Technical Meeting on Heavy Components Replacement in NPPs

“CNEA Experience on Nuclear Components Replacement”

26- 28 May 2009, Lynchburg, VA, USA Organized by IAEAHosted by Areva

Silvio FabbriNational Commission of Atomic EnergyArgentina

ARGENTINA

• 2,7 Millions Km²• 39 Millions people• 2 NPPs 9%• 1 under construction• 2 under study

Argentina Nuclear ActivitiesSince September 1994 the organisation of the Argentina nuclear activities is as follows:

� "Comisión Nacional de Energía Atómica" (CNEA), National Commission of Atomic Energy.

� "Autoridad Regulatoria Nuclear" (ARN), National Regulatory Board of Nuclear activities.

� "Nucleoeléctrica Argentina Sociedad Anónima" (NASA), which operates the NPPs, Atucha 1, Embalse and Atucha 2 (under construction).

National Commission of Atomic Energy• R&D in nuclear and related activities.• Fuel cycle.• Radwaste management.• Operation of the research reactors and other nuclear facilities.

• Technical support to the NPPs.

Constituyentes Atomic Center

Research Reactors and Critical Assemblies

RIO NEGRO PROVINCE

CNEACRITICALRA – 8 CABCNEARESEARCHRA – 6

SANTA FE PROVINCE

ROSARIO UNIVERSITY

RESEARCHRA – 4CAECNEAPRODUCTIONRA – 3CACCNEARESEARCHRA – 1

CORDOBA PROVINCE

CORDOBA UNIVERSITY

CRITICALRA – 0LOCATIONOPERATORTYPEFACILITY

Nuclear Power Reactors

NA – SA UNDER CONSTRUC.

-------------------PHWR700 Mwe

ATUCHA 2

NA – SAOPERATION1984CANDU600 Mwe

EMBALSE

NA – SAOPERATION1974PHWR360 Mwe

ATUCHA 1

OPERATORSTATUSGRID CONN.TYPEUNIT

Atucha 1 & 2 NPPs

Embalse NPP

Atucha 1

MZFR

Atucha 1 Reactor Pressure VesselType: PWRCoolant / Moderator: D2ODesigner: Siemens Electrical Power : 360 MwDesign Life Time (FPY): 32 Operation Time (FPY): 24Fuel: UO2Cladding Material: Zry-4Fuel Elements: 252Active length (mm): 5.300Operating Pressure (ata): 115

Atucha 1 Coolant ChannelFunctions

• Fixing the fuel assemblies

• Directing the coolant flow

• Separating the coolant flow from the moderator

• Thermal insulation against heating up the moderator by the coolant

Coolant Channels• number of channels: 253• active length: 5300 mm• total length: 10266 mm• material: Zry 4 and SS•Degradation:• oxidation and hydrogen (deuterium) absorption

• irradiation embrittlement • irradiation creep and growth• after 10 FPY the oxidation rate shows signs acceleration (breakaway)

Replacement: was initiated in 1990

Degradation of Coolant Channels

Atucha 1 Pool House for Spent Fuel Storage

Decontamination by Vibratory Polishing of the upper part of Atucha 1 NPP Coolant Channel – Cold Test -

• High temperature oxidation• Material = Stainless Steel 1.4541 • Long piece = 500 mm • Oxidation time = 2 hours at 600 ºC• Estimated thickness = 0.1µm• After one hour external and internal surfaces

of the tube were successfully cleaned.

Replacement of Nuclear Components• In 1995 two pressure tubes were replaced to evaluate the condition of the material of both tubes.

• In the research reactor RA-3 placed in Ezeiza Atomic Center the tank internals were replaced in order to obtain a power uprate of 10 thermal Mw.

ConclusionsThe activities, performed throughout 60 years of nuclear research, development and production in Argentina, formed high qualified personnel in CNEA and NASA, with excellent abilities and technologies that have established the knowledge to replace nuclear components in research and power reactors.

ManyThanks