Leader WP6 Task 6.3

Assessment, validation and adaptation of oxygen control and purification strategy

Task Leader: CEAParticipants: KIT, ENEA

Christian Latgé CEALaurent Brissonneau CEAAlfons Weissenburger KITAlessandro Gessi ENEA

Sub-tasks

5 sub-tasks:

-1 definition of the oxygen activity level/range versus the operating lead temperature-2 assessment of the different technological solutions (gas phase or lead oxide) for oxygen control considering the design of the pool type reactor-3 definition of the amount and location of O-meters-4 O behaviour during accidental conditions-5 qualification for lead purification during plant operation

Work schedule – proposed in Madrid            Draft (D12) contributions: end July 2012            Deliverable finalized by 2012 September 30th

Presentation during Meeting foreseen in 2012 (2nd semester) November? (and discussion)           

Dedicated meeting in CadaracheJuly 5th – 6th 2012Participants: Luigi Mansani, Christian Latge, Laurent Brissonneau, Alfons Weisenburger and Alessandro Gessi via Video conference

Luigi gave an overview on Design:Materials and boundary conditions:E.G. Cladding (15-15Ti) T avarage high 480°C but peak up to 550°C (GESA?)SG tubes (hot zone 450 – 480°C) 30years – thermal efficiency? – oxygen consumptionSG tube - double wall – different materials for water and Pb contactcold shut down at 380°C – impact on oxygen control avoid PbO formationAlfons and Christian (L. Martinelli) present material compatibility:Only minor number of tests in Pb- most in PbBi but less aggressive lower solubility T91 might be used up to 550°C but reduction in creep strength and oxidationAs wrapper ok – SG tubes: Coating – change to 316? – water side 316 preferrable15-15Ti (500°C might be ok) 550°C hot spot (duration?) might require surface improvementKIT calculated based on EFIT data – oxidation and oxygen consuption

Christian presents different aspects of Control and filteringOxygen level to be controlled – PbO formation at 380°C – corrosion at high TempSG water side: production of H2 - by decomposition of hydrazine and to the corrosion by the water of the steel (3Fe + 4H2O = Fe3O4 + 4H2) – double wall with He flow can minimize H ingress in pool - amount is significant (would require addtional oxygen to be supplied)

400°C

1,E-08

1,E-07

1,E-06

1,E-05

1,E-04

1,E-03

1,E-02

1,E-01

1,E+00

1,E+01

1,E+02

1,E+03

300 350 400 450 500 550 600 650

Température (°C)

[O] (

ppm

)

PbO (Gromov)

Concentration minimale pour former Fe3O4

___ à saturation Fe dans Pb----- à 10%saturation Fe dans Pb

Domaine large de fonctionnement

Domaine étroit de fonctionnement

480°C

400°C

Oxygen level required (380°C- 550°C)

530°C

?

?: possibility to decrease depends on coating properties2: if cladding are protected against dissolution

21

Dedicated meeting in CadaracheJuly 5th – 6th 2012Participants: Luigi Mansani, Christian Latge, Laurent Brissonneau, Alfons Weisenburger and Alessandro Gessi via Video conference

Luigi gave an overview on Design:Materials and boundary conditions:E.G. Cladding (15-15Ti) T avarage high 480°C but peak up to 550°C (GESA?)SG tubes (hot zone 450 – 480°C) 30years – thermal efficiency? – oxygen consumptionSG tube - double wall – different materials for water and Pb contactcold shut down at 380°C – impact on oxygen control avoid PbO formationAlfons and Christian (L. Martinelli) present material compatibility:Only minor number of tests in Pb- most in PbBi but less aggressive lower solubility T91 might be used up to 550°C but reduction in creep strength and oxidationAs wrapper ok – SG tubes: Coating – change to 316? – water side 316 preferrable15-15Ti (500°C might be ok) 550°C hot spot (duration?) might require surface improvementKIT calculated based on EFIT data – oxidation and oxygen consuption (short presentation)

Christian present different aspects of Control and filteringOxygen level to be controled – PbO formation at 380°C – corrosion at high TempSG water side: production of H2 - by decomposition of hydrazine and to the corrosion by the water of the steel (3Fe + 4H2O = Fe3O4 + 4H2) – double wall with He flow can minimize H ingress in pool - amount is significant (would require addtional oxygen to be supplied)

Use of Ta – Tantalum protection of the pump or the hot leg - associated with a very low oxygen content policy (Ta is not soluble in Pb but Ta oxidation must be avoided because the oxide is spalled off and oxygen embrittle tantalum) is not compatible with the protection management of the other materials. Moreover, it seems unrealistic to reach the oxygen content necessary to avoid Ta2O5 formation (less than 10-12 ppm).

