Makara/Geynisman, Aug. 31, Cryo Dept. Shutdown Status

Makara/Geynisman, Aug. 31, Current Operations Tevatron at LN2 temperature except A1, C4, D1, and E1 at room temperature. –Tunnel magnet cryostat vacuums at A25 and D35 regions are of concern. –D-Zero Cryo online with Tev Cryo Compr discharge/suction headers due to pond work. –3 FRIG Mycom comprs (plus CDF) running with helium precooled to LN2 temperature flowing through magnet strings. CHL helium inventory management system operating on clean Helium Tank Farm, though A0 GHe Recovery being vented due to CHL Main Helium Purifier plugged after 8-hour planned power outage. Currently CHL operating Screw Comprs on Mobile Helium Purifier while Main Purifier is being warmed up to room temperature for derime.

Makara/Geynisman, Aug. 31, Current Operations Pbar Helium system (Debuncher and S/C Notch Filter tank) will be cooled down to LHe temperature next week for testing; FRIG Compr system has been purified past several weeks via CDF and D-Zero Helium Purifiers while they were online with FRIG Compr suction/discharge headers. CHL Nitrogen Reliquefier plant off and LN2 supply dependent on vendor deliveries to CHL LN2 dewar tanks; deliveries are fine. CHL runs on a fire hose for ICW.

Makara/Geynisman, Aug. 31, FRIG Maintenance in progress –10 of 13 wet expander flywheels have been replaced –12 of 26 wet/dry expander overhauls of cold ends are completed (A1 thru C2, plus PBar) –Various vacuum, instrumentation, and controls maintenance continuing. CHL Maintenance in progress –Coldbox-1: Charcoal Adsorber east unit regeneration at high temperature completed and now cooling down. –Nitrogen Reliquefier plant maintenance in progress: Marley Cooling Tower refurbishment almost complete. Rotoflow compr aftercooler tube bundle was replaced. TSI Compr 3000 hp motor replaced and newly installed to be test run. –Various compr and facility maintenance in progress