IR 05000483/2014009

IR 05000483/2014009 & 07201045/2014001; 07/29/2015 - 01/16/2015; Callaway Plant-Independent Spent Fuel Storage Installation

ML15063A545
Person / Time
Site:	Callaway
Issue date:	03/04/2015
From:	Ray Kellar NRC/RGN-IV/DNMS/RSFSB
To:	Diya F Union Electric Co
Kellar R
References
IR 2014001, IR 2014009
Download: ML15063A545 (39)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION

REGION IV

1600 E LAMAR BLVD ARLINGTON, TX 76011-4511 March 4, 2015 Mr. Fadi Diya, Senior Vice President and Chief Nuclear Officer Union Electric Company P.O. Box620 Fulton, MO 65251 SUBJECT: CALLAWAY PLANT- INDEPENDENT SPENT FUEL STORAGE INSTALLATION (ISFSI) INSPECTION REPORT 05000483/2014009 AND 07201045/2014001

Dear Mr. Diya:

This letter refers to an inspection associated with the construction of your Independent Spent Fuel Storage Installation (ISFSI) conducted between July 29, 2014 through January 16, 2015.

The enclosed inspection report documents the inspection results which were discussed on February 8, 2015 with members of your staff.

The inspection examined activities conducted under your license as they relate to safety and compliance with the Commission's rules and regulations and with the conditions of your license.

The inspection reviewed compliance with the requirements specified in the Holtec International HI-STORM UMAX Canister Storage System Final Safety Analysis Report (FSAR), and Title 1O of the Code of Federal Regulations (CFR) Part 72, and Part 50. Within these areas, the inspection included a review of the ISFSI foundation subgrade, concrete mix design, inspection of the concrete batch plants, inspection of concrete forms, placement of the reinforcing steel, observations of concrete mixing, delivery, sampling, and placement for selected activities associated with the construction of the UMAX ISFSI. The inspection determined that Callaway's UMAX ISFSI construction was in conformance with the requirements of the Holtec FSAR, and the requirements and standards established by the American Concrete Institute (ACI) and the American Society for Testing and Materials (ASTM), as required by your general license. No violations of NRC regulations were identified.

However, the Holtec International HI-STORM UMAX Certificate of Compliance (CoC) 1040 had not been approved by the NRC at the time of the inspection. Additionally, after issuance of the CoC, the FSAR may need to be updated to incorporate any changes that have occurred as part of the NRC license approval process. Before the first use of the ISFSI for storage of spent fuel, the general licensee must verify that any changes in the final NRC license documents have been reviewed and resolved as compared to the documents that were used for construction of the UMAX ISFSI pad. In accordance with title 10 CFR 2.390 of the NRC's "Rules of Practice," a copy of this letter, its enclosure, and your response, if you choose to provide one, will be made available electronically for public inspection in the NRC Public Document Room or from the NRC's Agencywide Document Access Management System (ADAMS), accessible from the NRC Web site at http://www.nrc.gov/reading-rm/adams.html. To the extent possible, your response should not include any personal, privacy, or proprietary information so that it can be made available to the public without redaction.

Should you have any questions concerning this inspection, please contact the undersigned at 817-200-1191 or Mr. Lee Brookhart at 817-200-1549.

Sincerely,

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Ray L. Kellar, P.E., Chief Repository & Spent Fuel Safety Branch Division of Nuclear Materials Safety Dockets No.: 05000483, 07201045 Licenses No.: NPF-30

Enclosure:

Inspection Report 05000483/2014009 and 07201045/2014001 wtattachments:

1. Supplemental Information 2. Callaway UMAX ISFSI - Inspector Notes In a

REGION IV==

Dockets: 050-00483; 072-01045 Licenses: NPF-30 Report Nos.: 05000483/2014009; 07201045/2014001 Licensee: Ameren Corporation Facility: Callaway Plant and Independent Spent Fuel Storage Installation (ISFSI)

Location: Junction Highway CC and Highway 0, Fulton, Missouri Dates: July 29- July 31, 2014 August 5-August 6, 2014 September 8-September 9, 2014 November 4 - November 5, 2014 November 25- November 26, 2014 December 3 - December 4, 2014 December 29, 2014 January 5 - January 6, 2015 January 15 - January 16, 2015 Inspector: Lee E. Brookhart, Senior ISFSI Inspector Repository & Spent Fuel Safety Branch Accompanying Personnel: Eric J. Simpson, Health Physicist, Inspector-in-Training, Repository & Spent Fuel Safety Branch Approved By: Ray L. Kellar, P. E., Chief Repository & Spent Fuel Safety Branch Division of Nuclear Materials Safety Enclosure

EXECUTIVE SUMMARY Callaway Plant and Independent Spent Fuel Storage Installation (ISFSI)

NRC Inspection Report 05000483/2014009 and 07201045/2014001 The U.S. Nuclear Regulatory Commission (NRC) conducted an Independent Spent Fuel Storage Installation (ISFSI) inspection of the construction activities associated with Callaway's Holtec HI-STORM UMAX facility. Callaway's ISFSI will use a general license from the NRC.

The licensee had elected to use the Holtec HI-STORM UMAX Canister Storage System, Certificate of Compliance 1040, and Final Safety Analysis Report, Revision 2. The mulit-purpose canister MPC-37, designed to hold 37 spent fuel assemblies will be used at the site.

The UMAX constructed at Callaway has been designed to hold up to up to 48 spent fuel storage canisters in an 8 by 6 array.

The HI-STORM UMAX stores sealed MPCs containing spent fuel in an in-ground Vertical Ventilated Module (WM). The UMAX WM provides structural protection, cooling, and radiological shielding for the MPCs. The WM consists of five primary components. The Support Foundation Pad (SFP) (a reinforced pad that serves as the bottom of the WM), the Cavity Enclosure Containers (CECs) (the carbon steel enclosures that contain one MPC each),

the Self-hardening Engineered Subgrade (SES) (the middle section around the CECs), the ISFSI top pad (reinforced pad that provides shielding and a riding surface for the cask transporter), and the Closure Lid (whiclJ serves as the CEC lid and supplies the ventilation to the sealed canister).

The SFP is a reinforced concrete pad that was approximately 158 feet by 109 feet in dimension by 33 inches in depth. On top of the SFP, 48 CECs were placed that were approximately 20 feet tall with an inside diameter of approximately 8 feet. The SES middle lateral space between each CEC was filled in with Controlled Low-Strength Material (CLSM). The ISFSI top pad was a reinforced concrete pad with the same length and width dimensions of the SFP but had an approximately depth of 30 inches. The Closure Lids will be placed on each CEC once a sealed MPC has been placed inside.

The SFP was constructed in four sections; NRC inspectors observed the first section's concrete placement activities on November 5, 2014. On November 25 and 26, 2014, NRC inspectors observed a number of CEC placement activities. The first three feet of CLSM that was poured around the CECs to construct the SES was observed by NRC inspectors on December 4, 2015.

The ISFSI top pad was constructed in three sections. NRC inspectors observed the second section's concrete placement activities on January 16, 2015. On other site visits, NRC inspectors reviewed design documentation, rebar placement activities for the SFP and top pad, and subgrade density testing activities associated with the ground around the UMAX.

The SFP and top pad were designed and constructed in accordance with American Concrete Institute (ACI) 318-05, "Building Code Requirements for Structural Concrete." The inspection included a review of the concrete mix design, concrete material requirements, reinforcing bar specifications, concrete batch plant facilities along with direct observations of concrete mixing, placement, and sample testing of the various sections of the WM. The inspection determined that Callaway's UMAX ISFSI construction was performed in conformance with the requirements contained in the Holtec Preliminary UMAX FSAR, and the requirements and standards established by the ACI and the American Society for Testing and Materials (ASTM). No violations of NRC regulations were identified.

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Details related to the activities and documents reviewed are provided in Attachment 2, "Inspector Notes," to this report. The following provides a summary of the observations made during this inspection.

On-Site Fabrication of Components and Construction of an ISFSI (60853)

Cold Weather Concrete

• The licensee took adequate measures prior to and during concrete placement activities to ensure the concrete was maintained above required temperatures and provided adequate protection of concrete and reinforcement material following the guidance specified in ACI 306R, "Guide to Cold Weather Concreting" (Attachment 2: Category -

Cold Weather Requirements).

Concrete Curing

• The ACI requirement for maintaining concrete in a moist condition above 50 degrees F for the required minimum number of days after concrete placement was met (Attachment 2: Category- Concrete Curing).

Concrete Mixing & Delivery

• Both ready-mix concrete batch plants that were used to construct the UMAX ISFSI had been inspected by the licensee and reviewed by the NRC to meet the requirements of ASTM C 94, "Standard Specification for Ready-Mixed Concrete" (Attachment 2:

Category - Concrete Mixing & Delivery).

• Processes for concrete mixing and delivery followed the ASTM standards in respect to maximum mixing time, maximum/minimum drum revolutions, addition of water at the job site, and measurement of materials (Attachment 2: Category - Concrete Mixing and Delivery).

Concrete Placement

• Concrete forms were adequately controlled, constructed, and prepared in accordance with ACI requirements in regards to wetting of surfaces, removal of debris, control of mortar leaks and form deflection, removal of standing water, and application of release agents (Attachment 2: Category - Concrete Placement).

• The concrete for the UMAX constructed at Callaway met the applicable ACI requirements for placement rate, exclusion of foreign material, placement flow of Controlled Low-Strength Material (CLSM), and placement of grout under each Cavity Enclosure Container (CEC) (Attachment 2: Category - Concrete Placement).

Concrete Quality

• The concrete mix used in the various sections of the UMAX met the design specifications in respect to air entrainment, slump, temperature, density, and water/cement ratio (Attachment 2: Category - Concrete Quality).

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• Concrete mix ingredients met the applicable ASTM and ACI standards for type of cement, admixtures, fly ash, ground slag, and clean water (Attachment 2: Category - Concrete Quality).

• The 28 day concrete strength test reports confirmed that all sections of the UMAX ISFSI met the required concrete strength specified in the Holtec FSAR and design specifications (Attachment 2: Category - Concrete Quality).

Concrete Reinforcement

• The rebar placement on both the SFP and the top pad was constructed in accordance with FSAR and design specifications for type of rebar used, spacing, and minimum bend diameters (Attachment 2: Category - Concrete Reinforcement).

• The rebar was placed within the forms to meet the minimum concrete cover requirements specified in the ACI standards to protect the rebar from corrosion (Attachment 2: Category - Concrete Reinforcement).

• The tensile strength test reports for the placed rebar was reviewed and found to meet the 60 thousand pounds per inch (ksi) design requirement specified in the FSAR (Attachment 2: Category - Concrete Reinforcement).

Concrete Sampling

• The ACI and ASTM standards for concrete sampling were met with respect to sampling locations, methods, frequencies, number of samples, and methods for molding and curing strength test cylinders (Attachment 2: Category - Concrete Sampling).

• The field technicians responsible for sampling and making the concrete test cylinders were certified as ACI Grade I Field Testing Technicians (Attachment 2: Category-Concrete Sampling).

UMAX Design

• The subgrade and material that was backfilled around the completed UMAX met the FSAR requirements for density and shear wave velocity (Attachment 2: Category - Pad Design).

