ML18137A134
| ML18137A134 | |
| Person / Time | |
|---|---|
| Issue date: | 05/17/2018 |
| From: | Madhumita Sircar NRC/RES/DE/SGSEB |
| To: | |
| Brady B M, NRR-DMLR 415-2981 | |
| Shared Package | |
| ML18137A131 | List: |
| References | |
| Download: ML18137A134 (11) | |
Text
NRC's Research Perspectives on Irradiated ConcreteMadhumita Sircar US Nuclear Regulatory Commission Office of Nuclear Regulatory ResearchNEI-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
- RPV supported on concrete bioshield(CBS) *RPV supported on steel columns and horizontal steel frame anchored to CBS for lateral load transfer
- Other safety related concrete structure and components close to RPVReactor Concepts Manual (ML15252A444)
Research PerspectivesObjectives
-Estimation of expected level of radiation (neutron E>0.1 MeVand 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 PerspectivesOutcome-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 7Estimated 80 Year Neutron Fluence (E >0.1 MeV) at Outer RPV (Inner face of concrete is about 10% less). Source: ORNL/TM
-2018/769 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 support sanchorage-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 Irradiated Steel
-Concrete Bond Strength [Significant]
-Possible loss of bond due to the irradiation
-induced damage of concrete around rebars and support anchoragesRate Effects
-Require concrete harvested from decommissioned LWR NPPs
- at high dose, i.e., > 10 19n.cm-2@ E > 0.1 MeV
- w/ high silica content aggregate No relevant harvesting opportunity as of today.Likely source San Onofre , KeewauneeExamination of In
-Situ Damage, Monitoring, and Aging Management approachesIrradiated Concrete Creep
-Need for experimental data. Concrete creep may affect irradiation
-induced crackingIrradiation
-Assisted Alkali
-Silica Reaction
-Irradiation
-induced amorphization increases the dissolution rate of aggregates g Additional Knowledge Development 1 0 QUESTIONS?