PIP-II Cryogenic Distribution System

ED0049129 – CM 2K Pressure Safety Device-Rupture Disks Specification

PIP-II Cryogenic Distribution System ED0049129 CM 2K Rupture Disks specification

Fermi National Accelerator Laboratory 2

Document Approval

Signatures Required Date Approved

Originator: William Soyars, CDS engineer As in Teamcenter

Reviewer: Vrushank Patel, PIP-II L3M for CDS As in Teamcenter

Reviewer: Alex Martinez, PIP-II CAM for CDS As in Teamcenter

Reviewer: Matt Luedke, PIP-II Quality Assurance As in Teamcenter

Reviewer: Jeremy Nudell, PIP-II Project Engineer As in Teamcenter

Approver: Joe Ozelis PIP-II L2 for SRFCryo As in Teamcenter

Revision History

Revision Date Released Description

- 9/9/2026 Initial release

Fermi National Accelerator Laboratory 3

1. Introduction and Scope 4

2. Acronyms 5

3. Cryogenic Rupture Disk technical requirements 6

4. Additional technical requirements, information, and clarifications 9

5. Labelling 9

6. Transportation and handling 9

7. Document deliverables 10

8. In-coming Quality Check and Acceptance by FNAL 10

Fermi National Accelerator Laboratory 4

1. Introduction and Scope

1.1. PIP II Cryomodule (CM) Relief System

1.1.1. Fermi National Accelerator Laboratory (FERMILAB) located in Batavia, IL is building a next generation proton accelerator called the Proton Improvement Plan II (PIP-II). The

PIP-II accelerator (Linac) design is based on superconducting radio frequency (SRF) technology employed in up to twenty-five SRF cryomodules (CM). The linac requires cryogenic helium for operation. Figure 1-1 presents a schematic overview of the PIP-II

CM relief system. There are 25 CMs in the accelerator tunnel. The Safety Rupture Disks to protect from overpressure are circled in Figure 1-1.

1.1.2. The helium process line normally operates at sub-atmospheric conditions, about 30 mbar absolute pressure. Purity of the helium is very important and leaks from atmosphere shall be minimized

Figure 1-1 Schematic of PIP-II Relief system, with Cryomodule Rupture Disks indicated

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1.2. Scope and quantity

1.2.1. This specification is for cryogenic non-reclosable rupture disks on the Cryomodules

(CM) helium bath volume.

1.2.2. This order will be for thirty-three (33) rupture disk cartridges. 30 are at the higher set pressure and 3 are at the lower set pressure as shown in Table 3-1.

2. Acronyms

2.1.1. Technical acronyms

CDS Cryogenic Distribution System

CM Cryomodule (a proton beam accelerator cryogenic device)

He Helium

2.1.2. Organizational Acronyms

ANSI American National Standards Institute

ASME American Society of Mechanical Engineering

PIP-II Proton Improvement Plan II

FERMILAB Fermi National Accelerator Laboratory

2.2. Definitions

AMBIENT

a term used to define nominal environmental conditions, unless otherwise specified, of atmospheric pressure

CRYOGENIC

RUPTURE DISKS

a term used to refer collectively to Cryogenic Rupture Disk assemblies to be procured for installation on the Cryomodules

VENDOR

a term used to refer to the designer, fabricator, and supplier of the CRYOGENIC

RUPTURE DISKS

CODE

a term used to refer collectively to the various pressure safety standards to which the CRYOGENIC RUPTURE DISKS shall comply.

Linac a term that indicates a set of SRF cryomodules connected in series.

May a term which indicates that a provision is neither required nor prohibited

Shall a term which indicates that a provision is a requirement

Should a term which indicates that a provision is recommended as good practice but is not a requirement

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3. Cryogenic Rupture Disk technical requirements

3.1. Details of Cryomodule Rupture Disks are given in Table 3-1.

Table 3-1 Requirements for Rupture Disk on Cryomodules

FERMILAB Tag ID RD-nn21 RD-nn21

Identification number nn=02-25 nn=01

Fluid helium helium

Quantity in service during operations

24 1

Quantities to quote, including spares

30 3

Rupture disk size 4” 4”

Connecting pipe flanges, inlet 4”

CL 150

Flat face

4”

CL 150

Flat face

Connecting pipe flanges, outlet 4”

CL 150

Raised face preferred

4”

CL 150

Raised face preferred

Nominal Burst Temp [K] 294 294

Operating pressure [barg] -0.97 -0.97

Disk set pressure [barg] 3.1 1.75

Allowable overpressure 21% 21%

Relieving temperature 7 K 6 K

Required flow rate [helium gas kg/s]

8.87 8.51

Required flow rate [scfm air] 4960 4300

Expected Required orifice dia.

assuming KD=0.62 [in]

2.44 2.93

Cartridge style welded welded

Disk material Inconel Inconel

Process nominally at sub atmospheric press

Yes Yes

Superimposed backpressure at outlet

None, vents to atm. None, vents to atm.

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3.2. The CRYOGENIC RUPUTRE DISKS shall be ASME Section VIII Code NB/UD stamped.

3.3. The CRYOGENIC RUPUTRE DISKS shall be for cryogenic helium service.

3.4. The CRYOGENIC RUPUTRE DISKS shall fit between 4-inch ASME B16.5 flange connections as described in Table 3-1.

3.4.1. The rupture disk inlet will normally operate in process lines with sub-atmospheric service as noted in Table 3-1 and will use double O-ring connection with a mating flange on the process pipe.

