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Petten, Netherlands, 26 February, 2013 Kaspar Kööp, Marti Jeltsov Division of Nuclear Power Safety Royal Institute of Technology (KTH) Stockholm, Sweden Analyses of representative DEC events of the ETDR LEADER WP5 MEETING, Petten – 26 th of February 2013
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Analyses of representative DEC events of the ETDR

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LEADER WP5 MEETING, Petten – 26 th of February 2013. Analyses of representative DEC events of the ETDR. Kaspar Kööp, Marti Jeltsov Division of Nuclear Power Safety Royal Institute of Technology (KTH) Stockholm, Sweden. ETDR – ALFRED description. Pool-type 300 MWth - PowerPoint PPT Presentation
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Page 1: Analyses of representative DEC events of the ETDR

Petten, Netherlands, 26 February, 2013

Kaspar Kööp, Marti JeltsovDivision of Nuclear Power Safety

Royal Institute of Technology (KTH) Stockholm, Sweden

Analyses of representative DEC events

of the ETDR

LEADER WP5 MEETING, Petten – 26th of February 2013

Page 2: Analyses of representative DEC events of the ETDR

Slide 2Petten, Netherlands, 26 February, 2013

• Pool-type• 300 MWth• Core pressure drop 1 bar• Temperature

– Core inlet 400 C– Core outlet 480 C

• Coolant velocity– Average 2 m/s– Maximum 3 m/s

• Lead void effect at EOC (only the fuel zones)– +2 $

ETDR – ALFRED description

Page 3: Analyses of representative DEC events of the ETDR

Slide 3Petten, Netherlands, 26 February, 2013

• T-DEC1 – complete loss of forced flow + SCRAM fail

• T-DEC4 – complete loss of forced flow, complete loss of SCS, DHR system operating

