BZ-2025-14 Warm Structure RFI.pdf

LBNL Request for Information No. BZ-2025-14 Page 1

August 28, 2025

Subject: Request for Information (RFI) Number BZ-2025-14 Response Due Date: October 8, 2025

Introduction The University of California, Lawrence Berkeley National Laboratory (LBNL) is conducting market research to identify sources that possess the capabilities and experience necessary to fabricate a steel “Warm Structure” to meet AISC 360 Specification for Structural Steel Buildings in support of the DUNE- ND project.

Background The Deep Underground Neutrino Experiment project (DUNE) is a leading-edge, international experiment for neutrino science. Discoveries over the past half-century have put neutrinos, the most abundant matter particles in the universe, in the spotlight for further research. The DUNE Near Detector (DUNE-ND) will record neutrino interactions near the source of the beam, at Fermi National Accelerator Laboratory (FNAL) in Batavia, Illinois. A set of Far Detectors (DUNE-FD) will be installed at the Sanford Underground Research Facility in Lead, South Dakota to record neutrino interactions 1,300 kilometers downstream of the source. These detectors will enable scientists to search for new subatomic phenomena and potentially transform our understanding of neutrinos and their role in the universe.

Figure 1: DUNE Schematic. A neutrino beam is produced at Fermilab (right) which passes through a Near Detector (center) and Far Detector (left).

A key component of DUNE-ND is a particle detector housed inside of an insulated cryogenic tank or cryostat. The cryostat is filled with liquid argon and uses a membrane construction comprised of two main components, an interior “Cold Membrane” and an exterior steel frame, referred to as the “Warm Structure” (which is the subject of this RFI). The Cold Membrane provides thermal insulation and cryogen containment. The Warm Structure supports the liquid argon pressure load and weight of the detector. The tops of the Warm Structure walls support Lid Assemblies, which close out the vessel and suspend the particle detector payloads in the argon bath. One wall of the Warm Structure has a low-density ribbed sandwich panel design and is termed the Muon Window. Attached to one side and on top of the Warm Structure are mezzanines which support process equipment and instrumentation. The Warm Structure and its mezzanines are mounted on a mobile steel subframe termed “PRISM”.

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Figure 2: DUNE-ND Warm Structure Design. The Muon Window is the visible grey pane in the center, and the PRISM subframe is the rail-like structure at the bottom.

All of these components are made of carbon steel. They are insulated from the cryogenic volume by the Cold Membrane. The designs are required by FNAL safety standards to meet American Institute for Steel Construction 360: Specification for Structural Steel Buildings (AISC 360).

The Cold Membrane and Mezzanines are not in this RFI’s scope. This RFI is only for the structural frame components shown in Figure 2:

• Warm Structure

• Muon Window

• PRISM subframe

Preliminary Fabrication Plans Due to the unique access requirements of the underground facility where the DUNE-ND will be installed, the project has drafted the following fabrication plans. While these are preliminary and may be subject to revision, the logistical challenges are such that no major changes are foreseen.

Warm Structure Beams and PRISM Frame The beams are bolted together during installation to form the frame. Any fabrication required within individual beam subassemblies, such as welding, is addressed before frame assembly. Specifically, beam end plates and other stiffening members are welded using full penetration welds at critical joints, with fillet welds applied where additional reinforcement is necessary.

LBNL Request for Information No. BZ-2025-14 Page 3

Vapor Barrier The Vapor Barrier is formed by panels installed on the inside of the frame after the beams are fully assembled and bolted. To resist internal pressure loads the panels incorporate stiffener plates which are welded in place during fabrication. During cryostat installation, first each panel is lifted into position and clamped in place and then, once all panels are placed, the panels are welded along their edges to each other. The welds seal the barrier and prevent ambient air and accompanying humidity from entering the insulation volume, which is purged with dry nitrogen in operation.

Muon Window The Muon Window serves as one of the walls of the cryostat tank and uses a sandwich panel construction with inner and outer facings of steel plate which are bolted to a set of internal ribs. A perimeter frame made of machined I beams provides a bolted interface to the warm structure. The inner facing serves as a vapor barrier and is non-structurally welded all around to neighboring Vapor Barrier plates. The Muon Window design conforms to unique, science-driven requirements on total mass and mass uniformity allowed in the zone of the Warm Structure through which high-energy muon particles will pass.

The full scope of work will include factory acceptance validation testing, specifically a full assembly of the Warm Structure at the factory with LBNL and FNAL personnel in attendance, testing to specifications, and then disassembly for shipping to FNAL.

