pre-conceptual design study of astrid core · pdf fileiaea technical meeting on innovative...

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IAEA TECHNICAL MEETING ON INNOVATIVE FAST REACTOR DESIGNS WITH ENHANCED NEGATIVE REACTIVITY FEEDBACK FEATURESVienna - 27-29 February 2012 1

PRE-CONCEPTUAL DESIGN STUDY OF ASTRID CORE

Presented by Nicolas Devictor - SFR R&D Project

[email protected]

With contributions from Frédéric VARAINE – Philippe MARSAULT – Marie-Sophie CHENAUD – Bruno BERNARDIN – Alain CONTI - Pierre SCIORA – Christophe VENARD – Bruno FONTAINE – Laurent MARTIN – Gérard MIGNOT

And the support of AREVA NP and EDF

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Content

• Some points on the specifications

• Descriptions of the studied cores (SFRv2 and CFV)

• Behaviour of CFV and comparison with SFRv2

• Extrapolation to 3600 MWth

• Examples of orientations for improving performances of CFV

• Summary

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ASTRID core design is mainly guided by safety objectives :

1. Prevention of the core meltdown accident

To prevent meltdown accidents

-by a natural behavior of the core and the reactor (no actuation of the two shutdown systems)

-with adding passive complementary systems if natural behavior is not sufficient for some transient cases

2. Mitigation of the fusion accident

To garantee that core fusion accidents don’t lead to significant mechanical energy release, whatever ini tiator event

-by a natural core behavior

-with adding specific mitigation dispositions in case of natural behavior is not suffficient

Core design approach

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● Natural behavior favorable for transients of unprot ected loss of flow and loss of heat sinkTarget criteria : no sodium boiling for a ULOSSP transient

● Sodium void effect minimizedTarget criteria : Na void effect < 0

● Natural behavior favorable for a complete control r od withdrawal (with no detection) Target criteria : no fuel fusion

● Improved performancesTarget criteria : Cycle length ≈ 480 efpd, High fuel burnup, and breeding gain ≈ 0

+ Core design is extrapolable to higher power

Core design objectives

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Absorbing protection

Sodium plenumzone

Outer fissilezone

Inner fertile zone

Upper inner fissile zone

Lower inner fissile zone

Fertile blanket

Neutronic protection

Absorbing protection

Sodium plenumzone

Outer fissilezone

Inner fertile zone

Upper inner fissile zone

Lower inner fissile zone

Fertile blanket

Neutronic protection

CFV core

SFRv2 core

Core designs options : SFRv2 and CFV concepts

Fuel rod diameter increased

Spacer diameter reduced

Inner fissile zone

Reflector / shield

Outer fissile zone

206 cm

Inner fissile zone

Reflector / shield

Outer fissile zone

206 cm

Optimization of the leakagesin case of voiding conditions

(PatentCEA EDF AREVA)

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Sodium void effect = loss of sodium in the hottest zones of the core

Sodium loss in the upper reflectors : a few leakageseffect about -0,2 $

Sodium loss in the sodium plenum zone : increase of the leakageseffect about -1 $

Addition of neutron absorber above the sodium plenum zoneeffect about -0,5 $

Addition of an inner fertile zone : ↑ of the flux gradient at the interfaceeffect about -3 $

Move to a CFV geometry design : ↑ of the leakages surfaceeffect about -1,5 $

⇒⇒⇒⇒A global amplification based on individual effects

CFV core

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SFRv2 – AIM1 – 1500 MWth CFV – V1 - AIM1 – 1500 MWth

Spatial distribution of the sodium void effect Spatial distribution of Doppler

SFR-V2B and CFV cores layout

EA

NO

S/P

AR

IS C

ALC

ULA

TIO

NS

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SFR-V2B and CFV cores characteristics

Core 1500 MWth SFRV2B CFV-V1Number of fuel pin / SA 169 217

Fuel pin diameter (mm) 9,43 8,45

Pu enrichment E1/ E2 (%) 13,9 / 17,6 23,5 / 20

Height H1 / H2 (cm) 110 80 / 90

Number of SA C1 / C2 144 / 144 177 / 114

Number batch / Fuel cycle lenght

4 x 390 JEPP 4 x 360 JEPP

Void effect ($) - RZ +5,1 -0,5

Breeding gain -0,05 -0,02

TCT moyen fissile C1/C2 (GWj/t) 76 / 67 105 / 69

∆ρ∆ρ∆ρ∆ρ / cycle (pcm/jepp) -2,2 -4,3

Number of CR 18 + 6 (*) 12 + 6

Core diameter (cm) 326 340

Plin max BOL (W/cm) 407 483

Amplification based on individual effects

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CFV-V1: behaviour during ULOSSP

