Published November 1963
| Version v1
Book
A New Process for Producing Small UO2 Sintered Spheres Based on Isostatic Pressing
- 1. Centro Informazioni Studi Esperienze, Milan (Italy)
Description
In connection with the modern concepts of fluidized-bed and fixed-bed reactors the development o f economic processes for small UO2 sintered spheres production is of fundamental importance. The process described here consists essentially in forming the small spheres in a die and then pressing them isostatically. Research was developed mainly to determine which are the alloying elements, the lubricants and the solvents suitable for good die-forming at very low pressure, the drying processes before pressing and finally the best pressing conditions. The last operation was made very easy by eliminating the impermeable coating of the spheres to be pressed; this has been possible using a very viscous fluid, which does not penetrate into the porosities of the sphere's body. A particular study has been devoted to the effect of the value of the isostatic pressure on the density after sintering. The results obtained from the density measurements and from the metallographic observation (both at the optical and the electronic microscope) are compared to those obtained by the pellets produced (starting from the same powder) with standard processes. (author)
Abstract (French)
Etant donne que des types modernes de reacteurs a lit fluidise et a lit fixe ont ete mis au point, il est devenu extremement important de trouver des procedes economiques de fabrication de petits elements spheriques en oxyde d'uranium fritte. Le procede decrit par les auteurs consiste essentiellement a mouler de petites spheres, puis a leur faire subir un pressage isostatique. Les recherches ont eu surtout pour objet de determiner quels elements de l'alliage, lubrifiants et solvants conviennent au moulage a tres basse pression, quels procedes de sechage avant pressage il faut employer et, enfin, quelles sont les meilleures conditions de pressage. On a rendu cette derniere operation tres facile en eliminant le revetement impermeable des spheres a presser; il est possible d'y parvenir en utilisant un liquide tres visqueux qui ne penetre pas dans les porosites de la sphere. On a consacre une etude speciale a l'influence de la valeur de la pression isostatique sur la densite apres frittage. Les resultats des mesures de densite et des observations metallographiques (effectuees au microscope optique et au microscope electronique) font l'objet d'une comparaison avec ceux que donnent les pastilles fabriquees a partir de la meme poudre selon les procedes classiques. (author)Abstract (Spanish)
Dados los tipos de reactor de lecho fluidificado y de lecho fijo, la elaboracion de procedimientos economicos para producir pequenas esferas de UO2 sintetizado reviste fundamental importancia. El procedimiento descrito en la memoria consiste esencialmente en moldear las pequenas esferas en una matriz para prensarlas isostaticamente. Las investigaciones realizadas tenian por principal objeto determinar cuales son los elementos de aleacion, los lubricantes y los disolventes adecuados para un moldeado satisfactorio en matriz a muy baja presion, asi como el procedimiento mas indicado de secado antes del prensado y, por ultimo, las condiciones optimas de prensado. Esta ultima operacion se facilito en gran medida eliminando el revestimiento impermeable de las esferas que han de prensarse, lo cual se logro con ayuda de un fluido muy viscoso, que no penetra en los poros de las esferas. Se ha realizado un estudio especial para investigar el efecto de la presion isostatica en la densidad despues de la sinterizacion. Los resultados obtenidos por medicion de densidades y por examen metalografico (en microscopio optico y electronico) se comparan con los proporcionados por pastillas elaboradas con arreglo al procedimiento normal, a partir del mismo polvo. (author)Abstract (Russian)
V svyazi s sovremennoj kontseptsiej reaktorov s dvizhushchimsya i nepodvizhnym toplivom priobretaet sushchestvennoe znachenie razrabotka sposobov ehkonomichnogo izgotovleniya malykh spekshikhsya sharikov iz UO2. Opisyvaemyj sposob sostoit v osnovnom iz formovki nebol'shikh sharikov v matritse i v dal'nejshem ikh pressovanii pri izostaticheskom davlenii. Issledovaniya byli napravleny glavnym obrazom na izyskanie naibolee podkhodyashchikh dlya pressovaniya pod ochen' nizkim davleniem svyazyvayushchikh veshchestv, smazki i rastvoritelej, a takzhe na razrabotku sposobov sushki do pressovaniya i,nakonets,na opredelenie nailuchshikh uslovij samogo pressovaniya. Poslednyaya operatsiya byla znachitel'no oblegchena putem udaleniya s podlezhashchikh pressovaniya sharikov nepronitsaemoj obolochki; ehtogo udalos' dostich' blagodarya ispol'zovaniyu ochen' vyazkoj zhidkosti, kotoraya ne Pronikaet v pory sharikov. Osobo issledovano vliyanie velichiny izostaticheskogo davleniya na plotnost' posle spekaniya. Rezul'taty, poluchennye putem izmereniya plotnosti i putem metallograficheskogo nablyudeniya (kak pri pomoshchi opticheskogo, tak i ehlektronnogo mikroskopov) sravnivayutsya s rezul'tatami, poluchennymi na sharikakh, izgotovlennykh iz togo zhe samogo poroshka obychnymi sposobami. (author)Additional details
Additional titles
- Original title (English)
- Nouveau procede de fabrication, par pressage isostatique, de petits elements spheriques en oxyde d'uranium fritte; Novyj sposob izgotovleniya nebol'shikh spekshikhsya sharikov iz UO
Publishing Information
- Publisher
- IAEA
- Imprint Place
- Vienna (International Atomic Energy Agency (IAEA))
- Imprint Title
- New Nuclear Materials Including Non Metallic Fuel Elements. Vol. I. Proceedings of the Conference on New Nuclear Materials Technology, Including Non Metallic Fuel Elements
- Imprint Pagination
- 582 p.
- Series
- Proceedings Series
- Journal Page Range
- p. 165-189
- ISSN
- 0074-1884
Conference
- Title
- Conference on New Nuclear Materials Technology, Including Non Metallic Fuel Elements
- Dates
- 1-5 Jul 1963
- Place
- Prague (Czech Republic)
INIS
- Country of Publication
- International Atomic Energy Agency (IAEA)
- Country of Input or Organization
- International Atomic Energy Agency (IAEA)
- INIS RN
- 44074000
- Subject category
- S36: MATERIALS SCIENCE; S11: NUCLEAR FUEL CYCLE AND FUEL MATERIALS;
- Resource subtype / Literary indicator
- Conference
- Descriptors DEI
- DENSITY; ELECTRON MICROSCOPES; FLUIDIZED BED REACTORS; FUEL PELLETS; LUBRICANTS; METALLOGRAPHY; OPTICAL MICROSCOPES; PACKED BEDS; POWDERS; PRESSING; SINTERING; SOLVENTS; SPHERES; URANIUM DIOXIDE
- Descriptors DEC
- ACTINIDE COMPOUNDS; CHALCOGENIDES; FABRICATION; FUEL DISPERSION REACTORS; HOMOGENEOUS REACTORS; MATERIALS WORKING; MICROSCOPES; OXIDES; OXYGEN COMPOUNDS; PELLETS; PHYSICAL PROPERTIES; REACTORS; URANIUM COMPOUNDS; URANIUM OXIDES
Optional Information
- Notes
- 17 figs., 8 res. Imprint:In two volumes
- Secondary number(s)
- STI/PUB--77(v.1)