ML19319B310
| ML19319B310 | |
| Person / Time | |
|---|---|
| Issue date: | 11/13/2019 |
| From: | NRC/OCIO |
| To: | |
| Shared Package | |
| ML19319B303 | List: |
| References | |
| FOIA, NRC-2018-000831 | |
| Download: ML19319B310 (12) | |
Text
Harvesting of Materials from Operating and Decommissioning Nuclear Power Plants R. Tregoning, M. Audrain, M. Hiser, and P. Purtscher Office of Nuclear Regulatory Research U.S. Nuclear Regulatory Commission U.S.NRC - S/NRA/R Bilateral Meeting on Materials Issues September 18 - 20, 2018 NRA Headquarters, Tokyo, JAPAN This presentation was prepared as an account of work conducted by an agency of the U.S. Government. Neither the U.S.
Government nor any agency thereof, nor any of their employees, makes any warranty, expressed or implied, or assumes any legal liability or responsibility for any third partys use, or the results of such use, of any information, apparatus, product, or process disclosed in this report, or represents that its use by such third party would not infringe privately owned rights. The views expressed in this paper are not necessarily those of the U.S. Nuclear Regulatory Commission.
Motivation for Harvesting
- US utilities are interested in extending operating lifespans from 60 to 80 years:
- Key technical areas for aging management
- RPV embrittlement, irradiation-assisted degradation of internals, concrete structures and containment, electrical cables
- Plant shutdowns provide opportunities to harvest components during decommissioning
- Harvesting can provide valuable information on aging mechanisms to increase confidence in aging management
- Limited budgets make cooperation for new research, including harvesting, essential:
- Important to align interested parties
- Leverage resources for maximum benefit September 18 - 20, 2018 U.S.NRC - S/NRA/R Bilateral Meeting on Materials Issues 2
NRC Harvesting Experience
- NRC has participated in several programs:
- RPV, CRDM penetrations, RCS piping, RPV internals, neutron absorbers, and cables
- Materials harvested from unfinished, operating and decommissioning plants
- US and international programs
- NRC experience has demonstrated that is there is significant value in using harvested components to confirm data from other research programs September 18 - 20, 2018 U.S.NRC - S/NRA/R Bilateral Meeting on Materials Issues 3
Lessons Learned
- Technical
- Provides highly representative aged materials for research
- Important to gain as much background information on material and component as possible before committing to specific harvesting project
- Logistical
- Expensive and time-consuming effort
- Leveraging resources helps mitigate cost challenges
- Transportation of irradiated materials is cumbersome and time-consuming September 18 - 20, 2018 U.S.NRC - S/NRA/R Bilateral Meeting on Materials Issues 4
Ex-Plant Materials Harvesting Workshop
- Overview
Purpose:
Discuss benefits and challenges associated with harvesting
- Held at NRC HQ on March 7-8, 2017
- Participants included U.S. and international utilities and researchers
- Technical sessions
- Motivation, data needs, sources of materials, lessons learned and practical aspects of harvesting, and decision-making and planning
- Summary of discussion
- Focused on the importance of clearly identifying the need and purpose for performing a harvesting project.
- Harvesting is a complex and expensive proposition, but one that can be worthwhile if the need is clearly defined and addressed.