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SUPPLEMENTAL INSPECTION INFORMATION KEY POINTS OF CONTACT Licensee Personnel S. Abel, Director Engineering Projects S. Ewens, Project Manager ISFSI C. Jutting, Civil Engineer J. Mclnvale, Consulting Engineer T. Pettus, Supervising Engineer L. Ptasznik, Licensing Engineer G. Roesner, Consulting Engineer D. Shafer, Licensing Engineer Contractor Personnel J. Fosdick, Senior Civil Engineer, Holtec M. Hartwig, Construction Supervisor, MCI J. Lyles, Construction Supervisor, Holtec M. McNamara, VP Construction, Holtec C. Stewart, Project Engineer, MCI B. Vessels, Quality Control, Holtec INSPECTION PROCEDURES USED IP 60853 On-Site Fabrication of Components and Construction of an ISFSI LIST OF ITEMS OPENED, CLOSED, AND DISCUSSED Opened None Discussed None Closed None Attachment 1

LIST OF ACRONYMS/ABBREVIATIONS ACI American Concrete Institute ADAMS Agencywide Documents Access and Management System ANSI American National Standards Institute ASTM American Society for Testing and Materials CCC Continental Cement Company CECs Cavity Enclosure Containers CLSM Controlled Low-Strength Materials CMTR Certified Mill Test Results Coe Certificate of Compliance CFR Code of Federal Regulations DNMS Division of Nuclear Material Safety EDCR Engineer Design Change Request ESS Engineering Survey and Services F Fahrenheit FCR Field condition report FSAR Final Safety Analysis Report IMC Inspection Manual Chapter ISFSI Independent Spent Fuel Storage Installation ITS Important to Safety MPC Multi-Purpose Canister MO Missouri MOCON Mo-Con, Inc. of Fulton, MO Mo Dot Missouri Department of Transportation MSL Mean Sea Level NITS Not Important to Safety NRC U.S. Nuclear Regulatory Commission PA Protected Area pct pounds per cubic foot psi pounds per square inch QA Quality Assurance SES Self-hardening Engineered Subgrade SFP Holtec HI-STORM UMAX ISFSI support foundation pad TS Technical Specification Top Pad Holtec HI-STORM UMAX ISFSI top pad WM Vertical Ventilated Module-2-

ATTACHMENT 2 Callaway ISFSI Concrete Placement Category Topic Page#

Cold Weather Requirements Concrete Temperature 1 Cold Weather Requirements Inspection for Frost 1 Cold Weather Requirements Protection During Cold Weather 2 Concrete Curing High-Early-Strength Concrete 2 Concrete Curing Other Than High-Early-Strength Concrete 3 Concrete Mixing & Delivery Addition of Job Site Water 3 Concrete Mixing & Delivery Concrete Discharge Limits 3 Concrete Mixing & Delivery Concrete Mixing Revolutions 4 Concrete Mixing & Delivery Measurement of Aggregate Materials 5 Concrete Mixing & Delivery Measurement of Mixing Water 5 Concrete Mixing & Delivery Ready Mixed Concrete 5 Concrete Mixing & Delivery Slump Tolerances 1 6 Concrete Placement CLSM Placement 7 Concrete Placement Concrete Deposition 7 Concrete Placement Concrete Placement Rate 8 Concrete Placement Foreign Material in Concrete 8 Concrete Placement Retempered Concrete 8 Concrete Placement Prep. Construction Joints 8 Concrete Placement Prep. Formwork 1 9 Concrete Placement Prep. Formwork 2 9 Concrete Placement Prep. Laitance Removal 9 Concrete Placement Prep. Reinforcement 10 Concrete Placement Prep. Reinforcement Conditions 10 Concrete Placement Prep. Removal of Debris 10 Concrete Placement Prep. Water Removal 11 Concrete Quality Air-Entraining Admixture 11 Concrete Quality Cement Specification 11 Concrete Quality Clean Water Requirements 12 Concrete Quality Concrete Admixtures 12 WWW WWWW*X!diiAOJ.-44 IM'

Category Topic Page#

Concrete Quality Concrete Aggregates 13 Concrete Quality Concrete Air Content 13 Concrete Quality Concrete Strength Requirements 14 Concrete Quality Corrosion Protection 14 Concrete Quality Fly Ash 15 Concrete Quality Ground Slag 15 Concrete Quality Water/Cement Ratio 16 Concrete Reinforcement Field Bending of Bars 16 Concrete Reinforcement Minimum Bend Diameters 17 Concrete Reinforcement Rebar meets UMAX FSAR Requirements 17 Concrete Reinforcement Reinforcement Cover 1 18 Concrete Reinforcement Reinforcement Cover 2 18 Concrete Sampling Composite Sampling Requirement 1 18 Concrete Sampling Composite Sampling Requirement 2 19 Concrete Sampling Composite Sampling Requirement 3 19 Concrete Sampling Field Technician Requirements 20 Concrete Sampling Initial Sample Curing 20 Concrete Sampling Making & Curing Test Specimens 21 Concrete Sampling Required Number of Strength Samples 22 Pad Design Density of the SFP, SES, and Top Pad 22 Pad Design Subgrade and mud mat 23 Special Topics Cavity Enclosure Container Placement 25 Special Topics Grout Placement and Sampling 26

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Callaway ISFSI Concrete Placement Category: Cold Weather Requirements Topic: Concrete Temperature Reference: ASTM C 94, Sect 12.10 Edition 2014 Requirement Concrete delivered in cold weather shall have a minimum temperature of 50 degrees F.

The maximum temperature of concrete produced with heated aggregates, heated water, or both, shall at no time during its production or transportation exceed 90 degrees F.

Observation: The licensee maintained the concrete temperature as required during concrete placement operations. Project Specification Section 03300, Step 3.4 C. required the temperature of the concrete at the point of placement, shall be kept within the range of 5 0 degrees F to 90 degrees F. Holtec Procedure HSP-186, Exhibit 9.3, "Cold and Hot Weather Details,"

Step 2 required provisions shall be taken to ensure the all concrete shall be maintained at a temperature of not less than 50 degrees F for at least 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> after placement.

During placement of the UMAX support foundation pad (SFP) and the UMAX top pad conducted during the months of November and January 2014, ambient temperatures were commonly below 50 degrees F. The licensee utilized water heaters at the concrete batch plants to heat the water that was used in the concrete mix. The temperature of the concrete was documented on the concrete strength sample reports and recorded on HSP-186 Exhibit 9 .5 "Concrete Field Data Sheet." The NRC inspectors observed the measurement of the concrete temperature during concrete placement activities. During placement activities forthe SFP on November 5, 2014 the concrete temperature ranged from a minimum of 56 degrees to a maximum of 78 degrees F. During placement activities for the top pad on January 16, 2015 the concrete temperature ranged from a minimum of 56 degrees F to a maximum of 68 degrees F. All concrete placed for the UMAX pads on November 5, 2014 and January 16, 2015 were found to meetACI temperature requirements.

Documents (a) Callaway ISFSI Project Specification No. 1484040010-S-ISFSI-00001, Section Reviewed: 03300, "Cast in Place Concrete," Rev. O; (b) Holtec Procedure HSP-186, "Aggregate and Ready Mix Concrete Testing Requirements for ITS 'B' Applications," Rev 19; (c)

Engineering Surveys and Services Testing Laboratories, "Concrete Cylinder Test Reports," for Account No C 632 Dated: 12/12/2014, 12/10/2014, 12/05/2014, 12/04/2014, and 02/03/2015.

Category: Cold Weather Requirements Topic: Inspection for Frost Reference: ACI 318, Sect 5.12.2 Code Year 2005 Requirement All concrete materials and all reinforcement, forms, fillers, and ground with which concrete is to come in contact shall be free from frost.

Observation: NRC inspectors conducted visual inspections of the concrete placement area before placement activities of the SFP, self-hardening engineered subgrade (SES), and top pad.

NRC inspectors verified the subgrade was not frozen, and all reinforcements, forms, and ground were free from ice and frost. Per instructions found in Procedure HSP-186 in Exhibit 9.3 "Cold and Hot Weather Details," Holtec was required to keep temperature of the rebar above 35 degree F and 32 degrees F for the subgrade. These requirements Page I of27

followed ACI 306R, "Guide to Cold Weather Concreting," requirements and standards.

On colder mornings prior to the placement, Holtec utilized heaters to blow hot air into the form area for hours before placement activities were started to ensure the proper temperatures were attained.

Document& (a) Holtec Procedure HSP-186, "Aggregate and Ready Mix Concrete Testing Reviewed: Requirements for ITS 'B' Applications," Rev 19; (b) ACI 306R, "Guide to Cold Weather Concreting," 2010.

Category: Cold Weather Requirements Topic: Protection During Cold Weather Reference: ACI 318, Sect 5.12.1 Code Year 2005 Requirement Adequate equipment shall be provided for heating concrete materials and protecting concrete during freezing or near-freezing weather.

Observation: The licensee provided adequate equipment and kept the concrete above the required 50 degrees F during the concrete pour, placement, and curing. The ambient temperatures during the concrete placement of the SFP and top pad were commonly under 40 degrees F. Project Specification 03300, Step 3.4 E. required adequate protection of concrete placed in ambient temperature conditions below 40 degrees F by covering, insulating, and/or heating to maintain temperature above 50 degrees F. During cold weather concrete work, Holtec followed HSP-186 Exhibit 9.3 "Cold and Hot Weather Details" to ensure ACI 306R "Guide to Cold Weather Concreting" requirements and standards were followed.

Both batch plants utilized by Callaway to produce the concrete for the SFP, SES, and the top pad utilized water heaters to heat the concrete mixing water to ensure the concrete temperature during placement was above 50 degrees F. After placement, Holtec covered and monitored the temperature of the concrete to ensure it was protected adequately for the time required to cure.

Documents (a) Holtec Procedure HSP-186, "Aggregate and Ready Mix Concrete Testing Reviewed: Requirements for ITS 'B' Applications," Rev 19; (b) ACI 306R, "Guide to Cold Weather Concreting," 2010; (c) Callaway ISFSI Project Specification No. 1484040010-S-ISFSI-00001, Section 03300, "Cast in Place Concrete," Rev. 0.

Category: Concrete Curing Topic: High-Early-Strength Concrete Reference: ACI 318, Sect 5.11.2 Code Year 2005 Requirement High-early-strength concrete shall be maintained above 50 degrees F and in a moist condition for at least the first 3 days, except when cured in accordance with 5.11.3.

Observation: The top pad concrete mix design met the requirements for high-early-strength concrete.

The licensee regulated and maintained the concrete temperature above 50 degrees F and maintained the concrete in a moist condition for 3 days as required by the ACI code.

The fop pad design mix contained an admixture that caused an increase in the rate of hydration of the hydraulic cement and thus shortens the time of setting and increases the rate of strength development.

Documents (a) ACI CT-13, "Concrete Terminology," 2013.

Reviewed:

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Category: Concrete Curing Topic: Other Than High-Early-Strength Concrete Reference: ACI 318, Sect 5.11.1 Code Year 2005 Requirement Concrete (other than high-early-strength) shall be maintained above 50 degrees F and in a moist condition for at least the first 7 days after placement, except when cured in accordance with 5.11.3.

Observation: The SFP concrete did not meet the high-early-strength exemption and as such the bottom pad was cured in a moist condition above 50 degrees for seven days as required by the ACI code. Project Specification Section 3300 "Cast in Place Concrete," Step 3.4 E required the licensee to keep the concrete temperature above 50 degrees for seven days after placement using covering, heating, or insulation. SFP concrete was cured under moist condition for seven days utilizing a combination of a membrane sealing compound, sprayed water, and a plastic sheet covering to insulate the concrete for the seven days.

Documents (a) Callaway ISFSI Project Specification No. 1484040010-S-ISFSI-00001, Section Reviewed: 03300, "Cast-in-place Concrete," Rev. 0.

