ML18137A134
| ML18137A134 | |
| Person / Time | |
|---|---|
| Issue date: | 05/17/2018 |
| From: | Madhumita Sircar NRC/RES/DE/SGSEB |
| To: | |
| Brady B, NRR-DMLR 415-2981 | |
| Shared Package | |
| ML18137A131 | List: |
| References | |
| Download: ML18137A134 (11) | |
Text
NRCs Research Perspectives on Irradiated Concrete Madhumita Sircar US Nuclear Regulatory Commission Office of Nuclear Regulatory Research NEI-EPRI Concrete Workshop Washington, DC May 17, 2018
Overview
- Objectives and Outcome
- Engagement
- Plant Specific Information
- Additional Knowledge Development 2
Research Perspectives
- Reactor pressure vessel (RPV) generally supported under the inlet and/or outlet nozzles
- Nearest load-bearing concrete depends on the nozzle support design
- Other safety related concrete structure and components close to RPV Reactor Concepts Manual (ML15252A444)
Research Perspectives Objectives
- Estimation of expected level of radiation (neutron E>0.1 MeV and gamma) on concrete for the period of SLR (up to 80 years of operation) and propagation of radiation through concrete section
- Characterization of degradation due to radiation
- Characterization of concrete damage depth under structural constraints
- Structural significance for long-term operations considering current licensing basis design
- Programmatic aspects for managing the aging effects 4
Research Perspectives Outcome
- Approaches for confirmatory review of industry research to assess structural performance for the structures exposed to high radiation
- Technical bases to support updating regulatory guidance for structures exposed to high irradiation for operating life up to 80 years (SLR).
5
Research Perspectives
- Engagements
- NRC is conducting confirmatory research
- NRC-DOE-EPRI joint research MOU and roadmap
- NRC-NRA (Japan) bi-lateral research MOU - NRC received experimental data from recently completed NRAJ research
- Participating in International Committee on Irradiated Concrete (ICIC) 6
Estimated 80-Year Neutron Fluence (E > 0.1 MeV) on Concrete Estimated 80 Year Neutron Fluence (E >0.1 MeV) at Outer RPV (Inner face of concrete is about 10% less).
Source: ORNL/TM-2018/769 7
Plant-Specific Information to Develop Basic Understanding
- Current neutron fluence and gamma dose information
- Plant configuration and structural details of RPV supports and bioshield wall
- Concrete composition (aggregates, cement, grout, etc.),
reinforcement and supports anchorage
- Environment (temperature and humidity)
- CBS liner and attachment
- Current Licensing Basis design requirements (method, load combination, design codes)
- Inspection and monitoring methods 8
Plant-Specific Information to Develop Basic Understanding
- Support details
- Local design considerations - concrete, rebar, anchorages
- Characterization of load-resisting mechanisms (for example, steel-concrete bond strength)
Source: WCAP-14422 Rev. 2-A
Additional Knowledge Development Irradiated Steel-Concrete Bond Strength [Significant]
- Possible loss of bond due to the irradiation-induced damage of concrete around rebars and support anchorages Rate Effects
- Require concrete harvested from decommissioned LWR NPPs
- at high dose, i.e., > 1019 n.cm-2 @ E > 0.1 MeV
- w/ high silica content aggregate No relevant harvesting opportunity as of today.
Likely source San Onofre, Keewaunee Examination of In-Situ Damage, Monitoring, and Aging Management approaches Irradiated Concrete Creep
- Need for experimental data. Concrete creep may affect irradiation-induced cracking Irradiation-Assisted Alkali-Silica Reaction
- Irradiation-induced amorphization increases the dissolution rate of aggregates 1
QUESTIONS?