UNIVERSITÀ DI PISAUNIVERSITÀ DI PISA GRUPPO DI RICERCA NUCLEARE GRUPPO DI RICERCA NUCLEARE –– SAN PIERO A GRADO (GRNSPG)SAN PIERO A GRADO (GRNSPG)

Any reproduction, alteration, transmission to any third party or publication in whole or in part of this document and/or its content is prohibited unless the University of Pisa – San Piero a Grado Nuclear Research Group has

provided its prior and written consent. This document and any information it contains shall not be used for any other purpose than the one for which they were provided. Legal action may be taken against any infringer and/or

any person breaching the aforementioned obligations.

Exploitation of Exploitation of BEPUBEPU Approach for the Approach for the Licensing ProcessLicensing Process

OECD/NEA CNRA International Workshop on OECD/NEA CNRA International Workshop on

“New Reactor Siting, Licensing and Construction “New Reactor Siting, Licensing and Construction

Experience” Experience”

Hosted by the State Office for Nuclear Safety

Prague, Czech Republic

1515--17 September 2010 17 September 2010

Title Exploitation of BEPU Approach for the Licensing Process

Authors F. D’Auria, N. Muellner, D. Araneo, M. Cherubini, A. Del Nevo,

F. Moretti, C. Parisi, A. Petruzzi (GRNSPG/UNIPI – Italy)

O. Mazzantini (NA-SA, Buenos Aires – Argentina)

“with the contribution of about 40 colleagues”

Revision/Date 0 14 09 2010

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Any reproduction, alteration, transmission to any third party or publication in whole or in part of this document and/or its content is

prohibited unless the University of Pisa – San Piero a Grado Nuclear Research Group has provided its prior and written consent.

This document and any information it contains shall not be used for any other purpose than the one for which they were provided.

Legal action may be taken against any infringer and/or any person breaching the aforementioned obligations.

Exploitation of BEPU Approach for the Licensing Process

OECD/NEA CNRA Int. WS on “New Reactor Siting, Licensing and Construction Experience” OECD/NEA CNRA Int. WS on “New Reactor Siting, Licensing and Construction Experience”

-- State Office for Nuclear Safety Prague, Czech Republic – September 15-17 , 2010

List of content

The Atucha-2 NPP

The Licensing Framework

The Road-Map for BEPU

The BEPU Process

The Postulated Initiating Events (PIE)

The Computational Tools

The Uncertainty Method

Selected Outcomes from FSAR Chapt. 15

Conclusions

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Any reproduction, alteration, transmission to any third party or publication in whole or in part of this document and/or its content is

prohibited unless the University of Pisa – San Piero a Grado Nuclear Research Group has provided its prior and written consent.

This document and any information it contains shall not be used for any other purpose than the one for which they were provided.

Legal action may be taken against any infringer and/or any person breaching the aforementioned obligations.

Exploitation of BEPU Approach for the Licensing Process

OECD/NEA CNRA Int. WS on “New Reactor Siting, Licensing and Construction Experience” OECD/NEA CNRA Int. WS on “New Reactor Siting, Licensing and Construction Experience”

-- State Office for Nuclear Safety Prague, Czech Republic – September 15-17 , 2010

The AtuchaThe Atucha--2 NPP2 NPP 2 LOOPS 1 MCP, 1 UT SG each

1 PRZ

2160 MWth 1958 + 203 (nom. mod. T), or

2001 + 160 (max mod T)

+

14 from MCP

451 separated FC

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Any reproduction, alteration, transmission to any third party or publication in whole or in part of this document and/or its content is

prohibited unless the University of Pisa – San Piero a Grado Nuclear Research Group has provided its prior and written consent.

This document and any information it contains shall not be used for any other purpose than the one for which they were provided.

Legal action may be taken against any infringer and/or any person breaching the aforementioned obligations.