Category: Concrete Mixing & Delivery Topic: Addition of Job Site Water Reference: ASTM C 94, Section 12.7 Edition 2014 Requirement When a truck mixer or agitator is approved for mixing or delivery of concrete, no water from the truck water system or elsewhere shall be added after the initial introduction of mixing water for the batch except when on arrival at the job site the slump of the concrete is less than specified. When adding water, the drum or blades shall be turned an additional 30 revolutions or more if necessary, at mixing speed, until the uniformity of the concrete is within these limits.

Observation: NRC inspectors observed that no water additions were made to any trucks arriving on site during the three observed pad placement inspections. The licensee did add superplaticizer into some trucks that exhibited low slump properties prior to concrete placement. Each time an admixture was added to a truck, Holtec procedures and personnel required the truck to mix an additional 30 revolutions prior to placement.

Holtec procedure HSP-186 steps 8.1.1 and 8.2.5.4 included instructions indicating that water may only be added once when the concrete mixer arrives at the pour site, if the slump needed to be corrected. The documents include a time limit of 15 minutes, under which the entirety of the water needs to be added and a minimum number of30 drum revolutions to achieve mixing.

Documents (a) Holtec Procedure HSP-186, "Aggregate and Ready Mixed Concrete Testing Reviewed: Requirements for ITS 'B' Applications," Rev. 19; (b) ASTM C 94, "Standard Specification for Ready Mixed Concrete," 2014.

Category: Concrete Mixing & Delivery Topic: Concrete Discharge Limits Reference: ASTM C 94, Section 12. 7 Edition 2014 Requirement Discharge of the concrete shall be completed within 11/2 hours after the introduction of mixing water to the cement and aggregates or the introduction of the cement to the aggregates. These limitations are permitted to be waived by the purchaser if the concrete Page 3 of27

is of such slump after the 1 112 hour0.0013 days <br />0.0311 hours <br />1.851852e-4 weeks <br />4.2616e-5 months <br /> time limit has been reached that it can be placed, without the addition of water.

Observation: NRC observed concrete placement on three occasions at the Callaway Holtec HI-STORM UMAX ISFSI: November 5, 2014, December 4, 2014, and January 16, 2015.

During each concrete placement witnessed by NRC inspectors, all concrete trucks arrived on site within 90 minutes and with fewer than 300 revolutions on the concrete mixing drum prior to concrete placement.

This requirement was captured in the Project Specification Section 03300 which stated that the Construction Manager may reject any ready mixed concrete not placed within 90 minutes of batching or 300 drum revolutions since initial batching. Holtec Procedure HSP-186, step 8.2 cites a 90 minute time limit and a 300 revolution limit, but also granted the exception to use the concrete at the discretion of a Holtec representative which was in accordance with ASTM C 94 standards.

Documents (a) Holtec Procedure HSP-186, "Aggregate and Ready Mixed Concrete Testing Reviewed: Requirements for ITS 'B' Applications," Rev 19; (b) Callaway ISFSI Project Specification No. 1484040010-S-ISFSI-00001, Section 03300, "Cast-in-place Concrete, "

Rev. O; (c) ASTM C 94, "Standard Specification for Ready Mixed Concrete," 2014.

Category: Concrete Mixing & Delivery Topic: Concrete Mixing Revolutions Reference: ASTM C 94, Section 12.5 Edition 2014 Requirement Concrete that is completely mixed in a truck mixer will be mixed at 70 to 100 revolutions at the mixing speed designated by the manufacturer to produce the uniformity of concrete indicated in Annex Al . The mixing revolutions will begin after all ingredients including water, are in the drum. Additional revolutions by the mixer beyond the number found to produce uniformity of concrete shall be at a designated agitating speed.

Observation: All trucks observed by the NRC met the minimum mixing revolutions requirement.

Holtec Procedure HSP-186 step 8.1.1 required that after placement of the concrete ingredients into the delivery truck that the mixing process will be continued for 70 to 100 revolutions.

On November 5 and December 6, 2014 and January 16, 2015, NRC inspectors recorded drum revolutions for each concrete delivery truck as it arrived on the Callaway site for the Holtec HI-STORM UMAX ISFSI placement. NRC inspectors observed that none of the concrete mixing truck drums had less than 94 revolutions upon arrival at the Callaway site for any of the concrete placement events. These included observations of the SFP placement, the placement of the controlled low-strength material (CLSM) to make the SES, and the top pad placement. The mixing trucks in use adhered to the mixing requirements of ASTM C 94.

Documents (a) Holtec Procedure HSP-186, "Aggregate and Ready Mixed Concrete Testing Reviewed: Requirements for ITS 'B' Applications," Rev. 19; (b) ASTM C 94, "Standard Specification for Ready-Mixed Concrete," 2014.

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Category: Concrete Mixing & Delivery Topic: Measurement of Aggregate Materials Reference: ASTM C 94, Section 9.2.1 Edition 2014 Requirement Aggregates shall be measured by mass including the mass of dry materials plus the total mass of moisture (both absorbed and surface) contained in the aggregate. The quantity of aggregate used in any batch of concrete as indicated by the scale shall be within +/-

2% of the required mass when the mass is measured in individual weigh batchers. In a cumulative aggregate weigh batcher, the cumulative weight after each successive weighing shall be within+/- 1% of the required cumulative amount up to the point when the scale is used in excess of 30% of its capacity. For cumulative weights less than 30%

of the scale capacity, the tolerance shall be+/- 0.3% of scale capacity or+/- 3% of the required cumulative weight, whichever is less.

Observation: The aggregate scale indicators at both the Central Concrete and Mo-Con Inc. (MOCON)

batch plants that were used to provide concrete for the Holtec HI-STORM UMAX ISFSI had calibration records that met the requirements of ASTM C 94. Central Concrete's aggregate scale was calibrated by Precision Scale & Controls, Inc., on June 18, 2014.

The aggregate scale percent error was found to be well below the 1% requirement specified in the ASTM. The MOCON batch plant aggregate scale was calibrated by Precision Scale & Controls, Inc., on October 13, 2014. The aggregate scale error was to be well below the 1% requirement specified in the ASTM.

Documents (a) Precision Scale & Controls. Inc., Calibration Test Job Ticket #36374, dated June 18, Reviewed: 2014; (b) Precision Scale & Controls Inc., Calibration Test Job Ticket #37418, dated October 13, 2014; (c) ASTM C 94, "Standard Specification for Ready Mixed Concrete,"

2014.

Category: Concrete Mixing & Delivery Topic: Measurement of Mixing Water Reference: ASTM C 94, Section 9.3 Edition 2014 Requirement The added mixing water shall be measured by weight or volume to an accuracy of 1% of the required total mixing water.

Observation: The water meters at both the Central Concrete and MOCON batch plants that were used to mix concrete for the Holtec HI-STORM UMAX ISFSI were calibrated to meet the requirements of ASTM C 94. Central Concrete's water meter was calibrated by Precision Scale & Controls, Inc., on June 18, 2014. The water meter percent error ranged from .46% to .59%, which was below the 1% requirement specified in the ASTM. The MOCON batch plant water meter was calibrated by Precision Scale &

Controls, Inc., on October 13, 2014. The water meter percent error ranged from .15% to

.25%, which was below the 1% requirement specified in the ASTM.

Documents (a) Precision Scale & Controls Inc., Calibration Test Job Ticket #36374, dated June 18, Reviewed: 2014; (b) Precision Scale & Controls Inc., Calibration Test Job Ticket #37418, dated October 13, 2014; (c) ASTM C 94, "Standard Specification for Ready Mixed Concrete,"

2014.

Category: Concrete Mixing & Delivery Topic: Ready Mixed Concrete Reference: ACI 318, Sect 5.8.2 Code Year 2005 Requirement Ready-mixed concrete shall be mixed and delivered in accordance with the requirements Page 5 of27

of ASTM C 94 "Specification for Ready-Mixed Concrete" or ASTM C 685

"Specification for Concrete Made by Volumetric Batching and Continuous Mixing."

Observation: The concrete used for the Callaway UMAX was mixed and delivered in accordance with ASTM C 94. Holtec's quality assurance group and Callaway's ISFSI project management group inspected the MOCON and Central Concrete batch plants as well as the mixing trucks prior to concrete placement operations. The Central Concrete batch plant and their mixing trucks had a NRMCA certification, which satisfied the requirements of ASTM C 94. The MOCON batch plant and their mixing trucks had a Missouri Department of Transportation (MoDot) certification. The MoDot inspection criteria did not fully implement the requirements of ASTM C 94. As such, the licensee performed an additional audit of the MOCON plant and their mixing trucks to verify all requirements of ASTM C 94 were met. NRC inspectors reviewed the subsequent audit report and surveillances and found no issues related to compliance with ASTM C 94 standards.

Documents (a) Callaway ISFSI Project Specification No. 1484040010-S-ISFSI-00001, Section Reviewed: 03300, "Cast-in-place Concrete," Rev. O; (b) Holtec International Procedure HSP-186,

"Aggregate and Ready Mixed Concrete Testing Requirements for ITS 'B' Applications,"

Rev. 19; (c) Licensee provided document "ASTM C 94 comparison to MOCON surveillance excel sheet", dated October 23, 2014; (d) Surveillance Report "MOCON Inc. of Fulton," dated October 23, 2014.

Category: Concrete Mixing & Delivery Topic: Slump Tolerances 1 Reference: ASTM C 94, Section 7 .1.1 Edition 2014 Requirement Unless other slump tolerances are included in the project specifications, the following tolerances shall apply: When the slump specifications are written as a "maximum" or

"not to exceed" amount and the specified slump is 3 inches or less the slump tolerance is

+0/-1.5 inches. If the slump specified is more than 3 inches the slump tolerance is +0/-

2.5 inches.

Observation: Slump testing tolerances required by the Project Specification were followed and were found to be in compliance with ACI requirements. The slump tolerances for both the SFP and top pad were specified in Project Specification Section 03300, Step 2.3 A. The specified slump for the concrete to be placed in these pads were three to five inches with a maximum of eight inches when using a high range water reducer admixture. The licensee utilized a high range water reducer in the concrete mix design for the SFP and the top pad. Therefore, the slump for the concrete could range from three inches to eight inches. Slump tests were observed to be within the required range by the NRC inspection for placement activities associated with the SFP on November 5, 2014 and the top pad on January 16, 2015.

Documents (a) Holtec Procedure HSP-186, "Aggregate and Ready Mix Concrete Testing Reviewed: Requirements for ITS 'B' Applications," Rev 19; (b) Callaway ISFSI Project Specification No. 1484040010-S-ISFSI-00001, Section 03300, "Cast in Place Concrete,"

Rev. O; (c) ASTM C 94, "Standard Specification for Ready Mixed Concrete," 2014.

Page 6 of27

Category: Concrete Placement Topic: CLSM Placement Reference: Holtec HI-STORM UMAX FSAR Table 2.3.2. Revision 2 Requirement Controlled low-strength material (CLSM) must flow fluidly as a cohesive mixture and remain well consolidated with no separation of constituent materials.

Observation: CLSM forms the SES upon which the top pad is constructed. This is the area above the SFP described in the Holtec HI-STORM UMAX Final Safety Analysis Report (FSAR)

Figure 2.4.4 as Space "A."

During field observations on December 4, 2014, NRC inspectors observed placement of CLSM on the SFP and around the 48 grouted bases of the CECs. NRC inspectors also observed CLSM sampling activities and test cylinder preparations. Aspects of CLSM quality were assessed periodically through sampling evolutions during the placement activities. Technicians sampled the concrete for air content, temperature, and unit weight. All observed measurements of air content, temperature, and unit weight were acceptable, based on both the CLSM mix design specification and the Holtec FSAR.

