1. SNS PPU Cryomodule Thermal Shield
SNS PPU CRYOMODULE PDR
SNS PPU CRYOMODULE PDR
SNS PPU Cryomodule Thermal Shield
Matt Marchlik
Matt Marchlik
Wednesday, February 27
2019
Wednesday, February

2. Fabrication/Procurement methodology Remaining Tasks Summary
Outline
Requirements
Design
Assembly
Component/function
Fabrication/Procurement methodology
Remaining Tasks
Summary

3. Requirements
Provide 50 K thermal radiation shielding to the cold mass
Allow for thermal contraction from 300 – 50 K
Handle the shipping design loads
(4 vertical, 5 longitudinal, 1.5 transverse)
The shipping design loads and geometry mass has not significantly changed from the original design. The design is assumed to be adequate based on past performance

4. Design – Assembly Overview
Supply End Shield Extension
Shield segments
Axial nitronic rod patch panels
Tuner access
Panels
Helium line
Shield to space frame supports
Field probe cable
Heat intercept blocks
Return End Shield Extension
All shield segments and patch panels are made from (C11000 ETP Cu)

5. Design – Nitronic Rod Clearance
Axial rod clearance slots have been widened by ~.64” per recommendation of assembly personnel
Transverse rod clearance
Clearance for thermal contraction verified

6. Design – Tuner Access Panels
(other hidden)
Panel support bracket

7. Design – Shield/Space Frame Support
Shield support bands
(G11)
Corner support clamps
(304 SS)
Shield Spacer
(G11)

8. Design – Field probe cable intercept block
Original intercept block
Updated intercept block
The bottom block bolts onto the shield body. No back access is needed to clamp/unclamp the cable.
The original block had three cable grooves
Field probe cable heat intercept block was reduced in size and complexity

9. Design – Nitronic Rod Intercepts
Each transverse nitronic rod is heat intercepted inside of the thermal shield
Axial rods are not intercepted in the original design
It is assumed that previous calculations showed that the heat leak through the much longer rods is negligible
The original strap was made from solid copper sheet. An equivalent capacity braided copper strap was selected to replace the solid one
TIG braze

10. Design – Helium Line
7/8 in OD, .045 in wall copper tubing runs along the length of the shield
Tubing is segmented into 4 pieces by bellows assemblies
The tubing segments are torch brazed to the shield segment’s strain relief cut outs
Verified the wall thickness is acceptable per ASME B31.3
Verified that the SS to Cu adapter is acceptable per ASME B16.22

11. Design – Helium Line Brazed Shield Subassembly
Bellows lock rods prevent over stretch
SS to SS weld
TIG braze
SS to Cu socket braze
Bellows assemblies integrated between each shield segment
Tube brazed to the strain relief fingers of the shield segments

12. Design – Shield Extensions
Each end of the shield is capped by an extension assembly
Allow for end can connections to be made
Supports will vary from the standard flat straps shown here. Currently being designed

13. Design – Thermal Contraction
The shield assembly mounts “rigidly”(some flexibility in G11 supports) to the spaceframe.
300 – 50 K thermal contraction is ~.8 in
Hardware will be omitted at two seams of the assembly to allow each segment to contract individually. Done procedurally during assembly.
Some thermal contraction relief provided by twist in the 3/16” thick G11 bands

14. Procurement
The entire assembly, including extensions, will be procured as a complete assembly.
The SOW will be the primary fabrication control document. Drawings will direct fabricators to SOW
Fabrication plan/traveler
Materials
Welding
The shield circuit welds will be considered “code welds”.
WPS
PQR
Dimensional verification
Vendor site visits/witnessing
Shipping

15. Finalize and review any new drawings Start extension drawings
Remaining
Design
Minor changes to shield extensions
Shield extension supports
Drawings
Finalize and review any new drawings
Start extension drawings
Procurement
SOW
PR  PO

16. Summary Preliminary thermal shield design is in good shape
Interfaces with other subsystems have been verified
Currently being considered as extensions are developed
Existing drawings have been reviewed
Extensions still under development
Majority(~90%) of drawings for design changes have been started
Extension drawings still to be created
A couple of minor patch panel drawings to be created
Procurement path understood

17. Backup
Shield cooling line code calcs

18. Backup

19. Backup