)
Number of fissions / energy unit in SFR fuel: a ≈ 3,2.1010 fissions/ J
Retention rate in SFR fuel pins is negligible :
fuel claddings made of steel permeable to tritium fuel ≈ 0
PWR fuel claddings made of zircaloy Zr gettering effect (over 90% retention in
zircaloy claddings) due to tritium affinity with Zr and limited diffusion in ZrO2
Neutronic flux profiles can be taken into account thanks to radial and axial discretization of
the fuel core more precise evaluation of the tritium source term from ternary fissions
Tth
fuel yPsTatomsST
a)/(
PRODUCTION OF TRITIUM AND
TRANSFER INTO PRIMARY SODIUM
14 JUILLET 2017 ESNII+ European workshop | 2016 OCTOBER 5-7 th | PAGE 25
Neutronic reaction with 10B in B4C (control rods, neutron shielding) A source production based on 3 parameters:
N: 10B enrichment rate (atoms 10B)
: absorption cross section (≈ 3,2.10-27 cm2/atom 10B)
: neutron flux distributions (neutrons/cm2/s)
Retention rate in B4C: Thermal and Neutronic flux profiles along with control rods
must be taken into account:
if T < 650°C: the stable formation of LiT induces total retention of tritium in B4C
if T > 650°C: LiT decomposition reduced and temperature dependant retention
(wide range variability between 90% and 10%)
Transfer into primary sodium From fuel ternary fissions ≈ 100% of tritium production is released in sodium
From B4C (control rods and protections) important retention («B4C ») depending on
temperature (≈ 0% is released if T < 650°C)
NsTatomsS CB
T )/(4
CB
T
CBfuel
T
global SSST 44 )1( Typical value for a SFR(1) : STglobal ≈ 1100 TBq/GWe/year
(1) ASN « Livre blanc du tritium » 2014 (http://www.asn.fr/sites/tritium/ )
2 main sources of tritium production in the reactor core:
Permeation through metallic walls
Major part of tritium transfers between circuits
Main contributions for permeation through:
IHX tubes (Na Iary Na IIary) , sodium
circuits pipings (Na air atmosphere)
Complementary cooling down circuits
Cristallization of tritium in cold traps
Co-precipitation of NaT compound with higher
amounts of sodium hydride NaH due to hydrogen
production in tertiary circuits (water corrosion) and
permeation through steam generators towards
secondary sodium
Major contribution of tritium trapping in secondary
cold traps due to hydrogen higher concentrations in
favour of co-precipitation
Modeling with KUTIM code (TTT code in Japan,....)
| PAGE 26
MAIN TRITIUM TRANSFERS TO BE CONSIDERED
IN A SFR REACTOR
EVALUATION OF TRITIUM TRANSFERS IN SFR CIRCUITS
Modeling of hydrogen/tritium balances by KUTIM code
Transfers and physico-chemical behavior described in KUTIM code Material balance under steady state on both hydrogen isotopes H and T in each circuit
Assumption: all structures assumed in the diffusion steady state
14 JUILLET 2017 | PAGE 27
Fluid circuit or capacity « i »
Data:
Mass of fluid, flow rate
Unknown variables:
Concentrations
Material balance:
OUTINTorHfluid FFSdt
TorHdM
Flow [H]i , [T]i
Inlet permeation through metallic
walls (IHX, EPuR, inner vessel, SG)
Outlet permeation through metallic
walls (IHX, EPuR, inner vessel, SG,
pipings and storage capacities
Chemical equilibrium H- T
in gas phase:
H2 + T2 2 HT (Keq)
with [HT] >> [T2] in gas phase
Cristallization in cold traps:
formation of NaH and NaT crystals
Radioactive decay of tritium (KD)
Source of tritium released in primary
sodium through (from the core into
primary sodium only)
14 JUILLET 2017 | PAGE 28
FILTERS
14 JUILLET 2017
Up to now no mandatory for SFRs
| PAGE 29
ACP GETTERS
14 JUILLET 2017 | PAGE 30
CS ADSORBERS
14 JUILLET 2017 | PAGE 31
AEROSOL CONDENSERS
Na mass transfer in cover gas; impact on safety
| PAGE 32
• The concerns attached to these phenomena are:
- A correct knowledge of the temperature of structures, thermal stresses induced, and justification of the mechanical design,
- A correct assessment of the risk of sodium aerosols deposits that could induce perturbations in the correct operation of all the mechanisms quoted above. The facility could contribute to tests of such mechanisms
- A correct prevision of the location of those deposits, with the view at dosimetry concerns at the dismantling stage of the reactor, and even if experiments will be made only with stable isotopes.
