Abstract
If UO{sub 2} small spheres are used as fuel in a reactor in contact with the cooler, it is necessary to know the maximum value of the thermal stress, due to the work conditions in the reactor, which the small spheres are able to withstand without breaking. These conditions can be calculated if the physical properties of the material are known. Owing to the considerable number of properties involved, and in consideration of the uncertainty which always exists in each of them, it is preferable to test directly the spheres, submitting them to the same kind of stresses that they undergo in thereactor. In this work a thermal shock method for the small spheres has been studied, while conditions are indicated in which this method can reproduce stress conditions directly comparable with those existing in the reactor. As for small spheres, the difficulty consists in producing coolings with very high values of the coefficient of surface heat transfer. The experimental methods are described and the results obtained are indicated. The application of this method seems to be very interesting particularly in the field of the technological research for improving the characteristics of the UO{sub 2} small spheres by means of
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Perona, G.;
Brutto, E.;
Galbusera, U.;
Palladino, G.;
Sesini, R.
[1]
- Centro Informazioni Studi Esperienze, Milan (Italy)
Citation Formats
Perona, G., Brutto, E., Galbusera, U., Palladino, G., and Sesini, R.
Thermal Shock Tests on UO{sub 2} Small Spheres; Essais de choc thermique sur des elements spheriques de UO{sub 2}; Ispytaniya nebol'shikh sharikov iz UO{sub 2} teplovykh udarom; Ensayo de pequenas esferas de UO{sub 2} por choque.termico.
IAEA: N. p.,
1963.
Web.
Perona, G., Brutto, E., Galbusera, U., Palladino, G., & Sesini, R.
Thermal Shock Tests on UO{sub 2} Small Spheres; Essais de choc thermique sur des elements spheriques de UO{sub 2}; Ispytaniya nebol'shikh sharikov iz UO{sub 2} teplovykh udarom; Ensayo de pequenas esferas de UO{sub 2} por choque.termico.
IAEA.
Perona, G., Brutto, E., Galbusera, U., Palladino, G., and Sesini, R.
1963.
"Thermal Shock Tests on UO{sub 2} Small Spheres; Essais de choc thermique sur des elements spheriques de UO{sub 2}; Ispytaniya nebol'shikh sharikov iz UO{sub 2} teplovykh udarom; Ensayo de pequenas esferas de UO{sub 2} por choque.termico."
IAEA.
@misc{etde_22109659,
title = {Thermal Shock Tests on UO{sub 2} Small Spheres; Essais de choc thermique sur des elements spheriques de UO{sub 2}; Ispytaniya nebol'shikh sharikov iz UO{sub 2} teplovykh udarom; Ensayo de pequenas esferas de UO{sub 2} por choque.termico}
author = {Perona, G., Brutto, E., Galbusera, U., Palladino, G., and Sesini, R.}
abstractNote = {If UO{sub 2} small spheres are used as fuel in a reactor in contact with the cooler, it is necessary to know the maximum value of the thermal stress, due to the work conditions in the reactor, which the small spheres are able to withstand without breaking. These conditions can be calculated if the physical properties of the material are known. Owing to the considerable number of properties involved, and in consideration of the uncertainty which always exists in each of them, it is preferable to test directly the spheres, submitting them to the same kind of stresses that they undergo in thereactor. In this work a thermal shock method for the small spheres has been studied, while conditions are indicated in which this method can reproduce stress conditions directly comparable with those existing in the reactor. As for small spheres, the difficulty consists in producing coolings with very high values of the coefficient of surface heat transfer. The experimental methods are described and the results obtained are indicated. The application of this method seems to be very interesting particularly in the field of the technological research for improving the characteristics of the UO{sub 2} small spheres by means of additives. In fact it allows the control of the total interesting effect with a single measurement. (author) [French] Si l'on veut utiliser comme combustible dans un reacteur des elements spheriques de UO{sub 2} en contact avec le refroidisseur, il faut au prealable determiner la valeur maximum de la contrainte thermique - due aux conditions regnant dans le reacteura laquelle les elements sont capables de resister sans se fissurer. Il est possible de calculer ces conditions si l'on connait les proprietes physiques du materiau utilise. En raison du nombre important des proprietes a prendre en consideration, et compte tenu de l'incertitude qui existe toujours pour chacune d'elles, il est preferable de faire des essais thermiques en soumettant directement les elements a des contraintes analogues a celles qu'ils subissent dans la pile. Les auteurs exposent un procede dans lequel les elements spheriques sont soumis a un choc thermique et ils indiquent la maniere dont on parvient a simuler des contraintes