The CLSM mix design specification listed a target slump of 10 inches. However, it was not required that slump or flow consistency be measured as long as the CLSM remained consolidated and flowed well based on visual observation. NRC inspectors visually confirmed that the CLSM flowed as a cohesive homogeneous mixture during placement operations. Several lifts of CLSM were placed over several days to reach a subgrade depth of approximately 17 feet.

Documents (a) Holtec HI-STORM UMAX Canister Storage System Final Safety Analysis Report Reviewed: (FSAR), Rev. 2; (b) ACI 229R, "Report on Controlled Low-Strength Materials," 2013; (c) Callaway ISFSI Project Specification No. 1484040010-S-ISFSI-00001, Section 03300, "Cast-In-Place Concrete," Rev. O; (d) ASTM D 5971, "Standard Practice for Sampling Freshly Mixed Controlled Low-Strength Material," 2013; (e) Holtec Procedure HPP-2253-112, "Controlled Low Strength Material (CLSM) Mixing, Testing, Placement Requirements for the Callaway UMAX," Rev. O; (t) Holtec Licensing Drawing Package No. 8446; (g) Central Concrete 1000 PSI CLSM Mix #106.

Category: Concrete Placement Topic: Concrete Deposition Reference: ACI 318, Sect 5.10.l Code Year 2005 Requirement Concrete shall be deposited as nearly as practical in its final position to avoid segregation due to rehandling or flowing.

Observation: NRC inspectors observed the concrete for both the ISFSI support foundation pad and ISFSI top pad to be deposited as nearly as practical in its final position, thus avoiding segregation due to rehandling or flowing. Concrete was discharged fh>m the trucks via pumps and lowered via an "elephant trunk" into place. Positioning of the pump truck chute was manipulated by an operator on the ground adjacent to the area of placement, ensuring good deposit volumes, and eliminating any need to "drag" concrete with vibrators.

Documents None Reviewed:

Page 7 of27

Category: Concrete Placement Topic: Concrete Placement Rate Reference: ACI 318, Sect 5.10.2 Code Year 2005 Requirement Concreting shall be carried on at such a rate that concrete is at all times plastic and flows readily into spaces between reinforcement.

Observation: NRC inspectors observed that concrete placement activities for both the SFP and the top pad were placed in a plastic state, easily worked by concrete operators and crew. The concrete readily flowed into open spaces between the reinforcement bars.

Documents None Reviewed:

Category: Concrete Placement Topic: Foreign Material in Concrete Reference: ACI 318, Sect 5.10.3 Code Year 2005 Requirement Concrete that has partially hardened or been contaminated by foreign materials shall not be deposited in the structure.

Observation: During placement of the ISFSI top pad and ISFSI foundation pad operations, NRC inspectors verified that the licensee did not place partially hardened or contaminated concrete during placement activities.

Documents None Reviewed:

Category: Concrete Placement Topic: Retempered Concrete Reference: ACI 318, Sect 5.10.4 Code Year 2005 Requirement Retempered concrete or concrete that has been remixed after initial set shall not be used unless approved by the engineer.

Observation: During operations witnessed by the NRC inspectors, no observations were made of an attempt to place retempered or remixed concrete.

Documents None Reviewed:

Category: Concrete Placement Prep. Topic: Construction Joints Reference: ACI 318, Sect 6.4.2 Code Year 2005 Requirement Immediately before new concrete is placed, all construction joints shall be wetted and standing water removed.

Observation: NRC inspectors observed that no standing water was present within the formed area during placement operations associated with the SFP and top pad. Project Specification Section 03300 Step 3.2 E, required that the concrete joining surface be thoroughly wetted prior to placement of additional adjoining concrete. Procedure HSP-186 step 7 .14.2, also required thoroughly wetted concrete joining surface prior to fresh concrete placement. Procedure HSP-186 step 7.15 .5 .1, required a visual inspection of the area of the pour to ensure that no standing water in excess of Y-1" depth or debris was present prior to concrete placement.

Documents (a) Callaway ISFSI Project Specification No. 1484040010-S-ISFSI-00001, Section Reviewed: 03300, "Cast-in-place Concrete," Rev. O; {b) Holtec Procedure HSP-186, "Aggregate and Page 8 of27

Ready Mixed Concrete Testing Requirements for ITS 'B' Applications," Rev. 19.

Category: Concrete Placement Prep. Topic: Formwork 1 Reference: ACI 318, Sect 5.7.l ( c) Code Year 2005 Requirement Preparation before concrete placement shall include that forms shall be properly coated.

Observation: A form release agent and/or the use of waxed forms were verified to have been in place prior to concrete placement. The use of the release agent provided easy form removal once the concrete had set. Project Specification Section 03300 Step 3.4 A, required application of the release agent to formwork in accordance with release agent manufacturer's written recommendations.

Documents (a) Callaway ISFSI Project Specification No. 1484040010-S-ISFSI-00001, Section Reviewed: 03300, "Cast in Place Concrete," Rev. 0.

Category: Concrete Placement Prep. Topic: Formwork 2 Reference: ACI 318, Sect 6.1.2 Code Year 2005 Requirement Forms shall be substantial and sufficiently tight to prevent leakage of mortar.

Observation: NRC inspectors observed during the initial cQncrete placement of the SFP on November 5, 2014 and the second section placement of the top pad on January 16, 2015 that the forms were sufficiently tight and did not leak mortar. Callaway's ISFSI Project Specification for concrete formwork, Section 03100 Step 2.1 and 2 .2 required that the forms be matched, tight fitting, and stiffened to support the weight of the concrete without deflection detrimental to tolerances. NRC inspectors visually verified that the concrete formwork used in the SFP and the top pad for the Holtec HI-STORM UMAX ISFSI at Callaway were substantial, shored, and braced to prevent movement when filled with concrete. Further, the concrete formwork was free from visible gaps through which concrete paste could seep out.

Documents (a) Callaway ISFSI Project Specification No. 1484040010-S-ISFSI-00001 , Section Reviewed: 03100, "Concrete Formwork," Rev. 0.

Category: Concrete Placement Prep. Topic: Laitance Removal Reference: ACI 318, Sect 5.7.l (g) Code Year 2005 Requirement All laitance and other unsound material shall be removed before additional concrete is placed against hardened concrete.

Observation: All laitance and unsound material was properly removed before additional concrete was placed against hardened concrete. Project Specification, Section 03300 Step 3.2 D, required that all loose or deleterious materials be removed from exposed faces of all construction joints and the surfaces be roughened by air, water, wire brushing, mechanical abrading, chipping, or bush hammering to present a suitable surface to cast new concrete against. This requirement applied to only the third, and fourth sections of the SFP and the third section of the top pad which was joined to other sections.

Documents (a) Callaway ISFSI Project Specification No. 1484040010-S-ISFSI-00001, Section Reviewed: 03300, "Cast-in-place Concrete," Rev. O; (b) Holtec International Procedure HSP-186, Page 9 of27

"Aggregate and Ready Mixed Concrete Testing Requirements for ITS 'B' Applications,"

Rev. 19.

Category: Concrete Placement Prep. Topic: Reinforcement Reference: ACI 318, Sect 5.7.1 (e) Code Year 2005 Requirement Preparation before concrete placement shall include that reinforcement shall be thoroughly clean of ice or other deleterious coatings.

Observation: NRC inspectors visually verified that the reinforcement was free of any ice, dirt, loose rust, or other contaminants. Visual inspection of the pour area within the fonns was conducted on numerous occasions during rebar observations for both the SFP and the top pad.

Documents None Reviewed:

Category: Concrete Placement Prep. Topic: Reinforcement Conditions Reference: ACI 318, Sect 7.4.1 Code Year 2005 Requirement At the time concrete is placed, reinforcement shall be free from mud, oil, or other nonmetallic coatings that decrease bond.

Observation: NRC inspectors verified that no loose rust, oil, mud, or laitance were impacting the rebar prior to the concrete placements of the SFP on November 5, 2014 and the top pad on January 16, 2015. Project Specification, Section 03200 Step 3.5 M, required that rebar be clean prior to concrete placement. Holtec Procedure HSP-186 step 7 .14. 7, directed that all loose scale and rust be removed from reinforcing bars prior to concrete placement.

Documents (a) Holtec Procedure HSP-186, "Aggregate and Ready Mixed Concrete Testing Reviewed: Requirements for ITS 'B' Applications," Rev 19; (b) Callaway ISFSI Project Specification No. 1484040010-S-ISFSI-00001, Section 03200, "Concrete Reinforcement," Rev. 0.

Category: Concrete Placement Prep. Topic: Removal of Debris Reference: ACI 318, Sect 5.7.1 (b) Code Year 2005 Requirement Preparation before concrete placement shall include that all debris and ice shall be removed from spaces to be occupied by concrete.

Observation: This requirement was implemented for the concrete placement associated with the Holtec HI-STORM UMAX ISFSI at Callaway. NRC inspectors verified that all debris had been removed from the area within the concrete forms, which included no presence of ice during concrete placements observed on November 5, 2014 for the SFP and January 16, 2015 for the top pad.

Documents None Reviewed:

Page 10 of27

Category: Concrete Placement Prep. Topic: Water Removal Reference: ACI 318, Sect 5.7.l (f) Code Year 2005 Requirement Preparation before concrete placement shall include that water shall be removed from place of deposit before concrete is placed.

Observation: This requirement was implemented during concrete placement operations associated with the construction of the Holtec HI-STORM UMAX ISFSI at Callaway. All standing water was removed from inside the concrete formwork prior to concrete placement of the SFP observed by inspectors on November 5, 2014 and during placement of the top pad observed by inspectors on January 16, 2015.

Documents None Reviewed:

Category: Concrete Quality Topic: Air-Entraining Admixture Reference: ACI 318, Sect 3.6.4 Code Year 2005 Requirement Air-entraining admixtures shall confonn to ASTM C 260, "Specification for Air-entraining Admixtures for Concrete."

Observation: The air-entraining admixture used for both the SFP and top pad conformed to AS TM C 260. Project Specification Section 03300 Step 2.3, required air-entraining admixtures to meet ASTM C 260. For the SFP and top pad the licensee used Grace Concrete Product Daravair 1400 air-entraining admixture. The manufacturer's certificate of conformance was reviewed which documented that the Grace Daravair 1400 Air-entraining admixture met the requirements of ASTM C 260.

Documents (a) Callaway ISFSI Project Specification No. 1484040010-S-ISFSl-00001, Section Reviewed: 01410, "Testing Services," Rev. 2; (b) Grace Daravair 1400 data sheet, dated November 2007.

Category: Concrete Quality Topic: Cement Specification Reference: ACI 318, Sect 3.2.1 Code Year 2005 Requirement Cement shall conform to ASTM C 150, "Specification for Portland Cement."

Observation: The portland cement used for the Holtec Ill-STORM UMAX ISFSI constructed at Callaway conformed to the ASTM C 150 standard and other design requirements. The Project Specification Section 03300 Step 2.1.A, required that all portland cement shall conform to ASTM C 150, Type II (MH) requirements. Additionally, the specification required that the cement not contain more than 0.6 percent equivalent alkalis, the tricalcium aluminate concentration be limited to 8 percent, and the chloride ion concentration shall not exceed 0.05 percent. Continental Cement Company (CCC)

chemical assay results showed that none of the limits specified in ASTM C 150 had been exceeded in the portland cement produced by CCC. CCC was the producer of the portland cement used by both concrete batch plants that sourced the Callaway ISFSI construction, Central Concrete and MOCON. In addition, NRC inspectors reviewed a letter transmitted from CCC to MOCON which indicated that average chloride content of the cement, produced from January to May 2014 was 0.050%. The portland cement used for the Holtec ID-STORM UMAX ISFSI design at Callaway confonned to all standard and design requirements.

Page 11 of27

Documents (a) Callaway ISFSI Project Specification No. 1484040010-S-ISFSI-00001, Section Reviewed: 03300, "Cast-in-place Concrete," Rev. O; (b) Continental Cement Company, LLC Laboratory Test Reports, dated 5/30/14, 5/31114, 8/26/14, and 8/27/14; (c) Letter from Continental Cement Company to MOCON, Inc., June 16, 2014.

Category: Concrete Quality Topic: Clean Water Reauirements Reference: ACI 318, Sect3.4.l Code Year 2005 Requirement Water used in mixing concrete shall be clean and free from injurious amounts of oils, acids, alkalis, salts, organic materials, or other substances that may be deleterious to concrete or reinforcement.

Observation: All potable water sources were deemed suitable for making concrete by ASTM C 94 and ASTM C 1602 standards. The two sources of water used for concrete batched at Central Concrete and MOCON plants met drinking water requirements and were, therefore, acceptable for use in the concrete. Project Specification Section 03300, Step 2.1.C. l specified that the water used for concrete shall meet the requirements of ASTM C 94 and ASTM C 1602. Holtec procedure HSP-186, Exhibit 9.7 also had a requirement that mixing water be potable.

The water used at Central Concrete was sourced by the Callaway 2 Water District, a municipal water supplier. A letter, dated June 18, 2014, was reviewed that certified the water supplied as Missouri Department of Natural Resources approved and suitable for human consumption. Likewise, NRC inspectors reviewed a letter from the City of Fulton municipal water supply that certified the water used at MOCON as suitable for human consumption. The mixing water used in the production of concrete for the Holtec HI-STORM UMAX ISFSI at Callaway met all specified requirements.

Documents (a) Callaway ISFSI Project Specification No. 1484040010-S-ISFSI-00001, Section Reviewed: 03300, "Cast-in-place Concrete," Rev. O; (b) Holtec Procedure HSP-186, "Aggregate and Ready Mixed Concrete Testing Requirements for ITS 'B' Applications," Rev. 19; (c)

ASTM C 94, "Standard Specification for Ready Mixed Concrete;" 2014; (d) ASTM C 1602, "Standard Specification for Mixing Water Used in the Production of Hydraulic Cement Concrete," 2012.

Category: Concrete Quality Topic: Concrete Admixtures Reference: ACI 318, Sect 3.6.5 Code Year 2005 Requirement Water-reducing admixtures, retarding admixtures, accelerating admixtures shall conform to ASTM C 494, "Specification for Chemical Admixtures for Concrete."

Observation: The concrete mix design used for the SFP and the top pad at Callaway used water reducing admixtures that adhered to the requirements of ASTM C 494. Project Specification Section 03300, Step 2.2 required that water reducing admixtures of Types A and F conform to the requirements of ASTM C 494. NRC inspectors reviewed the product data sheet for Grace Concrete Products ADVA 140M, high-range water reducing admixture. The product data sheets indicated that it met the requirements of ASTM C 494 for Type A and F admixtures, as well as ASTM C 1017 requirements for Type I admixtures.

Page 12 of27

Documents (a) Callaway ISFSI Project Specification No. 1484040010-S-ISFSI-00001, Section Reviewed: 03300, "Cast-in-place Concrete," Rev. O; (b) ASTM C 494, "Standard Specification for Chemical Admixtures for Concrete," 2013.

Category: Concrete Quality Topic: Concrete Aggregates Reference: ACI 318, Sect 3 .3 .1 Code Year 2005 Requirement Concrete aggregates shall confirm to ASTM C 33 "Specification for Concrete Aggregates" or utilized by exception when shown by special test or actual service to produce concrete of adequate strength and durability and approved by the building official.

Observation: The aggregates utilized by the licensee fully conformed to ASTM C 33. Project Specification Section 03300, Steps 2.1.B.1, 2.1.B.2, and 2.1.B.4 specified that that fine and coarse aggregates shall conform to the requirements of ASTM C 33, "Standard Specification for Concrete Aggregates." The Project Specification also required that the coarse aggregates be Size No. 67, and Class 3M. Holtec procedure HSP-186,

"Aggregate and Ready Mixed Concrete Testing Requirements for ITS "B" Applications,"

Rev 19, Step 7.14.8 required that aggregate testing be completed and be shown to conform to ASTM C 33.

NRC inspectors reviewed laboratory test results for the coarse and fine aggregates used in the concrete for the Holtec HI-STORM UMAX construction at the Callaway site. The coarse aggregate used was State D Rock from the Mertens Quarry, Ausvasse, MO. The fine aggregate was Missouri River Sand, from Capital Sand, Jefferson City, MO.

According to tests run by Engineering Surveys and Services Testing Laboratories, Palmerton & Parrish, Inc., and MoDOT, both the coarse and fine aggregates used for the HI-STORM UMAX project met the qualifications of ASTM C 33. In particular, the State D Rock met all of the sieve test results to qualify as #67 aggregate, as well as qualifying for the class 3M, meeting all design requirements.

Documents (a) Holtec Procedure HSP-186, "Aggregate and Ready Mixed Concrete Testing Reviewed: Requirements for ITS 'B' Applications," Rev 19; (b) Callaway ISFSI Project Specification No. 1484040010-S-ISFSI-00001, Section 03300, "Cast-in-place Concrete," Rev. O; (c) ES&S Testing Laboratories, Coarse and Fine Aggregate ASTM C 33 Test Results, dated June 16, 2014; (d) Palmerton & Parrish, Inc., Summary of Coarse and Fine Aggregate Tests, dated April 24, 2014; (e) Missouri Department of Transportation (MoDOT), report of coarse aggregate test information from the Mertens Quarry, dated June 25, 2013.

Category: Concrete Quality Topic: Concrete Air Content Reference: ACI 318, Table 4.2.l Code Year 2005 Requirement Normal weight concrete exposed to freezing and thawing shall be air-entrained with air content indicated in Table 4.2.1. Tolerance on air content as delivered shall be +/- 1.5 percent. For specified compressive strength greater than 5,000 psi, reduction of air content indicated in Table 4.2. l by 1.0 percent shall be permitted.

Observation: NRC inspectors reviewed concrete test results for concrete sampling that took place Page 13 of27

during the initial placement for the SFP on November 5, 2014 and the top pad placement on January 16, 2015. All air entrainment results were between the specified tolerance range of 3.5 and 6.5%. ACI 318 required that concrete exposed to freezing and thawing cycles be air entrained to 5 +/- 1.5% for moderately exposed concrete with a nominal maximum aggregate size of 0.75 inch. ACI-318 provided for a 1% reduction of the air content for concrete with an f c greater than 5,000 psi. The Project Specification mirrored those requirements and specified an entrained air content of 5% for the concrete in both the SFP and the top pad for the Holtec HI-STORM UMAX ISFSI.

Holtec Procedure HSP-186 required that the concrete test results for air entrainment be recorded on Exhibit 9.12, "Uniformity Testing."

Documents (a) Holtec Procedure HSP-186, "Aggregate and Ready Mixed Concrete Testing Reviewed: Requirements for ITS 'B' Applications," Rev 19; (b) Callaway ISFSI Project Specification No. 1484040010-S-ISFSI-00001, Section 03300, "Cast-in-place Concrete,"

Rev. 0.

Category: Concrete Quality Topic: Concrete Strength Requirements Reference: ACI 318, Sect 5.6.3.3 Code Year 2005 Requirement Strength level of an individual class of concrete shall be considered satisfactoiy if both of the following requirements are met: (a) Eveiy arithmetic average of any three consecutive strength tests equals or exceeds fc (required 28 day concrete compressive strength) and (b) no individual strength test (average of2 cylinders) falls below fc by more than 500 psi.

Observation: NRC inspectors reviewed the 28-day break test results for the SFP and the top pad. The SFP test results were in compliance with all applicable requirements for compressive strength. For the SFP, all of the 28-day concrete sample break test data came in well within the Project Specification of 4,500 psi. Within the sample data set for the SFP, the arithmetic average compressive strength results ranged from 5,412 to 7,102 psi. No two samples in any data set for the SFP averaged below 5,035 psi. For the top pad, the arithmetic average compressive strength results ranged from 4,996 to 7,673 psi. No two samples for the top pad averaged below 4,881 psi. The concrete strength samples for the Holtec UMAX ISFSI met all design and code requirements.

Documents (a) Project Specification No. 1484040010-S-ISFSI-00001, Section 03300, "Cast-in-place Reviewed: Concrete," Rev. O; (b) Holtec HI-STORM UMAX Final Safety Analysis Report, Rev. 2; (c) Engineering Surveys and Services Testing Laboratories, "Concrete Cylinder Test Reports," dated 01/30/15, 02/13/2015, and 02/19/2015; (d) Engineering Surveys and Services Testing Laboratories, "Concrete Cylinder Test Reports," dated 12/04114, 12/05/14, 12/10/2014, and 12/12/14.

Category: Concrete Quality Topic: Corrosion Protection Reference: ACI 318, Sect 4.4.1 Code Year 2005 Requirement For corrosion protection of reinforcement in concrete, maximum water soluble chloride ion concentrations in hardened concrete at ages from 28 to 42 days contributed from the ingredients including water, aggregates, cementitious materials, and admixtures shall not exceed the limits of Table 4.4.1. The testing shall conform to ASTM C 1218.

Page 14 of27

Observation: A sample of the UMAX top pad mix design, which included all ingredients, was tested to have a maximum chloride ion concentration of 0.06% by weight of cement, which is far below the ACI limit of0.15%. The lab results were documented in CTL Group Water-Soluble Chloride Test Report, dated February 13, 2015 .

Documents (a) CTL Group, Water-Soluble Chloride Test Report, dated February 13, 2015.

Reviewed:

Category: Concrete Quality Topic: Fly Ash Reference: ACI 318, Sect 3.6.6 Code Year 2005 Requirement Fly ash or other pozzolans used as admixtures shall conform to ASTM C 618,

"Specification for Fly Ash and Raw or Calcined Natural Pozzolans for Use in Portland Cement Concrete.

Observation: The fly ash used in the mud mat under the SFP and in the SES components of the Holtec HI-STORM UMAX ISFSI met the ASTM C 618 requirements for Class C fly ash.

Project Specification 033000, Step 2.1.A.3 specified that certified mill test reports for fly ash used in all concrete shall conform to ASTM C 618 Class F. NRC inspectors reviewed laboratory test report data on the fly ash used during construction of certain components of the HI-STORM UMAX ISFSI. That data showed that the fly ash used by Holtec did not comply with the requirements of ASTM C 618 for Class F fly ash.

ASTM C 618 calls for fly ash to have a minimum combined oxide amount of70.0%

(consisting of total silicon dioxide, aluminum oxide, and iron oxide). The lab test results for the fly ash used by Holtec showed that the combined oxide amounts were 65 .41 %.

Therefore, the fly ash that was used qualified as Class C, but not Class F. This nonconformance was brought to Holtec's attention and was addressed in field condition report (FCR) FCR-2253-DCP02-002 and engineering design change request (EDCR)

EDCR-2253-DCP 02-059. The FCR was used to address the use of Class C fly ash in the mud mat for the SFP. The FCR concluded that the mud mat was not important to safety (NITS), served no structural function, and that the use of Class C fly ash in the mud mat was acceptable and no remediation was necessary. The EDCR was used to address the use of Class C fly ash in the SES which is an important to safety (ITS)

component of the HI-STORM UMAX ISFSI. The EDCR approved the use of Class C fly ash in the SES and was issued on November 13, 2014 prior to the first pour of the SES on December 4, 2014.