KTH contribution

Page 4: Analyses of representative DEC events of the ETDR

Slide 4Petten, Netherlands, 26 February, 2013

T-DEC1&4 RELAP5 model

Feedwater

Steam521-8

531-8

551-8 561-8

151-

8

Feedwater

Steam521-8

531-8

551-8 561-8

151-

8

841- 4

851- 8441-8

801- 4

811-4831-4

815

401-8

841- 4

-

801- 4

811-4831-4

815

841- 4

-

801- 4

811-4831-4

815

611- 8

841- 4

-

801- 4

811-4831-4

815

611-

711-

731-

741- 4

751- 8

761- 4

621- 4

641- 4

771

781- 8

601- 4

661- 4

611-

711- 8

731- 8

741- 4

751-

761- 4

621- 4

641- 4

771-8

781-

601- 4

661- 4

611-

711-

731-

741- 4

751-

761- 4

621- 4

641- 4

771-

781-

711-

731-

741- 4

751-

761- 4

621- 4

641- 4

771-

781

601- 4

661- 4

841- 8

-

801- 4

811-4831-4

815

841-

-

801- 8

811-8831-8

815

611-

841-

-

801-

811-831-

411-8

611-

711-

731-

741- 4

751-

761- 4

621- 4

641- 4

771

781

711-

731-

741- 4

751-

761- 4

621- 4

641- 4

771-

781-

601- 8

661- 8

611-

711-

731-

741- 8

751-

761- 8

621- 8

641- 8

841- 4

851- 8441-8

801- 4

811-4831-4

815

401-8

841- 4

-

801- 4

811-4831-4

815

841- 4

-

801- 4

811-4831-4

815

611- 8

841- 4

-

801- 4

811-4831-4

815

611-

711-

731-

741- 4

751- 8

761- 4

621- 4

641- 4

771

781- 8

601- 4

661- 4

611-

711- 8

731- 8

741- 4

751-

761- 4

621- 4

641- 4

771-8

781-

601- 4

661- 4

611-

711-

731-

741- 4

751-

761- 4

621- 4

641- 4

771-

781-

711-

731-

741- 4

751-

761- 4

621- 4

641- 4

771-

781

601- 4

661- 4

841- 8

-

801- 4

811-4831-4

815

841-

-

801- 8

811-8831-8

815

611-

841-

-

801-

811-831-

411-8

611-

711-

731-

741- 4

751-

761- 4

621- 4

641- 4

771

781

711-

731-

741- 4

751-

761- 4

621- 4

641- 4

771-

781-

601- 8

661- 8

611-

711-

731-

741- 8

751-

761- 8

621- 8

641- 8

ALFRED Nodalization scheme with RELAP5

8 SGs

8 Secondary loops Primary circuit

8 IC loops

Steam line

Feedwater line

100

101102109

110

115

060061-8 070

050

020

200 151-8

121-8

131-8

141-8

220

230

210

100

101102109

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100

101102109

110

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060061-8 070

050

020

200 151-8

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141-8

220

230

210

Feedwater

Steam521-8

531-8

551-8 561-8

151-

8

Feedwater

Steam521-8

531-8

551-8 561-8

151-

8

841- 4

851- 8441-8

801- 4

811-4831-4

815

401-8

841- 4

-

801- 4

811-4831-4

815

841- 4

-

801- 4

811-4831-4

815

611- 8

841- 4

-

801- 4

811-4831-4

815

611-

711-

731-

741- 4

751- 8

761- 4

621- 4

641- 4

771

781- 8

601- 4

661- 4

611-

711- 8

731- 8

741- 4

751-

761- 4

621- 4

641- 4

771-8

781-

601- 4

661- 4

611-

711-

731-

741- 4

751-

761- 4

621- 4

641- 4

771-

781-

711-

731-

741- 4

751-

761- 4

621- 4

641- 4

771-

781

601- 4

661- 4

841- 8

-

801- 4

811-4831-4

815

841-

-

801- 8

811-8831-8

815

611-

841-

-

801-

811-831-

411-8

611-

711-

731-

741- 4

751-

761- 4

621- 4

641- 4

771

781

711-

731-

741- 4

751-

761- 4

621- 4

641- 4

771-

781-

601- 8

661- 8

611-

711-

731-

741- 8

751-

761- 8

621- 8

641- 8

841- 4

851- 8441-8

801- 4

811-4831-4

815

401-8

841- 4

-

801- 4

811-4831-4

815

841- 4

-

801- 4

811-4831-4

815

611- 8

841- 4

-

801- 4

811-4831-4

815

611-

711-

731-

741- 4

751- 8

761- 4

621- 4

641- 4

771

781- 8

601- 4

661- 4

611-

711- 8

731- 8

741- 4

751-

761- 4

621- 4

641- 4

771-8

781-

601- 4

661- 4

611-

711-

731-

741- 4

751-

761- 4

621- 4

641- 4

771-

781-

711-

731-

741- 4

751-

761- 4

621- 4

641- 4

771-

781

601- 4

661- 4

841- 8

-

801- 4

811-4831-4

815

841-

-

801- 8

811-8831-8

815

611-

841-

-

801-

811-831-

411-8

611-

711-

731-

741- 4

751-

761- 4

621- 4

641- 4

771

781

711-

731-

741- 4

751-

761- 4

621- 4

641- 4

771-

781-

601- 8

661- 8

611-

711-

731-

741- 8

751-

761- 8

621- 8

641- 8

ALFRED Nodalization scheme with RELAP5

8 SGs

8 Secondary loops Primary circuit

8 IC loops

Steam line

Feedwater line

100

101102109

110

115

060061-8 070

050

020

200 151-8

121-8

131-8

141-8

220

230

210

100

101102109

110

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060061-8 070

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020

200 151-8

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141-8

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100

101102109

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060061-8 070

050

020

200 151-8

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141-8

220

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210

Page 5: Analyses of representative DEC events of the ETDR

Slide 5Petten, Netherlands, 26 February, 2013

• T-DEC1 – complete loss of forced flow + SCRAM fail• Pumps are tripped at 0s• Secondary side is operational, IC valves closed

T-DEC1 – Description

Page 6: Analyses of representative DEC events of the ETDR

Slide 6Petten, Netherlands, 26 February, 2013

T-DEC1 - loss of 8 pumps

Page 7: Analyses of representative DEC events of the ETDR

Slide 7Petten, Netherlands, 26 February, 2013

T-DEC1 - loss of 8 pumps

Page 8: Analyses of representative DEC events of the ETDR

Slide 8Petten, Netherlands, 26 February, 2013

T-DEC1 - loss of 8 pumps

Page 9: Analyses of representative DEC events of the ETDR

Slide 9Petten, Netherlands, 26 February, 2013

T-DEC1 - loss of 8 pumps

Page 10: Analyses of representative DEC events of the ETDR

Slide 10Petten, Netherlands, 26 February, 2013

• T-DEC4 – complete loss of forced flow + complete loss of secondary cooling system + SCRAM fail