Please refer to these drawings for details:

• DU-1004-8765 DUNE-ND Warm Structure

• DU-1004-9380 Muon Window

• DU-1005-7620 PRISM Frame

• DU-1005-8388 Warm Structure Assy

Preliminary Material Specifications Preliminary analysis assumed ASTM A572-65 steel with a yield strength of 65 ksi [448 MPa], however the project team is open to advice regarding possible replacement with equivalent steels such as 65 ksi A992. The project would prefer to specify a material that is available from domestic suppliers for multiple reasons including the Buy American Act, supply chain simplification, and potential tariffs, but alternatives may be considered.

Preliminary Procurement Strategy It is LBNL’s preference to find a qualified machine shop that can fabricate all three structural frame components to minimize risk and complexity. For logistical reasons one shop that can fabricate all three components is the ideal and preferred solution, but this is not an absolute requirement, and the project is willing to consider alternatives if this strategy proves non-viable. A degree of lower-tier subcontracting might also be acceptable. It is estimated that the solicitation and award fabrication will take place in Q1 2027.

LBNL is specifically seeking a supplier that possesses the following capabilities.

1. Structural welding

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2. Welding stainless steel to carbon steel

3. Dimensional inspection capability with ~0.5-1.0 mm accuracy at ~6-10 m scale

4. Finishing (paint or powder coat) at ~6-10 m scale

5. ISO 9001 or equivalent quality system

6. Crane or equivalent lifting equipment with minimum 15 ton capacity

NAICS Code and Size Standard The North American Industry Classification System (NAICS) Code for this acquisition will be 332999 (All Other Miscellaneous Fabricated Metal Product Manufacturing). The corresponding small business size standard is 750 or fewer employees.

Response Instructions Respondents who can demonstrate a proven record of delivering large complex fabrications of similar scope to the preliminary specifications above should email the LBNL Procurement Representative Brian Zatkow at bzatkow@lbl.gov with relevant company information. Please answer the following questions in your response:

1. Can you build all three structural frame components? If not, which of the three can you build? If you expect that any parts or processes will be subcontracted out rather than handled in-house, please indicate this as well.

2. Assuming all materials are already on-site, what is your estimate of a rough timeframe for fabrication?

3. Can you provide a budgetary estimate? It is understood that long-term materials costing is not possible due to volatility in the commercial metal market, so please do not try to forecast. A best guess based on current economic conditions is desired, ideally specifying materials, grades, tariffs etc. that were used for as the basis of estimate. Separating out materials and labor costs is not mandatory but would be very helpful for our budget planning purposes.

A list of similar previous jobs may be included, but contact information for previous customers is not required. Attachments or hyperlinks are both acceptable.

All responses must be submitted by email no later than 3:00pm Pacific on Wednesday, October 8, 2025.

Request for Information Only This RFI is for informational and planning purposes only. This is not a request for quote or proposal. It does not constitute a solicitation and shall not be construed as a commitment by the University. Responses in any form are not offers and no subcontract will be awarded as a result of this announcement. No inquiries regarding a bid package or solicitation will be answered, because there is no bid package or solicitation yet available. Any information submitted by respondents to this RFI is strictly voluntary.

In order to protect the procurement integrity of any future procurement that may arise from this RFI, information regarding the technical point of contact will not be given and no appointments for presentations will be made. No funds are available to pay for preparation of responses to this announcement, and no reimbursement will be made for any costs associated with providing information in response to this RFI or any follow-up information requests related to this RFI. Responding to this RFI mailto:bzatkow@lbl.gov

LBNL Request for Information No. BZ-2025-14 Page 5 does not provide any advantage or disadvantage to potential offerors if LBNL chooses to issue a formal solicitation at a later date.

This Request for Information is governed by procurement policies and procedures established under the University's Prime Contract with the U.S. Government, represented by the Department of Energy, for management and operation of LBNL.

Proprietary Information Because information received in response to this RFI may be used to structure future programs and may be made available to the public, respondents must not include any information in their responses that might be considered business sensitive, proprietary, or otherwise confidential. Responses must be submitted with the understanding that their contents may be publicly disclosed and, in the event of a public disclosure, LBNL will not notify respondents or provide any opportunity to revise or redact submitted information.

Brian Zatkow LBNL Procurement Representative

(510) 495-2547 bzatkow@lbl.gov

(End of RFI document) mailto:bzatkow@lbl.gov