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| docket = 07201051 | | docket = 07201051 | ||
| license number = | | license number = | ||
| contact person = Cuadrado J | | contact person = Cuadrado J | ||
| package number = ML18330A078 | | package number = ML18330A078 | ||
| document type = Meeting Briefing Package/Handouts, Slides and Viewgraphs | | document type = Meeting Briefing Package/Handouts, Slides and Viewgraphs | ||
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=Text= | =Text= | ||
{{#Wiki_filter: | {{#Wiki_filter:Holtec HI-STORE CISF Review - Discussion of 5/24/18 RAI Responses on Geotechnical Stability Assessment (Proprietary) | ||
-Discussion of 5/24/18 RAI Responses on Geotechnical Stability Assessment (Proprietary | Division of Spent Fuel Management, NMSS U.S. Nuclear Regulatory Commission Public Meeting with Holtec International October 23, 2018 | ||
Summary*March 28, 2018 | Summary | ||
-NRC issues request for additional information (RAI), Part 1: | * March 28, 2018 - NRC issues request for additional information (RAI), Part 1: | ||
-RAI 2 | - RAI 2 Requests additional details on geotechnical stability assessment for HI-STORE CISF site | ||
-STORE CISF site | * May 24, 2018 - Holtec submits response to RAI: HI-STORE Bearing Capacity and Settlement Calculations (HI-2188143) | ||
*May 24, 2018 -Holtec submits response to RAI: HI | * NRC staff has identified concerns with Holtec's response: | ||
-STORE Bearing Capacity and Settlement Calculations (HI | - Site geotechnical parameters used | ||
-2188143)*NRC staff has identified concerns with Holtec's response: | - Immediate soil settlement estimation | ||
-Site geotechnical parameters used | - Consolidation soil settlement estimation | ||
-Immediate soil settlement estimation | - Secondary settlement estimation | ||
-Consolidation soil settlement estimation | - Effects of Construction sequence on settlement | ||
-Secondary settlement estimation | - Pad interactions | ||
-Effects of Construction sequence on settlement | - Spatial Variation of Soil Properties on Pad Settlement | ||
-Pad interactions | |||
-Spatial Variation of Soil Properties on Pad Settlement Issue 1 -Representativeness of Soil Parameters Used (Table 5.3) | Issue 1 - Representativeness of Soil Parameters Used (Table 5.3) | ||
*Only unit weight measured at site; Friction angle () and Elastic modulus (E) derived from Standard Penetration Test Blow Count (N), | * Only unit weight measured at site; Friction angle () and Elastic modulus (E) derived from Standard Penetration Test Blow Count (N), | ||
*Response does not explain the applicability of the empirical relationship used for and E to conditions at site | Poissons ratio (µ) from literature | ||
*Response does not explain the applicability of | * Response does not explain the applicability of the empirical relationship used for and E to conditions at site | ||
*E for Residual soil not explained: in Table 5.3 = 27.81 | * Response does not explain the applicability of Poissons ratio (µ) to conditions at the site | ||
*Cohesion (C) for Residual Soil and Chinle Formation not explained; estimate assumes no friction | * E for Residual soil not explained: in Table 5.3 = 27.81 ksf but in page A.2 = 39.68 ksf | ||
-Applicant later assumes that both materials are cohesionless Issue 2 -Immediate Soil Settlement Estimation | * E for Chinle Formation: not clear whether effects of fractures were considered | ||
*Uses methodology suggested in Section 10.6.2.4.2, Settlement of Footings on Cohesionless Soils, of AASHTO LRFD Bridge Design Specification: | * Cohesion (C) for Residual Soil and Chinle Formation not explained; estimate assumes no friction | ||
-Response does not explain why the selected method for cohesionless soils would be appropriate for cohesive soil | - Applicant later assumes that both materials are cohesionless | ||
[ | |||
*Uses weighting scheme for two | Issue 2 - Immediate Soil Settlement Estimation | ||
-layer system (Residual Soil and Chinle Formation) given by Bowles (1997): | * Uses methodology suggested in Section 10.6.2.4.2, Settlement of Footings on Cohesionless Soils, of AASHTO LRFD Bridge Design Specification: | ||