Exploitation of BEPU Approach for the Licensing Process

OECD/NEA CNRA Int. WS on “New Reactor Siting, Licensing and Construction Experience” OECD/NEA CNRA Int. WS on “New Reactor Siting, Licensing and Construction Experience”

-- State Office for Nuclear Safety Prague, Czech Republic – September 15-17 , 2010

The AtuchaThe Atucha--2 NPP2 NPP

4 Moderator loops

Moderator pump

Flow direction during

normal operation

Flow direction during

normal operation

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Any reproduction, alteration, transmission to any third party or publication in whole or in part of this document and/or its content is

prohibited unless the University of Pisa – San Piero a Grado Nuclear Research Group has provided its prior and written consent.

This document and any information it contains shall not be used for any other purpose than the one for which they were provided.

Legal action may be taken against any infringer and/or any person breaching the aforementioned obligations.

Exploitation of BEPU Approach for the Licensing Process

OECD/NEA CNRA Int. WS on “New Reactor Siting, Licensing and Construction Experience” OECD/NEA CNRA Int. WS on “New Reactor Siting, Licensing and Construction Experience”

-- State Office for Nuclear Safety Prague, Czech Republic – September 15-17 , 2010

The Licensing Framework

Conservative and best estimate methods IAEA TECDOC-1332 (01-2003)

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Any reproduction, alteration, transmission to any third party or publication in whole or in part of this document and/or its content is

prohibited unless the University of Pisa – San Piero a Grado Nuclear Research Group has provided its prior and written consent.

This document and any information it contains shall not be used for any other purpose than the one for which they were provided.

Legal action may be taken against any infringer and/or any person breaching the aforementioned obligations.

Exploitation of BEPU Approach for the Licensing Process

OECD/NEA CNRA Int. WS on “New Reactor Siting, Licensing and Construction Experience” OECD/NEA CNRA Int. WS on “New Reactor Siting, Licensing and Construction Experience”

-- State Office for Nuclear Safety Prague, Czech Republic – September 15-17 , 2010

The Licensing Framework

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Any reproduction, alteration, transmission to any third party or publication in whole or in part of this document and/or its content is

prohibited unless the University of Pisa – San Piero a Grado Nuclear Research Group has provided its prior and written consent.

This document and any information it contains shall not be used for any other purpose than the one for which they were provided.

Legal action may be taken against any infringer and/or any person breaching the aforementioned obligations.

Exploitation of BEPU Approach for the Licensing Process

OECD/NEA CNRA Int. WS on “New Reactor Siting, Licensing and Construction Experience” OECD/NEA CNRA Int. WS on “New Reactor Siting, Licensing and Construction Experience”

-- State Office for Nuclear Safety Prague, Czech Republic – September 15-17 , 2010

The Road-Map for BEPU

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Any reproduction, alteration, transmission to any third party or publication in whole or in part of this document and/or its content is

prohibited unless the University of Pisa – San Piero a Grado Nuclear Research Group has provided its prior and written consent.

This document and any information it contains shall not be used for any other purpose than the one for which they were provided.

Legal action may be taken against any infringer and/or any person breaching the aforementioned obligations.

Exploitation of BEPU Approach for the Licensing Process

OECD/NEA CNRA Int. WS on “New Reactor Siting, Licensing and Construction Experience” OECD/NEA CNRA Int. WS on “New Reactor Siting, Licensing and Construction Experience”

-- State Office for Nuclear Safety Prague, Czech Republic – September 15-17 , 2010

THE BEPU PROCESS - THE POSTULATED INITIATING EVENTS

83 NPP Scenarios

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Any reproduction, alteration, transmission to any third party or publication in whole or in part of this document and/or its content is

prohibited unless the University of Pisa – San Piero a Grado Nuclear Research Group has provided its prior and written consent.

This document and any information it contains shall not be used for any other purpose than the one for which they were provided.

Legal action may be taken against any infringer and/or any person breaching the aforementioned obligations.

