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 AGING:

NRC PLANS AND ACTIVITIES EPRI Alloy 690/52/152 PWSCC Research Collaboration Meeting Nov 29 - Dec. 2, 2022 POC: Eric Focht, NRC 1

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 2

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 3

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

DOE EPRI Universities (e.g.,

Ore. State U.)

Cooperation Harvested components (e.g., Ringhals CRDM nozzles and SGT)

Service-aged materials Materials aged during PWSCC initiation project Continue aging service-aged materials Materials aged by others (e.g., ANL, universities)

Laboratory-aged materials 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

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

• 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) 5

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.

6

THE END 7