3.4.2. The inlet flange shall have a surface finish of 32 RA, suitable surface finish for mating flange with O-rings.

3.5. The CRYOGENIC RUPUTRE DISKS shall Operate in an indoor environment, within the linear accelerator tunnel.

3.6. The CRYOGENIC RUPUTRE DISKS shall be constructed using materials that are radiation tolerant and operate without degradation or performance deterioration.

3.7. The CRYOGENIC RUPUTRE DISKS shall be able to withstand full vacuum pressure across the disk. The process side is normally at vacuum as described in Table 3-1.

3.8. The CRYOGENIC RUPUTRE DISKS shall be made of Inconel

3.8.1. Inconel is to achieve more burst pressure stability near cryogenic temperature. There is a safety valve for smaller upset conditions and before disk opens there could be ~7 K helium gas flowing through a pipe tee about a foot away from the RD, which could see conduction cooling.

3.9. The CRYOGENIC RUPUTRE DISKS shall be a welded disk cartridge. See section 3.10.1 for geometry information.

3.9.1. The process line operates at sub-atmospheric cryogenic conditions, about 30 mbar absolute pressure and 2 K (-459 oF),. Purity of the helium is very important and any air in-leaks from atmosphere shall be minimized. Thus, welded disk is specified.

3.9.2. For leak tightness, the welded disk shall meet a helium mass spectrometer leak rate of

10-8 atm-cc/sec.

3.10. Geometry

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3.10.1. The welded disk cartridge shall fit in a flange space of approximately 3 inches. See Figure

3-1. Slight length differences can be accommodated. Cartridge height in excess of 3.75 inches can be considered but would require evaluation for suitability in the limited space. The piping below the rupture disk cartridge has not been fabricated yet.

3.10.2. The vent side flange will be rotatable.

Figure 3-1 Assumed Rupture disk cartridge height in the piping system

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3.11. The CROGENIC RUPUTRE DISKS shall be equipped with burst alert sensor on outlet. The sensor shall allow rupture disk assembly to maintain height requirements of 3.10. The sensor shall be the “normally closed” circuit type that becomes open circuit when disk bursts.

3.11.1. The sensor connector shall be 2-lead wire type.

3.12. External handling and centering accessory shall be added to the welded disk cartridge.

4. Additional technical requirements, information, and clarifications

4.1. The quantity of disks in service during operation is shown in Table 3-1. Also indicated are quantities for quotation, which includes spares.

4.2. Orifice sizing with the assumed discharge coefficient is intended to be consistent with the required flow rate. These are presented for guidance, and the vendor shall conduct their own sizing. Calculations for the tables use HePak software (Horizon Technologies, formerly

Cryodata) for helium properties. This references data from the U.S. National Institute of

Standards and Technology (NIST). The helium properties can be provided by FNAL upon request to aid vendor’s calculations.

5. Labelling

5.1. The rupture disk shall have label showing ASME code stamp, rupture disk model, serial number, set pressure, capacity, flow area, and temperature rating.

6. Transportation and handling

6.1. The CRYOGENIC RUPTURE DISKS shall be packed adequately for shipment to prevent any damage during transit to the FNAL site in Batavia, Illinois, USA.

6.2. Delivery at Place (DAP) to FNAL site in Batavia, Illinois, USA following Incoterms 2020 shall be used as the method of international shipping.

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7. Document deliverables

7.1. The following items shall be submitted in English with the proposal. Information considered proprietary should be identified as such.

7.1.1. Total cost to fabricate, test, and ship to FNAL site in Batavia, Illinois fully functional

CRYOGENIC RUPTURE DISKS ready for installation. Quantities for quotation are shown in Table 3-1.

7.1.2. Delivery schedule.

7.1.3. Lists of exceptions to this specification and reasoning for exceptions.

7.1.4. Technical details of the offered CRYOGENIC RUPTURE DISKS covering:

7.1.4.1. Rated capacity and size, including calculations and datasheets.

7.1.4.2. Drawings indicating dimensions.

7.1.4.3. Inlet and outlet flange size and description.

7.1.4.4. materials to be used for constructing

7.1.4.5. Provide expected leak rate across the welded disk assembly into vacuum on process side.

7.1.4.6. Verify reliefs will have ASME Code certification.

7.1.4.7. Manufacturing tolerance range for disk burst pressure

7.1.4.8. Disk discharge coefficient

7.2. The following items shall be submitted in English at the time of delivery to FNAL

7.2.1. Certificate of Compliance for the CRYOGENIC RUPTURE DISKS stating compliance with

ASME Section VIII with National Board certificates.

7.2.2. Mill/Material Traceability report

7.2.3. Burst Certification

8. In-coming Quality Check and Acceptance by FNAL

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8.1. Within two weeks upon receiving, FNAL will perform the following quality checks before accepting the CRYOGENIC RUPTURE DISKS:

8.1.1. Visual inspections for any shipping damage.

8.1.2. Verification of performance and serial number identifiers as labeled per 5.1 to the datasheets provided per 7.1.4.1.

8.1.3. Verification of mechanical size and interfaces to the drawings provided in 7.1.4.2.