Low temperature crack propagation of nickel-based weld metals in hydrogenated PWR primary water

Matias Ahonen, Ulla Ehrnstén, Hannu Hänninen

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review

Abstract

The effect of hydrogenated PWR primary water on the Low Temperature Crack Propagation (LTCP) susceptibility of nickel based weld metals Alloy 182, 82, 152 and 52 was studied performing J-R -tests at a slow displacement rate in simulated low temperature PWR primary water. When tested in an environment with high hydrogen content (100 cm3 H2/kg H2O), all the studied materials showed a remarkable decrease in the fracture toughness (JIC or JQ) values compared with the air test results. Alloy 182 showed the lowest average fracture toughness values in each test environment. The results obtained at a lower hydrogen content (~30 cm3 H2/kg H2O) suggest, that Alloy 182 is the most susceptible nickel based weld metal to LTCP, especially at low hydrogen contents. Intergranular cracking was predominant when the JIC value was low. Test results of pure weld metal Alloys 182 and 52 were also compared with the results of dissimilar metal weld (DMW) specimens of Alloy 182 and 52. The pure weld metals were substantially more susceptible to LTCP than the DMW specimens. Pre-exposure to high temperature hydrogenated water did not affect the fracture toughness of any of the test materials. The degradation in toughness is assumed to be caused by a hydrogen-induced intergranular cracking mechanism, where the precipitates in the weld metals acting as hydrogen trapping sites play an important role. The LTCP susceptibility of the studied alloys is discussed based on the present hydrogen embrittlement mechanisms.
Original languageEnglish
Title of host publicationFontevraud 7
Subtitle of host publicationContribution of materials investigations to improve the safety and performance of LWRs, 26-30 September, 2010, Avignon, France
Number of pages11
Publication statusPublished - 2010
MoE publication typeNot Eligible

Fingerprint

Crack propagation
Welds
Nickel
Metals
Hydrogen
Water
Dissimilar metals
Fracture toughness
Temperature
Hydrogen embrittlement
Toughness
Precipitates
Degradation
Air

Keywords

  • nuclear
  • LTCP
  • hydrogen
  • Ni-based weld metals

Cite this

Ahonen, M., Ehrnstén, U., & Hänninen, H. (2010). Low temperature crack propagation of nickel-based weld metals in hydrogenated PWR primary water. In Fontevraud 7: Contribution of materials investigations to improve the safety and performance of LWRs, 26-30 September, 2010, Avignon, France
Ahonen, Matias ; Ehrnstén, Ulla ; Hänninen, Hannu. / Low temperature crack propagation of nickel-based weld metals in hydrogenated PWR primary water. Fontevraud 7: Contribution of materials investigations to improve the safety and performance of LWRs, 26-30 September, 2010, Avignon, France. 2010.
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Ahonen, M, Ehrnstén, U & Hänninen, H 2010, Low temperature crack propagation of nickel-based weld metals in hydrogenated PWR primary water. in Fontevraud 7: Contribution of materials investigations to improve the safety and performance of LWRs, 26-30 September, 2010, Avignon, France.

Low temperature crack propagation of nickel-based weld metals in hydrogenated PWR primary water. / Ahonen, Matias; Ehrnstén, Ulla; Hänninen, Hannu.

Fontevraud 7: Contribution of materials investigations to improve the safety and performance of LWRs, 26-30 September, 2010, Avignon, France. 2010.

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review

TY - GEN

T1 - Low temperature crack propagation of nickel-based weld metals in hydrogenated PWR primary water

AU - Ahonen, Matias

AU - Ehrnstén, Ulla

AU - Hänninen, Hannu

N1 - Project code: 41755 Proc. on a CD-ROM, ISBN N/A

PY - 2010

Y1 - 2010

N2 - The effect of hydrogenated PWR primary water on the Low Temperature Crack Propagation (LTCP) susceptibility of nickel based weld metals Alloy 182, 82, 152 and 52 was studied performing J-R -tests at a slow displacement rate in simulated low temperature PWR primary water. When tested in an environment with high hydrogen content (100 cm3 H2/kg H2O), all the studied materials showed a remarkable decrease in the fracture toughness (JIC or JQ) values compared with the air test results. Alloy 182 showed the lowest average fracture toughness values in each test environment. The results obtained at a lower hydrogen content (~30 cm3 H2/kg H2O) suggest, that Alloy 182 is the most susceptible nickel based weld metal to LTCP, especially at low hydrogen contents. Intergranular cracking was predominant when the JIC value was low. Test results of pure weld metal Alloys 182 and 52 were also compared with the results of dissimilar metal weld (DMW) specimens of Alloy 182 and 52. The pure weld metals were substantially more susceptible to LTCP than the DMW specimens. Pre-exposure to high temperature hydrogenated water did not affect the fracture toughness of any of the test materials. The degradation in toughness is assumed to be caused by a hydrogen-induced intergranular cracking mechanism, where the precipitates in the weld metals acting as hydrogen trapping sites play an important role. The LTCP susceptibility of the studied alloys is discussed based on the present hydrogen embrittlement mechanisms.

AB - The effect of hydrogenated PWR primary water on the Low Temperature Crack Propagation (LTCP) susceptibility of nickel based weld metals Alloy 182, 82, 152 and 52 was studied performing J-R -tests at a slow displacement rate in simulated low temperature PWR primary water. When tested in an environment with high hydrogen content (100 cm3 H2/kg H2O), all the studied materials showed a remarkable decrease in the fracture toughness (JIC or JQ) values compared with the air test results. Alloy 182 showed the lowest average fracture toughness values in each test environment. The results obtained at a lower hydrogen content (~30 cm3 H2/kg H2O) suggest, that Alloy 182 is the most susceptible nickel based weld metal to LTCP, especially at low hydrogen contents. Intergranular cracking was predominant when the JIC value was low. Test results of pure weld metal Alloys 182 and 52 were also compared with the results of dissimilar metal weld (DMW) specimens of Alloy 182 and 52. The pure weld metals were substantially more susceptible to LTCP than the DMW specimens. Pre-exposure to high temperature hydrogenated water did not affect the fracture toughness of any of the test materials. The degradation in toughness is assumed to be caused by a hydrogen-induced intergranular cracking mechanism, where the precipitates in the weld metals acting as hydrogen trapping sites play an important role. The LTCP susceptibility of the studied alloys is discussed based on the present hydrogen embrittlement mechanisms.

KW - nuclear

KW - LTCP

KW - hydrogen

KW - Ni-based weld metals

M3 - Conference article in proceedings

BT - Fontevraud 7

ER -

Ahonen M, Ehrnstén U, Hänninen H. Low temperature crack propagation of nickel-based weld metals in hydrogenated PWR primary water. In Fontevraud 7: Contribution of materials investigations to improve the safety and performance of LWRs, 26-30 September, 2010, Avignon, France. 2010