WJP applicability study for pwr components as a pwscc mitigation technique

Ryuji Kimura, Noboru Saito, Hisamitsu Hato, Akihiro Kanno, Masami Ando, Hiroshi Muto, Fujio Yoshikubo, Morio Sato, Hiroyuki Kawamoto

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Water Jet Peening (WJP) has been widely applied to nuclear power plants in Japan as one of mitigation techniques against Stress Corrosion Cracking (SCC) initiation [1]. WJP utilizes high pressure water flow including numerous cavitation bubbles and improves surface residual stress of susceptible materials used in reactor internals from tensile stress to compressive stress without significant plastic deformation, hardening, heating and furthermore retrieval of foreign materials. An inspection relief for the Primary Water SCC (PWSCC) concerned components, by means of peening technique application, has been discussed among PWR owners in the US for about last 10 years. The topical report on PWSCC mitigation by surface stress improvement (Material Reliability Program (MRP)-335, revision 3-A) was published through the above activities by Electric Power Research Institute (EPRI) MRP [2]. The target components, where PWSCC is concerned, are listed as Reactor Pressure Vessel Head Penetration Nozzles (RPVHPNs), such as Control Rod Drive Mechanism Nozzle (CRDMN), and dissimilar metal welds (DMWs) of Reactor Coolant System (RCS) nozzles, and performance criteria for peening are defined in the topical report. Moreover, the technical basis for PWSCC mitigation by surface stress improvement (MRP-267, revision 2) was published by EPRI MRP [3].The report details numerous data for each peening technique which show the effectiveness in mitigating the PWSCC initiation and its sustainability, i.e. state of stress. The report also includes the process control; covering nozzle diameter, water flow rate, application time, jet stand-off, impingement angle and stationary nozzle time for WJP [3]. RPVHPNs inner diameter (ID), such as CRDMN ID, is in narrower areas than the other target components of peening techniques. Hence the WJP nozzle should be set appropriate condition, e. g. sufficient stand-off distance or angle of the WJP nozzle, in line with the MRP-267 in order to ensure the stress improvement effect by WJP. Further, the reactor pressure vessel head, which has the RPVHPNs including the CRDMNs, is placed on the refueling floor and under atmosphere condition during outage, and therefore, the CRDMNs have to be filled with water by plugging etc. for WJP application on CRDMN ID. Thus the CRDMN ID becomes a closed narrow chamber. In such a closed narrow chamber, water flow might become complex and disturb the cavitation collapse on the target surface, resulting in decreased stress improvement. Additionally, WJP has been rarely applied in a narrow closed water chamber, and only a few residual stress measurement data are available for such a WJP treated specimen. For the above reason, we has conducted a WJP test utilizing the water chamber and measured the residual stress of the test coupon simulating the CRDMN ID before and after WJP application as our own research. As a result, an improvement in residual stress was ensured even in an application of WJP in a closed narrow water chamber, which assumes CRDMN ID configuration, and created a depth over the performance criteria (0.01" (0.25 mm) in depth) stated in MRP-335 [2]. As an another applicability study, we developed a WJP tool for Bottom Mounted Instrument (BMI) Nozzles and confirmed that the residual stress of BMI ID and Outer Diameter (OD) can be improved . The background of this study is that BMI nozzle is under discussion for inspection relief as one of the components which are concerned about PWSCC. Especially, BMI ID is narrow area for WJP application; on the other hand it does not need to become a closed chamber since the reactor pressure vessel, which has the BMI Nozzles on the bottom head, is filled with water during outage. As a result, it is ensured that the residual stress for BMI ID and OD is improved by WJP to a depth of at least 0.2mm which is deeper than the performance criteria for the depth of compressive residual stress of Austenitic Stainless Steel in Japan (3.9 x 10-3" (0.1mm) in depth).

Original languageEnglish
Title of host publicationCodes and Standards
PublisherAmerican Society of Mechanical Engineers (ASME)
Volume1B-2017
ISBN (Electronic)9780791857915
DOIs
Publication statusPublished - 2017 Jan 1
Externally publishedYes
EventASME 2017 Pressure Vessels and Piping Conference, PVP 2017 - Waikoloa, United States
Duration: 2017 Jul 162017 Jul 20

Other

OtherASME 2017 Pressure Vessels and Piping Conference, PVP 2017
CountryUnited States
CityWaikoloa
Period17/7/1617/7/20

Fingerprint

Shot peening
Nozzles
Water
Control rods
Residual stresses
Pressure vessels
Stress corrosion cracking
Compressive stress
Cavitation
Outages

ASJC Scopus subject areas

  • Mechanical Engineering

Cite this

Kimura, R., Saito, N., Hato, H., Kanno, A., Ando, M., Muto, H., ... Kawamoto, H. (2017). WJP applicability study for pwr components as a pwscc mitigation technique. In Codes and Standards (Vol. 1B-2017). American Society of Mechanical Engineers (ASME). https://doi.org/10.1115/PVP2017-66164

WJP applicability study for pwr components as a pwscc mitigation technique. / Kimura, Ryuji; Saito, Noboru; Hato, Hisamitsu; Kanno, Akihiro; Ando, Masami; Muto, Hiroshi; Yoshikubo, Fujio; Sato, Morio; Kawamoto, Hiroyuki.

