Spoke CDS PDR Closeout J. G. Weisend II June 10, 2016

Spoke CDS PDR - J.G. Weisend II General Comments The level of detail and work presented was impressive, particularly for a PDR. The expertise and experience of IPN Orsay in this area is impressive. In particular, their experience with projects such as SPIRAL 2 has been suitably applied. The development of the prototype valve box is very important for reducing risk. The tests planned at both Orsay and Uppsala will provide timely valuable information on the CDS performance. A possible issue is seen the presence or not of heaters on the 2 K system of the spoke cryomodules. The requirement for the presence of these heaters needs to be checked and possibly changed. The delivery and installation schedule needs to be reworked to allow meeting the current pressure test date. ESS and IPN Orsay will work together to accomplish this goal. There is clearly no float in the schedule. No significant safety issues were identified. No technical showstoppers were identified. Almost all requirements, including interfaces have been identified and are close to agreement. Final agreement and entry into DOORS should take place by August. June 2016 Spoke CDS PDR - J.G. Weisend II

Spoke CDS PDR - J.G. Weisend II Decision The Review Committee finds that the Spoke CDS is ready to move into detailed design with the goal of being ready for the scheduled CDR on October 20th, 2016 June 2016 Spoke CDS PDR - J.G. Weisend II

Answers to Charge Questions 1. Has the project and supporting activities for the CDS for Spoke Linac progressed in accordance with the activities and milestones for this Work Unit recorded in the ESS ACCSYS Project Plan? Yes 2. Has the CDS-SL preliminary design been documented appropriately and presented in a suitable format to enable review? 3. Have the correct design options for the CDS-SL as well as their verification methods been selected and described? Yes, but additional details on verification methods should be presented at the CDR. 4. Have all the CDS interfaces with other systems been recognized? 5. Have all or a sufficient coverage of requirements for the CDS-SL and its interfaces been identified and documented? Yes, but final agreement on requirements need to be reached in August 2016 June 2016 Spoke CDS PDR - J.G. Weisend II

Answers to Charge Questions 6.        Does the CDS-SL preliminary design comply with the requirements for the system and its interfaces? Generally Yes, Some changes are required ( see recommendations) 7.        Is the CDS-SL preliminary design sufficiently developed for transition to the detailed design?  Yes 8.        Does the Work Unit or its partner CNRS/IPNO require additional input from ESS or the other partners to proceed to the CDS-SL detailed design?  Generally no, but additional discussions with ICS concerning electronics need to be held and ESS shall define requirements on accessibility behind the LWUs June 2016 Spoke CDS PDR - J.G. Weisend II

Spoke CDS PDR - J.G. Weisend II Recommendations Review the requirements for heaters on the 2 K system of the Spoke Cavity Cryomodules. Are such heaters required? If not there may be significant control implications. WP4 and ESS   shall review these requirements and change as appropriate to address the control issue. Consider increasing the Kv of CV63 and CV01 to allow for additional margin. Investigate the choice of valve characteristics as well. Standardize the electronic controls for the valve positioners between all the cryomodules and the entire cryogenic distribution system. These electronics must be mounted in the Klystron Gallery. Make consistent between WP4, WP5 and WP11 the meaning of PS and MAWP (these should be the same) Specify the PS as an interface requirement. The goal should be that the PS is always set lower at the cryoplant than in the cryomodules or cryogenic distribution system. June 2016 Spoke CDS PDR - J.G. Weisend II

Spoke CDS PDR - J.G. Weisend II Recommendations Perform an analysis of possible thermoacoustic oscillations and install check valves or other solutions as required. Remove intermediate electrical feed through on the level gauges extending the capillary tubing up to room temperature. Plan on shielding the pressure sensors from radiation damage (see the Wroclaw approach). Guidance should be given by ESS AD Safety Group Reconsider allowed space in the jumper connection to improve the ease of welding. Update instrumentation table for CDR to show range and communication protocol. At CDR, show plans for assembly tooling, transport containers and movement of the CDS components in the tunnel.. June 2016 Spoke CDS PDR - J.G. Weisend II

Spoke CDS PDR - J.G. Weisend II Recommendations Vacuum systems including gauges, feed throughs etc. must meet the ESS Vacuum Handbook requirements. (See comments by Marcelo Juni Ferreira on submitted documents) IPNO and ESS ICS shall work together to ensure that the readout electronics provided by IPNO are consistent with ESS standards. Optimize the installation plan to try to maintain the integrated CDS pressure test date and to combine activities so that the IPNO installation team can work continuously. ESS shall ensure that the ODH system in the tunnel is ready prior to the CDS Pressure Test ( January 2018 ) ESS shall investigate the allowable occupancy of the tunnel during installation activities. For the CDR, documents shall be provided 5 weeks in advance as stipulated in the Technical Annex. . June 2016 Spoke CDS PDR - J.G. Weisend II

Spoke CDS PDR - J.G. Weisend II Thanks again for all the hard work in developing the design and preparing for the review. Thanks to the review committee for their hard work and time. June 2016 Spoke CDS PDR - J.G. Weisend II