• Pumps and SCS are tripped at 0s, IC valves opened at 1s

T-DEC4 – Description

Page 11: Analyses of representative DEC events of the ETDR

Slide 11Petten, Netherlands, 26 February, 2013

T-DEC4 – loss of flow + loss of SCS + IC valves open

Page 12: Analyses of representative DEC events of the ETDR

Slide 12Petten, Netherlands, 26 February, 2013

T-DEC4 – loss of flow + loss of SCS + IC valves open

Page 13: Analyses of representative DEC events of the ETDR

Slide 13Petten, Netherlands, 26 February, 2013

T-DEC4 – loss of flow + loss of SCS + IC valves open

Page 14: Analyses of representative DEC events of the ETDR

Slide 14Petten, Netherlands, 26 February, 2013

T-DEC4 – loss of flow + loss of SCS + IC valves open

Page 15: Analyses of representative DEC events of the ETDR

Slide 15Petten, Netherlands, 26 February, 2013

T-DEC1&4 RELAP5 model

Feedwater

Steam521-8

531-8

551-8 561-8

151-

8

Feedwater

Steam521-8

531-8

551-8 561-8

151-

8

841- 4

851- 8441-8

801- 4

811-4831-4

815

401-8

841- 4

-

801- 4

811-4831-4

815

841- 4

-

801- 4

811-4831-4

815

611- 8

841- 4

-

801- 4

811-4831-4

815

611-

711-

731-

741- 4

751- 8

761- 4

621- 4

641- 4

771

781- 8

601- 4

661- 4

611-

711- 8

731- 8

741- 4

751-

761- 4

621- 4

641- 4

771-8

781-

601- 4

661- 4

611-

711-

731-

741- 4

751-

761- 4

621- 4

641- 4

771-

781-

711-

731-

741- 4

751-

761- 4

621- 4

641- 4

771-

781

601- 4

661- 4

841- 8

-

801- 4

811-4831-4

815

841-

-

801- 8

811-8831-8

815

611-

841-

-

801-

811-831-

411-8

611-

711-

731-

741- 4

751-

761- 4

621- 4

641- 4

771

781

711-

731-

741- 4

751-

761- 4

621- 4

641- 4

771-

781-

601- 8

661- 8

611-

711-

731-

741- 8

751-

761- 8

621- 8

641- 8

841- 4

851- 8441-8

801- 4

811-4831-4

815

401-8

841- 4

-

801- 4

811-4831-4

815

841- 4

-

801- 4

811-4831-4

815

611- 8

841- 4

-

801- 4

811-4831-4

815

611-

711-

731-

741- 4

751- 8

761- 4

621- 4

641- 4

771

781- 8

601- 4

661- 4

611-

711- 8

731- 8

741- 4

751-

761- 4

621- 4

641- 4

771-8

781-

601- 4

661- 4

611-

711-

731-

741- 4

751-

761- 4

621- 4

641- 4

771-

781-

711-

731-

741- 4

751-

761- 4

621- 4

641- 4

771-

781

601- 4

661- 4

841- 8

-

801- 4

811-4831-4

815

841-

-

801- 8

811-8831-8

815

611-

841-

-

801-

811-831-

411-8

611-

711-

731-

741- 4

751-

761- 4

621- 4

641- 4

771

781

711-

731-

741- 4

751-

761- 4

621- 4

641- 4

771-

781-

601- 8

661- 8

611-

711-

731-

741- 8

751-

761- 8

621- 8

641- 8

ALFRED Nodalization scheme with RELAP5

8 SGs

8 Secondary loops Primary circuit

8 IC loops

Steam line

Feedwater line

100

101102109

110

115

060061-8 070

050

020

200 151-8

121-8

131-8

141-8

220

230

210

100

101102109

110

115

060061-8 070

050

020

200 151-8

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141-8

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230

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100

101102109

110

115

060061-8 070

050

020

200 151-8

121-8

131-8

141-8

220

230

210

Feedwater

Steam521-8

531-8

551-8 561-8

151-

8

Feedwater

Steam521-8

531-8

551-8 561-8

151-

8

841- 4

851- 8441-8

801- 4

811-4831-4

815

401-8

841- 4

-

801- 4

811-4831-4

815

841- 4

-

801- 4

811-4831-4

815

611- 8

841- 4

-

801- 4

811-4831-4

815

611-

711-

731-

741- 4

751- 8

761- 4

621- 4

641- 4

771

781- 8

601- 4

661- 4

611-

711- 8

731- 8

741- 4

751-

761- 4

621- 4

641- 4

771-8

781-

601- 4

661- 4

611-

711-

731-

741- 4

751-

761- 4

621- 4

641- 4

771-

781-

711-

731-

741- 4

751-

761- 4

621- 4

641- 4

771-

781

601- 4

661- 4

841- 8

-

801- 4

811-4831-4

815

841-

-

801- 8

811-8831-8

815

611-

841-

-

801-

811-831-

411-8

611-

711-

731-

741- 4

751-

761- 4

621- 4

641- 4

771

781

711-

731-

741- 4

751-

761- 4

621- 4

641- 4

771-