Codes and Standards. Vol. 1B-2017 American Society of Mechanical Engineers (ASME), 2017.

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Kimura, R, Saito, N, Hato, H, Kanno, A, Ando, M, Muto, H, Yoshikubo, F, Sato, M & Kawamoto, H 2017, WJP applicability study for pwr components as a pwscc mitigation technique. in Codes and Standards. vol. 1B-2017, American Society of Mechanical Engineers (ASME), ASME 2017 Pressure Vessels and Piping Conference, PVP 2017, Waikoloa, United States, 17/7/16. https://doi.org/10.1115/PVP2017-66164
Kimura R, Saito N, Hato H, Kanno A, Ando M, Muto H et al. WJP applicability study for pwr components as a pwscc mitigation technique. In Codes and Standards. Vol. 1B-2017. American Society of Mechanical Engineers (ASME). 2017 https://doi.org/10.1115/PVP2017-66164
Kimura, Ryuji ; Saito, Noboru ; Hato, Hisamitsu ; Kanno, Akihiro ; Ando, Masami ; Muto, Hiroshi ; Yoshikubo, Fujio ; Sato, Morio ; Kawamoto, Hiroyuki. / WJP applicability study for pwr components as a pwscc mitigation technique. Codes and Standards. Vol. 1B-2017 American Society of Mechanical Engineers (ASME), 2017.
@inproceedings{e8f768303b764cf9a910168f4e764fed,
title = "WJP applicability study for pwr components as a pwscc mitigation technique",
abstract = "Water Jet Peening (WJP) has been widely applied to nuclear power plants in Japan as one of mitigation techniques against Stress Corrosion Cracking (SCC) initiation [1]. WJP utilizes high pressure water flow including numerous cavitation bubbles and improves surface residual stress of susceptible materials used in reactor internals from tensile stress to compressive stress without significant plastic deformation, hardening, heating and furthermore retrieval of foreign materials. An inspection relief for the Primary Water SCC (PWSCC) concerned components, by means of peening technique application, has been discussed among PWR owners in the US for about last 10 years. The topical report on PWSCC mitigation by surface stress improvement (Material Reliability Program (MRP)-335, revision 3-A) was published through the above activities by Electric Power Research Institute (EPRI) MRP [2]. The target components, where PWSCC is concerned, are listed as Reactor Pressure Vessel Head Penetration Nozzles (RPVHPNs), such as Control Rod Drive Mechanism Nozzle (CRDMN), and dissimilar metal welds (DMWs) of Reactor Coolant System (RCS) nozzles, and performance criteria for peening are defined in the topical report. Moreover, the technical basis for PWSCC mitigation by surface stress improvement (MRP-267, revision 2) was published by EPRI MRP [3].The report details numerous data for each peening technique which show the effectiveness in mitigating the PWSCC initiation and its sustainability, i.e. state of stress. The report also includes the process control; covering nozzle diameter, water flow rate, application time, jet stand-off, impingement angle and stationary nozzle time for WJP [3]. RPVHPNs inner diameter (ID), such as CRDMN ID, is in narrower areas than the other target components of peening techniques. Hence the WJP nozzle should be set appropriate condition, e. g. sufficient stand-off distance or angle of the WJP nozzle, in line with the MRP-267 in order to ensure the stress improvement effect by WJP. Further, the reactor pressure vessel head, which has the RPVHPNs including the CRDMNs, is placed on the refueling floor and under atmosphere condition during outage, and therefore, the CRDMNs have to be filled with water by plugging etc. for WJP application on CRDMN ID. Thus the CRDMN ID becomes a closed narrow chamber. In such a closed narrow chamber, water flow might become complex and disturb the cavitation collapse on the target surface, resulting in decreased stress improvement. Additionally, WJP has been rarely applied in a narrow closed water chamber, and only a few residual stress measurement data are available for such a WJP treated specimen. For the above reason, we has conducted a WJP test utilizing the water chamber and measured the residual stress of the test coupon simulating the CRDMN ID before and after WJP application as our own research. As a result, an improvement in residual stress was ensured even in an application of WJP in a closed narrow water chamber, which assumes CRDMN ID configuration, and created a depth over the performance criteria (0.01{"} (0.25 mm) in depth) stated in MRP-335 [2]. As an another applicability study, we developed a WJP tool for Bottom Mounted Instrument (BMI) Nozzles and confirmed that the residual stress of BMI ID and Outer Diameter (OD) can be improved . The background of this study is that BMI nozzle is under discussion for inspection relief as one of the components which are concerned about PWSCC. Especially, BMI ID is narrow area for WJP application; on the other hand it does not need to become a closed chamber since the reactor pressure vessel, which has the BMI Nozzles on the bottom head, is filled with water during outage. As a result, it is ensured that the residual stress for BMI ID and OD is improved by WJP to a depth of at least 0.2mm which is deeper than the performance criteria for the depth of compressive residual stress of Austenitic Stainless Steel in Japan (3.9 x 10-3{"} (0.1mm) in depth).",
author = "Ryuji Kimura and Noboru Saito and Hisamitsu Hato and Akihiro Kanno and Masami Ando and Hiroshi Muto and Fujio Yoshikubo and Morio Sato and Hiroyuki Kawamoto",
year = "2017",
month = "1",
day = "1",
doi = "10.1115/PVP2017-66164",
language = "English",
volume = "1B-2017",
booktitle = "Codes and Standards",
publisher = "American Society of Mechanical Engineers (ASME)",

