ML16209A479
| ML16209A479 | |
| Person / Time | |
|---|---|
| Issue date: | 08/09/2016 |
| From: | Matthew Hiser, Amy Hull, Pat Purtscher, Robert Tregoning NRC/RES/DE/CMB |
| To: | |
| Hiser M | |
| References | |
| Download: ML16209A479 (14) | |
Text
Strategic Approach for Ex-Plant Materials Harvesting Matthew Hiser Amy Hull Patrick Purtscher Robert Tregoning U.S. NRC NRC-NRAJ Bilateral Technical Information Exchange Meeting Nuclear Regulatory Commission Headquarters August 8-9, 2016
Purpose
- Create a framework for a strategic approach to harvesting ex-plant materials to support regulatory needs associated with subsequent license renewal (SLR)
- Ex-plant materials offer unique environmental exposure that cannot be entirely replicated by laboratory testing with fresh materials
- Align high priority data needs identified in SLR activities with harvesting opportunities from decommissioning plants 2
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Background===
- To date, harvesting opportunities have been limited due to few decommissioning plants
- Zion in U.S., Zorita in Spain
- However, several U.S. plants have already shut down or are planning to do so in the near future
- Kewaunee, San Onofre, Crystal River, Vermont Yankee, Oyster Creek, Fort Calhoun, Clinton, Quad Cities, Diablo Canyon
- This provides a unique opportunity to plan harvesting to address the highest priority technical and regulatory issues 3
Harvesting Experience
- Past harvesting efforts have generally involved reactive decision-making
- Limited opportunities to acquire ex-plant materials
- Limited strategic planning for harvesting
- Harvesting projects with NRC involvement:
- Reactors internal materials from Zorita
- Concrete from Zorita
- Neutron absorber material from Zion
- Cables from Zion and Crystal River 4
Zorita Internals Research Project Timeline 5
Approach: Assessment of Technical Issues and Available Materials for Harvesting
- Utilize various sources of technical information with respect to anticipated degradation in NPPs out to 80 years of operation
- Identify high-priority data needs that could be addressed through harvesting ex-plant materials
- Focus on identifying characteristics of important systems, structures, and components (SSCs) for harvesting
- Gather information on ex-plant material expected to be available based on identified needs
- May be from both operating and decommissioning reactors 6
Implementation
- What might the output of this activity look like?
- For example, the review may show there is value in acquiring CASS material around 15% delta ferrite with various dose ranges (<0.08 dpa, 1-3 dpa, and >5 dpa)
- Once that need is identified, this activity would identify what SSCs might be the best candidates for harvesting
- For example, perhaps lower support columns would be identified as the ideal SSC to address the CASS data need
- As decommissioning plants announce their plans, there is a clear list of SSCs and their characteristics (metallurgy, temperature, fluence, etc.) that would be desired to address the data need 7
Current NRC Activities
- NRC is working with Pacific Northwest National Lab (PNNL) to identify technical issues that may be best addressed by ex-plant harvesting
- Focused on unique value of harvesting to understand material properties in difficult to replicate environments
- NRC also seeking interest from other stakeholders to better understand availability of materials for harvesting
- Considering a public workshop in fall 2016
- Stakeholders include EPRI, DOE, U.S. industry, international partners
Discussion Topics
- Japanese approach to ex-plant material harvesting
- Information on available harvesting opportunities from Japanese reactors
- Is it known which plants will not restart?
- Opportunities for coordination / cooperation on ex-plant harvesting
Backup Slides Neutron Absorbers from Zion
- Materials Harvested:
- Select Boral NAM panels from Regions 1 and 2 of the Zion SFP
- Scope:
- Visual and microstructural examinations (incl. areal density)
- Corrosion testing
Purpose:
- Identify degradation mechanisms and estimate degradation rate
- Confirm results of in-situ areal density measurements
- Provide confirmatory data to support regulatory decision-making
- Timeline:
- Initial discussions in 2014, harvesting in 2015, testing in 2015-2016
- Coordination:
- EPRI, ZionSolutions, SRNL 11
Zorita Internals Research Project (ZIRP)
- Materials Harvested:
- Baffle plate and core barrel weld materials
- Scope:
- Mechanical testing (tensile, CGR, FT)
- Microstructural characterization (void swelling)
Purpose:
- High-fluence (up to 50 dpa) IAD effects with representative LWR exposure conditions to
- Support regulatory decision-making associated with SLR
- Timeline:
- Initial discussions in 2006, harvesting in 2013, testing ongoing through 2016
- Coordination:
- EPRI, international consortium, Studsvik, Halden 12
Concrete from Zorita (Plan)
- Materials Harvested:
- Concrete from structures that are in close proximity to RPV
- Scope:
- Mechanical testing (compressive, tensile, modulus of elasticity)
- Microstructural characterization
- Physical change
Purpose:
High fluence in combination with temperature and humidity that are representative of LWR environmental effects on structural and shielding performance Supports regulatory decision-making associated with SLR
- Timeline:
- Initial discussions in 2014, harvesting in 2015, testing 2016-2018
- Coordination:
- NRC , ENRESA and CSN 13
Cables: Zion and Crystal River
- Materials Harvested:
- Low and Medium Voltage Cables
- Scope:
- Condition monitoring to assess cable performance under normal operating conditions (accelerated aging) and accident conditions
Purpose:
- Cable degradation due to normal operating environment and accident conditions
- Supports regulatory decision-making associated with SLR
- Timeline:
- Initial discussions in 2012; Cable samples harvested from Zion in 2013
- Plan is to harvest additional samples from Crystal River and Zion in 2015
- Testing expected to be completed in 2017
- Coordination: