Exhibit B- Basis of Design Report.pdf

FermiForward

Fermilab Utilities Infrastructure Project:

Kautz Road Substation Basis of Design Report Reference: Task Order 5

100% Final Design | November 13, 2025

© Keys Photography

This report takes into account the particular instructions and requirements of our client. It is not intended for and should not be relied upon by any third party and no responsibility is undertaken to any third party.

Job number 288168-06

Arup US, Inc.

35 East Wacker Drive, Suite 1800 Chicago, IL 60601

USA

arup.com

Task Order 5 | 100% Final Design | November 13, 2025 | Arup US, Inc.

Contents

1. Introduction 1

1.1 Purpose 1

1.2 Project History 1

2. Substation Electrical 2

2.1 Transformer T-85 2

2.2 Secondary Cable Bus 2

2.3 Control Building 3

2.4 Circuit Breaker CB 119 6

2.5 Motor Operated Disconnects 7

2.6 Capacitor Coupled Voltage Transformer 7

2.7 Harmonic Filters 7

2.8 Grounding 8

2.9 13.8kV Feeder Replacement 8

2.10 Temporary Construction Power 10

2.11 Firewall Placement 10

3. Structural 12

3.1 Evaluation of Existing Control Building 12

3.2 Fire Wall Construction 15

3.3 Relocated Light and Static Poles 16

3.4 Oil Containment 16

3.5 New Standby Generator 16

3.6 New Permanent Prefabricated Telecom Building 16

3.7 Harmonic Filter Pad 17

3.8 Transformer T-85 17

3.9 Circuit Breaker CB-119 18

3.10 New Auxiliary Transformer 18

3.11 New Cable Bus 18

3.12 Motor Operated Disconnects MOD-85, MOD-86, MOD-87, and MOD-88 18

4. Geotechnical 19

4.1 General 19

4.2 Design Basis 19

4.3 Ground Conditions and Geotechnical Design Parameters 19

4.4 Freeze-Thaw 20

4.5 Seismic Design Parameters 20

4.6 Shallow Foundations 20

4.7 Deep Foundations 20

4.8 Foundation Re-Use 21

4.9 Pavement 21

4.10 Retaining Walls and Lateral Earth Pressure 21

4.11 Drainage 21

4.12 Earthworks 22

4.13 Electrical Considerations 22

4.14 Trenchless Technologies 22

4.15 Transformer Oil Containment Volume 22

5. Civil 23

5.1 Site Constraints 23

5.2 Storm Drain 23

5.3 Accelerator Campus Feeder Extension 24

5.4 Fencing 24

5.5 Asphalt Paving 24

5.6 Containment 24

5.7 Wetlands 25

Tables

Table 2-1: Replacement of Harmonic Filters 7

Table 2-2: Main Injector Feeder Replacement Summary 9

Table 2-3: Recommended Separation Distances 10

Table 3-1: Firewall Design Options 15

Table 4-1: Structural Components on Shallow Foundations 20

Table 4-2: Structural Components on Deep Foundations 21

Table 5-1: New Oil Containment Calculations 25

Figures

Figure 2-1: Existing CB 119 Nameplate 6

Figure 2-2: Harmonic Filter Single Line Diagram 8

Figure 3-1: Top of Basement Wall Detail - North and East Walls 13

Figure 3-2: Top of Basement Wall Detail - South Wall 13

Figure 3-3: Basement Wall Conduit Penetration Spacing 14

Figure 3-4: Drilled Pier Section 15

Figure 3-5: Harmonic Filter Pad Replacement Plan 17

Appendices

Appendix A A-1

Existing Conditions Report A-1

Appendix B B-1

Vendor Information B-1 B.1 Power Bus Way – 13.8kV Cable Bus B-2 B.2 Crown – 13.8kV Arc Resistant Switchgear B-3 B.3 Southern States – 345kV Motor Operated Disconnect B-4

Appendix C C-1

Geotechnical Desk Study Technical Notes C-1

Appendix D D-1

Requirements List D-1

Appendix E E-1

Temporary Construction Power E-1

Appendix F F-1

Preliminary Geotechnical Design Technical Note F-1

Appendix G G-1

Geotechnical Engineering Report G-1

Kautz Road Substation

Task Order 5 | 100% Final Design | November 13, 2025 | Arup US, Inc. Basis of Design Report Page 1

1. Introduction

1.1 Purpose

This report is provided to communicate key elements and design considerations to facilitate preparation of design documents for the substation upgrade works at Kautz Road Substation (KRS); a part of Fermi Forward

Discovery Group, LLC’s (FermiForward) larger sitewide utility infrastructure upgrades program at Fermilab.

This document serves to define scope and forms the basis for the design which will be documented in the final design package.

1.2 Project History

The KRS upgrades project is based on works defined in the Conceptual Design Report (CDR) prepared by

Jacobs in July 2020. This CDR was used by FermiForward to establish the programmatic baseline and costs for the project and establish CD-1.

Arup US, Inc (“Arup”) was subsequently commissioned by FermiForward to provide 30% preliminary design services for upgrades at KRS based on a Statement of Work (SoW) for Architectural/Engineering professional services dated November 2, 2022. This SoW and additional information provided by FermiForward clarified the recommendations of the CDR as it regards the KRS, and focused 30% preliminary design activities on the study of two (2) key decision criteria as follows:

1. Evaluation of oil containment facilities code compliance.

2. Equipment separation requirements and fire wall installation.

Arup, alongside subconsultant Primera Engineers Ltd. (“Primera”), completed the 30% preliminary design in

February 2023.

The results of the 30% design informed the design criteria that were used as inputs into the next design phase defined by the Fermilab SoW entitled “Task 02 – Engineering Phase 2 CD-2/3A Preliminary Design of Kautz

Road Substation” and additional clarifying information provided by FermiForward. The existing conditions described in the Existing Conditions Report included in Appendix A were also considered in the design development. The 100% preliminary design, including the CD-2 package as well as the CD-3A and CD-3B advanced procurement packages for selected equipment, was completed by Arup in October 2024.

The current design phase is defined by Fermilab SoW entitled “UIP Subproject 2 – Kautz Road Substation

Replacement Statement of Work (SOW) – New Task Release for Final Design of Kautz Road Substation

Replacement.” The focus of this stage of the project is to create a 100% Final Design set of documents for construction.

Task Order 5 | 100% Final Design | November 13, 2025 | Arup US, Inc. Basis of Design Report Page 2

2. Substation Electrical

Substation electrical engineering work for the design was focused on the replacement of the following existing substation equipment:

• 345/13.8kV transformer T-85

• 13.8kV bus duct; to be replaced with 13.8kV cable bus routed from all four transformer secondaries to the control building

• Prefabricated control building including 13.8kV arc resistant switchgear, relay control panels, and 125VDC battery systems

• Control building auxiliary transformer and generator

• 345kV circuit breaker CB 119

• 345kV motor operated disconnects MOD-85, MOD-86, MOD-87, and MOD-88

• 345kV capacitor coupled voltage transformers CCVT 119-1 and CCVT 119-2

• 13.8kV harmonic filters TRANS T-86, TRANS T-87, TRANS T-88

• 13.8kV feeders

2.1 Transformer T-85

During 30% preliminary design, the replacement of existing transformer T-85 (T-85) was identified as a critical path item due to procurement lead time as well as the overall impact to site design for oil containment, foundations, and secondary routing.

T-85 is being replaced due to its age and existing conditions. It is assumed that the existing foundation will be reused.

T-85 is currently a 3-winding transformer; however, it has been determined by FermiForward that a conventional

2-winding transformer will be used as the replacement with the following ratings:

• 345kV to 13.8kV

• 40/53/66.6MVA, ONAN/ONAF/ONAF

• Suitable for pulsed load

Virginia Transformer / Georgia Transformer is the awarded vendor for the T-85 replacement. Their draft shop drawings were used as the basis of design. The design must be revisited and updated based on the final shop drawings, which were not available at the time of this submission.

Short circuit levels were checked in ETAP using updated fault information provided by ComEd (including 30% future growth) and the resulting fault levels were less than the specified short circuit ratings of 40kA for T-85 on both the primary and secondary.

2.2 Secondary Cable Bus

The existing 13.8kV overhead bus ducts from each transformer secondary to the control building shall be replaced due to their age and existing conditions, including a history of failures. It was decided during 30% preliminary design that the bus ducts will be replaced with cable bus.

Task Order 5 | 100% Final Design | November 13, 2025 | Arup US, Inc. Basis of Design Report Page 3

2.2.1 Proposed Cable Bus Sizing

The cable bus design shall use 4-750 MCM copper cables per phase to achieve a 3000A capacity rating. This capacity is based on the current 13.8kV switchgear main bus rating, which is not being modified as part of the new control building scope.

The number of conductors and sizes have been recommended by Power Bus Way, a cable bus manufacturer, and assumes the cable bus will be routed overhead reusing the existing bus duct structures. Refer to Appendix B.1 for further information from Power Bus Way.

2.2.2 Proposed Cable Bus Routing

The cable bus shall be routed from the transformer secondaries to the 13.8kV switchgear in the control building via overhead structures as shown on drawing E-218.

Prior to installation of the new cable bus, all bus duct secondaries from existing transformers T-85 through T-88 shall be removed. Existing bus duct structures shall be reused (or replaced if condition requires) and modified to provide adequate support for the new cable bus installation.

Each existing transformer secondary housings (T-86, T-87, and T-88) will require modifications to accept new cable bus in place of the bus duct. The awarded cable bus manufacturer shall design new interfaces between the cable bus and transformer secondary housings.

The cable bus shall penetrate the new prefabricated control building wall using a sealed 2-hour fire rated sleeve seal system. Cable bus routing methods inside the control building to the 13.8kV switchgear shall be coordinated with the design of the building and switchgear.

2.3 Control Building

The 13.8kV switchgear within the existing control building shall be replaced with new arc-resistant switchgear with microprocessor-based relays. The installation of arc-resistant switchgear will require reconstruction of the control building structure. It was decided during 30% preliminary design that the existing control building will be replaced with a prefabricated structure containing new switchgear, relay control panels, and 125VDC battery systems, and the existing control building basement structure will be reused. The existing basement has a

35’ x 95’ internal dimension, and there is no need to increase the size of the basement.

The vendor that supplied the prefabricated control building for Fermilab’s Master Substation, Avail Enclosure

Systems, has confirmed that they can manufacture a 125’ x 40’ building (shipping splits to be coordinated). The proposed new control building is 5’ wider than existing. The location and assumed support conditions are described in the structural design in Section 3.

2.3.1 15kV Arc Resistant Switchgear

There are four (4) bus ties at KRS that require visual validation of physical isolation for lockout-tagout (LOTO) purposes, which need to be rated at 3000A and be of arc resistant construction. The existing bus ties are manual operated switches (MOS) but are not arc resistant.

Two options were investigated for the bus ties which are summarized below. Both options are acceptable to

FermiForward.

1. 3000A bus tie switch with LOTO provisions

− Similar to existing KRS bus switches

− Switch would remain connected to the bus when open

− External LOTO key device would need to be incorporated into the door design

− Status of switch position can be monitored via auxiliary position contacts

Task Order 5 | 100% Final Design | November 13, 2025 | Arup US, Inc. Basis of Design Report Page 4

− View of switch open position is available

− The 15kV switchgear is arc resistant rated for personnel safety

2. 3000A bus tie circuit breaker with LOTO provisions:

− Circuit breaker would be racked out of bus connected position via remote operator

− External LOTO key device would need to be incorporated into the door design

− Status of circuit breaker position can be monitored via auxiliary position contacts

− View of circuit breaker disconnect from bus not available

− Shutters provide barrier between the circuit breaker and live bus terminals when in the racked-out position

− The 15kV switchgear is arc resistant rated for personnel safety

Arup reached out to several manufacturers for solutions for both options. Crown Technical Systems can provide arc resistant switches with a viewing window (Option 1), which was used as the basis of design for the control building layout. Refer to Appendix B.2 for further details from Crown on their switchgear offering including equipment dimensions. ABB, Eaton, and Siemens can provide circuit breakers with remote operated integral racking (Option 2), however the required external LOTO key device is still being investigated by these vendors.

Short circuit levels were checked in ETAP using updated fault information provided by ComEd (including 30% future growth) and the resulting fault levels at 13.8kV were less than the specified short circuit rating of 40kA for the medium voltage switchgear.

2.3.2 Auxiliary Transformer & Generator

The existing KRS control building receives auxiliary power from 225kVA transformer TR-KRS-1 via a 400A automatic transfer switch which receives an alternate power source from a 100kW standby generator.

Load calculations were conducted to determine whether this equipment should be upsized based on the intended loads for the new control building. It was determined that the auxiliary transformer will be upsized to 300kVA, and the standby generator will be upsized to 175kW. The new auxiliary transformer will be dry type, so no oil containment is required.

2.3.3 Relay & Communications Systems

The SCADA (Supervisory Control and Data Acquisition) and Communication Network for the 345/13.8kV substation is designed to facilitate efficient, secure, and reliable monitoring, control, and data acquisition of all substation operations. The communication system integrates protective relays, metering devices, and RTUs

(Remote Terminal Units) to ensure seamless interaction with the central control center and other remote interfaces.

2.3.3.1 Network Architecture

The communication network follows a redundant Ethernet-based topology using multiple SEL-2731 managed

Ethernet switches, ensuring high-speed data exchange and minimal latency. The system is designed with fiber optic and copper-based Ethernet connections to provide a robust and noise-immune data transmission medium.

Refer to control building system architecture drawing E-122.

Task Order 5 | 100% Final Design | November 13, 2025 | Arup US, Inc. Basis of Design Report Page 5

2.3.3.2 Devices and Protocols

The SCADA network incorporates a variety of SEL (Schweitzer Engineering Laboratories) devices, including:

• SEL-751 relay for 345kV circuit breaker protection.

• SEL-787 relays for transformer protection.

• SEL-735 power quality meters for accurate monitoring of electrical parameters.

• SEL-487B relay for 345kV differential protection.

• SEL-787 relays for transformer differential protection.

• SEL-751 relays for 13.8kV breaker and feeder protection.

• SEL-787Z relays for 13.8kV bus differential protection.

• SEL-3555 RTAC (Real-Time Automation Controller) for data concentration, automation, and SCADA interface.

• SEL-3620 security gateway for firewall protection and secure remote access.

• SEL-2488 GPS time synchronization device, distributing IRIG-B signals for time-stamped event recording.

The communication protocols include:

• DNP3 and Modbus TCP/IP for SCADA system data exchange.

• IRIG-B timing signals for precise synchronization of all substation events.

2.3.3.3 Time Synchronization

A precise timing system is implemented using SEL-2488 GPS clocks to ensure accurate timestamping of events and synchronized protection operations. The IRIG-B signals are distributed through coaxial and twisted-pair cables to various relays and control devices.

2.3.3.4 Cybersecurity Measures

To ensure a secure and reliable SCADA network, the following cybersecurity measures are implemented:

• SEL-3620 security gateways provide secure encrypted access and firewall protection.

• User authentication and logging for controlled access to SCADA systems.

2.3.3.5 Alarm and Event Monitoring

The system is designed to monitor substation alarms and operational statuses through SEL-2523 Annunciators and event logging mechanisms. All alarms, breaker statuses, and metering data are locally monitored in annunciators and transmitted to the central control center for real-time monitoring and control.

2.3.3.6 Remote Access and Integration

The substation SCADA system is integrated with the remote operation center via secured routers and gateways, allowing real-time remote monitoring, control, and diagnostics. Fiber-optic communication lines ensure high-speed, interference-free data transfer between field devices and the SCADA master station.

Task Order 5 | 100% Final Design | November 13, 2025 | Arup US, Inc. Basis of Design Report Page 6

2.3.3.7 Communication Redundancy

To ensure uninterrupted data communication, the SCADA network is designed with dual redundant Ethernet paths between switches, RTUs, and the control center. The split relay connections across multiple Ethernet switches enhance system reliability and prevent communication failures.

2.4 Circuit Breaker CB 119

It was determined during 30% preliminary design that existing 345kV circuit breaker CB 119 shall be replaced due to its high maintenance cost. It is assumed that the existing foundation will be reused. The nameplate of existing CB 119 is provided in Figure 2-1. Hitachi submitted a bid for the CD-3A advanced procurement package and FermiForward has chosen to move forward with this vendor for a like-for-like replacement of CB

119.

CB 119 is a gas-filled circuit breaker located in the substation yard that is the critical means of protection for

ComEd’s incoming 345kV transmission line. The new circuit breaker will connect to the existing buses on either side of the breaker, and shall be dead-tank design, comprised of three poles with separate support structures for each pole. The new circuit breaker will require a continuous current rating of 2000A.

Short circuit levels were checked in ETAP using updated fault information provided by ComEd (including 30% future growth) and the resulting fault levels at 345kV were less than the specified short circuit rating of 40kA for

CB-119.

Figure 2-1: Existing CB 119 Nameplate

Task Order 5 | 100% Final Design | November 13, 2025 | Arup US, Inc. Basis of Design Report Page 7

2.5 Motor Operated Disconnects

It was determined during 30% preliminary design that existing 345kV motor operated disconnects MOD-85, MOD-86, MOD-87, and MOD-88 shall be replaced due to their age and existing conditions. The height of the new MODs will need to be coordinated with the existing 345kV buses. It is assumed that the existing MOD steel structures will be replaced, and the existing foundations will be reused.

Like the existing MODs, the new MODs will require double end breaks and a continuous current rating of

1600A.

Short circuit levels were checked in ETAP using updated fault information provided by ComEd (including 30% future growth) and the resulting fault levels at 345kV were less than the specified short circuit rating of 40kA for

MODs.

Southern States has been contacted for replacement options for the four (4) MODs. Refer to Appendix B.3 for a drawing of the MOD proposed by Southern States as well as a budgetary quote.

2.6 Capacitor Coupled Voltage Transformer

Due to their age and existing conditions, the replacement of existing 345kV capacitor coupled voltage transformers CCVT 119-1 and CCVT 119-2 is included as an add-alternate bid option in the design. It is assumed that the existing foundations will be reused.

2.7 Harmonic Filters

It was determined during 30% preliminary design that existing 13.8kV harmonic filters TRANS T-86, TRANS

T-87, TRANS T-88 shall be replaced due to their age, existing conditions, and a history of failures.

Refer to Table 2-1 for details on the replacement of the harmonic filters. FermiForward has provided the single line diagram in Figure 2-2 as well as specifications for the harmonic filter reactors, resistors, and capacitors which were used as the basis of design.

Table 2-1: Replacement of Harmonic Filters

Harmonic Filter Replacement Foundation

TRANS T-86 Like-for-like Assumed existing foundation will be reused

TRANS T-87 Like-for-like Assumed existing foundation will be reused

TRANS T-88 Replacement to match TRANS T-86 and TRANS-87 Existing foundation to be replaced

Task Order 5 | 100% Final Design | November 13, 2025 | Arup US, Inc. Basis of Design Report Page 8

Figure 2-2: Harmonic Filter Single Line Diagram

2.8 Grounding

The grounding for the new equipment will be connected to the existing ground grid. The general contractor must ensure that the grounding system for all equipment is intact and connected to the substation ground grid at a minimum of two locations, forming part of the overall mesh. Refer to drawings E-206, E-207, and E-240 for details on the existing and proposed grounding design.

For connecting the new equipment to the existing ground grid, the general contractor shall verify that all riser connections are properly installed and securely connected to the main ground grid. Where feasible, existing risers will be utilized. Once all new equipment has been connected, the contractor must confirm that the overall ground grid resistance complies with IEEE-80 recommendations.

Existing 13.8kV busduct will be replaced with cable bus. The cable bus must be grounded at an interval of

3 feet.

2.9 13.8kV Feeder Replacement

In order to coordinate with the switchgear arrangement of the new control building and eliminate the risk of re-using aging cables, new 750MCM triplexed aluminum cables will be provided at all outgoing circuit breakers.

All existing feeders will be pulled back to the first splice or termination point outside of KRS, and new cable will only be provided between this circuit breaker and this first splice or termination point. The length of each cable will be dependent upon the final switchgear configuration and manhole entry point of each feeder within the cable vault.

Task Order 5 | 100% Final Design | November 13, 2025 | Arup US, Inc. Basis of Design Report Page 9

An optional scope is provided for the complete replacement of all 13.8kV feeders serving the Main Injector. This scope includes in-kind replacement of feeders from their first splice point outside of KRS to their final termination points within the Main Injector campus. Segments of feeders replaced as part of KRS substation base scope are not included in the Main Injector Feeder Replacement package. Select segments of Feeder 52 were identified by FermiForward as being recently installed and consequently removed from scope, totaling approximately 2,900 linear feet of cable. Feeders added to the Main Injector ductbanks as part of the recent

LBNF project are also not included in the replacement scope of work. A summary of feeders and estimated lengths included as part of this scope is provided in Table 2-2 below.

Table 2-2: Main Injector Feeder Replacement Summary

Feeder to be Replaced (Feeder ID)

Approximate Feeder Length (ft)

Feeder 52 7,925

Feeder 53 6,090

Feeder 61A 4,325

Feeder 61B 4,325

Feeder 62A 2,055

Feeder 62B 2,055

Feeder 71A 2,165

Feeder 71B 2,165

Feeder 72A 5,508

Feeder 72B 5,508

Feeder 73A 7,511

Feeder 73B 7,511

Feeder 82 2,856

Feeder 85 2,598

Feeder 94 8,908

Feeder 95 2,225

Feeder 96 6,144

Feeder 97 9,738

Total 89,612

Work within energized electrical equipment, switches, or manholes is prohibited, unless otherwise directed by

FermiForward. Load transfers between feeders and feeder replacements shall be sequenced such that outages to

Main Injector load centers are minimized. Phasing plans are provided within the design drawings to demonstrate power continuity requirements. The Contractor will be responsible for developing their own construction phasing plans based on these requirements and submitting them to FermiForward & Engineer for approval.

Task Order 5 | 100% Final Design | November 13, 2025 | Arup US, Inc. Basis of Design Report Page 10

2.10 Temporary Construction Power

During construction, the KRS control building and switchyard will be de-energized. Temporary construction power will need to be provided to the site from the Fermilab Master Substation. A preliminary construction power sketch was developed to identify locations for temporary power infrastructure, construction staging, and site limitations. The sketch also identifies the recommended MV feeders that could be utilized for a temporary construction electrical service. The Contractor will be responsible for providing temporary electrical distribution equipment to supply construction needs while also maintaining power to critical loads at the KRS site designated by FermiForward, including power to the basement sump pump and to a permanent structure used to house telecommunications equipment. The existing control building transformer can be relocated and reused to step down temporary construction power for the site. De-energization and relocation of the existing control house transformer shall be coordinated with FermiForward. The Contractor shall confirm the available fault current at the temporary power distribution system and utilize distribution equipment with sufficient withstand rating.

Refer to Appendix E for the Temporary Construction Power Sketch.

2.11 Firewall Placement

IEEE 979-2012 “Guide for Substation Fire Protection” outlines substation fire protection practices based on industry standards and best practices. It should be considered the definitive guide for the design of fire protection schemes regarding substation design. Chapter 7 of IEEE 979 provides guidelines for spatial separation distances for outdoor mineral-oil-insulated equipment. Two methods for determining acceptable minimum separation distances are provided: 1) a prescriptive method outlined in Section 7.2, and 2) a performance-based alternative outlined in Section 7.3. The final paragraph of Section 7.1 of IEEE 979 states:

“When it is not practical to apply the recommended spatial separations to new or existing substations, mitigating measures such as firewalls, thermal barriers, flame-suppressing stone ground cover, automatic suppression systems, and the use of less flammable dielectric fluids can be used to reduce spatial separation values while maintaining an adequate level of protection.”

The recommended separation distances from mineral-oil-insulated equipment to buildings and to other mineral-oil-insulated equipment are outlined in Section 7.2.2 of IEEE 979 as summarized in Table 2-3 below.

Table 2-3: Recommended Separation Distances

Mineral oil volume (gal) Separation distance (ft)

<500 Footnote 1

500 to 5,000 25

>5,000 50

1Determining the type of physical separation to be used for mineral oil volumes less than

500 gallons should be based on consideration of the following:

- Type and quantity of oil in the equipment

- Size of a postulated oil spill (surface area and depth)

- Construction of adjacent structures

- Rating and bushing type

- Fire-suppressing systems provided

- Protection clearing time

All existing transformers at KRS have oil volumes exceeding 5,000 gallons. The new Transformer T-85 is anticipated to also have an oil volume exceeding 5,000 gallons. The required separation distance is measured from the edge of the anticipated oil spill of a given transformer to the nearest building surface or piece of adjacent equipment containing oil. When a transformer is surrounded by a containment pit with a concrete curb, the edge of the anticipated oil spill fire is to be taken as the edge of the oil containment pit. Therefore, based on

Section 7.2.2 of IEEE 979, a separation distance of 50 feet from the control building to the inside edge of the nearest oil containment pit would be required. The edge of any portion of transformer equipment containing oil should also be at least 50 feet from the nearest edge of the oil containment pit of the adjacent transformer.

Task Order 5 | 100% Final Design | November 13, 2025 | Arup US, Inc. Basis of Design Report Page 11

The required separation distances of 50 feet for both equipment pit to buildings and equipment pit to equipment cannot be met under the current configuration of equipment and oil containment pits. Therefore, fire barriers are recommended to protect the control building and transformers. Fire barriers consisting of prefabricated panels supported by steel framing from behind are recommend at this site with the following requirements:

• A minimum of 2-hour fire rating.

• Firewall plan dimensions should be sufficient to provide unobstructed sight line distances that match or exceed the required fire separation distances to adjacent oil insulated equipment and/or buildings.

• The firewall height is determined by extending a sight line between the tallest piece containing oil of the transformer under consideration to an adjacent building roof or adjacent piece of oil insulated equipment.

The firewall height should extend at least one foot above the critical sight line to provide the required fire protection. Any unobstructed sight lines to adjacent equipment or buildings with distances exceeding the minimum required separation distances need not be considered. Refer Dwg E-200, E-201 and E-202 for

Firewall location and heights.

• Per IEEE-979, the barrier should extend at least to the outermost boundary of the oil-containment area.

Based on the existing oil containment configuration and control building, a firewall configuration was determined as shown on sheets E-200, E-201, E-202, and S-210. The proposed heights for the new firewalls are

18 feet above grade between the transformer and the control building, and 23 feet between the two transformers.

The two firewalls that separate adjacent transformers will have fireproof cladding on the backside steel.

Two other fire protection standards were also reviewed: NFPA 850, and FM Global Property Loss Prevention

Data Sheets. The proposed firewall layout adheres to the requirements outlined in these standards in addition to

IEEE 979.

Task Order 5 | 100% Final Design | November 13, 2025 | Arup US, Inc. Basis of Design Report Page 12

3. Structural

Structural engineering work for the design was focused on the investigation of the following key project design elements:

1. Evaluation of existing control building.

2. Design of extended control building footprint.

3. Design of foundation for new firewall.

4. Design of new foundation for relocated existing lighting and static pole structures.

5. Design of new extended oil containment pit containment curb.

6. Design of new concrete pad for a new standby generator.

7. Design of new concrete pad for new permanent cabinet for fiber termination.

8. Replacement of harmonic filter pad (Bus 8-1 & 9-1).

9. Evaluation of existing concrete pad of new Transformer T-85.

10. Evaluation of existing concrete pad for a new Circuit Breaker CB-119.

11. Evaluation of existing concrete pad for a new auxiliary transformer.

12. Evaluation of existing bus duct foundation for new cable bus.

13. Evaluation of existing foundations for motor-operated disconnects structures MOD-85, MOD-86, MOD-87, and MOD-88.

3.1 Evaluation of Existing Control Building

3.1.1 Existing Basement Walls

An evaluation of the existing control building basement walls was performed with the existing documents provided by FermiForward. The structural drawings provided did not specify the concrete strength, rebar strength, or design soil pressures. However, the 1996 KRS design calculations show that a concrete strength of

4,000 psi and rebar strength of 60 ksi was assumed. The design soil density of 130 pcf and active pressure coefficient (Ka) of 0.5 were also defined in the calculation package. A live load surcharge of 1,000psf has been applied at ground level, consistent with the 1997 design approach. Based on these assumptions for surcharge and soil loading and the reinforcement shown in the walls, temporary shoring will be required to be installed before the existing Level 1 framing is removed and must remain in place until the new Level 1 framing is installed. The new floor framing will be specified to be designed and fabricated by a prefabricated building manufacturer as part of the control building to resist a factored load of 6 kips/ft applied normal to the top of basement walls.

The existing basement walls and columns will provide support at the base of the new prefabricated building.

According to the existing drawings, a continuous L4x4x3/8 steel angle with ½-inch diameter x 5-inch-longlong welded studs at 18 inches is installed at the top of the basement wall for the original prefabricated building. A positive connection from the new prefabricated building floor beams to the wall can be provided through welding to existing embedded steel angles and adding a new steel plate with post-installed anchorage into the top of wall where required. The prefabricated building reactions shall be provided by the prefabricated building manufacturer for review. The final embed configuration shall be coordinated prior to installation based on the reactions and requirements to be provided by the prefabricated building manufacturer. Refer to Figure 3-1 and

Figure 3-2 below.

Task Order 5 | 100% Final Design | November 13, 2025 | Arup US, Inc. Basis of Design Report Page 13

Figure 3-1: Top of Basement Wall Detail - North and East Walls

Figure 3-2: Top of Basement Wall Detail - South Wall

Task Order 5 | 100% Final Design | November 13, 2025 | Arup US, Inc. Basis of Design Report Page 14

Additionally, new wall penetrations will be required for (12) 5-inch conduits entering the basement from below-grade on the North wall. According to the existing drawings, the existing wall at 12 inches on center vertically and 10 inches on center horizontally. To avoid damaging the existing reinforcement, the conduit spacing will be adjusted as shown in Figure 3-3 to align with the existing rebar layout. The wall shall be scanned for existing rebar prior to drilling holes.

Figure 3-3: Basement Wall Conduit Penetration Spacing

3.1.2 Existing Steel Columns

The existing HSS4x4x3/16 basement columns supporting the floor structure appear to be in sufficient condition for potential reuse. However, the existing steel columns may not have adequate structural capacity for the new loads. Potential sources of increased loading include, but are not limited to, an expanded building footprint, additional control building equipment, and updated building code requirements along with their associated reference standards. The prefabricated building loads shall be provided by the prefabricated building manufacturer for review prior to installation.

3.1.3 Existing Mat Foundation

The existing control building is supported by a 16-inch-thick mat foundation, reinforced with #5 bars spaced at

10 inches on center, both top and bottom, in each direction. Loads applied to the foundation are assumed to be similar to existing. Checks indicate sufficient capacity to support the column loads.Foundation for Control

Building Expansion

The final control building is expected to have a footprint of approximately 40 feet by 125 feet, which exceeds the dimensions of the existing basement. As a result, new foundations will be required. Coordination with prefabricated building manufacturers indicates that the foundations will need to support point loads spaced roughly 12 feet apart.

The prefabricated building reactions shall be provided by the prefabricated building manufacturer for review prior to installation. In the interim, preliminary assumptions have been made regarding the building loads.

However, the final design of the supporting concrete structure remains pending until actual reactions are provided.

Task Order 5 | 100% Final Design | November 13, 2025 | Arup US, Inc. Basis of Design Report Page 15

For the purposes of design without the prefabricated building manufacturer on board, the following factored loads have been applied at the embeds and shafts at the assumed support locations:

Pu = 100 kips (C), 5 kips (T)

Vux = 3.1 kips

Vuy = 6.4 kips

Typical details from the prefabricated building manufacturers show that a 12-inch horizontal steel surface is sufficient to facilitate a field-welded connection to the foundation. A steel embed plate mounted on top of an 18-inch by 18-inch concrete pilaster will be provided at each new spread footing location and on top of the perimeter wall footing. The prefabricated building reactions shall be provided by the prefabricated building manufacturer for review. The final embed configuration shall be coordinated prior to installation based on the reactions and requirements provided by the prefabricated building manufacturer.

New 2' diameter, 40' long pile are proposed to be installed at the grid lines for the extended footprint. This is pending further coordination with the selected prefabricated building manufacturer.

3.2 Fire Wall Construction

3.2.1 Firewall Superstructure

Three firewall types went through schematic design and cost estimates were provided for each type.

Table 3-1: Firewall Design Options

Option 1 Option 2 Option 3

Cast-in-Place Concrete Walls Precast Concrete Walls Prefabricated Walls with Steel Support

Option 3 was selected based on similar work performed previously at the Master Substation.

The design of the prefabricated firewall and supporting steel structure will be by a firewall manufacturer, such as

Durasystems. The columns for the prefabricated walls are assumed to be steel tube sections with cap plates at the top and base plates with anchor bolts for connection to the piers below.