- Slides and summary report can be found at https://drive.google.com/open?id=0B5DWMLch5YSXcnpZZ0JOS055QUU September 18 - 20, 2018 U.S.NRC - S/NRA/R Bilateral Meeting on Materials Issues 5
Current Work
- Develop strategic approach to materials harvesting
- Past efforts have been reactive to individual plants shutting down
- Identify target harvesting candidates early in the shutdown process
- Prioritize data needs best addressed by harvesting, considering:
- Applicability of harvested material for addressing gaps
- Importance of harvested materials over laboratory aging
- Fleet-wide vs plant-specific applicability of data
- Regulatory considerations
- Harvesting cost/complexity
- Database for sources of materials
- Compilation of previously harvested materials and components from NRC-sponsored programs available at US national labs
- NRC is interested in engaging with other organizations in developing a broader database September 18 - 20, 2018 U.S.NRC - S/NRA/R Bilateral Meeting on Materials Issues 6
Ex-plant Materials of Interest - Metals
- High fluence & highly embrittled vessel with well-established unirradiated properties (or a means to estimate them)
- Through-thickness section to validate fluence & attenuation models
- Measure fluence, toughness, & chemistry as a function of through-thickness position
- Samples from virtually any vessel
- Of sufficient size to enable measurement of both the Charpy transition curve and Master Curve transition temperature, T0
- Objectives
- Enables demonstration of the conservatism of regulatory approaches for transition temperature prediction
- Provides data supporting evolution from the use of correlative (Charpy-based) to direct measurement (fracture toughness-based) approaches September 18 - 20, 2018 U.S.NRC - S/NRA/R Bilateral Meeting on Materials Issues 7
Ex-plant Materials of Interest - Metals
- CASS and Internals
- High fluence reactor internals
- >50 dpa 304 SS from high core outlet temp plant
- Bounding temperature and high fluence for void swelling
- Thermally aged unirradiated CASS
- >30 years at ~320°C; Validate accelerated aging data
- Moderate fluence (1-2 dpa) CASS
- Bolster technical basis for embrittlement in this fluence range
- Components with known flaws
- Example: weld overlays over known flaws
- Evaluation or NDE reliability
- Assess effectiveness of mitigation techniques
- Components with limiting fatigue life
- Confirm fatigue calculations are accurate by inspecting for flaws September 18 - 20, 2018 U.S.NRC - S/NRA/R Bilateral Meeting on Materials Issues 8
Ex-plant Materials of Interest - Electrical
- Cables
- Low and medium voltage cables
- Cables protected with fire retardant coating
- Electrical components
- 1E MOVs from harsh and mild environments
- 1E Air operated valves; 4160 1E breakers
- 1E Molded case breakers 480V, 250V DC, 125 VDC,
- 1E Relays from mild environment GE - HFA, Agastat timing relays, any from Westinghouse, Potter Brumfield, Stuthers Dunn etc.,
- Electrical penetrations; Batteries
- Fire research interest
- Electrical enclosures
September 18 - 20, 2018 U.S.NRC - S/NRA/R Bilateral Meeting on Materials Issues 9
Ex-plant Materials of Interest - Concrete
- Structures exposed to high radiation
- Post-tensioned structures
- Corrosion of reinforcing steel, tendon, liner, embedment
- Spent fuel pool and transfer canal-boric acid attack on concrete in PWRs
- Alkali Aggregate Reaction
- Large structural sections for testing September 18 - 20, 2018 U.S.NRC - S/NRA/R Bilateral Meeting on Materials Issues 10
Summary
- Harvesting can yield highly representative and valuable data on materials aging
- A focused approach to choosing harvested materials is necessary to get best outcomes
- NRC is working on a sources of materials database and prioritizing data needs based on relevant criteria to inform decisions on specific harvesting opportunities
- NRC welcomes opportunities for cooperation and leveraging with other interested research organizations September 18 - 20, 2018 U.S.NRC - S/NRA/R Bilateral Meeting on Materials Issues 11
Suggested NRC/NRA Collaboration
- NRC is interested in the status of the planned work on harvesting RPV materials and concrete from Hamaoka 1 and, if it has been completed, if those results can be shared with the NRC.
- NRC wishes to learn about any other harvesting programs that NRA and/or CRIEPI are either planning or are already in progress
- If such programs are in progress, NRC would be interested in obtaining any information that can be shared
- If such programs are being planned, NRC would be interested in learning about any partnering opportunities that NRA foresees
- NRC would like to determine NRAs interest in participating in a harvesting project identified by the US or another country. If NRA is potentially interested in such a program, NRC can contact NRA and provide information if such harvesting opportunities develop September 18 - 20, 2018 U.S.NRC - S/NRA/R Bilateral Meeting on Materials Issues 12