Accidental events:If air ingress:PbO is produced on Pb bulk surface, but very slow dissolution rate on surface, and risks of entrainment if vortices…

- Detection in cover gas (N2 or O2) by MS or gas chromatography- Confirmation in Pb by O-meter

If water ingress:very small amont of PbO produced continuously

- Water seems relative stable in Pb Detection by O-meter and more probably by H-meter in gas plenum or water by SM or IR spectroscopy

- Double wall SG – water leak more unlikely

Loss of oxygen supply:- Seems not to critical – redundancy of systems – O-meter can detect this event

Oxygen sensors location

To be located before and after the zones that are susceptible to consume oxygen.• In the inner vessel : near the Pb flow• At the top and at the bottom of each SGU• In the cold stream in the cold zone at the entry of the core.

Sensor in cold stream and bottom of SGU – similar data – some kind of redundancy Quasi stagnant Pb zones should be monitored

+ one at outlet of Mass Exchanger – monitor functionality of Mass Exchanger (AW)? Do we need sensors at all SGU? - increase safety(LB) at least 3 sensors at equivilant location – avoid shut down if one sensor broke

[O] control strategy in hot and cold plenum

480 °C

400 °C

SGU

[O]HSG (Hot SGU)

[O]Cp (Cold plenum)

[O]HSG depends on oxidation/corrosion in core RC1

[O]CSG depends on oxidation/corrosion in SGU and possible PbO precipitation RC2

RC2 RC1

O-meter

[O]CSG (Cold SGU)

Oxygen sensors location

To be located before and after the zones that are susceptible to consume oxygen.• In the inner vessel : near the Pb flow• At the top and at the bottom of each SGU• In the cold stream in the cold zone at the entry of the core.

Sensor in cold stream and bottom of SGU – similar data – some kind of redundancy Quasi stagnant Pb zones should be monitored

+ one at outlet of Mass Exchanger – monitor functionality of Mass Exchanger (AW)? Do we need sensors at all SGU? - increase safety(LB) at least 3 sensors at equivilant location – avoid shut dwon if one sensor broke

Oxygen supply

Need – amount of oxygen required to stabilize materials

4343

,

43,

,

)(

4

OFeandoxygenofweightmolecularMMscaleoxideofdensityscaleoxideofthickness

claddingofsurfacetotalFoxidationoxygenofweightwt

MMFwt

OFeo

ox

B

B

Bo

OFe

oBoxBBo

Oxide scale growth – oxygen needed (oxygen control) filtering (spallation)

PbBi facing materials will be grouped:HX, Claddings, Wrapper, Core internals T91, Core internals 316Loxide scale growth – oxygen consumption – oxides to be removed (filter)

Weigth of oxygen to form magnetite and spinel / Alumina formation analogousThis is the amount of oxygen to be added by OCS system

We need oxide scale formation as function of time and temperature

As example:Oxide scale growth on EFIT fuel pin, wrapper – T91 - ELFR Assuming parabolic growth

4000 5000 6000 7000 8000

400

420

440

460

480

Tem

pera

ture

°C

lenght of fuel cladding

For fuel cladding: Temperature distribution along cladding (x1……x4)

sp, = 1355.5m2, swo = 1095 m², swi =1040 m2, Ftot. = 3491m2

6000ton Pb – 10-6wt% oxygen 60g oxygen in Pb

tktx )(C])(T[0.002540.897- k(T)

T(x))dx(t, F(231.55

64 = T)(t,owtx4

x1

Oxide scale growth – oxygen needed (oxygen control) filtering (spallation) (addressed in SEARCH and LEADER)

EFIT Design: 15-15Ti for fuel pins and T91 for the wrapper

Unknown – oxide scale growth of austenitic steels between 270 and 500°C:

Assumption based on experimental data (max. values measured): to be updated with all available resultsData to be cross checked and discussed1µm scale at 400°C after 10000h3.5 µm at 450°C at 5000h6.4 µm at 500°C at 5000h

tTTtd )410831.0(),(

Oxygen consumption - oxide scale formation of EFIT

(proper fit between 400 and 550°C)

Zone, i

Zone Position xi –xi-1 [m]

Ti [°C] Surface, si [m2]

Pins + wrapp. dummies

3 -7,763 to -5,805 400 1140 6222 -5,805 to -4,905 400 - 480 494,7 2861 -4,905 to -3,840 480 609.5 338

Sum 2244.2 1246

Temperatures and surfaces sp + sw and sd in core zones at different elevations.

Structure part Surf.[m3] Material T[°C]1 Core vessel and diagrid, elev. -7763 – elev. -3840 3675.84 T91,316

L400-480

2 Inner vessel above core, elev. -3840 – elev. + 406 206.6 316L 4803 Pump ducts 63.6 316L 4804 SG pump pools 154 T91 4805 Steam generators 1566 T91 400-4806 Dip coolers 1457 T91 4007 Lift machine 16.57 316L 4808 Filter units 21,5 316L 4009 Vessel & diagrid restrain support up to elev. +1085 314,5 316L 400-410

Sum 7475.61

Required amount of oxygen for oxidation in kgClad 15-15 Ti / wrapper T91 – EFIT amount of oxide required

0 2000 4000 6000 8000 10000 12000 140000

20000

40000

60000

80000

100000

120000

140000

t [h]

tota

l con

sum

ptio

n [k

g]

↑ 1. shut down

↑2. shut down

↑assembly exchange

↑SG tube exchange

low temperature (400°C) oxidation

Just remind: 6000ton Pb – 10-6wt% oxygen 60g oxygen in Pb

Oxygen consumption in kg/h of fuel assembly (EFIT data) 15-15Ti clad, T91 wrapper

0 2000 4000 6000 8000 10000 12000 140000.00

50.00

100.00

150.00

200.00

250.00

300.00

t [h]

cons

umpt

ion

rate

[kg/

h]

↖ 0,28 kg/h preoxidation

↑1,1 kg/h without preoxidation

SG tube exchange

↑ 0,43 kg/h

assemblyexchange

↙ 1. shut down ↙ 2. shut

down

500h preox.

800h preox

Simulation of start-up, shut downs, fuel assembly exchange (1/3) and SG exchange

0 200 400 600 800 1000 12000.00

10.00

20.00

30.00

40.00

50.00

60.00

70.00

80.00

90.00

100.00

t [h]

oxyg

en c

onsu

mpt

ion

rate

[kg/

h]

500h preox. no GESA

500h preox, GESA on act. pin parts

500h preox. GESA on act. pin parts & SG tubes

no preoxidation no

GESAno GESA

GESA on act. pin partsGESA on act. pin parts & SG tubes

Influence of pre-oxidation and GESA surface treatment

Oxygen sensors location

To be located before and after the zones that are susceptible to consume oxygen.• In the inner vessel : near the Pb flow• At the top and at the bottom of each SGU• In the cold stream in the cold zone at the entry of the core.

Sensor in cold stream and bottom of SGU – similar data – some kind of redundancy Quasi stagnant Pb zones should be monitored

+ one at outlet of Mass Exchanger – monitor functionality of Mass Exchanger (AW)? Do we need sensors at all SGU? - increase safety(LB) at least 3 sensors at equivilant location – avoid shut dwon if one sensor broke

Oxygen supply

Start up ~100g/h – after 5000h some g/h – remember at Start up we can have about 600g oxygen in lead – Pre-oxidation (by start-up procedure)Nominal oxygen 10-6wt% 6t Pb – 60g oxygen For normal operation – oxygen supply seems feasible - More than One oxygen supply - redundancy, homogenous supply

Method to supply:Gas-Phase – Solid PbO Mass exchanger

Alfons Weisenburger LEADER – Karlsruhe November 22nd 2012 – Task 6.319 KIT

Mass exchanger with integrated pump:

Designed for Brest 300 4 to be installed downstream steam genearetor - upstream main pumpeach can deliver ~1g/h

Solubility PbO (T) ?Stability of PbO pebbles?