directement comparables a celles qui existent dans le reacteur. Comme il s'agit de spheres de petite dimension, la difficulte consiste a produire des refroidisseurs dont le coefficient de transmission superficielle est tres eleve. Les auteurs exposent les methodes experimentales utilisees et les resultats obtenus. Le procede decrit par les auteurs presente un interet particulier dans le domaine de la recherche technologique, car il permet d'ameliorer les caracteristiques des spheres de l'UO{sub 2} au moyen de produits d'addition. En fait, il permet de controler par une seule operation de mesure l'effet global auquel on s'interesse. (author) [Spanish] Si en un reactor-se utilizan como combustible pequenas esferas de UO{sub 2} en contacto con el refrigerante, es preciso conocer el valor maximo de la tension termica que. debido a las condiciones de trabajo en el reactor, las pequenas esferas son capaces de soportar sin romperse. Estas condiciones pueden evaluarse si se conocen las propiedades fisicas del material. Pero en razon del considerable numero de propiedades que intervienen, y habida cuenta de la incertidumbre que siempre existe respecto de cada una de ellas, es preferible ensayar directamente las esferas sometiendolas a tensiones analogas a las que estan expuestas en el reactor. En la memoria se estudia un metodo de ensayo de dichas esferas por choque termico y se indican las condiciones en que tal metodo permite reproducir tensiones termicas directamente comparables con las reinantes en el reactor. En cuanto a las pequenas esferas, la dificultad estriba en lograr condiciones de refrigeracion en las que el coeficiente de transmision superficial de calor sea muy elevado. Se describen los metodos experimentales aplicados y se exponen los resultados obtenidos. La aplicacion de este metodo presenta, al parecer, considerable interes, sobre todo en lo que concierne a las investigaciones encaminadas a mejorar las caracteristicas de las esferas de UO{sub 2} por medio de aditivos. En e fecto, permite verificar el efecto global con una sola medicion. (author) [Russian] Ispol'zuya malye pariki iz UO{sub 2} v kachestve yadernogo topliva v reaktore, gde oni nakhodyatsya v soprikosnovenii s teplonositelem, neobkhodimo znat' maksimal'nuyu pri rabochem rezhime reaktora velichinu termicheskikh napryazhenij, kotorye mogut vyderzhivat' bez povrezhdeniya ehti shariki. Esli izvestny fizicheskie svojstva materiala, to mozhno rasschitat' ehti napryazheniya pri rabochem rezhime. Odnako vvidu mnogochislennosti podlezhashchikh uchetu faktorov i neizbezhnoj doli neopredelennosti kazhdogo iz nikh predstavlyaetsya predpochtitel'nym provesti neposredstvennye ispytaniya ehtikh sharikov, podvergnuv ikh tem zhe napryazheniyam, kakie oni ispytyvayut v reaktore. V nastoyashchej rabote byl izuchen metod teplovogo udara v primenenii k malym sharikam i ukazyvayutsya usloviya, pri kotorykh ehtot metod pozvolyaet proizvesti napryazheniya, neposredstvenno sravnimye s temi, kotorye sushchestvuyut v reaktore. V sluchae malykh sharikov zatrudnenie zaklyuchaetsya v osushchestvlenii okhlazhdeniya, pozvolyayushchego dostigat' ochen' bol'shikh znachenij koehffitsienta poverkhnostnoj teploperedachi. Opisyvayutsya ehksperimental'nye metody i soobshchayutsya poluchennye rezul'taty. Primenenie ehtogo' metoda, po-vidimomu., predstavlyaet bol'shoj interes, v osobennosti v oblasti tekhnologicheskikh izyskanij s tsel'yu uluchsheniya svojstv malykh sharikov iz UO{sub 2} putem vklyucheniya dobavochnykh komponentov. Fakticheski,ehtot metod daet vozmozhnost' pri pomoshchi odnogo tol'ko izmereniya kontrolirovat' izuchaemoe vozdejstvie. (author)}
place = {IAEA}
year = {1963}
month = {Nov}
}
title = {Thermal Shock Tests on UO{sub 2} Small Spheres; Essais de choc thermique sur des elements spheriques de UO{sub 2}; Ispytaniya nebol'shikh sharikov iz UO{sub 2} teplovykh udarom; Ensayo de pequenas esferas de UO{sub 2} por choque.termico}
author = {Perona, G., Brutto, E., Galbusera, U., Palladino, G., and Sesini, R.}
abstractNote = {If UO{sub 2} small spheres are used as fuel in a reactor in contact with the cooler, it is necessary to know the maximum value of the thermal stress, due to the work conditions in the reactor, which the small spheres are able to withstand without breaking. These conditions can be calculated if the physical properties of the material are known. Owing to the considerable number of properties involved, and in consideration of the uncertainty which always exists in each of them, it is preferable to test directly the spheres, submitting them to the same kind of stresses that they undergo in thereactor. In this work a thermal shock method for the small spheres has been studied, while conditions are indicated in which this method can reproduce stress conditions directly comparable with those existing in the reactor. As for small spheres, the difficulty consists in producing coolings with very high values of the coefficient of surface heat