}

TY - GEN

T1 - WJP applicability study for pwr components as a pwscc mitigation technique

AU - Kimura, Ryuji

AU - Saito, Noboru

AU - Hato, Hisamitsu

AU - Kanno, Akihiro

AU - Ando, Masami

AU - Muto, Hiroshi

AU - Yoshikubo, Fujio

AU - Sato, Morio

AU - Kawamoto, Hiroyuki

PY - 2017/1/1

Y1 - 2017/1/1

N2 - Water Jet Peening (WJP) has been widely applied to nuclear power plants in Japan as one of mitigation techniques against Stress Corrosion Cracking (SCC) initiation [1]. WJP utilizes high pressure water flow including numerous cavitation bubbles and improves surface residual stress of susceptible materials used in reactor internals from tensile stress to compressive stress without significant plastic deformation, hardening, heating and furthermore retrieval of foreign materials. An inspection relief for the Primary Water SCC (PWSCC) concerned components, by means of peening technique application, has been discussed among PWR owners in the US for about last 10 years. The topical report on PWSCC mitigation by surface stress improvement (Material Reliability Program (MRP)-335, revision 3-A) was published through the above activities by Electric Power Research Institute (EPRI) MRP [2]. The target components, where PWSCC is concerned, are listed as Reactor Pressure Vessel Head Penetration Nozzles (RPVHPNs), such as Control Rod Drive Mechanism Nozzle (CRDMN), and dissimilar metal welds (DMWs) of Reactor Coolant System (RCS) nozzles, and performance criteria for peening are defined in the topical report. Moreover, the technical basis for PWSCC mitigation by surface stress improvement (MRP-267, revision 2) was published by EPRI MRP [3].The report details numerous data for each peening technique which show the effectiveness in mitigating the PWSCC initiation and its sustainability, i.e. state of stress. The report also includes the process control; covering nozzle diameter, water flow rate, application time, jet stand-off, impingement angle and stationary nozzle time for WJP [3]. RPVHPNs inner diameter (ID), such as CRDMN ID, is in narrower areas than the other target components of peening techniques. Hence the WJP nozzle should be set appropriate condition, e. g. sufficient stand-off distance or angle of the WJP nozzle, in line with the MRP-267 in order to ensure the stress improvement effect by WJP. Further, the reactor pressure vessel head, which has the RPVHPNs including the CRDMNs, is placed on the refueling floor and under atmosphere condition during outage, and therefore, the CRDMNs have to be filled with water by plugging etc. for WJP application on CRDMN ID. Thus the CRDMN ID becomes a closed narrow chamber. In such a closed narrow chamber, water flow might become complex and disturb the cavitation collapse on the target surface, resulting in decreased stress improvement. Additionally, WJP has been rarely applied in a narrow closed water chamber, and only a few residual stress measurement data are available for such a WJP treated specimen. For the above reason, we has conducted a WJP test utilizing the water chamber and measured the residual stress of the test coupon simulating the CRDMN ID before and after WJP application as our own research. As a result, an improvement in residual stress was ensured even in an application of WJP in a closed narrow water chamber, which assumes CRDMN ID configuration, and created a depth over the performance criteria (0.01" (0.25 mm) in depth) stated in MRP-335 [2]. As an another applicability study, we developed a WJP tool for Bottom Mounted Instrument (BMI) Nozzles and confirmed that the residual stress of BMI ID and Outer Diameter (OD) can be improved . The background of this study is that BMI nozzle is under discussion for inspection relief as one of the components which are concerned about PWSCC. Especially, BMI ID is narrow area for WJP application; on the other hand it does not need to become a closed chamber since the reactor pressure vessel, which has the BMI Nozzles on the bottom head, is filled with water during outage. As a result, it is ensured that the residual stress for BMI ID and OD is improved by WJP to a depth of at least 0.2mm which is deeper than the performance criteria for the depth of compressive residual stress of Austenitic Stainless Steel in Japan (3.9 x 10-3" (0.1mm) in depth).

