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Limitations of Ir{sup 192} as a Radiographic Source for the Control of Reactor Pressure-Vessels; Limitations de {sup 192}Ir en Tant que Source pour l'Examen Radiographique des Caissons Etanches de Reacteurs; Nedostatki Iridiya-192 v kachestveradiograficheskogo istochnika dlya kontrolya za korpusami reaktorov vysokogodavleniya; Limitaciones del {sup 192}Ir como Fuente Radiografica en el Control de Recipientes de Presion para Reactores

Conference:

Abstract

Published data and the results of our own investigations have shown that the advantage of Ir{sup 192} with regard to the quality of radiographs is obvious when comparing it with Co{sup 60} even with thicknesses over 80 mm of irradiated steel. The application of Ir{sup 192} in practice is limited by the alternative: either a very long exposure time or a source of very high activity. Where the exposure (Ci. min) for 1 m of radiographed weld is plotted against the specific activity of the source, diagrams show that, for practically attainable specific activities kilo-curie sources must be used for greater thicknesses. For such sources, self-absorption may become an important factor. An analysis of the influence of self-absorption causing a reduction of the source effectiveness and the filtration effect in the source is made by determining an equivalent increase of thickness of irradiated steel and by calculating the effective linear absorption coefficient as a function of the source dimensions and the thickness of the irradiated steel. Even in cases of relatively large source dimensions the filtration effect does not diminish the effective linear absorption coefficient to such an extent that the advantage in quality against Co{sup 60} would be lost.  More>>
Authors:
Horvat, D. [1] 
  1. Nuclear Institute ''J. Stefan'' Ljubljana, Yugoslavia (Slovenia)
Publication Date:
Sep 15, 1965
Product Type:
Conference
Report Number:
IAEA-SM-63/22
Resource Relation:
Conference: Symposium on Non-Destructive Testing in Nuclear Technology, Bucharest (Romania), 17-21 May 1965; Other Information: 8 refs., 1 tab., 6 figs.; Related Information: In: Non-Destructive Testing in Nuclear Technology Vol. I. Proceedings of a Symposium on Non-Destructive Testing in Nuclear Technology| 408 p.
Subject:
36 MATERIALS SCIENCE; COBALT 60; FILMS; HALF-LIFE; IRIDIUM 192; IRRADIATION; NONDESTRUCTIVE TESTING; PRESSURE VESSELS; REACTOR VESSELS; SELF-ABSORPTION; SHAPE; STEELS; THICKNESS; WELDED JOINTS
OSTI ID:
22121938
Research Organizations:
International Atomic Energy Agency, Vienna (Austria)
Country of Origin:
IAEA
Language:
English
Other Identifying Numbers:
Other: ISSN 0074-1884; TRN: XA13M2520078049
Submitting Site:
INIS
Size:
page(s) 61-72
Announcement Date:
Aug 27, 2013

Conference:

Citation Formats

Horvat, D. Limitations of Ir{sup 192} as a Radiographic Source for the Control of Reactor Pressure-Vessels; Limitations de {sup 192}Ir en Tant que Source pour l'Examen Radiographique des Caissons Etanches de Reacteurs; Nedostatki Iridiya-192 v kachestveradiograficheskogo istochnika dlya kontrolya za korpusami reaktorov vysokogodavleniya; Limitaciones del {sup 192}Ir como Fuente Radiografica en el Control de Recipientes de Presion para Reactores. IAEA: N. p., 1965. Web.
Horvat, D. Limitations of Ir{sup 192} as a Radiographic Source for the Control of Reactor Pressure-Vessels; Limitations de {sup 192}Ir en Tant que Source pour l'Examen Radiographique des Caissons Etanches de Reacteurs; Nedostatki Iridiya-192 v kachestveradiograficheskogo istochnika dlya kontrolya za korpusami reaktorov vysokogodavleniya; Limitaciones del {sup 192}Ir como Fuente Radiografica en el Control de Recipientes de Presion para Reactores. IAEA.
Horvat, D. 1965. "Limitations of Ir{sup 192} as a Radiographic Source for the Control of Reactor Pressure-Vessels; Limitations de {sup 192}Ir en Tant que Source pour l'Examen Radiographique des Caissons Etanches de Reacteurs; Nedostatki Iridiya-192 v kachestveradiograficheskogo istochnika dlya kontrolya za korpusami reaktorov vysokogodavleniya; Limitaciones del {sup 192}Ir como Fuente Radiografica en el Control de Recipientes de Presion para Reactores." IAEA.
@misc{etde_22121938,
title = {Limitations of Ir{sup 192} as a Radiographic Source for the Control of Reactor Pressure-Vessels; Limitations de {sup 192}Ir en Tant que Source pour l'Examen Radiographique des Caissons Etanches de Reacteurs; Nedostatki Iridiya-192 v kachestveradiograficheskogo istochnika dlya kontrolya za korpusami reaktorov vysokogodavleniya; Limitaciones del {sup 192}Ir como Fuente Radiografica en el Control de Recipientes de Presion para Reactores}
author = {Horvat, D.}
abstractNote = {Published data and the results of our own investigations have shown that the advantage of Ir{sup 192} with regard to the quality of radiographs is obvious when comparing it with Co{sup 60} even with thicknesses over 80 mm of irradiated steel. The application of Ir{sup 192} in practice is limited by the alternative: either a very long exposure time or a source of very high activity. Where the exposure (Ci. min) for 1 m of radiographed weld is plotted against the specific activity of the source, diagrams show that, for practically attainable specific activities kilo-curie sources must be used for greater thicknesses. For such sources, self-absorption may become an important factor. An analysis of the influence of self-absorption causing a reduction of the source effectiveness and the filtration effect in the source is made by determining an equivalent increase of thickness of irradiated steel and by calculating the effective linear absorption coefficient as a function of the source dimensions and the thickness of the irradiated steel. Even in cases of relatively large source dimensions the filtration effect does not diminish the effective linear absorption coefficient to such an extent that the advantage in quality against Co{sup 60} would be lost. Possibilities of improvement due to a new shape of radiographic sources are discussed. In the case of narrow primary beams these new sources give smaller effective dimensions and allow shorter source-to-film distances. A further advantage of Ir{sup 192} is obvious from the diagrams of the weight of the exposure equipment for Ir{sup 192} and Coso taking in account equivalent activities of both sources regarding the same exposure time. The economic disadvantages, because of the short half-life,of Ir{sup 192} are discussed and a rough economical comparison between Co{sup 60} and Ir{sup 192} at different extensiveness and densities of the radiographic control is given. (author) [French] Les donnees publiees et les resultats des etudes faites par l'auteur montrent que, pour ce qui est de la qualite des radiographies,{sup 192}Ir presente un avantage tres net sur {sup 60}Co, meme pour des epaisseurs d'acier irradie superieures a 80 mm. Dans la pratique, l'emploi de {sup 192}Ir est limite parce qu'il faut un temps d'exposition tres long ou une source tres intense. Des diagrammes donnent, en fonction de l'activite specifique de la source, le temps d'exposition necessaire pour radiographier une soudure de 10 cm; ces diagrammes montrent que, compte tenu des activites specifiques que l'on peut obtenir dans la pratique, il faut des sources de l'ordre du kilocurie pour des epaisseurs plus importantes. Pour de telles sources, l'auto-absorption peut devenir un facteur important. Onanalysel'influence de l'auto-absorption, qui reduit l'efficacite de la source, et l'effet de filtration dans la source en determinant l'augmentation correspondante de l'epaisseur d'acier irradie et en calculant le coefficient reel d'absorption lineique en fonction des dimensions de la source et de l'epaisseur d'acier irradie. Meme lorsque les dimensions de la source sont relativement importantes, l'effet de filtration ne diminue pas le coefficient reel d'absorption lineique au point de faire disparaitre l'avantage de {sup 192}Ir