781-

601- 8

661- 8

611-

711-

731-

741- 8

751-

761- 8

621- 8

641- 8

841- 4

851- 8441-8

801- 4

811-4831-4

815

401-8

841- 4

-

801- 4

811-4831-4

815

841- 4

-

801- 4

811-4831-4

815

611- 8

841- 4

-

801- 4

811-4831-4

815

611-

711-

731-

741- 4

751- 8

761- 4

621- 4

641- 4

771

781- 8

601- 4

661- 4

611-

711- 8

731- 8

741- 4

751-

761- 4

621- 4

641- 4

771-8

781-

601- 4

661- 4

611-

711-

731-

741- 4

751-

761- 4

621- 4

641- 4

771-

781-

711-

731-

741- 4

751-

761- 4

621- 4

641- 4

771-

781

601- 4

661- 4

841- 8

-

801- 4

811-4831-4

815

841-

-

801- 8

811-8831-8

815

611-

841-

-

801-

811-831-

411-8

611-

711-

731-

741- 4

751-

761- 4

621- 4

641- 4

771

781

711-

731-

741- 4

751-

761- 4

621- 4

641- 4

771-

781-

601- 8

661- 8

611-

711-

731-

741- 8

751-

761- 8

621- 8

641- 8

ALFRED Nodalization scheme with RELAP5

8 SGs

8 Secondary loops Primary circuit

8 IC loops

Steam line

Feedwater line

100

101102109

110

115

060061-8 070

050

020

200 151-8

121-8

131-8

141-8

220

230

210

100

101102109

110

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020

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Page 16: Analyses of representative DEC events of the ETDR

Slide 16Petten, Netherlands, 26 February, 2013

T-DEC4 with 1 working pump

Page 17: Analyses of representative DEC events of the ETDR

Slide 17Petten, Netherlands, 26 February, 2013

T-DEC4 with 1 working pump

Page 18: Analyses of representative DEC events of the ETDR

Slide 18Petten, Netherlands, 26 February, 2013

T-DEC4 with 1 working pump

Page 19: Analyses of representative DEC events of the ETDR

Slide 19Petten, Netherlands, 26 February, 2013

• TR-4 – a transient event due to reactivity insertion (enveloping SGTR, flow blockage, core compaction)

KTH contribution

Page 20: Analyses of representative DEC events of the ETDR

Slide 20Petten, Netherlands, 26 February, 2013

• TR-4 – a transient event due to reactivity insertion (enveloping SGTR, flow blockage, core compaction)

Steam Generator Tube Leakage (SGTL) is assumed to be the cause for reactivity insertion (voiding of part of active region• We address the task on the transport of bubbles that have

leaked in the SG to the primary coolant flow• Reactor is at hot full power (HFP)• Actions:

– First thermal-hydraulic part (CFD analysis of bubble transport)– Neutronic part (SERPENT code to look at the consequences of different

local core voiding that are typical for SG leakage)

TR-4 – Description

Page 21: Analyses of representative DEC events of the ETDR

Slide 21Petten, Netherlands, 26 February, 2013

• ALFRED – Advanced Lead Fast Reactor European Demonstrator• Power – 125 MWel (300 MWth, ~41% efficiency)• 8 steam generators with 8 axial pumps• 2 independent DHRs using SG tubes

ALFRED design

Page 22: Analyses of representative DEC events of the ETDR

Slide 22Petten, Netherlands, 26 February, 2013

• Core – submerged in the bottom middle part of the pool• 8 SGs – located inside the primary circuit radially

around the core• One co-axial pump per SG• High P secondary vs low P primary system

• SG tube rupture and leakage events in PWRs suggest that it can be a concern in LFRs

• Risk of core voiding in case of SGTL due to:– Proximity of SGs to core– Nature (shape) of the flow path– Leak-Before-Break (LBB) (< liter/day in PWRs)

• SGTL can hinder licensing due to:– Potential severe consequences (core damage)– Lack of operational experience (uncertainty in frequency

of SGTL)

Motivation

Page 23: Analyses of representative DEC events of the ETDR

Slide 23Petten, Netherlands, 26 February, 2013

Objectives• To assess the risk related to SGTL

• To identify the scenarios of core voiding

• To quantify the likelyhood that a steam bubble is transported from a SG to the core– Identify the uncertainties in SGTL– Quantifiy these uncertainties