AB - Water Jet Peening (WJP) has been widely applied to nuclear power plants in Japan as one of mitigation techniques against Stress Corrosion Cracking (SCC) initiation [1]. WJP utilizes high pressure water flow including numerous cavitation bubbles and improves surface residual stress of susceptible materials used in reactor internals from tensile stress to compressive stress without significant plastic deformation, hardening, heating and furthermore retrieval of foreign materials. An inspection relief for the Primary Water SCC (PWSCC) concerned components, by means of peening technique application, has been discussed among PWR owners in the US for about last 10 years. The topical report on PWSCC mitigation by surface stress improvement (Material Reliability Program (MRP)-335, revision 3-A) was published through the above activities by Electric Power Research Institute (EPRI) MRP [2]. The target components, where PWSCC is concerned, are listed as Reactor Pressure Vessel Head Penetration Nozzles (RPVHPNs), such as Control Rod Drive Mechanism Nozzle (CRDMN), and dissimilar metal welds (DMWs) of Reactor Coolant System (RCS) nozzles, and performance criteria for peening are defined in the topical report. Moreover, the technical basis for PWSCC mitigation by surface stress improvement (MRP-267, revision 2) was published by EPRI MRP [3].The report details numerous data for each peening technique which show the effectiveness in mitigating the PWSCC initiation and its sustainability, i.e. state of stress. The report also includes the process control; covering nozzle diameter, water flow rate, application time, jet stand-off, impingement angle and stationary nozzle time for WJP [3]. RPVHPNs inner diameter (ID), such as CRDMN ID, is in narrower areas than the other target components of peening techniques. Hence the WJP nozzle should be set appropriate condition, e. g. sufficient stand-off distance or angle of the WJP nozzle, in line with the MRP-267 in order to ensure the stress improvement effect by WJP. Further, the reactor pressure vessel head, which has the RPVHPNs including the CRDMNs, is placed on the refueling floor and under atmosphere condition during outage, and therefore, the CRDMNs have to be filled with water by plugging etc. for WJP application on CRDMN ID. Thus the CRDMN ID becomes a closed narrow chamber. In such a closed narrow chamber, water flow might become complex and disturb the cavitation collapse on the target surface, resulting in decreased stress improvement. Additionally, WJP has been rarely applied in a narrow closed water chamber, and only a few residual stress measurement data are available for such a WJP treated specimen. For the above reason, we has conducted a WJP test utilizing the water chamber and measured the residual stress of the test coupon simulating the CRDMN ID before and after WJP application as our own research. As a result, an improvement in residual stress was ensured even in an application of WJP in a closed narrow water chamber, which assumes CRDMN ID configuration, and created a depth over the performance criteria (0.01" (0.25 mm) in depth) stated in MRP-335 [2]. As an another applicability study, we developed a WJP tool for Bottom Mounted Instrument (BMI) Nozzles and confirmed that the residual stress of BMI ID and Outer Diameter (OD) can be improved . The background of this study is that BMI nozzle is under discussion for inspection relief as one of the components which are concerned about PWSCC. Especially, BMI ID is narrow area for WJP application; on the other hand it does not need to become a closed chamber since the reactor pressure vessel, which has the BMI Nozzles on the bottom head, is filled with water during outage. As a result, it is ensured that the residual stress for BMI ID and OD is improved by WJP to a depth of at least 0.2mm which is deeper than the performance criteria for the depth of compressive residual stress of Austenitic Stainless Steel in Japan (3.9 x 10-3" (0.1mm) in depth).

UR - http://www.scopus.com/inward/record.url?scp=85034015400&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85034015400&partnerID=8YFLogxK

U2 - 10.1115/PVP2017-66164

DO - 10.1115/PVP2017-66164

M3 - Conference contribution

AN - SCOPUS:85034015400

VL - 1B-2017

BT - Codes and Standards

PB - American Society of Mechanical Engineers (ASME)

ER -