sur {sup 60}Co quant a la qualite de la radiographie. L'auteur examine les possibilites d'amelioration grace a. une forme nouvelle des sources. Ces nouvelles sources donnent, dans le cas de faisceaux primaires etroits, des dimensions efficaces plus reduites et permettent de diminuer la distance source-film. Un autre avantage de {sup 192}Ir ressort nettement des diagrammes donnant le poids des appareils de radiographie avec {sup 192}Ir et {sup 60}Co, compte tenu de l'intensite de la source dans chaque cas pour obtenir un meme temps d'exposition. L'auteur discute les desavantages de {sup 192}Ir sur le plan economique, du fait de sa courte periode; sur ce meme plan, il compare approximativement Registered-Sign Degree-Sign Co et {sup 192}Ir suivant la sensibilite et la precision desirees lors de l'examen radiographique. (author) [Spanish] Los datos publicados en la literatura y los resultados de las investigaciones del autor han puesto de manifiesto las ventajas evidentes que el {sup 192}Ir presenta sobre el {sup 60}Co en cuanto a la calidad de las radiografias obtenidas, aun con espesores de acero superiores a 80 mm. En la practica, la aplicacion del {sup 192}Ir esta supeditada a la siguiente alternativa: exposicion sumamente prolongada, o bien empleo de una fuente de actividad muy elevada. Si se representa graficamente la exposicion (Ci x min) correspondiente a 1 m de soldadura radiografiada, en funcion de la actividad especifica de la fuente, se observa que para espesores superiores a 80 mm y con las actividades especificas alcanzables en la practica, es necesario usar fuentes del orden del kilocurie. En ellas, la autoabsorcion puede llegar a ser un factor de importancia. Se analizan en la memoria la disminucion que la autoabsorcion provoca en la eficacia de la fuente y el efecto de filtracion en la misma; para ello se determina un aumento equivalente en el espesor del acero y se calcula el coeficiente de absorcion lineal efectiva en funcion de las dimensiones de la fuente y del espesor del acero irradiado. Aun tratandose de fuentes de dimensiones relativamente grandes, el efecto de diltracion no provoca en el coeficiente de absorcion lineal efectiva una disminucion capaz de anular las ventajas respecto del {sup 60}Co. Se analizan en el trabajo las posibilidades de mejora debidas al empleo de fuentes radiograficas modificadas. En el caso de haces primarios angostos, estas nuevas fuentes dan menores dimensiones efectivas y permiten trabajar con menores distancias entre fuente y pelicula. Otra ventaja del {sup 192}Ir se observa al comparar los pesos de los equipos necesarios para el {sup 192}Ir y para el {sup 60}Co, tomando en cuenta actividades equivalentes de ambas fuentes para igual tiempo de exposicion. Se analizan en el trabajo las desventajas economicas del {sup 192}Ir debidas a su corto periodo, y se presenta una comparacion economica aproximada entre {sup 60}Co y {sup 192}Ir para diferentes espesores y densidades del control radiografico. (author) [Russian] Opublikovannye dannye i rezul'taty nashih sobstvennyh issledovanij pokazali, chto preimushhestvo iridija-192 v otnoshenii kachestva rentgenovskih snimkov javljaetsja ochevidnym po sravneniju s kobal'- tom-60 dazhe pri Julpine obluchaemoj stali svyshe 80 mm. Primenenie iridija-192 na praktike ogranichivaetsja al'ternativoj: ili trebuetsja ochen' dlitel'noe vremja obluchenija ili istochnik ochen' vysokoj aktivnosti. Diagrammy, gde vychercheno obluchenie, vyrazhennoe v kjuri v minutu dlja odnogo metra radiografirovannoj svarki v otnoshenii udel'noj aktivnosti istochnika, pokazyvajut, chto v otnoshenii prakticheski dostupnyh udel'nyh aktivnostej istochniki v kilokjuri prihoditsja ispol'zovat' dlja bol'shej tolshhiny. Dlja takih istochnikov samopogloshhenie mozhet stat' vazhnym faktorom. Analiz vlijanija samopogloshhenija, vyzyvajushhego snizhenie jeffektivnosti istochnika i jeffektov fil'tracii v istochnike, proizvoditsja putem opredelenija jekvivalentnogo uvelichenija tolshhiny obluchaemoj stali i putem rascheta kojefficienta jeffektivnogo linejnogo pogloshhenija v kachestve funkcii razmerov istochnika i tolshhiny obluchaemoj stali. Dazhe v sluchajah s razmerami sravnitel'no krupnyh istochnikov jeffekt fil'tracii ne umen'shaet kojefficient jeffektivnogo linejnogo pogloshhenija v takoj stepeni, chtoby proishodila uterja preimushhestva v kachestve po sravneniju s kobal'tom-60. Obsuzhdajutsja vozmozhnosti uluchshenija v svjazi s novoj konfiguraciej radiograficheskih istochnikov. Jeti novye istochniki dajut v sluchae uzkih pervichnyh puchkov men'shie jeffektivnye razmery i dopuskajut men'shie rasstojanija mezhdu istochnikom i plenkoj. Drugoe preimushhestvo iridija-192 vidno iz diagramm vesa oborudovanija dlja obluchenija dlja iridija-192 i kobal'ta-60, uchityvaja jekvivalentnye aktivnosti oboih istochnikov v otnoshenii togo zhe samogo vremeni obluchenija. Obsuzhdae.tsja vopros ob jekonomicheskih nedostatkah iridija-192 vvidu ego korotkogo perioda poluraspada, i daetsja gruboe jekonomicheskoe sravnenie jeffektivnosti kobal'ta-60 i iridija-192 pri razlichnyh diapazonah i plotnostjah radiograficheskogo kontrolja. (author)}
place = {IAEA}
year = {1965}
month = {Sep}
}