- Finally the validation of the design of
the so-called upper closure of the main
vessel (temperature of the reactor upper
slab and cooling circuits dedicated, design
of penetrations)
Main influent parameters :
Vessel diameter (if increase, R decrease)
Saturation vapour pressure (related to
latent heat of evaporation)
Targon (ex: PHENIX (1974) (fresh argon inlet
position),
Gas velocity and local thermal-hydraulics
(over the Na)
DT Na/roof
Based on Sh = 0,643.(Gr.Sc)0.25 (Boolter relation)
Revap = 0.643 D.rs/F . (Gr.Sc)0.25 kg/s.m2
With Gr = g. F3/n2.(1-gs/ga) And Sc = n/D
With : D = diffusion coefficient (m2/s)
r s = Na density at Na-gas interface (kg/m3)
F = diameter of the free surface (m)
n = viscosity (m2/s)
g = 9.81 m/s
gs = gas density at Na-gas interface (kg/m3)
ga = gas density at infinite (kg/m3)
OLIVIER.GASTATALDI@
CEA.FR
CLEANING and DECONTAMINATION
Definition Cleaning concerns all the operations used to remove the sodium from the walls
of a vessel or a component to prevent the chemical risk (combustion, corrosion)
and facilitate the dismantling
Cleaning is always done with the aim to re-use the component (in operation)
By eliminating the sodium, sodium activation products and other radionuclides (ie 137Cs) in sodium are also removed:
It corresponds to the first decontamination phase.
The aim of decontamination is to remove the radionuclides (strongly) deposited or
that diffused in the component.
Lower the dose rate at levels acceptable for component manual handling (repair…)
≈< 100µGy/h contact
And preserve component integrity
OLIVIER.GASTATALDI@
CEA.FR
CHARACTERISTICS OF CLEANING AND
DECONTAMINATION PROCESS
It must be efficient
It must not be aggressive versus the material (if it
must be re-used)
It must be safe
It must produce a minimum of effluents
It must be relatively fast
It must comply with an industrial scale
Need of compromises
Speed / efficiency / cost / wastes
OLIVIER.GASTATALDI@
CEA.FR
METHOD USED IN PHENIX
Cleaning by CO2 bubbling
The component is introduced in the cleaning pit
The pit is filled with a small quantity of water
The carbonic gas bubbles in the water and the
humidity generated reacts with sodium.
If reaction too slow water is re-heated :
increases dew point more water circulates
Operating parameters :
the % of H2,
the component temperature,
the pit pressure
OLIVIER.GASTATALDI@
CEA.FR
IN SITU CLEANING PROCESSES
WVN or WVCO2
H2 bubbles
wet N2 flow
Gaz boundary
layer
Hydrous
Soda
SODIUMReaction zone
Water diffusion towards interface
Dry Soda
Process is controlled :
% of H2
dew point at inlet and outlet of gas
CO2 is preferred except if risk of
plugging by carbonates
Water should be avoided if a risk of
aqueous soda flow on large
sodium retentions.
OLIVIER.GASTATALDI@
CEA.FR
CLEANING METHODS
Vacuum evaporation
Wrongly called vacuum distillation
Consists in heating the component to evaporate sodium
Boiling point of sodium
880°C at atmospheric pressure
315 < T < 500°C at 5.10-6 < P < 4.10-3 bar
Advantages
No chemical compound introduced
No corrosion risk
Drawbacks Heavy method to implement Significant strains on the component No effect on sodium oxide... Requires rinsing phase
OLIVIER.GASTATALDI@
CEA.FR
METHOD USED IN PHENIX
Vacuum cleaning
No spraying ramp in PHENIX pits
Pit is under vacuum (-400 mbar)
cold steam
Inert gas is CO2 carbonation
Advantages :
Good efficiency
Low temperature reached
Limited corrosion with CO2
Drawbacks
Control of reaction
Pit in partial vacuum
Risk of carbonate barrier
between water and sodium
OLIVIER.GASTATALDI@
CEA.FR
CLEANING METHODS
Use of alcohols : issues
Problem of reprocessing of active organic effluents (potentially tritiated)
Problem of inflammability of the alcohol
Problem of initial cost
Hazards with alcool-alcoolate degradation (« Ethylcarbitol *») (accident close to Rapsodie in
March 1994, then in KIT Germany in 1995) (use of heavy alcools prohibited now)
• CH3CH2OCH2CH2OCH2CH2OH
Ref: P. Marmonier, J. Desreumaux, 'Alcohol explosion during Rapsodie fast reactor decommissionning.'
ANS – 1999 Winter Meeting – Long Beach (Californie).