Documents (a) Callaway ISFSI Project Specification No. 1484040010-S-ISFSI-00001, Section Reviewed: 03300, "Cast-in-place Concrete," Rev. O; (b) Analytical Testing Service Laboratories, Inc. ASTM C 618 and AASHTO M295 compliant test report for Thomas Hill Fly Ash Sample 3000 Ton Composite, dated June 18, 2014; (c) Field Condition Report (FCR)

No. FCR-2253-DCP02-002; (d) Engineering Design Change Request (EDCR) 2253-DCP 02-059.

Category: Concrete Quality Topic: Ground Slag Reference: ACI 318, Sect 3.6.7 Code Year 2005 Requirement Ground-granulated blast-furnace slag used as an admixture shall conform to ASTM C 989, "Specification for Ground Granulated Blast-Furnace Slag for Use in Concrete and Mortars."

Page 15 of27

Observation: The slag used in the concrete to construct the Holtec HI-STORM UMAX ISFSI met the ASTM C 989 standard. NRC inspectors reviewed the Material Certification Report for the slag used in the concrete mix design for the ISFSI project at Callaway. The Holcim, Inc. GranChem brand slag Material Certification Report demonstrated the slag met the requirements of ASTM C 989.

Documents (a) Callaway ISFSI Concrete Mix Design, "4500 PSI with Air With 40% Slag, Mix Reviewed: #457;" (b) Material Certification Report, for Holcim, Inc. GranChem brand slag cement, dated April 1-30, 2014.

Category: Concrete Quality Topic: Water/Cement Ratio Reference: ACI 318, Sect 4.2.2, Table 4.2.2 Code Year 2005 Requirement Concrete that wiIJ be subject to the exposures given in Table 4.2.2 of ACI 318 shall conform to the corresponding maximum water-cementitious materials ratios and minimum strength requirements of that table.

Observation: The concrete supplied for construction of the ISFSI UMAX met the water to cement ratio requirements. Project Specification 03300, Step 2.3 .A. l, required that that the water to cement ratio shall not exceed 0.50 for either the HI-STORM UMAX SFP or top pad. The approved concrete mix designs for the SFP and top pad specified water to cement ratios of0.425 and 0.44, respectively.

NRC inspectors reviewed all of the batch tickets for concrete sampled during the SFP pour observed on November 5, 2014. The water to cement ratios for those concrete batches ranged from 0.39 to 0.43, never exceeding the design specification of 0.50.

NRC inspectors likewise reviewed the batch tickets for the concrete sampled during the January 16, 2015 pour of the top pad, those concrete batches tickets also fell well below the 0.50 design requirement and met the ACI 318 Table 4.2.2 requirements.

Documents (a) Callaway ISFSI Project Specification No. 1484040010-S-ISFSI-00001, Section Reviewed: 03300, "Cast-in-place Concrete," Rev. O; (b) Callaway UMAX [support foundation pad]

Concrete Mix Design. "4500 PSI with Air with 40% Slag, Mix #457," with retarder, w/c

= 0.425; (c) Callaway ISFSI [top pad] Concrete Mix Design, "4500 PSI with Air with 40% Slag, Mix #457," with set-accelerating admixture, w/c = 0.44.

Category: Concrete Reinforcement Topic: Field Bending of Bars Reference: ACI 318, Sect 7.3.1 Code Year 2005 Requirement Reinforcement partially embedded in concrete shall not be field bent, except as shown on the design drawings or permitted by the engineer.

Observation: ACI 318-05, Section 7.3 .1 requires that all reinforcement shall be bent cold, unless otherwise permitted by the engineer. Some of the reinforcing bars in the top pad required rebending due to clearance concerns for concrete aggregate flow between the reinforcing bars and the top section of the cavity enclosure containers. Holtec contractor MC International sent 149 of the previously bent #11 bars to Nu Way Inc. for cold bending. Holtec had personnel on site at Nu Way during the additional bending activities and verified that no heat was used during the rebar bending. NRC inspectors reviewed the engineering design. quality plan, and surveillance report related to the Page 16 of27

additional bending required for the top pad. Based on documents reviewed and discussion with Holtec, NRC concluded that the additional bending of rebar at the Callaway site was performed in accordance with the requirements of ACI 318.

Documents (a) MC Industrial Request for Information #0060-0, dated January 9, 2015; (b) Holtec Reviewed: Form QA-14, "Exhibit 7.5.3: Dedication Report and Quality Plan for Fabrication or Services," dated January 12, 2015; (c) Holtec International Surveillance Report MCI/Nu Way Job #S2014-102, dated January 7, 2015.

Category: Concrete Reinforcement Topic: Minimum Bend Diameters Reference: ACI 318, Sect 7.2. Code Year 2005 Requirement The minimum bend diameter, measured on the inside of the bar, shall not be less than the following: for No 11 rebar the minimum bend diameter is 8 bar diameters.

Observation: The NRC inspectors found that the rebar bend diameters met the minimum requirements specified by ACI code. ACI 318-05, Table 7.2 specified the minimum bend diameter for reinforcing bar (rebar) used in concrete as a function of reinforcing bar diameter. NRC inspectors measured the rebar bends while accompanying a Holtec QC inspector at the ISFSI site on July 30, 2014 and again for the top pad rebar on January 5 and 16, 2015.

Specifically, NRC inspectors reviewed the 90 degree bends of the #11 bars used for the SFP design. In this case, the ACI specified minimum bend diameter is 8 times the diameter of the #11 bar or roughly 12 inches (to be conservative). No discrepant rebar bends were identified.

Documents (a) ACI-318, "Building Code Requirements for Structural Concrete and Commentary, "

Reviewed: 2005.

Category: Concrete Reinforcement Topic: Rebar meets UMAX FSAR Requirements Reference: HI-STORM UMAX FSAR Table 2.3.2 Revision 2 Requirement Rebar is of Grade 60 Rebar, Rebar is #11 @9" (each face, each direction) for ISFSI Foundation Pad and ISFSI Top Pad, with a 60 ksi yield strength Observation: The rebar sizing, tensile strength, and spacing for the HI-STORM UMAX ISFSI at Callaway met all applicable standards and specifications. Project Specification 03200, Step 2.1 A required that steel reinforcement bars be ASTM A615 Grade 60. The FSAR required that the bars have minimum yield strength results of 60,000 psi. The NRC inspectors reviewed the certified mill test results (CMTRs) for the reinforcing bars delivered for the Callaway UMAX project. Those CMTRs indicated that all of the rebar received for the UMAX project had yield strength results that exceeded 60,000 psi.

Visual inspection of the reinforcement rebar verified that the rebar had the required markings for # 11 grade 60 bars.

The Holtec HI-STORM UMAX FSAR Table 2.3.2 lists the required spacing for #11 rebar in the SFP and the top pad as 9 inches (each face, each direction). Holtec International Drawing No. 8961 incorporated these requirements and provided a tolerance of+/- 1 inch. An engineering design change request, EDCR-2253-DCP 02-074, was initiated by Holtec to relax the indicated tolerances from +/-1 inch to+/- 3 inches by applying the standards of ACI-1 17, Section 2.2.5. Section 2.2.5 required spacing Page 17 of27

tolerances of+/- 3 inches for reinforcements in concrete slabs that are not pre-stressed.

EDCR-2253-DCP 02-074 was accepted by Holtec on December 21, 2014.

Documents (a) Callaway ISFSI Project Specification No. 148404001 O-S-ISFSI-00001, Section Reviewed: 03200, "Concrete Reinforcement," Rev. O; (b) Holtec HI-STORM UMAX Final Safety Analysis Report, Rev. 2; (c) Certified Mill Test Reports from CMC Steel Texas, Roll Dates for May 3, 2014, June 8, 2014, and July 15, 2014; (d) Holtec International Drawing No. 8961, "Cask Storage (ISFSI) Pad Details;" (e) Engineering Design Change Request (EDCR) EDCR-2253-DCP 02-074, Rev O; (f) ACI-117, "Specification for Tolerances for Concrete Construction and Materials," 2010.

Category: Concrete Reinforcement Topic: Reinforcement Cover 1 Reference: ACI 318, Sect 7. 7.1 (b) Code Year 2005 Requirement For concrete permanently exposed to earth or weather, a minimum concrete cover of2 inches shall be provided for number 6 through 18 reinforcement.

Observation: NRC Inspectors verified that the licensee provided a minimum of two inches of clear cover between the outside edge of the reinforcing bars and the formwork for where the concrete would be permanently exposed to earth or weather. The areas verified by the NRC inspectors included the SFP sides and the top surface of the top pad. This requirement was specified in the Holtec Drawing 8961.

Documents (a) Holtec Drawing 8961, Project Spec 2253 "Cask Storage (ISFSI) Pad Details," Rev. 2.

Reviewed:

Category: Concrete Reinforcement Topic: Reinforcement Cover 2 Reference: ACI 318, Sect 7.7.l(a) Code Year 2005 Requirement For Concrete cast against and permanently exposed to earth, a minimum concrete cover of 3 inches shall be provided for reinforcement.

Observation: Inspectors verified that the licensee provided a minimum of three inches of clear cover between the outside edge of the reinforcing bars and the ISFSI mud mat where the concrete was cast against the earth. The three inch clearance was verified prior to the first pour of the bottom SFP section on November 5, 2014. This requirement was specified in Holtec Drawing 8961 and in the Holtec UMAX FSAR in Table 2.3.2.

Documents (a) Holtec Drawing 8961, Project Spec 2253, "Cask Storage (ISFSI) Pad Details," Rev.

Reviewed: 2; (b) Holtec UMAX Final Safety Analysis Report, Rev 2.

Category: Concrete Sampling Topic: Composite Sampling Reauirement 1 Reference: ACI 318, Sect 5.6.3.1. Code Year 2005 Requirement Samples for strength tests shall be taken in accordance with ASTM C 172 "Method of Sampling Freshly Mixed Concrete."

Observation: Concrete sampling operations were observed by NRC inspectors to conform to ASTM C 172 requirements. Holtec Procedure HSP-186, step 6.4 required that concrete should be tested as specified by ASTM C 172. HSP-186 steps 7.3.2 and 7.3.3 required that concrete for sampling should be acquired after 15% and before 85% of the mixer drum has been discharged. The NRC inspector verified during the observed portion of the SFP Page 18 of27

and top pad placements that the concrete sampling practices employed on site adhered to the requirements specified in the standard and procedure. Tests for slump, temperature, air entrainment, and unit weight were performed at the prescribed required intervals.

Documents (a) Holtec Procedure HSP-186, "Aggregate and Ready Mixed Concrete Testing Reviewed: Requirements for ITS "B" Applications," Rev. 19; (b) ASTM C 172, "Standard Practice for Sampling Freshly Mixed Concrete," 2014.

Category: Concrete Sampling Topic: Composite Sampling Requirement 2 Reference: ASTM C 172, Sect 4.1 Edition 2014 Requirement The elapsed time shall not exceed 15 min. between obtaining the first and final portions of the composite sample.

Observation: Concrete sample testing was observed to have been performed within the required time frame. ASTM C 172, Section 4.1 required that the elapsed time between the first and final portions of concrete composite sampling for slump, air entrainment, and temperature not exceed 15 minutes. Additional requirements were that the concrete tests start within 5 minutes of taking the final portion of the composite sample and that molded specimens for strength testing be started within 15 minutes following the completed composite sample. The Engineering Survey and Services (ESS) Test Procedure, step 4 indicated that the time between the initial and final portions of composite sampling shall in no instance exceed 15 minutes.

NRC inspectors observed concrete sampling activities during the SFP placement on November 5, 2014, the CLSM placement on December 6, 2014, and the top pad placement on January 16, 2015. The concrete technicians performed sampling, testing, and molded 6 inch by 12 inch cylinders for strength testing within the 15 minute time envelope consistently. The sampling events were scheduled in accordance with the requirements ofHoltec Procedure HSP-186.