-Response does not explain why depth causing settlement would be 5 x pad width when EChinle Formation/EResidual | - Response does not explain why the selected method for cohesionless soils would be appropriate for cohesive soil | ||
Issue 3 -Consolidation Settlement Estimation | [CResidual Soil = 4000 psf, CChinle Formation = 8060 psf in Table 5.3] | ||
*Uses Consolidation Pressure | * Uses weighting scheme for two-layer system (Residual Soil and Chinle Formation) given by Bowles (1997): | ||
(), Compressive Ratio (), and Recompression/Swell Ratio ()from Chinle Formation to calculate settlement of Residual Soil: | - Response does not explain why depth causing settlement would be 5 x pad width when EChinle Formation/EResidual Soil 98 or 69 (Criterion from Bowles is 10 for Chinle Formation to be hard to undergo immediate settlement) | ||
-No explanation provided for why Chinle Formation values are appropriate | |||
*Response does not explain how Consolidation Pressure was obtained, nor does it justify use of the formula to estimate consolidation settlement | Issue 3 - Consolidation Settlement Estimation | ||
*Consolidation Pressure | * Uses Consolidation Pressure ( ), Compressive Ratio ( ), and Recompression/Swell Ratio ( ) from Chinle Formation to calculate settlement of Residual Soil: | ||
(), Compressive Ratio | - No explanation provided for why Chinle Formation values are appropriate | ||
(), and Recompression/Swell Ratio | * Response does not explain how Consolidation Pressure was obtained, nor does it justify use of the formula to estimate consolidation settlement | ||
()in Chinle Formation are measured from two different samples at 74 and 100 ft depth: | * Consolidation Pressure ( ), Compressive Ratio ( ), and Recompression/Swell Ratio ( ) in Chinle Formation are measured from two different samples at 74 and 100 ft depth: | ||
-No explanation provided for why the use of two different samples is appropriate Issue 3 -Consolidation Settlement Estimation (cont.)*Consolidation estimated for upper 6 ft of Residual Soil Layer using Chinle Formation parameters: | - No explanation provided for why the use of two different samples is appropriate | ||
-No explanation provided for what prevents lower 6 ft of Residual Soil from undergoing consolidation settlement | |||
*No explanation for why Chinle Formation would not undergo consolidation settlement when consolidation parameters are measured from samples of this formation | Issue 3 - Consolidation Settlement Estimation (cont.) | ||
*No explanation for why weight of the vertical cask transporter (VCT) is not included in calculating the applied transient load causing settlement Issue 4 -Secondary Settlement Estimation | * Consolidation estimated for upper 6 ft of Residual Soil Layer using Chinle Formation parameters: | ||
*No discussion is provided for why secondary settlement would be negligible Issue 5 -Effects of Construction Sequence in Settlement | - No explanation provided for what prevents lower 6 ft of Residual Soil from undergoing consolidation settlement | ||
*Response does not explain why the Immediate Settlements from placing the Controlled Low Strength Material (CLSM) (1.962e8 lbs), ISFSI Pad (3.006e7 lbs), and MPCs with closure lid (3.625e7 lbs) on top of the Support Foundation Pad, would not contribute toward the cumulative settlement against the Permissible Long | * No explanation for why Chinle Formation would not undergo consolidation settlement when consolidation parameters are measured from samples of this formation | ||
-Term Settlement of 0.2 in (Table 2.3.1 of UMAX FSAR) | * No explanation for why weight of the vertical cask transporter (VCT) is not included in calculating the applied transient load causing settlement | ||
-Pouring of CLSM, construction of top ISFSI Pad, and placement of MPCs into storage are expected to occur more than 7 days after construction of the Support Foundation Pad Issue 5 -Effects of Construction Sequence in Settlement (cont') | |||
Issue 6 -Interaction Among Pads*Pad dimensions: | Issue 4 - Secondary Settlement Estimation | ||
*Pad-to-pad separation distance (along shorter dimension) = 35 ft Issue 6 -Interaction Among Pads(cont.)*Stress below the pads would not be uniform | * No discussion is provided for why secondary settlement would be negligible | ||
