ML17309A074
| ML17309A074 | |
| Person / Time | |
|---|---|
| Site: | Seabrook  |
| Issue date: | 06/06/2017 |
| From: | - No Known Affiliation |
| To: | Division of Operating Reactor Licensing |
| References | |
| 17-953-02-LA-BD01 | |
| Download: ML17309A074 (7) | |
Text
1 SeabrookLANPEm Resource From:
Greene, Joshua <Joshua.Greene@nexteraenergy.com>
Sent:
Tuesday, June 06, 2017 3:34 PM To:
Poole, Justin
Subject:
[External_Sender] FW: Updated MPR Slides on LAR Audit Questions Attachments:
June2017_siteVisitTopics_001_MPR input final.ppt
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[External_Sender] FW: Updated MPR Slides on LAR Audit Questions Sent Date:
6/6/2017 3:33:45 PM Received Date:
6/6/2017 3:34:03 PM From:
Greene, Joshua Created By:
Joshua.Greene@nexteraenergy.com Recipients:
"Poole, Justin" <Justin.Poole@nrc.gov>
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6/6/2017 3:34:03 PM June2017_siteVisitTopics_001_MPR input final.ppt 1803210 Options Priority:
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1 Impact of In-plane Expansion Exceedances on Structural Capacity Address implications of exceedances (deviation) in in-plane expansion beyond the plateau levels observed on MPR/FSEL test specimens with regard to impact on structural capacity in shear, flexure and rebar anchorage.
In-Plane expansion values for Seabrook Station are impacted by factors not included in MPR/FSEL testing MPR/FSEL Test Programs Seabrook Station In-Plane Expansion Measurement Taken Before application of load In situ with loads applied In-Plane Expansion Measurement Considers ASR expansion of specimen Shrinkage ASR expansion of wall or slab Shrinkage Creep External loads (incl. ASR expansion of backfill)
2 Impact of In-plane Expansion Exceedances on Structural Capacity Apparent in-plane expansion in MPR/FSEL test programs increased with application of load during testing
3 Impact of In-plane Expansion Exceedances on Structural Capacity Chemical prestressing ASR-induced expansion in the in-plane directions produces chemical prestressing Behavior of specimens consistent with calculations that considered level of in-plane ASR expansion and properties of steel reinforcement Effect of prestressing is not lost at in-plane expansion levels above those seen in the test programs Literature review Extensive literature has not identified any indication from industry documents or researchers that direction of expansion has a significant effect on shear capacity, flexural capacity or reinforcement performance, with the exception of chemical prestressing Volumetric expansion acceptance criterion Conservatively based on the in-plane expansion from the test specimens before load testing, which does not include the expansion from applied load
4 Integrated Effect of Microcracking, Building Deformation on Structural Capacity How is the impact on structural capacity of integrated effects of ASR micro-cracking and global manifestations addressed in the proposed method of evaluation of ASR-affected structures?
MPR/FSEL test programs Applied loads during tests generated macro-cracking Validated use of code equations when evaluating structural capacity of ASR-affected structures Application to Seabrook Station Structural evaluations address the impacts of global manifestations on structural capacity Use code equations and acceptance criteria Limits and acceptance criteria from MPR/FSEL test programs are applied conservatively to Seabrook Station Limits/criteria reflect the expansion measurements from the test specimens prior to external loading.
All cracking (whether from ASR or external loads) is included when using the criteria
5 Compressive Strength Verification Will the specified minimum concrete compressive strength used in the design calculations of ASR-affected structures be periodically validated, as a backstop against structural degradation?
ASR reduces material properties measured from cores, but such reductions do not affect structural performance of reinforced concrete Core removed from a structure loses its structural context (e.g., confinement and chemical prestressing)
Properties of cores removed from ASR-affected reinforced concrete structures are not representative of in situ structural performance.
MPR/FSEL Test Program Confirmed use of material properties obtained from extracted cores is not appropriate to calculate structural capacity of an ASR-affected element Tests of cores show moderate decrease in compressive strength from ASR Load tests results exceeded the theoretical capacities calculated using nominal material properties and ACI equations Application to Seabrook Station Use of nominal compressive strength is appropriate for calculating structural capacities of ASR-affected elements Applying limits of MPR/FSEL test program provides conservatism