Documents (a) Holtec Procedure HSP-186, "Aggregate and Ready Mixed Concrete Testing Reviewed: Requirements for ITS 'B' Applications," Rev. 19; (b) Engineering Survey and Services (ESS) Test Procedure, "Sampling Fresh Concrete," Rev. O; (c) ASTM C 172, "Standard Practice for Sampling Freshly Mixed Concrete," 2014.

Category: Concrete Sampling Topic: Composite Sampling Requirement 3 Reference: ASTM C 172, Section 5.2.3 Edition 2014 Requirement Sample the concrete by collecting two or more portions taken at regularly spaced intervals during discharge of the middle portion of the batch. Do not obtain samples until after all the water has been added to the mixer; also do not obtain samples from the vety first or last portions of the batch discharge.

Observation: NRC inspectors confirmed that the concrete technicians followed the sampling requirements of ASTM C 172 for each of the three sections of the UMAX ISFSI which were observed. ASTM C 172, Section 5.2.3 required that concrete composite samples for testing not be taken from the first 15% or last 15% of the concrete truck's drum discharge. NRC inspectors observed concrete sampling activities during the SFP placement November 15, 2014, the placement ofCLSM on December 4, 2014, and the Page 19 of27

top pad placement on January 16, 2015. Each composite sample was taken after the initial discharge into the ISFSI structure and prior to final discharge. At the time of each observed sample, the discharge chute was diverted to the two wheel barrows used by the sampling technicians. Each wheel barrow was half filled in tum and then filled completely in tum prior to sample testing.

Documents (a) Engineering Survey and Services (ESS) Test Procedure, "Sampling Fresh Concrete,"

Reviewed: Rev. O; (b) ASTM C 172, "Standard Practice for Sampling Freshly Mixed Concrete,"

2014.

Category: Concrete Sampling Topic: Field Technician Requirements Reference: ACI 318, Sect 5.6.1 Code Year 2005 Requirement The field technicians making and curing specimens for acceptance testing shall be certified ACI Field Testing Technicians, Grade I or equivalent.

Observation: All concrete technicians utilized by the licensee possessed an ACI Concrete Field Testing Technician Grade 1 certification ID card. The testing certification requirement was specified in Holtec procedure HSP-186 Step 5.3.6. All personnel used during the concrete placement operations for making and curing concrete specimens were verified to be certified ACI Field Testing Technicians. Three individuals were perfonning the concrete sampling during concrete placement for the SFP, SES, and top pad. The NRC inspector reviewed the training certificates of all technicians used during the construction of the Holtec HI-STORM UMAX ISFSI at Callaway. All were suitably qualified.

Documents (a) Holtec Procedure HSP-186, "Aggregate and Ready Mix Concrete Testing Reviewed: Requirements for ITS 'B' Applications," Rev 19; (b) ACI Certification ID #00061976, Expires 03/05/2016; (c) ACI Certification ID #00061976, Expires 03/05/2016; (d) ACI Certification ID #01165725, Expires 04/07/2019; (e) ACI Certification ID #01270445, Expires 06/22/2018.

Category: Concrete Sampling Topic: Initial Sample Curing Reference: ASTM C 31, Section 10 .1.1 Edition 2012 Requirement If the specimens cannot be molded at the place where they will receive initial curing, immediately after finishing move the specimens to an initial curing place for storage.

Lift and support the cylinders from the bottom of the molds. Immediately after molding and finishing, the specimens shall be stored for a period up to 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> in a temperature range from 60 and 80 degrees F. Record the temperature using a maximum-minimum thermometer.

Observation: ASTM C 31, Section 10.1.1 required that if concrete specimens cannot be molded atthe place where they will receive initial curing, to immediately after finishing move the specimens to an initial curing place for storage. It was further stated that upon finishing, the specimens be stored for a period up to 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> in a temperature range from 60 to 80 degrees F. This requirement is mirrored in the Engineering Survey and Services testing procedure and Holtec Procedure HSP-186, Exhibit 9.9.

NRC inspectors observed concrete sampling activities on three occasions during the Page 20 of27

construction of the Holtec HI-STORM UMAX ISFSI at the Callaway site. On all occasions the concrete specimens were stored onsite near the location where they were formed. Adjacent to the concrete testing station and cylinder molding area was a sample curing hut that had been built onsite for temporary storage. The curing hut was cooled in the summer and heated during the winter. On the wall of the hut were devices that monitored ambient temperature and tracked the time. During the initial concrete placement for the SFP, NRC inspectors discovered that the curing hut heaters were not operating for the first hour of use that day. The temperature in the hut was measured to be 56 degrees F. Two sets of concrete samples were inside the cure hut at the time, MOCON ticket #35994 and Central Concrete ticket #424. Once identified, the problem was resolved by the licensee and Holtec by plugging the heaters into an electrical source. The incident was written up in FCR #2253-DCP02-013. The resolution was to verify that the concrete samples in question met the 28-day cylinder break test requirement of 4,500 psi. NRC verified that the concrete samples in question passed the 28-day break test benchmark of 4,500 psi. NRC inspectors reviewed cure hut data logs which showed that at no other time did the temperature go below 60 or exceed 80 degrees F while storing concrete samples. This failure constitutes a violation of minor significance and is not subject to formal enforcement action in accordance with 2.3 of the Enforcement Policy. *

Documents (a) Holtec Procedure HSP-186, "Aggregate and Ready Mixed Concrete Testing Reviewed: Requirements for ITS 'B' Applications," Rev. 19; (b) ASTM C 31, "Standard Practice for Making and Curing Test Specimens in the Field" Edition 2012; (c) Engineering Survey and Services Test Procedure, "Making and Curing Concrete Test Specimens in the Field," Rev. 0.

Category: Concrete Sampling Topic: Making & Curing Test Specimens Reference: ACI 318, Sect 5.6.3.2. Code Year 2005 Requirement Cylinders for strength tests shall be molded and laboratory-cured in accordance with ASTM C 31 "Practice for Making and Curing Concrete Test Specimens in the Field."

Observation: Concrete testing cylinders were molded in accordance with the ASTM C 31 standard.

Project Specification Section 01410, Step 3.3.C.2 and C.S .. required the taking and storage of samples of concrete to follow ASTM C 31 requirements. Holtec Procedure HSP-186, Step 6.5 required the concrete cylinders to be prepared and cured in accordance with ASTM C 31. NRC inspectors observed the testing personnel follow the requirements of ASTM C 31 during sampling activities that took place on November 5, 2014 for the SFP and on January 16, 2015 for samples made on concrete operations for the top pad.

Documents (a} Callaway ISFSI Project Specification No. 1484040010-S-ISFSI-00001, Section Reviewed: 01410, "Testing Services," Rev. 2; (b) Holtec Procedure HSP-186, "Aggregate and Ready Mix Concrete Testing Requirements for ITS 'B' Applications," Rev 19; (c) ASTM C 31, "Standard Practice for Making and Curing Test Specimens in the Field," 2012.

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Category: Concrete Sampling Topic: Required Number of Strength Samples Reference: ACI 318, Sect 5.6.2.1 Code Year 2005 Requirement Samples for strength tests of each class of concrete placed each day shall be taken not less than once a day nor less than once for each 150 cubic yd of concrete, nor less than once for each 5,000 square ft of surface area for slabs or walls.

Observation: The required number of strength test samples were taken for concrete activities assoc_iated with the SP and the top pad. Holtec Procedure HSP-186 "Aggregate and Ready Mix Concrete Testing Requirements for ITS "B" Applications," Rev 19, Step 6.2 established a sampling frequency consistent with the ACI requirements. NRC inspectors observed the licensee performing the sampling of the concrete in accordance with the HSP-186 procedure.

Documents (a) Holtec Procedure HSP-186, "Aggregate and Ready Mix Concrete Testing Reviewed: Requirements for ITS 'B' Applications," Rev 19.

Category: Pad Deshm Topic: Density of the SFP. SES. and Top Pad Reference: Holtec HI-STORM UMAX FSAR Table 2.3.2. Revision 2 Requirement The UMAX support foundation pad (SFP) and the UMAX top pad shall have a minimum density of 150 pcf. The self-hardening engineered subgrade (SES) shall have a minimum density of 120 pcf.

Observation: The density specification for the SFP and top pad were changed by Holtec from the 150 pcf specified minimum density to 120 pcf for the SFP and 13 5 pcf for the top pad. The SES minimum density requirement remained at 120 pcf.

The minimum density requirement for the SFP was changed from 150 pcf to 120 pcf through Holtec Evaluation, "10 CFR 72.48 Screening #1079," dated July 22, 2014. The evaluation documented that the SFP only performs a structural function, and as such, reducing the density requirement did not impact the structural integrity of the SFP as long as the minimum concrete compressive strength was maintained. The reduction in the concrete density could slightly reduce long term settlement because the overall weight of the structure would be slightly reduced. Additionally, the 72.48 screen determined that the shielding effectiveness of the UMAX ISFSI structure is not reduced because the SFP does not act as a radiation shield for dose rates at ground level.

The density of the concrete for the SFP was measured during concrete placement sample testing. NRC inspectors reviewed the testing data for all sections of the SFP. Testing results showed that none of the concrete placed had densities below 120 pcf. The testing results documented the samples as having a density between 141. 7 pcf and 148.3 pcf.

The density of the SES was determined by the testing samples taken during concrete placement of the CLSM. NRC inspectors reviewed the test results for the first three feet of CLSM placement. The density of the CLSM was documented as ranging from 134. 7 pcf to 138.9 pcf, exceeding the minimum density requirement of 120 pcf specified in the FSAR.

The minimum density requirement for the top pad was changed from 150pcfto135 pcf Page 22 of27

through Holtec Evaluation, "10 CFR 72.48 Full Evaluation # 1100," dated November 25, 2014 and Engineering Change Order (ECO) #5021, dated November 21, 2014. The evaluation stated, reducing the density requirement did not impact the structural integrity of the top pad as long as the minimum compressive strength was maintained. The reduction in the density could slightly reduce the effects of settlement because the overall weight of the structure would be slightly reduced. The evaluation determined that the proposed change would result in a slight decrease to the concrete density of the top pad, which would result in an insignificant impact to the overall shielding effectiveness of the HI-STORM UMAX System. The actual concrete density of the UMAX top pad will be considered in the site-specific evaluations.

The density of the top pad was measured during concrete placement sample testing.

NRC inspectors reviewed the testing data for all sections of the top pad. Testing results showed that none of the concrete placed had densities below 135 pcf. The testing results documented the test samples as having a density between 139.1 pcf and 147.3 pcf.

Documents (a) Holtec Evaluation, "10 CFR 72.48 Screening #1079," dated July 22, 2014; (b)

Reviewed: Engineering Surveys and Services Testing Laboratories, "Concrete Cylinder Test Reports," dated 12/04/14, 12/05/14, 12/10/2014, and 12/12/14; (c) Holtec Evaluation,

"10 CFR 72.48 Screening #1079," dated July 22, 2014; {d) Engineering Surveys and Services Testing Laboratories, "Concrete Cylinder Test Reports," dated 12111114; (e)

Holtec Evaluation, "10 CFR 72.48 Full Evaluation #1100," dated November 25, 2014; (f) Holtec Engineering Change Order #5021, dated November 21, 2014; (g) Engineering Surveys and Services Testing Laboratories, "Concrete Cylinder Test Reports," dated 01/30/15, 02/13/2015, and 02/19/2015 .

