Price: Printed Copy $5.45 Microfiche $2.25 Thu report win prepared of nn aoraunl or work iponiorad by the Untied Stolw Govctnmanl N«ilh« th« Unitod SlalM nor In* United StatM Atomic Ensrqy Gimmictinn. not any of Ihcir kmplofMff, not an|i ol Ihfir cnntt'icloii. lubcrinlidrtoti, or then vntploT***. tnahM anj Manaarr. Hpint m implind. or «iim«< rmy teqd ImUltf or npouibililT lot 111. m curnry comphrlptiM* at ulttulnMi of aay information, apparatut. ptiHjuct nr prric*M (JitcloHtd. or r.prtwnri thai

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... lit uM woukl not utlrlBg* ptivulrlv ownM riqhtj PAGE 1 1 10 10 13 14 15 15 48 51 51 53 53 54 57 57 iii ABSTRACT This is the 31st quarterly and eighth annual report on the Advanced Plutonium Fuels Program at the Los Alamos Scientific Laboratory. Most of the investigations discussed here arc of the continuing type. -Results and conclusions described may thorof ore be changed or augmented as the work continues. Published reference to results cited its this report should not be made without obtaining explicit permission to do so (com the person in charge of the work. iv PROJECT 401 EXAMINATION OF FAST JIBACTOH FUELS Person ID Charge: Principal Investigators: 1. WTIlODt'CTION Tills project la directed toward the examination and comparison of the effect* of neutron irradiation on LMFittt Program fuel materials. Ualrradiated and irradiated materials arc examined as requested by the Fuels ami Materials Branch of DIUU). Capabilities arc established and are txlng expanded (or providing conventional) prelrraiiiated and postlrradiailon examination*. Nondestructive tests are conducted In a hot cell facility specifically modified for examining irradiated prototype fuel plus at a rate commensurate with schedules established by D!UU>. Characterization of unirradiated and irradiated fuels by analytical chemistry methods were continued and additional .'icthod* were modified and mechanized for hot coll application. Macro-six! m&roextmlnaUons were made on fuel and cladding using the shielded electron microprobe, radiocnemlstry, gamma scanner, mass spectrometers, and other analytical facilities. New capabilities wore applied In gamma scan-iinj, analyses to assess spatial distributions of fuel and fission products, mass spcctromeirle measurements of burnup and fission gas constituents, chemical analyses, and measurement of carbon and oxygen In irradiated fuels. Microstruetura! analyses o! unirradjated asd Irradiated materials was continued uslnj; optical ctsd eleclromlcrotcopy, and autoradlographlc and x-ray techniques. New etching and mounting techniques were developed for high burnup materials. It. EQUIPMENT DEVELOPMENT A. tq-Cclt Equipment 1. System for Obtaining Weight and Density of Fual Pins. A system nM been Installed to measure In air or in a suitable fluid the weights of irradiated fuel pins up So 61 in. in length In a vertical position. Using tho weights in air and in a fluid, the density of irradiated fuel pins can be determined. The system consults of a 1000-g analytical balance, with a sensitivity of 0.1 mg, mounted on a cell roof plug directly above a small hole through the plug. A piano wire is attached to the balance and hangs Into the operating cell. The fuel pins are weighed by attrchlng them to a holding device on the end of the piano wire and suspending them In a 132-ntm (G-in.) diameter tube Installed in the cell. The fill and drain system to permit using a suitable fluid in itw submersion of the fuel pins for density determination has been completed and Installed. The unit is now operational for Irradiated pins. 2. Sodium Olsiillation Furnace. The furnace was completed, and thermocouples were attached to both the helling plate and a "dummy" uranium carbide fuel sample mouatcd In the usual metallography grinding gauge and cup. A temperature of 30f.°C was attained by the "dummy" fuel sample while maintilning Che beating plnte at 4S0°C. To permit heating the I Mel samples to the desired 4S0°C during distillation, the "dummy" sample will be included In 4. Fission Gas Sampling System. In order to imp-ove the accuracy of the void volume measurements obtained from fuel pins, a new drilling system was designed lor pins .p to 9.5 mm (0.375 in.) in diameter. The improved device utilizes a smaller chamber to house the drill. The preceding unit had the flexibility of puncturing capsules or pins from 3.2 to 32 mm (0.125 to 1.25 in.) in diameter, and thus the drill housing had to be large. The new device has been used successfully on several fuel pins. A request has been received to double-puncture through a 29 mm (1.125 in.) diameter capsule which is NaK filled. The NaK must be frozen during the puncturing operation. Equipment is presently being designed to satisfy this request. Improvements Made in the Metallography Cells. Another filter assembly was built and installed in the Slurper Drains of the Metallography Cells. The filter utilizes a disposable package concept for easier replacement. Teflon O-rings are used to eliminate previous problems of swelling encountered with neoprene and viton O-rings. A bell jar assembly utilizing a heating plate was fabricated to permit potting of metallography samples in a new epoxy resin. A temperature of 80°C is required for proper curing. Two new fixtures were fabricated aud Installed to improve efficiency in preparing metallographic samples. A newly designed macrophotography Loading. Device was fabricated and placed in service. A Vacuum Potting Box, with design requirements furnished by the metallographer, was fabricated and prepared for installation. A micrometer stand for verification of (he grinding depth obtained during metallograph sample preparation has been designed and fabricated. 11. Miscellaneous Equipment. a. A seccnd trunnion fixture for loading the radiography cask has been placed in service. This eliminates the necessity for transferring the fixture between the Wing 9 and DP-West Facilities. b. The radiography cr.»i <vas overhauled. The lead screw shaft end was modified, machined, and new drive gears installed with dowel pins for more reliable operation.