Part 851 & Vacuum Systems

1. Part 851 & Vacuum Systems Office of Science Accelerator Safety Workshop W.R. Casey NSLS-II Project Brookhaven National Laboratory August 12, 2008

2. Vacuum System Design Issue Part 851 defines a vacuum system as a pressure system because of the potential for back-pressurization which invokes ASME Pressure Vessel Code, Section VIII Discussed at length at SC sponsored Accelerator Safety Workshop held 8/07 Uncertainty was expressed regarding interpretation and implementation of requirement Potential impact to design of NSLS-II and other new accelerators was noted

3. Approach to Addressing Pressure System Requirements for Vacuum Systems • Developed during break-out session at Accelerator Safety Workshop • ORNL, BNL, ANL, LANL, TJNL, and others • Prevent pressure differential greater than 15 psig through use of pressure relief devices (prevent over-pressurization if accidentally backfilled) • Develop guidance that defines the design, fabrication, inspection, & test requirements for a vacuum vessel.

4. Approach to Addressing Pressure System Requirements for Vacuum Systems (cont.) • Form a working group to further develop this guidance. • Issue guidance as an Office of Science document, most likely as an attachment to the Implementing Guidance for the DOE Accelerator Safety Order 420.2B.

5. Status of Effort • Working Group was formed Jan. 2008 • Technical issues were discussed during 6 conference calls from January to April. • Six drafts of consensus standard were reviewed • Final draft issued 6/17/08 • Edited version issued 7/17/2008

6. Members of Working Group • Argonne National Laboratory • Jeffrey T Collins • William F Toter • Brookhaven National Laboratory • Robert Casey (Chair) • Edwin Haas • Dick Hseuh • Steven Kane • Edward Lessard • Sushil Sharma • Fermi National Accelerator Laboratory • Daniel R Olis • David R Pushka • Oak Ridge National Laboratory • Peter Ladd • Stanford Accelerator Center • R. Keith Jobe

7. Summary of Standard • Key features of standard • Defines design requirements for all vacuum vessels • Requires ASME code compliance for vacuum vessels subject to over pressurization > 15 psig • Defines requirements for equivalent level of safety when ASME code does not apply (because of pressure range, vessel geometry, use of special materials, etc) • Provides exemption for vacuum vessels with energy less than 100,000 joules or vessels with small dimensions (cross-sectional area less than 28.5 in2)

8. Summary of Standard (cont.) • Defines • Authority having jurisdiction • Engineering evaluation • Independent design professional • Pressure Safety Committee • Responsible vacuum system design engineer • Vacuum systems • Category I • Category II • Category III

9. Summary of Standard (cont.) • Defines responsibilities and qualification requirements for the responsible design engineer, independent reviewer, authority having jurisdiction, and Pressure Safety Committee • Establishes requirements for • Design • Design review • Fabrication • Welding • Inspection • Testing • Pressure Relief • Records

10. Summary of Standard (cont.) • Two Appendices • Appendix A defines “Engineering Evaluations” • Appendix B defines independent review requirements for Category III vacuum vessels

11. Current Status • The working group is very satisfied with its product – there was a true consensus. • Definitions and requirements are being incorporated into BNL Pressure Safety requirements (other Labs are doing the same) • However – we need for this standard to be recognized by the Office of Science and incorporated into the Accelerator Safety Order (or other appropriate documents)

12. Next Step • Review standard at break-out session • Incorporate any additions, deletions, modifications to standard • Identify responsibility and process for moving the document into the Office of Science • Establish time line for official recognition of standard