IERC Hellens Hall 2 x 2pt5 x 1 meter Cryostat draft specification.docx

Revision 0 01-09-2023 Atmospheric Cryostat Draft Specification

Dave Pushka, P.E., FERMILAB 1/09/2023 Rev 0

Revision 0: Original Draft of Specification.

SUMMARY

A shallow membrane cryostat is needed to provide a liquid argon and/or liquid nitrogen bath approximately 1 meter deep for detector and robotic elements testing at Fermilab in the Helen Edwards Engineering Facility. This specification provides the requirements for a design build procurement of this cryostat.

REQUIREMENTS

Size: 2 meter (+ / - 5 cm) internal width,

2.5 meter (+ / - 5 cm) internal length, 1 meter (+ / - 5 cm) liquid depth.

External width less than 3.5 meters (11 feet, 8 inches) External length of less than 4.0 meters (13 feet, 4 inches) External height of less than 2.5 meters (8 feet, 4 inches)

Type of Construction:

Inner pressure containment: a metallic membrane to provide leak tight containment of the liquid and gas Insulation: a heat barrier with properties and thickness sufficient to limit the heat flux to less than 10 w/m2 and transfer the loads from the metallic membrane to the exterior structure Secondary barrier: a metallic-base flexible material, i.e. triplex to provide physical protection that contains the liquid cryogen in case of a failure of the inner metallic membrane Exterior: a metallic structure capable of supporting all types of loads, including weight of the filled cryostat and its top plate with equipment and personnel, internal pressure from the liquid and gas, and all other occasional loads.

Materials of Construction:

Inner Surface in contact with liquid: 304L stainless steel Secondary barrier: triplex (typical) Exterior: carbon steel Insulation: polyurethane foam. Nominal density of 2 pounds per cubic foot.

Nominal Insulation Thicknesses:

Bottom: 0.5 meters (approximately 20 inches) Sides: 0.5 meters (approximately 20 inches) Top (Cover) 0.5 meters (approximately 20 inches) Minimum Nominal Metal Thicknesses:

Inner stainless-steel surfaces: 1.25 millimeters (approximately 0.05 inches) Exterior steel surfaces: 3 millimeters (approximately 0.12 inches) Exterior steel structure: 3 to 5 millimeters or thicker as required Penetrations:

Quantity of 7 penetrations nominal 6-inch inner diameter with conflat flanges at both the exterior and interior.

Interior stainless-steel surfaces: 1.25 millimeters (approximately 0.05 inches Required Features:

Externally stiffened membrane cryostat with a two-part top cap; one part includes penetrations, and one fixed part is designed to be easily removable with an overhead gantry crane (by others).

Appropriate lifting lugs are required on both the fixed top cap and on the removable top cap.

Four (4) lifting points shall be included on the sides of the external cryostat sized for lifting the complete assembly (vessel empty condition) to facilitate loading and unloading this cryostat from a flatbed truck trailer.

Cryostat Welding shall be performed by welders qualified in accordance with ASME Section IX A film shall be embedded within the insulation capable of containing the liquid in case of a spill from the primary membrane. The secondary barrier is only present at the bottom and along the sides. It is not present on the roof.

Four (4) hard points shall be included at the bottom corners of the external cryostat shell to allow installation of rollers to facilitate moving this assembly into the building.

Eight (8) KF-50 ports shall be included in the external cryostat shell (one on each side of the vessel and on each side, one on each side of the secondary barrier) to facilitate vacuum leak checking of the insulation space.

One (1) KF-50 ports shall be included in the removable top cap (on the upper surface) to facilitate vacuum leak checking of the insulation space.

One (1) KF-50 ports shall be included in the fixed top cap (on the upper surface) to facilitate vacuum leak checking of the insulation space.

Seal between the fixed top cap and the external cryostat and between the removable top cap and the external cryostat will be made from a sheet of closed cell silicon intended to reduce boil off leakage from the joint, but not to eliminate it. The top cap removable section is not intended to be fastened to the external cryostat. Rather, a nominal internal pressure of approximately 0.2 psig will lift the removable top cap and prevent the cryostat from being pressurized.

Stainless steel channel strut shall be installed along all four (4) walls at 0.5 meter and 0.8 meter above the inner bottom. Strut corners do not need to join.

Regulatory Requirements:

Cryostat design and construction shall be done to comply with the requirements listed in the Fermilab ESH Manual Chapter 5031.7 “Requirements for the Design, Fabrication, Erection, Quality Control, Testing, Maintenance, Repair, and Operation of Metallic Membrane Cryostats” and its Technical Note (attached).

SCOPE OF WORK

The vendor shall:

· Perform calculations and develop a cryostat design which meets the requirements of this specification.

· Procure and fabricate the material to build the Cryostat as per the design developed above.

· Perform engineering analysis to shown material stresses are below the ASME allowable stresses per Section II, Part D. Engineering analysis can be ASME Section VIII division 1 or division 2.

· Perform All welding using a TIG (Tungsten Inert Gas) process on the welds in contact with the liquid cryogens. All TIG welding shall be performed with an argon purge gas and a 99.9% argon backing gas. Backing gas oxygen concentration shall be measured and documented on a written fabrication report for all welds.

Painting and marking:

· The Cryostat internal surfaces, all stainless steel, and all internal components shall not be painted.

· Only the Cryostat external surfaces made of carbon steel shall be primed and painted with an oil base enamel.

Shipping transportation to Fermilab:

· Shipping shall be as provided for under the purchase order.

INSPECTION HOLD POINTS:

The following are hold points in the fabrication and assembly process to allow Fermilab staff to visit the vendor’s facility, inspect and / or witness quality assurance steps:

· Completion of the cryostat design and Completion of calculation package.

· Vendor shall submit all weld procedure specifications (WPS), weld procedure qualification records (PQR) and welder qualification records (WQR) for all welds and all welder performing work on this Cryostat prior to the start of welding.

· All Helium Mass Spectrometry.

· Leak testing of the assembled vessel.

PRE-AWARD SUBMITTALS

The following items are requested with Request for Proposal and will be used in evaluating the proposals:

· Vendor’s equipment list indicating shop space, machine tools, inspection equipment, and other equipment needed to perform fabrication and assembly shown on the drawings.

· Vendor’s list of experience with other projects similar to this project.

· Vendor’s Exceptions to requirements on drawings or this document

· Vendor’s Manufacturing Plan including:

· Location where the Cryostat assembly will be performed

· Location where the non-destructive testing including helium mass spectrometry will occur.

· Vendor’s ASME code stamp status (this vessel is not to be code stamped).

· Helium Mass Spectrometry Leak Testing Procedure, including a plan for when the leak tests occur.

· Number of ASNT qualified level 1, 2, or 3 Helium Mass Spectrometry Technicians

· Number of Welders Qualified to perform the welds in accordance with ASME section IX.

· Vendor’s proposed Quality Control / Quality Assurance Plan

· Vendor’s proposed delivery schedule

POST-AWARD RAW MATERIAL & DOCUMENTATION SUBMITTALS

The vendor shall provide documentation certifying that the material is as specified on the drawings and as listed below. Fermilab will approve these procedures and other documentation prior to the vendor performing the work.

· Design Calculations

· Material Certificate of Conformance (COC) for the Cryostat materials prior to fabricating.

· Weld procedure specifications (WPS)

· Weld procedure qualification record (PQR)

· Welder qualification record (WQR)

· Written Inspection Report format and Internal Quality Control plans

FINISHED MATERIAL SUBMITTALS

The vendor shall provide the following after fabricating:

1. Design Calculations

2. Material Certificate of Conformance (COC)

3. Certified Test Report (CTR) for all materials used for the Cryostat.

4. Complete results of helium mass spectrometry performed on the Cryostat.

5. Written Inspection Report including Backing Gas oxygen concentration for all welds.

IMAGES OF CONCEPTUAL DESIGN

1. Removable Cover Lifted:

2. Cross Section Showing Insulation:

Conceptual Design Notes:

Items in Red are Carbon Steel Carbon steel external stiffeners shown in images are not sized in terms or quantity, depth or thickness.

Removable top cap stiffeners may be made of carbon steel Items shown in gray or blue are stainless steel Items shown in muted yellow are the rigid polyurethane insulation Hard points for rollers or castors are not shown Lifting points for the top cap sections and external cryostat are not shown.

KF50 connections to the insulation space are not shown.

Corners of the inner membrane may be radiused to not more than 200 millimeters or chamfered to not more than 200 millimeters. This results in a flat inner membrane surface of 1.6 meters by 2.1 meters.

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