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Potential Studsvik Contribution to PERFECT
Anders Jenssen, Martin König and Anders
Molander Studsvik Nuclear AB SE-611 82
Nyköping SWEDEN Kjell Pettersson MATSAFE AB
Seminar Bruxelles March 13, 2003
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Suggestions for a potential Studsvik
contribution to PERFECT

• To determine the fracture toughness JIC for
  relevant plant materials measured by conventional
  techniques and compare with a modified new
  technique
• To study size criteria for irradiated steels
• To understand the results and generate input data
  for modeling
• To estimate the impact on safety assessments and
  structural integrity analyses

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Background
The fracture toughness of nuclear materials is an
important parameter for safety assessments and
structural integrity analyses The conventional
methods make use of CT- or SNEB- specimens which
are submitted to pre-fatigue and then tested for
JIC at specified temperature During these
circumstances the crack formed before JIC testing
is transgranular In plant the crack can be
intergranular which could affect the results,
possibly in a negative way Lower fracture
toughness may be measured due to intergranular
crack propagation in the irradiated material
during JIC testing
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Background, cont
Due to the mechanical properties and changed
deformation mechanism of an irradiated material
size criteria commonly used can be irrelevant.
It is suggested to test an unirradiated
material with similar properties as an irradiated
material. Difficult material choice but a
precipitation hardened material may be used.
Fracture toughness tests are performed with
IGSCC cracks as described above.
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Experimental

• Fracture toughness tests are performed using CT
  specimens
• Fatigue in air or in autoclave in LWR environment
• Creation of an IGSCC crack in simulated
  environment
• JICtesting
• Comparisons between different cracking modes and
  materials are performed.
• Existing in-house material irradiated in a LWR or
  material cut from a nuclear power plant can be
  used.
• The results will determine subsequent work.

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Relevant facilities at Studsvik
The Hot Cell Laboratory
The R2 reactor
The Corrosion Laboratory
The Active Metals Laboratory
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Relevant projects at Studsvik Corrosion and Water
Chemistry

• PRIS Tensile testing of a flux thimble tube
  irradiated in a PWR (70dpa) and fracture
  toughness measurements using the PLT-techniques
• IASCC Crack growth rate measurements of
  irradiated materials in BWR and PWR environment
  within an international program
• Surveillance testing All Swedish surveillance
  testing performed at Studsvik
• Other ongoing IASCC and SCC projects (BWR, PWR,
  Fusion)
• Radiolysis and ECP modeling for BWR and PWR
  conditions

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The PLT technique
Pin - Loading Technique
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Summary
Fracture toughness
Size criteria
Experimental studies
Fracture toughness data during realistic
conditions

Evaluation and modeling input
Impact on safety assessments and structural
integrity analyses