-End closer to next pad would have larger stress than the far end; hence, settle more | |||
*Pad tilting (rotation): Does not appear to be calculated Issue 7 -Spatial Variation of Soil Properties on Pad Settlement | Issue 5 - Effects of Construction Sequence in Settlement | ||
*5 boreholes in the pad area*No explanation whether difference in material properties would produce excessive differential settlement of the Spent Fuel Pad | * Response does not explain why the Immediate Settlements from placing the Controlled Low Strength Material (CLSM) (1.962e8 lbs), ISFSI Pad (3.006e7 lbs), | ||
*Part of RAI 2 | and MPCs with closure lid (3.625e7 lbs) on top of the Support Foundation Pad, would not contribute toward the cumulative settlement against the Permissible Long-Term Settlement of 0.2 in (Table 2.3.1 of UMAX FSAR) | ||
-2 Conclusions | - Pouring of CLSM, construction of top ISFSI Pad, and placement of MPCs into storage are expected to occur more than 7 days after construction of the Support Foundation Pad | ||
*NRC staff needs additional information to address RAIs on geotechnical stability and determine compliance with NRC's safety regulations | |||
*Timely completion of NRC review of Holtec's HI | Issue 5 - Effects of Construction Sequence in Settlement (cont') | ||
-STORE CISF application requires complete and high quality responses to NRC staff's questions | |||
*NRC staff is open to additional discussion with applicant prior to submission of responses}} | Issue 6 - Interaction Among Pads | ||
* Pad dimensions: 438 ft x 183 ft | |||
* Pad-to-pad separation distance (along shorter dimension) = 35 ft | |||
Issue 6 - Interaction Among Pads (cont.) | |||
* Stress below the pads would not be uniform | |||
- End closer to next pad would have larger stress than the far end; hence, settle more | |||
* Pad tilting (rotation): Does not appear to be calculated | |||
Issue 7 - Spatial Variation of Soil Properties on Pad Settlement | |||
* 5 boreholes in the pad area | |||
* No explanation whether difference in material properties would produce excessive differential settlement of the Spent Fuel Pad | |||
* Part of RAI 2-2 | |||
Conclusions | |||
* NRC staff needs additional information to address RAIs on geotechnical stability and determine compliance with NRC's safety regulations | |||
* Timely completion of NRC review of Holtec's HI-STORE CISF application requires complete and high quality responses to NRC staff's questions | |||
* NRC staff is open to additional discussion with applicant prior to submission of responses}} |
Latest revision as of 11:20, 20 October 2019
ML18330A079 | |
Person / Time | |
---|---|
Site: | HI-STORE |
Issue date: | 11/21/2018 |
From: | Cuadrado J Spent Fuel Licensing Branch |
To: | Yoira Diaz-Sanabria Division of Spent Fuel Management |
Cuadrado J | |
Shared Package | |
ML18330A078 | List: |
References | |
Download: ML18330A079 (13) | |
Text
Holtec HI-STORE CISF Review - Discussion of 5/24/18 RAI Responses on Geotechnical Stability Assessment (Proprietary)
Division of Spent Fuel Management, NMSS U.S. Nuclear Regulatory Commission Public Meeting with Holtec International October 23, 2018
Summary
- March 28, 2018 - NRC issues request for additional information (RAI), Part 1:
- RAI 2 Requests additional details on geotechnical stability assessment for HI-STORE CISF site
- May 24, 2018 - Holtec submits response to RAI: HI-STORE Bearing Capacity and Settlement Calculations (HI-2188143)
- NRC staff has identified concerns with Holtec's response:
- Site geotechnical parameters used
- Immediate soil settlement estimation
- Consolidation soil settlement estimation
- Secondary settlement estimation
- Effects of Construction sequence on settlement
- Pad interactions
- Spatial Variation of Soil Properties on Pad Settlement
Issue 1 - Representativeness of Soil Parameters Used (Table 5.3)
- Only unit weight measured at site; Friction angle () and Elastic modulus (E) derived from Standard Penetration Test Blow Count (N),
Poissons ratio (µ) from literature