Exploitation of BEPU Approach for the Licensing Process

OECD/NEA CNRA Int. WS on “New Reactor Siting, Licensing and Construction Experience” OECD/NEA CNRA Int. WS on “New Reactor Siting, Licensing and Construction Experience”

-- State Office for Nuclear Safety Prague, Czech Republic – September 15-17 , 2010

THE BEPU PROCESS - THE COMPUTATIONAL TOOLS

~ 20 Codes

coupling

qualification

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Any reproduction, alteration, transmission to any third party or publication in whole or in part of this document and/or its content is

prohibited unless the University of Pisa – San Piero a Grado Nuclear Research Group has provided its prior and written consent.

This document and any information it contains shall not be used for any other purpose than the one for which they were provided.

Legal action may be taken against any infringer and/or any person breaching the aforementioned obligations.

Exploitation of BEPU Approach for the Licensing Process

OECD/NEA CNRA Int. WS on “New Reactor Siting, Licensing and Construction Experience” OECD/NEA CNRA Int. WS on “New Reactor Siting, Licensing and Construction Experience”

-- State Office for Nuclear Safety Prague, Czech Republic – September 15-17 , 2010

ITF

Nodalizations

Specific

experimental data

ITF

Calculation

Accuracy

Quantification (°)

Accuracy

Extrapolation (°)

Generic

experimental

data

ASM

Calculation

a

ih

j

GI FG

gc

d

e

f

l

LN (°)

m

n

YES

FG

k

(°) Special methodology developed

Stop of the

process

NO

NO

Demonstration

of Similarity (°)

(Phenomena Analysis)

(Scaling Laws)

Code

Nodalization and

user qualification

GeneralQualification

Process

b

Uncertainty

Plant

nodalization

Plant

calculation

ITF

Nodalizations

Specific

experimental data

ITF

Calculation

Accuracy

Quantification (°)

Accuracy

Extrapolation (°)

Generic

experimental

data

ASM

Calculation

a

ih

j

GI FG

gc

d

e

f

l

LN (°)

m

n

YES

FG

k

(°) Special methodology developed

Stop of the

process

NO

NO

Demonstration

of Similarity (°)

(Phenomena Analysis)

(Scaling Laws)

Code

Nodalization and

user qualification

GeneralQualification

Process

b

Uncertainty

Plant

nodalization

Plant

calculation

THE BEPU PROCESS - THE UNCERTAINTY METHOD

THE ACCEPTABILITY

THRESHOLDS

(for the use of the uncertainty

method)

10/21

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Any reproduction, alteration, transmission to any third party or publication in whole or in part of this document and/or its content is

prohibited unless the University of Pisa – San Piero a Grado Nuclear Research Group has provided its prior and written consent.

This document and any information it contains shall not be used for any other purpose than the one for which they were provided.

Legal action may be taken against any infringer and/or any person breaching the aforementioned obligations.

Exploitation of BEPU Approach for the Licensing Process

OECD/NEA CNRA Int. WS on “New Reactor Siting, Licensing and Construction Experience” OECD/NEA CNRA Int. WS on “New Reactor Siting, Licensing and Construction Experience”

-- State Office for Nuclear Safety Prague, Czech Republic – September 15-17 , 2010

THE BEPU PROCESS - THE CASE ‘A’ AND THE CASE ‘B’

For DBA (logic diagram)

Case A (BE): All I&C considered functioning

(except PIE) serves to demonstrate the realistic

accident course – 4 redundancies working.

Case B (Conservative Case): Controls having

favorable influence are not considered. All limitation

systems are assumed to be available and a failure of

the first reactor trip system is postulated (single

failure & repair case for most effective redundancies).

Related to each Transient

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Any reproduction, alteration, transmission to any third party or publication in whole or in part of this document and/or its content is

prohibited unless the University of Pisa – San Piero a Grado Nuclear Research Group has provided its prior and written consent.

This document and any information it contains shall not be used for any other purpose than the one for which they were provided.

Legal action may be taken against any infringer and/or any person breaching the aforementioned obligations.

Exploitation of BEPU Approach for the Licensing Process

OECD/NEA CNRA Int. WS on “New Reactor Siting, Licensing and Construction Experience” OECD/NEA CNRA Int. WS on “New Reactor Siting, Licensing and Construction Experience”

-- State Office for Nuclear Safety Prague, Czech Republic – September 15-17 , 2010

The complexity of the models

Selected Outcomes from FSAR Chapt. 15

The Input DeckThe Input Deck

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Any reproduction, alteration, transmission to any third party or publication in whole or in part of this document and/or its content is

prohibited unless the University of Pisa – San Piero a Grado Nuclear Research Group has provided its prior and written consent.

