sodium coolant: activation, species production coolant ... · sodium pollution 1/2 this coolant...

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

[email protected]

(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.”

mailto:[email protected]

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



COLD TRAP: MODELING


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


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:


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:

http://www.asn.fr/sites/tritium/

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


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)


FILTERS

14 JUILLET 2017

Up to now no mandatory for SFRs

| PAGE 29

ACP GETTERS


CS ADSORBERS


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

- ....


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

sodium coolant: activation, species production coolant ... · sodium pollution 1/2 this coolant...

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