3.2.2 Firewall Foundations

Based on ACI 318-19 13.4.4.2, portions of deep foundation members in air, water, or soils not capable of providing adequate restraint throughout the member length to prevent lateral buckling shall be design as column.

Therefore, the vertical reinforcement is increased to meet 1% in accordance with ACI 318-19 10.6.1.1. The foundation design for the proposed firewall are to be 4' diameter, 30' long drilled shaft. Pile reinforcement is

(23)-#8 vertical bars with #5 ties spaced at 12”.

Figure 3-4: Drilled Pier Section

Task Order 5 | 100% Final Design | November 13, 2025 | Arup US, Inc. Basis of Design Report Page 16

3.3 Relocated Light and Static Poles

The existing two light and static poles will be relocated. To provide proper lighting at the gate entrance, the existing light and static pole will be relocated approximately 22 feet South, and due to the new harmonic filter pad, the lighting and static pole will be moved approximately 18 feet to the North. The current steel superstructure has been observed to be in sufficient condition for reuse. A new foundation will be constructed at the new proposed location with the assumption that there is no change in loading.

The existing light and static pole foundation is a 4’-0” diameter drilled shaft with a depth of 20 feet, and the reinforcement is (16)-#8 vertical bars with #5 ties spaced at 12”.

The base reactions provided by the existing light and static pole vendor are 11.8 kips axial, 13.5 kips shear, and

968.7 k-ft moment for one pole, and 7.67 kips axial, 7.43 kips shear, and 515.3 k-ft moment for the second pole, according to the existing structural drawings, 3-6-17 SC-2 Rev 7, dated 4/23/97. As the load factors are not provided in the existing drawings, a 1.6 load factor is assumed for the existing base reactions to confirm the structural pile capacity. If necessary, the Contractor shall design and provide any upgrades to the existing light and static pole structure. Lighting and static pole is assumed to be installed and supported by the new foundation with no change in loading.

The new foundation design assumes the same diameter as the existing drilled shaft to consider the mounting of the existing pole based on the 29"x29" base plate shown in the Existing Submittal from 3-6-17 073 Electrical

Installation dated 12/18/96. The new foundation design is a 4'-0" diameter, 30' long drilled shaft. Based on ACI

318-19 13.4.4.2, portions of deep foundation members in air, water, or soils not capable of providing adequate restraint throughout the member length to prevent lateral buckling shall be design as column with a minimum of

1%. Pile reinforcement is (28)-#8 vertical bars (1.22% reinforcement) with #5 ties spaced at 12”.

3.4 Oil Containment

The oil containment areas are proposed to be expanded by extending the oil containment pits, utilizing the same clay base for the new extension, and constructing new concrete walls. For the in-place condition, the transformer pit concrete walls lateral loads are balanced.

The oil containment pit walls are not designed to resist unbalanced soil loads. As noted on the Drawings, the

Contractor shall design and install temporary bracing for the containment pit walls whenever adjacent backfill material is removed. Refer to Section 5 of this report for containment volume sizing.

3.5 New Standby Generator

The existing standby generator pad is approximately 123" x 60" based on scaling the existing electrical drawings, 3-6-17 E-200 Rev 10, dated 12/9/98. No structural details were found in the 3-6-17 SC set.

The existing pad will be demolished and replaced to accommodate a new standby generator, which requires a larger foundation and a different conduit layout.

The weight of the new generator is 6354 lbs. The dimension of the generator is 143 x 50.4 x 128.7 (L x W x H).

Per the geotechnical engineering report, the concrete pad needs to meet the frost depth requirements, and the

DuPage County requires frost depth of at least 3.5 ft. The new foundation design assumes a 48" thick concrete pad with #5 @ 12" OC each way on top and bottom.

3.6 New Permanent Prefabricated Telecom Building

There is currently Fermilab, City of Batavia, and ComEd fiber that is routed through the Kautz Road Substation.

During construction of the KRS upgrades, fiber lines need to remain operational and be rerouted. Fermilab has requested a permanent prefabricated structure to house the fiber patch panel for termination of the Fermilab and

City of Batavia fiber. This structure will require a concrete pad as well as auxiliary power for building conditioning.

Task Order 5 | 100% Final Design | November 13, 2025 | Arup US, Inc. Basis of Design Report Page 17

The client has expressed no specific preference regarding the construction method (e.g., precast concrete versus steel) or the selection of a particular manufacturer for the prefabricated structure. The prefabricated building is assumed to be made of precast concrete with a minimum f'c of 4,000 psi and reinforced with ASTM Grade 60 reinforcement.

The proposed prefabricated building is assumed to be 6 feet by 6 feet, with a height of 8 feet. Final dimensions may be adjusted based on electrical clearance requirements and prefabricated manufacturer.

The structural scope of work includes the design of concrete pad and input into specification of permanent prefabricated structure.

Per the geotechnical engineering report, the concrete pad needs to meet the frost depth requirements, and the

DuPage County requires frost depth of at least 3.5 ft. The new foundation design assumes a 48" thick concrete pad with #5 @ 12" OC each way on top and bottom. The concrete pad extends 1 foot beyond the building footprint on three sides and 3 feet in front of the door.

3.7 Harmonic Filter Pad

The existing harmonic filter foundation pad for Bus 8-1 & 9-1 will be demolished and replaced to accommodate the new harmonic filter. The new harmonic filter at this location requires a foundation pad that is 3’-0” wider than the existing pad and will require conduit penetrations with a layout that differs from the existing conditions.

Refer to Figure 3-5 below, where the new foundation pad is indicatively shown in red.