• To estimate void accumulation rates in the core

• To estimate the consequent effect to power (or to neutron flux) with a neutronic code

Page 24: Analyses of representative DEC events of the ETDR

Slide 24Petten, Netherlands, 26 February, 2013

• SGT leakage is considered during normal operation• If steam bubbles are dragged to the core then there are 3 distinct

scenarios of safety concern:a) Homogeneous voiding of the coolant (continuous leak, small bubbles)b) Bubbles stuck in spacers (mid-size bubbles)c) Slugs of void entering the core (formed in stagnation zones)

Depending on the scenario...– RIA– Local damage (burn-out) of the fuel– Overpressurization of the vessel

...can happen.

Scenarios

Page 25: Analyses of representative DEC events of the ETDR

Slide 25Petten, Netherlands, 26 February, 2013

• Aleatory and epistemic uncertainties assessed in the SGTL scenarios and phenomenology:

Crack size and morphology Bubble size distribution Leak rate through the crack Bubble drag correlation

• Bubble size distribution

• Leak rate depends on crack size, morphology and pressure differences between two sides– ”Leak-before-break”

Uncertainties

K. Terasaka et al. (2011) A. V. Beznosov et al. (2005)

Page 26: Analyses of representative DEC events of the ETDR

Slide 26Petten, Netherlands, 26 February, 2013

Non-linear drag coefficientm, , as a function of bubble diameter

Validation is done by comparing with predictions from Stokes and Mendelsons law

Bubbles were modeled:• As Lagrangian particles• Constant density• Drag coefficient• With/without turbulent dispersion

Tomiyama et al. correlation chosen:

Drag coefficient

0 1 2 3 4 5 6 7 8 9 100

0.1

0.2

0.3

0.4

0.5

bubble diameter [mm]

velo

city

[m/s

]

Stokes lawMendelsons eq. for PbMori et al. data for Hg

0 1 2 3 4 5 6 7 8 9 100

0.1

0.2

0.3

0.4

0.5

bubble diameter [mm]

velo

city

[m/s

]

Stokes lawMendelson eq.Schiller-NaumannModif. Schiller-NaumannRodrigueTomiyama et al.

Page 27: Analyses of representative DEC events of the ETDR

Slide 27Petten, Netherlands, 26 February, 2013

Bubbles are injected at - 3 different height levels in SG (bottom, middle, top) - at the exit of the core - at the pump outlet

to estimate probabilities:P1 – that bubble enters coreP2 – that bubble proceeds to pumpP3 – that bubble stays in the primary loop

Steam accumulation rate in the primary system:

and in the core (assumed bubbles get stuck there):

Approach to estimate core voiding

P1

P2

P3

Hot free surface

Cold free surface

2

13

Page 28: Analyses of representative DEC events of the ETDR

Slide 28Petten, Netherlands, 26 February, 2013

ALFRED CAD model

Page 29: Analyses of representative DEC events of the ETDR

Slide 29Petten, Netherlands, 26 February, 2013

ALFRED CFD model• 45° CFD model is being created

• Simplified modeling of complex (SG, lower/upper grids) components (porous media, momentum source etc)

• Consists of 7 regions a• Downcomer• Lower grid• Lower inactive region• Active region• Upper inactive region• Pump channel• Steam generator

Page 30: Analyses of representative DEC events of the ETDR

Slide 30Petten, Netherlands, 26 February, 2013

Example of ELSY modeling

Core

SG

Down-comer

Pump

Page 31: Analyses of representative DEC events of the ETDR

Slide 31Petten, Netherlands, 26 February, 2013

Example of ELSY results dbubble=0.2 mm dbubble=0.4 mm

dbubble=0.5 mm dbubble=1.0 mm

Very small bubbles are dragged to core (<0.4 mm), whereas middle size ones are not

Page 32: Analyses of representative DEC events of the ETDR

32

Summary

• Steam generator tube leakage accident is addressed– Motivation, scenarios, uncertainties

• Nominal operational primary flow conditions will be modeled with a CFD code Star-CCM+

• Neutronics part of the analysis will be done using Serpent Monte Carlo code

• Input for neutronic calculation– void characteristics:

• accumulation rates• voiding scenarios are input for neutronics calculation

– geometry• ALFRED model exists in the house

Page 33: Analyses of representative DEC events of the ETDR

Slide 33Petten, Netherlands, 26 February, 2013

Thank you!