ML22321A021

Alloy 690/52/152 Thermal Aging: NRC Plans and Activities

ML22321A021
Person / Time
Issue date:	12/02/2022
From:	Eric Focht NRC/RES/DE
To:
Eric Focht 301-415-2094
References
Download: ML22321A021 (7)

Text

ALLOY 690/52/152 THERMAL 1 AGING:

NRC PLANS AND ACTIVITIES EPRI Alloy 690/52/152 PWSCC Research Collaboration Meeting Nov 29 - Dec. 2, 2022 POC: Eric Focht, NRC

2 INTRODUCTION

• NRC Alloy 690/52/152 PWSCC CGR Testing Program

• NRC-sponsored testing at PNNL and ANL completed in 2020

• Expert Panel identified thermal aging as a potential PWSCC accelerator

• Long-range ordering (LRO) or other hardening mechanism (e.g., short-range ordering, carbide precipitation)

• NRR requested plan to address thermal aging of Alloy 690/52/152

• Literature review by PNNL

• Plan by RES

3 BACKGROUND: ALLOY 690/52/152 THERMAL AGING

• Thermal aging effects detection

• Direct: TEM, XRD

• Indirect: hardness, resistivity

• For example, increased hardness may be indicative of LRO => increased PWSCC susceptibility

• Potential aging mechanisms

• LRO, SRO

• Carbide precipitation

• Hardening near fusion boundaries

• Hardness increases detected in commercially representative Alloy 690

• VTT (Finland), Oregon State University, ANL

• Very limited PWSCC CGR testing on thermally aged materials

4 PLAN TO ADDRESS ALLOY 690/52/152 THERMAL AGING

• PWSCC susceptibility is the primary concern

• LRO significantly increases PWSCC susceptibility

• Other aging mechanisms might be operating

• Very limited PWSCC CGR testing on thermally aged materials Cooperation Service-aged materials Laboratory-aged materials Materials aged during DOE PWSCC initiation project Harvested components Continue aging service-EPRI (e.g., Ringhals CRDM aged materials nozzles and SGT)

Universities (e.g., Materials aged by others (e.g., ANL, Ore. State U.) universities)

5 PLAN TO ADDRESS ALLOY 690/52/152

• PWSCC susceptibility is the primary concern THERMAL AGING

• LRO significantly increases PWSCC susceptibility

• Other aging mechanisms might be operating

• Very limited PWSCC CGR testing on thermally aged materials

• Cooperation

• DOE, EPRI

• Universities (e.g., Ore. State U.)

• Service-aged materials

• Harvested components

• Ringhals CRDM nozzles and SGT

• Laboratory-aged materials

• Materials aged during PWSCC initiation project

• Continue aging service-aged materials

• Materials aged by others (e.g., ANL, universities)

6 CURRENT ACTIVITIES

• ANL research

• Evaluate furnace-aged Alloy 690/152/LAS weldment

• Evaluate autoclave-aged CRDM Alloy 690 HAZ

• Hardness, XRD

• Attempting to acquire Ringhals 2 CRDM and SGT materials

• Service-aged materials

• No solid plan, yet. Focusing to obtaining materials first.

• Alloy 690/52/152 PWSCC initiation testing specimen evaluations.

• Hardness testing, FIB trenching to obtain specimens for future use.

7 THE END