This document and any information it contains shall not be used for any other purpose than the one for which they were provided.

Legal action may be taken against any infringer and/or any person breaching the aforementioned obligations.

Exploitation of BEPU Approach for the Licensing Process

OECD/NEA CNRA Int. WS on “New Reactor Siting, Licensing and Construction Experience” OECD/NEA CNRA Int. WS on “New Reactor Siting, Licensing and Construction Experience”

-- State Office for Nuclear Safety Prague, Czech Republic – September 15-17 , 2010

Selected Outcomes from FSAR Chapt.15

TOP VIEW

SIDE VIEW

The CFDThe CFD

The boron injection in the

moderator tank

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Any reproduction, alteration, transmission to any third party or publication in whole or in part of this document and/or its content is

prohibited unless the University of Pisa – San Piero a Grado Nuclear Research Group has provided its prior and written consent.

This document and any information it contains shall not be used for any other purpose than the one for which they were provided.

Legal action may be taken against any infringer and/or any person breaching the aforementioned obligations.

Exploitation of BEPU Approach for the Licensing Process

OECD/NEA CNRA Int. WS on “New Reactor Siting, Licensing and Construction Experience” OECD/NEA CNRA Int. WS on “New Reactor Siting, Licensing and Construction Experience”

-- State Office for Nuclear Safety Prague, Czech Republic – September 15-17 , 2010

Selected Outcomes from FSAR Chapt.15

The 3D NK & THThe 3D NK & TH

The Power & Flow-Rate in

each of 451 FC

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Any reproduction, alteration, transmission to any third party or publication in whole or in part of this document and/or its content is

prohibited unless the University of Pisa – San Piero a Grado Nuclear Research Group has provided its prior and written consent.

This document and any information it contains shall not be used for any other purpose than the one for which they were provided.

Legal action may be taken against any infringer and/or any person breaching the aforementioned obligations.

Exploitation of BEPU Approach for the Licensing Process

OECD/NEA CNRA Int. WS on “New Reactor Siting, Licensing and Construction Experience” OECD/NEA CNRA Int. WS on “New Reactor Siting, Licensing and Construction Experience”

-- State Office for Nuclear Safety Prague, Czech Republic – September 15-17 , 2010

Selected Outcomes from FSAR Chapt.15

The Fuel AnalysisThe Fuel Analysis The The Code Coupling

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Any reproduction, alteration, transmission to any third party or publication in whole or in part of this document and/or its content is

prohibited unless the University of Pisa – San Piero a Grado Nuclear Research Group has provided its prior and written consent.

This document and any information it contains shall not be used for any other purpose than the one for which they were provided.

Legal action may be taken against any infringer and/or any person breaching the aforementioned obligations.

Exploitation of BEPU Approach for the Licensing Process

OECD/NEA CNRA Int. WS on “New Reactor Siting, Licensing and Construction Experience” OECD/NEA CNRA Int. WS on “New Reactor Siting, Licensing and Construction Experience”

-- State Office for Nuclear Safety Prague, Czech Republic – September 15-17 , 2010

Selected Outcomes from FSAR Chapt.15

The Application The Application

of Uncertaintyof Uncertainty

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Any reproduction, alteration, transmission to any third party or publication in whole or in part of this document and/or its content is

prohibited unless the University of Pisa – San Piero a Grado Nuclear Research Group has provided its prior and written consent.

This document and any information it contains shall not be used for any other purpose than the one for which they were provided.

Legal action may be taken against any infringer and/or any person breaching the aforementioned obligations.