Category: Pad Desi211 Topic: Subgrade and mud mat Reference: Holtec HI-STORM UMAX FSAR Table 2.3.2 Revision 2 Requirement Average density of the subgrade up to approximately 78 feet below the ISFSI foundation pad shall have the density of 120 pcf and a strain compatible effective shear wave velocity of 485 ft/sec minimum. The soil around the UMAX shall have the density of 110 pcf and strain compatible effective minimum shear wave velocity of 450 ft/sec minimum Observation: Callaway's UMAX ISFSI soil properties around and beneath the UMAX met the FSAR design requirements. The UMAX ISFSI is located "Plant East" of Unit I in an area that was a proposed location for Unit 2, which was never constructed. The Unit 2 proposed area served as a storm water detention basin for the plant and was originally filled with water. At Callaway, the standard plant floor elevation for safety related structures is at elevation 2,000 feet, plant datum. This equates to approximately 840 feet above mean sea level (MSL). Once the water was removed the site topography around the excavation area was generally flat with the top area being approximately 2,000 feet per plant datum, and the bottom of the excavation area being generally flat at 1,983 feet elevation.

A Geotechnical Data Report CEC-RP 001-01, "Callaway Energy Center ISFSI,"

Revision 1, was prepared by GEI Consultants Inc. The purpose of the report was to present the geotechnical field and laboratory data on soil and rock obtained for the Page 23 of27

design and construction of the proposed ISFSI. The report contained analyses of the field explorations, which included boring and geophysical testing of the ISFSI location.

Eleven boring locations were selected for analysis. Four of those borings were drilled through the bedrock to approximately 66 to 70 feet below the 1,983 ft elevation {plant elevation of 1,917 to 1,912 feet). The other seven borings went down from the 1,983 ft elevation till bedrock was struck at approximately 17 to 32 feet down, depending on the location of the bore sample. The borehole locations and depths were chosen to comply with the guidance in Appendix C of Regulatory Guide 3.73, "Site Evaluation and Design Earthquake Ground Motion for Dry Cask Independent Spent Fuel Storage and Monitored Retrievable Storage Installations," and Regulatory Guide 1.132 "Site Investigations for Foundations of Nuclear Power Plants."

At the bore hole locations cross-hole seismic surveys were performed to determine shear wave velocity, compression wave velocity, and the material properties of the then current soil and bedrock below the proposed ISFSI location. Hager-Richter Geoscience, Inc.

performed a cross-hole seismic survey at borings positions located at the proposed ISFSI location. The purpose of the survey was to measure the shear wave velocity and compression wave velocity of the soil and rock. The results were presented in Attachment E of the GEI report CEC-RP 001-01. The surveys concluded that the average shear wave velocity exceeded the FSAR required minimum values of 485 ft/sec at approximately 7.5 feet below the 1983 feet elevation. Values ranged from 572 ft/sec at 7.5 feet down to 6,000 plus ft/sec at 64 feet down from the 1983 feet elevation. These results exceed the FSAR requirements.

Results from the bore samples determined the first layer of soil was classified as modified loess, deposited as wind-blown silt, but altered by weathering to a mottled brown gray. The next layer was described as accretion gley, a deposit of gray silty clay.

The following layer was described as glacial till, distinguished by the presence of significant quantities of silt, sand, and gravel. The following layer of subgrade was determined to be Graydon Chert Conglomerate, consisting of rock fragments in a mudstone matrix, followed by the limestone bedrock.

In order to set the UMAX on suitable soil, approximately 13 feet of soil needed to be removed from the 1,983 elevation level (the bottom of the Unit 2 area storm water detention basin) to ensure the UMAX would reside solely on the glacial till subgrade.

The unit weight for the glacial till, 130 pcf, was selected based on published values for similar material in the Manual on Estimating Soil Properties for Foundation Design, edition 1990 published by Electric Power Research Institute. A unit weight of 140 pcf, was selected for the Graydon Chert Conglomerate layer which varied from about elevation 1,967 to 1,950 feet. A unit weight of 160 pcf was selected for the limestone bedrock which was below the conglomerate layer. Once the licensee removed the 13 feet of soil to the 1,970 elevation, the unit weight of the remaining soil beneath the UMAX exceeded the FSAR minimum requirement of 120 pcf.

Since the proposed bottom of the SFP was to be located at the 1,977 elevation, the licensee placed approximately 7 feet of Engineered Fill (also know as Structural Fill)

once the proposed location had been excavated 13 feet down to the 1970 elevation mark.

The Engineered Fill consisted of sand and gravel or crushed limestone. The Engineered Page24 of27

Fill was required to he compacted to 95% of maximum dry density per ASTM D 1557,

"Standard Test Methods for Laboratory Compaction Characteristics of Soil Using Modified Effort." NRC inspectors reviewed the ASTM D 1557 compaction test report and verified by review of nuclear density test results that the licensee had placed and compacted the Engineered Fill as required for the 7 feet of fill that brought the foundation from 1,970 elevation to the 1,977 elevation. Nuclear density tests for the Engineered Fill, perfonned at various locations and varies depths, ranged from 129 to 147 pcf exceeding the FSAR minimum requirement of 120 pcf.

Once the UMAX was constructed, the licensee backfilled three of the sides around the UMAX (plant north, plant west, and plant south sides) with common fill (a mixture of modified loess, accretion gley, glacial till, and Mo Dot Type 3 aggregate). The plant east side was backfilled with Engineered Fill, as this was the location of the "approach apron" which would support the vertical cask transporter when fuel is transferred from the reactor's fuel building. Proctors were perfonned on the common fill to detennine the maximum dry unit weight and optimum moisture content. Project Specifications required the common fill to be compacted to a minimum of95% of the maximum dry unit weight. Nuclear density test reports were reviewed and confinned that the licensee compacted the common and Engineered fill to the required levels, which exceeded the 110 pcf requirement. The shear wave velocity of the common fill was estimated to be greater than 500 ft/sec. The modified loess near the surface (prior to excavation) had a measured shear wave velocity of 500 ft/sec. Since the common fill was a compacted layer of a higher quality backfill the shear wave velocity was assumed to he much greater than the 450 ft/sec requirement listed in the FSAR. The shear wave velocity for the Engineered Fill was evaluated in GE calculation CEC-CS004. GEi consultants selected 1,000 ft/sec as the typical value for well compacted sand and gravel. This value is relatively consistent with the 800 ft/sec value NRC NUREG CR-6855 "Parametric Evaluation of Seismic Behavior of Freestanding Spent Fuel Dry Cask Storage Systems" uses for engineered fill. In each occurrence the common fill and Engineered Fill exceeded the FSAR minimum requirement of 450 and 485 ft/sec.

Documents (a) Holtec HI-STORM UMAX Canister Storage System Final Safety Analysis Report Reviewed: (FSAR), Rev. 2; (b) Geotechnical Data Report CEC-RP 001-01, "Callaway Energy Center ISFSI," Revision 1; (c) GEi Calculation, "Site Response for ISFSI at Callaway Energy Center," dated June 7, 2013; (d) GEI Calculation CS 001-01, "Soil Properties for Design ofISFSI at Callaway Energy Center," dated May 16, 2013; (e) GEi Report,

"Geotechnical Recommendations for Callaway Energy Center ISFSI," dated June 11, 2013; (f) GEI Calculation CEC-CS 005-00, "Liquefaction Resistance and Post-Earthquake settlement for ISFSI at Callaway Energy Center," dated March 18, 2013; (g)

Engineering Surveys and Services, Compaction Test Report, dated June 23, July 14, and July 21, 2014; (h) Engineering Surveys and Services, Field Density Test Reports, dated July 07, July 14, July 15, July 18, July 28, Dec 19, 2014, and January 26, 2015.

Category: Special Topics Topic: Cavity Enclosure Container Placement Reference: Holtec Procedure HPP-2253-110 Revision 0 Requirement That all cavity enclosure containers be properly placed onto the support foundation pad and vertically plumb prior to baseplate grouting and placement of the self-hardening Page 25 of27

engineered subgrade.

Observation: During field construction observations on November 25 and 26, 2014, NRC inspectors observed the offloading, upending, and installation of several CECs onto the Holtec m-STORM UMAX SFP at the Callaway site. The SFP surface had been surveyed and a chalk grid line was established to assist with aligning the CECs atop the SFP in the designed configuration. As directed by the governing procedures, the concrete surface locations for each of the CECs had been roughened and cleaned prior to its placement.

NRC inspectors observed the activities to establish the plumpness of each CBC. Vertical plumb measurements were conducted by the use of lasers and a six foot level to ensure the CECs would be level with top pad.

Documents (a) Holtec Procedure HPP-2253-110, "Cavity Enclosure Container (CBC) Offload, Reviewed: Receipt Inspection, and Installation," Rev. 0.

Category: Special Topics Topic: Grout Placement and Sampling Reference: Holtec Procedure HPP-2253-111 Rev.O Requirement Grout shall be placed and tested according to approved procedures and ASTM C 476 and ASTM C 109 standards.

Observation: The 48 cavity enclosure containers (CECs) which were placed on top of the SFP, rested on four leveling screws. The presence of these four leveling screws and foot pads created a minimum void space of 1.75" between each CBC base plate and the SFP on which they rested. Holtec Procedure HPP-2253-111 required the void under the CECs to be grouted to provide the same structural support as the SFP. The grout ensured that each CEC would remain vertically plumb while several lifts of controlled low-strength materials (CLSM) were poured to fill the ISFSI middle section by approximately 17 feet and enclosing the space in the ISFSI structure between and around the CECs. The placed grout would help ensure that the CECs would resist lifting while the CLSM was placed.

During field observations on November 25 and 26, 2014, NRC inspectors observed grout placement and sampling activities at Callaway for the Holtec ill-STORM UMAX ISFSI. Square forms, roughly 9 feet on edge, were installed around each CBC base for containing the grout. The SFP pad surface in the areas where the CECs had been placed were roughened prior their placement and the grout placement operations. This roughened surface was wetted by procedure prior to placement of the grout. Excess surface water was removed with a shop vac. Five Star 100 non-shrink grout was pumped around and beneath the base of each CECs. NRC inspectors observed that the grout was pumped into the forms primarily from one side to prevent air pockets from forming beneath the CBC base. The grout was placed until it reached about 0.5 inches over the bottom lip of the CEC base plate. At the midpoint of each CEC grouting operations, a sample was taken directly from the pump discharge into a 6" by 12" concrete test cylinder as a vessel from which the testing personnel used to prepare 2" by 2" grout sample cubes. NRC inspectors observed that the technician followed the proper procedures when preparing grout test cubes. These cubes once prepared were taken to a heated enclosure onsite for storage till preparations were made to send the samples to a testing lab. The number of samples taken was in compliance with ASTM standards and the Holtec procedure.

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Once the grout forms were filled, the surface was covered to protect against cold weather conditions. A mobile ground defroster unit was onsite from which water was circulated through hoses around and atop the forms to keep the temperature above 40 degrees F.

The heat of hydration and use of the mobile defroster were sufficient to keep the placed grout above 40 degrees F. The mobile defroster unit was used throughout the night to allow the grout to cure at the appropriate temperature.

Documents (a) Holtec Procedure HPP-2253-111, "Cavity Enclosure Container (CEC) Base Plate Reviewed: Grouting, 11 Rev. O; (b) Callaway ISFSI Project Specification No. 1484040010-S-ISFSI-00001, Section 03600, Non-shrink Gout, "Rev. O; (c) ASTM C 476, "Standard Specification for Grout for Masonry, 11 201 O; (d) Five Star Fluid Grout 100 manufacturers' data sheet; (e) Mortar Cube Test Reports dated December 2-9, 2014, December 29-31, 2014, and January 6, 2015.

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