Na + R-OH ----> RONa + 1/2 H2
Exothermic
DÉCONTAMINATION
DES COMPOSANTS
SODIUM DES RNR
40
Decontamination process history
PARCODINE 77 (industrial product) H2SO4 + H3PO4 + wetting agents
A1 SP A1 : Alcaline NaOH 20 g/L + KMnO 4 2 g/L 3 h@60°C
SP : SulfoPhosphoric H2SO4 12,5 g/L + H3PO4 190 g/L 6 h@60°C
Validated on PHENIX PP and IHX : Licence process until 1992
SPm: Sulfo Phosphoric modified
H2SO4 12,5 g/L + H3PO4 45g/L 6 h@ 60°C
Validated on a PHENIX IHX after 10 years in operation
Licence process since 1992
No more alcaline bath
H3PO4 content divided by 4
(less phosphate in liquid wastes)
41
CONTAMINATION AFTER CLEANING
AND DECONTAMINATION
EI B : lavage et décontamination
1
10
100
1000
10000
-1 -2 -3 -4 -5 -6 -7 -8 -9 -10
Mètres
µG
y/h
Avant lavage
Après lavage
1er SPm
2ème SPm
Total Activity along PHENIX IHX B
after cleaning and two decontamination runs
Before cleaning
After cleaning
1st SPm
2nd SPm
Meters
PHENOMENOGY OF STRESS CORROSION CRACKING
| PAGE 42
SODIUM'S CHEMICAL AFFINITY FOR WATER
Laboratory
Cleaning pit
(Phénix)
Steam
generator
Na (Noah)
treatment
Effect of jet on the target
Effect of PD – Swelling
Spalling/bursting
CAB HC | 6 NOVEMBRE 2013 44
Sodium-water reaction in SGU
Na
H2O
SGU Na-H2O : a violent and exothermal chemical reaction
Main reaction
Na + H2O NaOH + ½ H2 + 162 kJ/water mole (at
500°C)
Complete, quasi-instantaneous and non-reversible
reaction
Many secondary reactions
2Na + NaOH 2 1 [O2-]Na + [H-]Na Na2O + NaH
Equilibrium reaction depending on sodium
temperature and hydrogen dissolved and hydrogen
partial pressure equilibrium
Above about 300°C, and with sodium in excess,
hydroxide is decomposed in sodium oxide and
hydride (reaction 1)
Above 410°C, reaction (2) occurs only if PH2
reach Pequilibrium in cover gas; The experimental
conditions doesn’t satisfy this condition; Thus the
decomposition of NaOH is total.
Reaction rates depend on temperature
ORIGINS : Normal operation of steam generator induces
damage of heat exchange tubes
tube corrosion : mainly in welding zones, inducing leaks
due to cracking
thermal chocks : when under-saturated water is injected at
super heater inlet (Phenix), inducing thermal fatigue,when
fluctuation of heat exchange conditions
impossible tube expansion: buckling, inducing
differential expansion with envelope
tube bundle vibrations : hydraulic effect of sodium flow,
inducing tube wear
Pressure Temperature
Time (s) Time (s)
Effects: chemical,
mechanical,
thermal
No leak Micro leak small leak evolution
NOAH PROCESS FOR NA FROM THE MAIN CIRCUITS
45
Used for:
- Rapsodie
- PFR & KNK2
- SPX
- Phenix
OLIVIER.GASTATALDI@
CEA.FR
Na cleaning using H2O + CO2 : Carbonation process
0
0,5
1
1,5
2
2,5
3
3,5
4
0 50 100 150 200
Time (h)
Th
ickn
ess o
f so
diu
m
carb
on
ate
d
Used for residual Na after draining
Gas reacting with sodium hydroxyde :
Continuous slow kinetic,
sodium hydroxyde sodium bicarbonate
No corrosion
NaOH + CO2 NaHCO3
NaHCO3 + NaOH Na2CO3
Equilibrium reaction :
Na2CO3 + CO2 + H2O ↔ 2 NaHCO3
Some tracks of research for the future
- Develop a phenomenological model for ACP deposition
model
- Develop a model for the Tritium source term
- Develop a model to describe the aerosols behaviour in the
cover gas
- Develop a model to describe the interaction between Na
residual layer and water (vapor, spray...).
- Develop a mass transfer model for RVC trap (adsorption)
for very low 137Cs contamination
- ....
14 JUILLET 2017 | PAGE 47
Thank You for your kind attention!
| PAGE 48
ASTRID MAIN STRUCTURAL MATERIALS AND
OPERATING CONDITIONS
| PAGE 49
QUALITY MONITORING BY PLUGGING METER
Ostwald and Miers temperature-concentration graph for a
defined impurity : O; H ; ...
temperature cycle
record the plug formation with flow rate monitoring in the restricted area at the cold point (‘’12 grooves’’) (Plugging T)
constant pressure drop line
indication of the temperature where the impurities are starting to precipitate
As well as indication of
Dissolution temperature :
Concentration
solubility sur-solubility
nucleation Stability
meta-
stability
To Tsat
Tplug Tmin T un- plug
98°C
[impurity]
variation
Temperature
ROTATING PLUGS
PP IHX
Large Rotating Plug LRP
Small Rotating Plug SRP
SGU
LRP
SRP
IHX
IHX
IHX
IHX IHX
IHX
IHX
PP
PP
PP