LiH Casting & Testing1 Lithium Hydride Disc Casting & Testing Approaches C. M. Lei March 2, 2007

LiH Casting & Testing2 Stainless steel 316L 12” pipe (12.00”OD, 11.50”ID) #4 tapped holes on this side, 16 places

LiH Casting & Testing3 Stainless steel 316L plate, 3/16” thick Ceramic fiber gasket with 1/8” thru’ holes, 16 places Cut-out for central pipe holding with 0.06” ceramic fiber gasket (good within 1,420C) 3/16” thru’ holes for thermal- couples placement, 12 places

LiH Casting & Testing4 12 thermalcouples (possibly attched with flexible cable at end) Thermalcouple holders, soldered to end cover 1” copper pipe attached

LiH Casting & Testing5 These 2 nuts welded together with a ceramic fiber gasket embedded inside Thermalcouple holders, one end soldered to end cover, the other end tapped with 5/16-24 threads

LiH Casting & Testing6 Container ready to receive Molten LiH

LiH Casting & Testing7 Casting Approach: The following tasks will be performed in a Glove Box under an Argon gas atmosphere. 1. An excess of solid Lithium Hydride granuals will be heated in a Stainless Steel "ladle" to 100 F above the meliting point of Lithium Hydride (1,372 F or 750 C). 2. The molten Lithium Hydride will be poured from the ladle into the container. The container will be vibrated as the LiH solidifies. 3. When done, remove all screws and nuts then slide the end cover out carefully. Note: An adaptor plate with a vibrator underneath are not shown LiH would shrink and voids might be formed during the cooling

LiH Casting & Testing8 1” foam boards Removable, flexible silicone cooling tube (3/8”OD, 1/16” wall) Heater to be attached inside this tube Exposed thermal couple thru’ foam board SET UP FOR THE THERMAL TEST Heater wiring outlet

LiH Casting & Testing9 Last Minute Concerns from Tom, Postin Products LiH is very likely to stick to the end cover and hence it can not be removed smoothly. And there is no known mold- release or material equivalent that can withstand the high temperature. A smooth surface may not be able to achieved on the top due to the surface tension and different cooling rates through out the LiH disc.

LiH Casting & Testing10 Proposed Solutions Leave the end cover on and do not remove it when casting is done. Use rigid plates with very high temperature resistant, and low thermal conductivity for the top and bottom covers. Similar thermalcouple positioning will be kept. A floating top cover and a fastened bottom end cover are the proposed conceptual design now. A combination of ceramic fiber gasket and glass ceramic plate can be the candidate for such end covers –Withstand temperature up to 1,420 C and 680C correspondingly –Thermal k ~ 0.07 and 0.8 W/mK (needed to be confirmed) Note: Thermal k of LiH at room temperature is expected to be within 4 ~ 10 W/mK