Search

Occasional Topics
OTjapan Measures for Tsunami Striking Nuclear Power Station in Japan
Special Article: The Great Tohoku Earthquake (1)
OTjapan The Tragedy of “To Be” Principle in the Japanese Nuclear Industry
EJAMOT_CN3_Figure1_The_outside_view_of_CEFR OTChinaPlanning and Consideration on SFR R&D Activities in China
< All Occasional Topics

Information
ICMST-Kobe 2014
Nov 2(Sun) - 5(Wed), 2014
Kobe, Japan
Nuclear Regulation Authority Outline of the New Safety Standards for Light Water Reactors for Electric Power Generation
For Public Comment
Outline of New Safety Standard (Design Basis)
For Public Comment
New Safety Standards (SA) Outline (Draft)
For Public Comment
Outline of New Safety Standard(Earthquake and Tsunami)(DRAFT)
Issues
  Vol.5 No.4(Feb-25)
Vol.5 No.3(Nov-25)
Vol.5 No.2(Aug-26)
Vol.5 No.1(May-27)
< Other Issues

Featured Articles
EJAM5-3NT58 "Development of Future Prediction of Animation by coupling of Principle Component Analysis and Singular Spectrum Analysis"
EJAM5-3NT58 Validation of Multifrequency and Window-Multifrequency Techniques using Remote Field Eddy Currents for ISI of FBR Tubes
EJAM5-3NT59 Remote Controlled Robot with expandable features

JSM
Contacts
(EJAM): ejam@jsm.or.jp
(JSM): secretariat@jsm.or.jp
HP: http://www.jsm.or.jp
(in English)

 
Vol.1 No.4 previous GA 11 - 12 - AA SP1 ( 11 - 12 - 13 - 14 ) - NT 19 - 20 - 21 - 22 next Vol.2 No.2
Vol.2, No.1, NT19 EJAM (2-1-NT19) -INLAY METHOD USING THE CYLINDRICAL CONTAINER FOR REACTOR VESSEL OF PWR

INLAY Method Using the Cylindrical Container for Reactor Vessel of PWR

 
THE KANSAI ELECTRIC POWER CO., INC. (KEPCO)
MITSUBISHI HEAVY INDUSTRIES, LTD. (MHI)
 

KEYWORDS:
INLAY, Cylindrical Container, Ambient temperature temper bead welding, PWSCC, Alloy 600/690, Austenitic stainless steels, Reactor vessel

 
1. Technical summary
 
Classification
(I: Inspection, II: Repair, III: Replacement, IV: Preventive Maintenance, V: Others)
 
(1) This is a repair method against PWSCC (Primary Water Stress Corrosion Cracking) of outlet / inlet nozzle to safe-end weld of Reactor vessel (RV) of PWR.

(2) INLAY method using the cylindrical container was applied for Ohi Nuclear Power Station Unit 3 of KEPCO in 2009 for the first time in Japan. (Fig.1,2,3)
 
EJAM2-1NT19-Fig.1_INLAY_method_using_the_cylindrical_container_for_RV
 
Fig.1 INLAY method using the cylindrical container for RV
(at Ohi Nuclear Power Station Unit 3 of KEPCO)
 
EJAM2-1NT19-Fig.2_The_procedure_of_INLAY_method_applied_for_Ohi_Nuclear_Power_Station_Unit3_of_KEPCO
 
Fig.2 The procedure of INLAY method applied for
Ohi Nuclear Power Station Unit 3 of KEPCO
 
EJAM2-1NT19-Fig.3_Installation_of_the_cylindrical_container_for_RV_at_Ohi_Nuclear_Power_Station_Unit3_of_KEPCO
 
Fig.3 Installation of the cylindrical container for RV
at Ohi Nuclear Power Station Unit 3 of KEPCO
 
(3)The cavity must be filled with water to avoid much exposure from Core Internals (CI) while out of RV. The cylindrical container is installed on RV to secure atmospheric working space inside outlet nozzle. (Fig.4 ,Fig.5)
 
EJAM2-1NT19-Fig.4_Photos_of_cylindrical_container_at_the_shop_of_MHI(a)
(a) Test in water
 
EJAM2-1NT19-Fig.4_Photos_of_cylindrical_container_at_the_shop_of_MHI(b)
(b) Inner view
 
Fig.4 Photos of cylindrical container at the shop of MHI
 

このページのコンテンツには、Adobe Flash Player の最新バージョンが必要です。

Adobe Flash Player を取得

 
Fig.5 Installing test of the cylindrical container into water at the shop of MHI
 
(4) INLAY method using the cylindrical container was performed as follows (Fig.2);
  1. Machining for the part where SCC had been found and removed during the last outage
  2. Partial repair welding with Alloy 600
  3. Circumferential grooving to remove Alloy 600 of the inner surface
  4. Circumferential welding with PWSCC resistant Alloy 690

(5) The partial repair welding is performed close to the nozzle as shown in Fig.1. This means the heat treatments for the nozzle, made of low allow steel, shall be applied to relief the welding heat effect, however it is difficult to apply them because of the structural situation. Then the ambient temperature temper bead welding technique was developed to make the heat treatments unnecessary. (Fig.6)
 
EJAM2-1NT19-Fig.6_Monitoring_view_of_the_ambient_temperature_temper_bead_welding
 
Fig.6 Monitoring view of the ambient temperature temper bead welding
 
2. Scope
(1) Components: Reactor Vessel (RV) of PWR

(2) Location: Dissimilar welds of outlet / inlet nozzle of RV concerned PWSCC

(3) Material: Alloy600 (Nickel based alloy)

(4) Condition: This method can be applied underwater.
 
3. Features
(1) The cylindrical container: Repair or preventive maintenance can be applied, even when the cavity is filled with water.(Reduction of drainage process)

(2) The ambient temperature temper bead welding is applied.

(3) Reduction of radiation exposure by the following measures;
  1. Blast decontamination
  2. Thick wall of the platform and equipped shielding tube into the nozzle
 
4. Examples of Application
(1) Ohi Nuclear Power Station Unit 3 of KEPCO in 2009
 
5. Reference
None
 
6. Contact
Japan Society of Maintenology (ejam@jsm.or.jp)