transfer. The experimental methods are described and the results obtained are indicated. The application of this method seems to be very interesting particularly in the field of the technological research for improving the characteristics of the UO{sub 2} small spheres by means of additives. In fact it allows the control of the total interesting effect with a single measurement. (author) [French] Si l'on veut utiliser comme combustible dans un reacteur des elements spheriques de UO{sub 2} en contact avec le refroidisseur, il faut au prealable determiner la valeur maximum de la contrainte thermique - due aux conditions regnant dans le reacteura laquelle les elements sont capables de resister sans se fissurer. Il est possible de calculer ces conditions si l'on connait les proprietes physiques du materiau utilise. En raison du nombre important des proprietes a prendre en consideration, et compte tenu de l'incertitude qui existe toujours pour chacune d'elles, il est preferable de faire des essais thermiques en soumettant directement les elements a des contraintes analogues a celles qu'ils subissent dans la pile. Les auteurs exposent un procede dans lequel les elements spheriques sont soumis a un choc thermique et ils indiquent la maniere dont on parvient a simuler des contraintes directement comparables a celles qui existent dans le reacteur. Comme il s'agit de spheres de petite dimension, la difficulte consiste a produire des refroidisseurs dont le coefficient de transmission superficielle est tres eleve. Les auteurs exposent les methodes experimentales utilisees et les resultats obtenus. Le procede decrit par les auteurs presente un interet particulier dans le domaine de la recherche technologique, car il permet d'ameliorer les caracteristiques des spheres de l'UO{sub 2} au moyen de produits d'addition. En fait, il permet de controler par une seule operation de mesure l'effet global auquel on s'interesse. (author) [Spanish] Si en un reactor-se utilizan como combustible pequenas esferas de UO{sub 2} en contacto con el refrigerante, es preciso conocer el valor maximo de la tension termica que. debido a las condiciones de trabajo en el reactor, las pequenas esferas son capaces de soportar sin romperse. Estas condiciones pueden evaluarse si se conocen las propiedades fisicas del material. Pero en razon del considerable numero de propiedades que intervienen, y habida cuenta de la incertidumbre que siempre existe respecto de cada una de ellas, es preferible ensayar directamente las esferas sometiendolas a tensiones analogas a las que estan expuestas en el reactor. En la memoria se estudia un metodo de ensayo de dichas esferas por choque termico y se indican las condiciones en que tal metodo permite reproducir tensiones termicas directamente comparables con las reinantes en el reactor. En cuanto a las pequenas esferas, la dificultad estriba en lograr condiciones de refrigeracion en las que el coeficiente de transmision superficial de calor sea muy elevado. Se describen los metodos experimentales aplicados y se exponen los resultados obtenidos. La aplicacion de este metodo presenta, al parecer, considerable interes, sobre todo en lo que concierne a las investigaciones encaminadas a mejorar las caracteristicas de las esferas de UO{sub 2} por medio de aditivos. En e fecto, permite verificar el efecto global con una sola medicion. (author) [Russian] Ispol'zuya malye pariki iz UO{sub 2} v kachestve yadernogo topliva v reaktore, gde oni nakhodyatsya v soprikosnovenii s teplonositelem, neobkhodimo znat' maksimal'nuyu pri rabochem rezhime reaktora velichinu termicheskikh napryazhenij, kotorye mogut vyderzhivat' bez povrezhdeniya ehti shariki. Esli izvestny fizicheskie svojstva materiala, to mozhno rasschitat' ehti napryazheniya pri rabochem rezhime. Odnako vvidu mnogochislennosti podlezhashchikh uchetu faktorov i neizbezhnoj doli neopredelennosti kazhdogo iz nikh predstavlyaetsya predpochtitel'nym provesti neposredstvennye ispytaniya ehtikh sharikov, podvergnuv ikh tem zhe napryazheniyam, kakie oni ispytyvayut v reaktore. V nastoyashchej rabote byl izuchen metod teplovogo udara v primenenii k malym sharikam i ukazyvayutsya usloviya, pri kotorykh ehtot metod pozvolyaet proizvesti napryazheniya, neposredstvenno sravnimye s temi, kotorye sushchestvuyut v reaktore. V sluchae malykh sharikov zatrudnenie zaklyuchaetsya v osushchestvlenii okhlazhdeniya, pozvolyayushchego dostigat' ochen' bol'shikh znachenij koehffitsienta poverkhnostnoj teploperedachi. Opisyvayutsya ehksperimental'nye metody i soobshchayutsya poluchennye rezul'taty. Primenenie ehtogo' metoda, po-vidimomu., predstavlyaet bol'shoj interes, v osobennosti v oblasti tekhnologicheskikh izyskanij s tsel'yu uluchsheniya svojstv malykh sharikov iz UO{sub 2} putem vklyucheniya dobavochnykh komponentov. Fakticheski,ehtot metod daet vozmozhnost' pri pomoshchi odnogo tol'ko izmereniya kontrolirovat' izuchaemoe vozdejstvie. (author)}
place = {IAEA}
year = {1963}
month = {Nov}
}