Etouffement

3000s

Na boiling margin at the top ~ 55°C

Temps (0 à 5000s)

CAT

HA

RE

CA

LCU

LAT

ION

S

Na density FB

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LIPOSO: SFRv2 vs. CFV V1

LIPOSO :

CFV : T max 680 °C

V2B : T max 726 °C

V2B

CFV

V2B

CFV

~45% Qn

Outlet core T Power

Core flowrate

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CFV V1 vs SFRv2: summary of results on loss of flow situations

Best estimate calculations ⇒⇒⇒⇒ trends

(uncertainty analysis is on-going)

CFV V1 V2B

ULOSSPMargin to Na boiling of

≈≈≈≈ 55°CNa boiling in ≈≈≈≈ 100s

ULOF Na boiling in ≈≈≈≈ 3500s Na boiling in ≈≈≈≈ 100s

ULOHSTemperature of

neutronic shutdown : 700°C

Temperature of neutronic shutdown :

800°C

LIPOSO 680°C / 45%Pn 736°C / 43%Qn

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CFV V1 : Control rod withdrawal

CRW Plin/Plin0AA1

TRTC threshold 1.14

AA2Neutronique

threshold 1.30

CRW without detection

Fuel melting if >1.46

V1

BRI 1.40 Yes Yes No melting

BRE 1.50 Yes Yes Melting

V1_18 Ddc

BRI 1.28 Yes Limit No melting

BRE 1.28 Yes Limit No melting

BRE 1.29 yes Limit No melting

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SFR-V2B and CFV cores characteristics - extrapolation

SFRV2B-V0-AIM1-

1500MWth

SFRV2B-V0-ODS-

3600MWth

CFV-V1-AIM1-

1500MWth

CFV-V1 ODS 3600 MWth

Pu enrichment E1/ E2 (%) 13,9 / 17,6 14,6 / 17,4 23,5 / 20 22,7 / 21,7

Height H1 / H2 (cm) 110 100 80 / 90 80 / 100

Number of SA C1 / C2 144 / 144 267 / 186 177 / 114 348 / 126

Number batch / Fuel cycle lenght 4 x 390 JEPP 5 x 400 JEPP 4 x 360 JEPP 5 x 388 JEPP

Void effect ($) - RZ +5,1 + 4.9 -0,5 -0,4

Breeding gain -0,05 0 -0,02 0,06

TCT moyen fissile C1/C2 (GWj/t) 76 / 67 105 / 69 120

∆ρ∆ρ∆ρ∆ρ / cycle (pcm/jepp) -2,2 -1,1 -4,3 -2

Number of CR 18 + 6 24 + 12 12 + 6 24 + 12

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For loss of flow situations

Improve the intrinsic behaviour

� Decrease the fuel nominal temperature

� Increase the number of fuel pin in a SA

�Decrease the specific power

Adapt the reactor design for favouring the core behaviour, as for instance

� Architecture that eases the natural convection actuation

�Increase the dilatation capabilities of the shaft of the CR

� Halving time of primary pump

Orientations for improving inherent behaviour of CFV V1

For control rod withdrawal situations

Improve the intrinsic behaviour

� Decrease the reactivity in each CR (decrease the loss of reactivity / cycle or increase

the number of CR)

�Increase the margin to fuel melting (decrease the specific power)

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Summary and next steps

• CFV core: a promising core for an improved intrinsi c behaviour in case of unprotected situations and con trol rod withdrawal

•Analysis of severe accidents conditions are on-goin g (TIB, and situations with large degradations independently of the initiators – analysis under the frame of the 4th DiD Level)

•2012

• Definition of version 2 of CFV core for improving i nherent behaviour (with the objectives to increase the sodi um boiling margin and robust demonstration of no fuel melting in case of CRW)

• Report of the comparison between CFV and SFRv2 and feasibility points for the selection of the ASTRID reference core

• 1st qualification program and checking of the consisten cy of that planning with ASTRID planning

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Thank you for your attention

1988-1998

1985 - 1998

1973 - 2010

ASTRID

Commercial reactor

1967 - 1983

RAPSODIE

pre-conceptual design study of astrid core · pdf fileiaea technical meeting on innovative...

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