"" """ " " " " " u. 1' AM L. , Wait N o 7 . . ., ** .. .. . . OP JUAN INT 15.1. W . _ ' YW'9" LAW .. .. .. .. M I LL OR. UNCLASSIFIED ORNL . . * 11 MAJA te 2 * 1 . 128 i u * ******* ULTA ':0: precitation at the American Nuclear Society Fall Meeting, San Francisco, 021!.vinia, November 30-December , 1964. os non-phiag را برای ج- ومن) FABRICATION OF SMALL-DIAMETER ALUMINUM-S:EATED IRRADIATION CAPSULES AUG 1 1 1964 J. D. Seace? und it. L. Lotts Metals and Ceramics Division Oak Ridge Nacional Laboratory Oak Ridge, Tennessee MASTER SUMMARY 1. A me, e mua of way whormation, w A. Makes my w Heine, www the Cow w n. pra 'multo mo tiohisten met Megan a Nou Con, or ho g docent, w met w wees water a more porno a bo Co ter tuyo at ustat. . www. eno a ma the A adm tror, opgement sur delingen met e te at my para, home water mo ammorum de or hoe ay or w ater, mother o de , wer weg goren acting a of Comen of meran berland te ho represes LEGAL NOTICE another, espeed or implied, no respon document, we do l l of the Commuted: maand want that ther Nee Vattend Matrhungen the more om A reliable procedure has been developed for making small-diameter aluminun-sheathed irradiation capsules with high-integrity ision-welded ciosures. Typically, an irradiation capsule (Fig. 1) consists on a 3;'S-in.-diam aluminum tube loaned with compacted PuO2-A2 pellets. These capsules, which are being used to validate the design of the elements For the FIR target, are currently being irradiated in the MAR (ref. 3) and ir, a Savannah River Laboratory production reactor. Mie major problem in fabricating aluminum capsules has been ena- closure welås. Tais problem, which increases with decreasino tube diameter, is typii'ied by "blowouts" or large voiá treas at the root of the weld caused by the expansion of Gases inside the tube during welding. The "blowoui" problem can be solved by welding under a vacuum with an electron deam; however, the necessity for a heliun atmosphere inside the tube for leak testing and heat transfer, plus the expense of electron-beam equilucent, essentially eliminates this method. In developing a successful fusion-welding procedure, a large number of conventional weld joints, namely, butt, plug, and edge fusion designs, were examined without satisfaction in light of a complete spectrum of welding variables. With the joints investigated, the required rull weld penetration could not be consistently obtained nor could the "blowout" problem be eliminated regardless of the type of external heat sink applied. lom , Research sponsored by the U. S. Atomic Energy Commission under contract with the Union Carbide Corporation. 2Speaker. Sponsor: A. R. Olsen. 3J. D. Sease and D. M. Hewette II, Fabrication and Preirradiation Data for HFI? Prototype Target Rods, ORNL TM-811 (June, 1964). NCT FOR PUBLIC RELEASE OFFICIAL 1.77i.urlör SAME. OFFICIAL REQUEST WAY BE FILLEO. REPCRT CONTA!KS li bitilG OF PATENT INTEREST PROCEDURES ON FILE IN RECEIVING SECTION. - - - - -- - : The closure-welding procedure developed uses a standard tungsüen inert-gas welding torch and a constant-current programmed direct-current welding power supply. The weld is made under a helium blanke with the rod rotating and with a heat sink attached to the tube. The success of this welding procedure is the result of two significant developments: First, rull one-wall thickric:68 weld penetration results from a step-type Lid-flug design with a unique filler-metal principle (see insert, wg. 1) in which the filler-metal is an integral part of the machined tube hardware. Second, the "blowout" problem is eliminated by reducing the internal pressure in the tube. Before welding, the end plug is mechanically bonded to the tube by deforming the tubing in te swagging groove (Hg. 1, insert), thereby effecting a vacuum-tight seal. The internal. gas pressure can then be reduced by submerging the closed end of the tube in a bath of liquid nitrogen, thus chilling th: gas in the tube. Using this procedure, 10 out of ll weld attempts on the last group of plutonium-containing irradiation samples were successful ir. obtaining full weld penetration. These welds were examined by soft x-ray techniques. The major application for the welding procedure at ORNL is the fabrication of the HFIR target elements. The fabrication for the first loading of the target, which will contain 242 Pu, should present no particular problem as the fabrication can be a gloved-box type oneration. Subsequent loadings of the target will contain the transplutonic elements, thus making complete remote fabrication mandatory. The fabrication of the transplutonic-containing elements will be accomplished in the Oak Ridge National Laboratory's Transuranium Facility. Currently, an in-cell welding machine is being designed utilizing the principles outlined. The major design problem in the in-cell machine is remote torch position- ing and maintaining a reduced pressure inside the tube during welding. = - . - : . * 1. . 7 * * - * - . . I. . - ... - -:- i 5 : -. . i. - ra mi " . l. 11 . : - -. F - - . . . . . L'. - - - ue - - - - . .. - - . - - - - - .. . O E UNCI ASSII11) ORMI.-086 62.2126 S 2572 in. 20 in. ACTIVE LENGTH -** --... - m ï 35 PELLETS ni --- - PuO, AI COMI ACTED ... - - -CAN FUIT. TUBE erore PELLET !.*** 0.250-in. DIAM COMPACTED AI TOWDER SUPPORT SLEEVE .....VENT HOLES . ",". . . hooº 0.050 in. TYP. Ale 0.027-in. WALL AI TUBING SECTION ^.^ 0.571 in. PELLET (AFTER MESSING) Ai !! W1% Co MONITORING VIRE WM. Figl Compiutton og Typene In botom Copsile SE? 1. HT ' 1. DATE FILMED 1 / 5 /165 LAN sim . LEGAL NOTICE This report was prepared as an account of Government sponsored work. Neither the United States, aor the Commission, nor any person acting on behalf of the Commission: A. Makes any warranty or representation, expressed or implied, with respect to the accu- racy, completeness, or usefulness of the information contained in this report, or that the use of any information, apparatus, method, or process disclosed in this report may not infringe privately owned rights; or B. Assumes any llabilities with respect to the use of, or for damages resulting from the use of any information, apparatus, method, or process disclosed in this report. As used in the above, “person acting on behalf of the Commission” includes any em- ployos or contractor of the Commission, or employee of such contractor, to the extent that such employee or contractor of the Commission, or employee of such contractor prepares, disseminates, or provides access to, any information pursuant to his employment or contract with the Commission, or his employment with such contractor. END .