Exploitation of BEPU Approach for the Licensing Process

OECD/NEA CNRA Int. WS on “New Reactor Siting, Licensing and Construction Experience” OECD/NEA CNRA Int. WS on “New Reactor Siting, Licensing and Construction Experience”

-- State Office for Nuclear Safety Prague, Czech Republic – September 15-17 , 2010

Selected Outcomes from FSAR Chapt.15

Selected FC

The Fuel AnalysisThe Fuel Analysis

The Enthalpy Release to the Fuel during LBLOCA

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Any reproduction, alteration, transmission to any third party or publication in whole or in part of this document and/or its content is

prohibited unless the University of Pisa – San Piero a Grado Nuclear Research Group has provided its prior and written consent.

This document and any information it contains shall not be used for any other purpose than the one for which they were provided.

Legal action may be taken against any infringer and/or any person breaching the aforementioned obligations.

Exploitation of BEPU Approach for the Licensing Process

OECD/NEA CNRA Int. WS on “New Reactor Siting, Licensing and Construction Experience” OECD/NEA CNRA Int. WS on “New Reactor Siting, Licensing and Construction Experience”

-- State Office for Nuclear Safety Prague, Czech Republic – September 15-17 , 2010

Selected Outcomes from FSAR Chapt.15

The MechanicalThe Mechanical

LoadsLoads The Stress on RPV internal during LBLOCA

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Any reproduction, alteration, transmission to any third party or publication in whole or in part of this document and/or its content is

prohibited unless the University of Pisa – San Piero a Grado Nuclear Research Group has provided its prior and written consent.

This document and any information it contains shall not be used for any other purpose than the one for which they were provided.

Legal action may be taken against any infringer and/or any person breaching the aforementioned obligations.

Exploitation of BEPU Approach for the Licensing Process

OECD/NEA CNRA Int. WS on “New Reactor Siting, Licensing and Construction Experience” OECD/NEA CNRA Int. WS on “New Reactor Siting, Licensing and Construction Experience”

-- State Office for Nuclear Safety Prague, Czech Republic – September 15-17 , 2010

Selected Outcomes from FSAR Chapt.15

The Radiological The Radiological

Impact Impact

Fuel Rupture &

Coolant Radioactivity

The Radioactivity in

Primary Circuit

The Radioactivity in

Containment

The Radioactivity in

Environment

The Doses

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Any reproduction, alteration, transmission to any third party or publication in whole or in part of this document and/or its content is

prohibited unless the University of Pisa – San Piero a Grado Nuclear Research Group has provided its prior and written consent.

This document and any information it contains shall not be used for any other purpose than the one for which they were provided.

Legal action may be taken against any infringer and/or any person breaching the aforementioned obligations.

Exploitation of BEPU Approach for the Licensing Process

OECD/NEA CNRA Int. WS on “New Reactor Siting, Licensing and Construction Experience” OECD/NEA CNRA Int. WS on “New Reactor Siting, Licensing and Construction Experience”

-- State Office for Nuclear Safety Prague, Czech Republic – September 15-17 , 2010

The ATUCHA-2 FSAR Chapt. 15 – PAPER FORMAT

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Any reproduction, alteration, transmission to any third party or publication in whole or in part of this document and/or its content is

prohibited unless the University of Pisa – San Piero a Grado Nuclear Research Group has provided its prior and written consent.

This document and any information it contains shall not be used for any other purpose than the one for which they were provided.

Legal action may be taken against any infringer and/or any person breaching the aforementioned obligations.

Exploitation of BEPU Approach for the Licensing Process

OECD/NEA CNRA Int. WS on “New Reactor Siting, Licensing and Construction Experience” OECD/NEA CNRA Int. WS on “New Reactor Siting, Licensing and Construction Experience”

-- State Office for Nuclear Safety Prague, Czech Republic – September 15-17 , 2010

Conclusive remarks

The Atucha-2 (about 800 MWe) NPP is to be licensed by

BEPU

FSAR Chapt. 15 issued for internal review

to be transmitted to Regulatory Authority

Challenges:

simulation of control systems

use of CFD

use of 3D NK & Coupling

application of uncertainty method

Suitable Safety Margins calculated

(‘new’ computational methods applied to ‘old’ NPP

design)

21/21