Figure 3-5: Harmonic Filter Pad Replacement Plan

Due to the potential for magnetic interference from steel reinforcement, fiberglass reinforcement will be used in the new foundation pad. Additionally, stainless steel expansion anchors should be used to mount all electrical equipment. The thickness of concrete pad and fiberglass reinforcement as the existing harmonic filter pad is assumed to be adequate for the new harmonic filter.

Per the geotechnical engineering report, the edge of the concrete pad is thickened to meet the frost depth requirements, and the DuPage County requires frost depth of at least 3.5 ft. The requirement for fiberglass reinforcement, stainless steel anchors, and supporting pad design will need to be re-confirmed with the harmonic filter manufacturer.

3.8 Transformer T-85

The existing transformer pad is 2'-6" thick with 5' thickened edges with a 32 ft by 16 ft footprint, based on the existing structural drawings, SC-2 dated 4/23/97. The existing pad is located within the oil containment pit. The existing transformer is 390 kips based on the nameplate data.

The weight of the new transformer is quoted as 283,682 lbs on the draft shop drawings dated 8/15/2025, with approximately 442" length x 222" width x 380" height. The footprint of the replacement transformer will also fit on the footprint of the existing transformer foundation. Based on the weights and base dimensions of the new

T85 transformer, no modifications are anticipated to be made in the existing foundations.

Task Order 5 | 100% Final Design | November 13, 2025 | Arup US, Inc. Basis of Design Report Page 18

3.9 Circuit Breaker CB-119

The final Circuit Breaker CB119 selection will occur after the 100%FD documents are issued. The adequacy of the existing foundation will need to be re-verified when the final Circuit Breaker selection is made.

It is assumed that new CB119 will be a like-for-like replacement. New equipment assumed to be installed and supported by the existing foundation with no changes in loading. Equipment anchorage to be provided by

Contractor. No modifications are anticipated to be made in the existing foundations based on this assumption.

3.10 New Auxiliary Transformer

The final auxiliary transformer selection will occur after the 100%FD documents are issued. The adequacy of the existing foundation will need to be re-verified when the final auxiliary transformer selection is made.

It is assumed that new auxiliary transformer will be a like-for-like replacement. New equipment assumed to be installed and supported by the existing foundation with no changes in loading. Equipment anchorage to be provided by Contractor. No modifications are anticipated to be made in the existing foundations based on this assumption.

3.11 New Cable Bus

The existing bus duct support structures consist of 37 drilled piers, each supporting a steel column composed of a square tube section. Miscellaneous steel framing is located at the top of the column to provide connection to the existing bus ducts.

The existing bus duct will be demolished and replaced with a new cable bus. The cable bus manufacturer shall verify and validate that the existing support structure, connections, and anchorage are adequate for the new cable bus. If necessary, the cable bus manufacturer shall design and provide any upgrades to the existing support structure to support the new cable bus.

The existing bus duct foundations are to be reused if shown to have adequate capacity for the new cable bus. The base reactions provided by the existing bus duct vendor are 4.7 kips axial, 0.68 kips shear, and 8.8 k-ft moment, according to the existing structural drawings, 3-6-17 SC-2 Rev 7, dated 4/23/97. As the load factors are not provided in the existing drawings, a 1.6 load factor is assumed for the existing base reactions to verify the structural pile capacity. Based on the existing structural drawings, 3-6-17 SC-2 Rev 7, dated 4/23/97, 2’-6” diameter x 12’-0” long pier capacity is 5 kips horizontal and 60 k-ft moment.

The new reactions shall be provided by the cable bus manufacturer for review.

3.12 Motor Operated Disconnects MOD-85, MOD-86, MOD-87, and MOD-88

The existing motor-operated disconnect structures are each supported by four drilled piers, with each pier supporting a steel column. Due to the condition of the steel structure, the steel structure will be replaced on a like-for-like basis by the Contractor.

The base reactions provided by the existing motor-operated disconnects structure vendor are 4.43 kips axial, 1.55 kips shear, and 39.6 k-ft moment, according to the existing structural drawings, 3-6-17 SC-2 Rev 7, dated

4/23/97. As the load factors are not provided in the existing drawings, a 1.6 load factor is assumed for the existing base reactions to verify the structural pile capacity. Based on the existing structural drawings, 3-6-17

SC-2 Rev 7, dated 4/23/97, each 3’-0” diameter by 12’-0” deep pier has a capacity of 5 kips horizontal and 80 k-ft moment.

The existing foundations will be reused, assuming no change in loading by the new structure.

Task Order 5 | 100% Final Design | November 13, 2025 | Arup US, Inc. Basis of Design Report Page 19

4. Geotechnical

4.1 General

This section should be read in conjunction with the Geotechnical Data Report (GDR) (Task Order 5, September 24th, 2025), included in this Basis of Design as Appendix A to the Geotechnical Engineering Report

(GER) (Task Order 5, November 13, 2025) (Appendix G). The (GER) provides a comprehensive summary of the subsurface investigation data, geotechnical interpretations, and the design recommendations for geotechnical elements associated with the upgrades at the KRS.

4.2 Design Basis

Geotechnical design work shall comply with the applicable aspects of the following codes and standards:

• International Building Code (IBC) 2021

• ASCE Minimum Design Loads for Buildings and Other Structures, ASCE 7-16

• AASHTO LRFD Bridge Design Specification 10th Edition (2024) Load Factors

• ASTM D2487-17 Standard Practice for Classification of Soils for Engineering Purposes (Unified

Classification System), ASTM International

• FHWA Earth Retaining Structures, FHWA NHI-07-071, 2008

• FHWA Evaluation of Soil and Rock Properties,…