Solid phase mass exchanger – designed by IPPE

P.N. Martynov et. al - ICONE17-75506/75504

PbO Pb + O

Scheme for automatic control unit:

Preliminary sketch of the ancillary loop for chemistry regulationThe ancillary loop for chemistry regulation should include:an heat exchanger to control the temperature of the lead oxygen supply, PbO reduction (possibly coupled with filtration) - each can by by-passedThe loop is controlled by one or two oxygen probes: • at the bottom and possibly at the top of the steam generator for the SGU • at the top of the steam generator and possibly at the bottom of the core for the core.

OSD at the top of the SGU: the lead is reduced if the oxygen content is too high at the end of the SGU, till it remains high enough at the top of the SGU.In case of high consumption in the core and low consumption in the SGU (case of fresh steels after refuelling), oxygen can be supplied at the bottom of the core and in the SGU. If oxygen concentration is homogeneous in the cold and hot plenum, oxygen supply should be preferentially done at the top of the SGU.

It should be insured that the input flow will be mixed correctly before it is distributed in the component/core.

O control strategy (OCS)

480 °C

400 °C

SGU O consumption (Rc)O supply/suppress (Rs)O regulation

ArAr

Rc1Rc2

Rs1

Rs2

Heat Exchanger

PbO orAr/Air+1%H2O

H2

If RC2 is too high, necessity to increase [O] in cold plenum, to avoid dissolution in coreIf RC1 is too high, necessity to increase [O] in hot plenum, to avoid dissolution in SGUIf [O]CP is too high, necessity to lower it , to avoid PbO precipitation in cold plenum

Option: 1 OCSfor each SGU(but may be possibility to reduce the complexity of this system)

Preliminary sketch of the ancillary loop for chemistry regulationThe ancillary loop for chemistry regulation should include:an heat exchanger to control the temperature of the lead oxygen supply, PbO reduction (possibly coupled with filtration) - each can by by-passedThe loop is controlled by one or two oxygen probes: • at the bottom and possibly at the top of the steam generator for the SGU • at the top of the steam generator and possibly at the bottom of the core for the core.

OSD at the top of the SGU: the lead is reduced if the oxygen content is too high at the end of the SGU, till it remains high enough at the top of the SGU.

+OSD at cold plenum of core -in case of high consumption in the core and low consumption in the SGU (case of fresh steels after refuelling)

One OSD at each SGU + 3 OSD at cold plenum position

It should be insured that the input flow will be mixed correctly before it is distributed in the component/core.

FiltrationAssessment for magnetite production: between 10 and 50 kg/year. This magnetite can not be reduced and must then be trapped by filtering.By extrapolating the results of small loop test pressure drop of one bar could be roughly obtained for 10 kg of impurities on 30m² of filters, according to DEMETRA results. Of course, operation on bigger loops should be required to qualify the filter.

Different filter types: Tangential filtering to avoid rapid plugging and high pressure drops.If PbO reduction is not feasible for filter cleaning, a counter pressure in the loop could be used to remove the trapped impurities (MYRRHA design).In SEARCH – dedicated Task of Filtering effciency

Integrated Purification Unit of SuperPhenix

Filtration unit (Integrated option)

InInlet

480 °C

400 °C

SGU

Outlet

Inlet

Filter (PbO, Activated corrosion products, fission products and fuel (if pin rupture)

Internal Plug

Handling cask (for filter)

EMP

Heat Exchanger (if required)

Work schedule:       Draft (D12) contributions: Mid December 2012 from CEA to KIT and ENEA        Deliverable finalized by March 2013

Tritium production9g / 40 years

Oxygen supply:Some g/h

H solubility 1order of magnitude lower than O-will most probably diffuse outwardsCombine with O – H2O