- Response does not explain the applicability of the empirical relationship used for and E to conditions at site
- Response does not explain the applicability of Poissons ratio (µ) to conditions at the site
- E for Residual soil not explained: in Table 5.3 = 27.81 ksf but in page A.2 = 39.68 ksf
- E for Chinle Formation: not clear whether effects of fractures were considered
- Cohesion (C) for Residual Soil and Chinle Formation not explained; estimate assumes no friction
- Applicant later assumes that both materials are cohesionless
Issue 2 - Immediate Soil Settlement Estimation
- Uses methodology suggested in Section 10.6.2.4.2, Settlement of Footings on Cohesionless Soils, of AASHTO LRFD Bridge Design Specification:
- Response does not explain why the selected method for cohesionless soils would be appropriate for cohesive soil
[CResidual Soil = 4000 psf, CChinle Formation = 8060 psf in Table 5.3]
- Uses weighting scheme for two-layer system (Residual Soil and Chinle Formation) given by Bowles (1997):
- Response does not explain why depth causing settlement would be 5 x pad width when EChinle Formation/EResidual Soil 98 or 69 (Criterion from Bowles is 10 for Chinle Formation to be hard to undergo immediate settlement)
Issue 3 - Consolidation Settlement Estimation
- Uses Consolidation Pressure ( ), Compressive Ratio ( ), and Recompression/Swell Ratio ( ) from Chinle Formation to calculate settlement of Residual Soil:
- No explanation provided for why Chinle Formation values are appropriate
- Response does not explain how Consolidation Pressure was obtained, nor does it justify use of the formula to estimate consolidation settlement
- Consolidation Pressure ( ), Compressive Ratio ( ), and Recompression/Swell Ratio ( ) in Chinle Formation are measured from two different samples at 74 and 100 ft depth:
- No explanation provided for why the use of two different samples is appropriate
Issue 3 - Consolidation Settlement Estimation (cont.)
- Consolidation estimated for upper 6 ft of Residual Soil Layer using Chinle Formation parameters:
- No explanation provided for what prevents lower 6 ft of Residual Soil from undergoing consolidation settlement
- No explanation for why Chinle Formation would not undergo consolidation settlement when consolidation parameters are measured from samples of this formation
- No explanation for why weight of the vertical cask transporter (VCT) is not included in calculating the applied transient load causing settlement
Issue 4 - Secondary Settlement Estimation
- No discussion is provided for why secondary settlement would be negligible
Issue 5 - Effects of Construction Sequence in Settlement
- Response does not explain why the Immediate Settlements from placing the Controlled Low Strength Material (CLSM) (1.962e8 lbs), ISFSI Pad (3.006e7 lbs),
and MPCs with closure lid (3.625e7 lbs) on top of the Support Foundation Pad, would not contribute toward the cumulative settlement against the Permissible Long-Term Settlement of 0.2 in (Table 2.3.1 of UMAX FSAR)
- Pouring of CLSM, construction of top ISFSI Pad, and placement of MPCs into storage are expected to occur more than 7 days after construction of the Support Foundation Pad
Issue 5 - Effects of Construction Sequence in Settlement (cont')
Issue 6 - Interaction Among Pads
- Pad dimensions: 438 ft x 183 ft
- Pad-to-pad separation distance (along shorter dimension) = 35 ft
Issue 6 - Interaction Among Pads (cont.)
- Stress below the pads would not be uniform
- End closer to next pad would have larger stress than the far end; hence, settle more
- Pad tilting (rotation): Does not appear to be calculated
Issue 7 - Spatial Variation of Soil Properties on Pad Settlement
- 5 boreholes in the pad area
- No explanation whether difference in material properties would produce excessive differential settlement of the Spent Fuel Pad
- Part of RAI 2-2
Conclusions
- NRC staff needs additional information to address RAIs on geotechnical stability and determine compliance with NRC's safety regulations
- Timely completion of NRC review of Holtec's HI-STORE CISF application requires complete and high quality responses to NRC staff's questions
- NRC staff is open to additional discussion with applicant prior to submission of responses