Objetivo The monitoring of scrap and finished products for radioactivity can be ensured only with measuring systems and equipment arrangements featuring a high detection sensitivity and capable of meeting all the application-conditioned requirements. For the determination only of the activity (i.e. counting rate metering), two-detector arrangements with plastic scintillators have major advantages over all the other measuring systems. Following parameters have been determined in extensive tests with punctiform and areal radiation sources: local sensitivity profile of the two-detector arrangement; change of the background level; effect of geometry and shielding material on the counting rate. An extended series of tests with different measuring systems has made it clear that a single-detector arrangement over the scrap load fails to meet all the requirements, and that subject to the provision of enough sensitive detectors, the problem adapted signal evaluation and display is an important selection criterion. It has been established that measuring systems using large-area scintillators feature a high detection probability, without substantially changing the supply routes of scrap-processing plants. Such monitoring systems can be installed for incoming and outgoing control purposes at scrap traders and scrap users, but also at territorial borders to prevent the import of radioactive scrap and finished products.When components are replaced as a result of repair, modernization or closure of nuclear plants, large quantities of more or less contaminated steel scrap are produced. This scrap is partially contaminated. About 30 to 40% could be released for general use. At the beginning of 1988, the Commission on Radiological Protection submitted a recommendation for the treatment of nuclear scrap. This recommendation addresses questions of re-use with and without a permit under nuclear regulations and the pertinent upper limits for specific activity and surface contamination. The probability of radioactive charge materials reaching steelworks is very slight for various reasons, especially because of the statutory provisions. Nonetheless, it seems necessary to investigate quantitative methods and to develop a sensitive and reliable measurement technique for scrap inspection, which must be suitable for automatic operation. In a previous project British Steel built and tested a laboratory version of a scintillation counter. Following on from this work, British Steel and BFI propose to undertake the following tasks: - further development of radiation measurement to the point of industrial applicability; - testing of the prototype (or perhaps other instruments available on the market) under realistic conditions, the investigations at British Steel being conducted mainly with sealed radiation sources and those at BFI with open sources; - identification of sources of radioactive scrap and assessment of the potential hazard they represent. Once the metrological problems have been solved a strategy will have to be developed for application of the findings to inspection of incoming material and/or laboratory testing, if such action proves to be necessary. Testing in the laboratory can be carried out with commercially available instruments. Programa(s) ECSC-WORKENV 5C - Fifth research programme (ECSC) "Technical control of nuisances and pollution at the place of work and in the environment of iron and steel works", 1985-1989 Tema(s) 3 - Impact studies Convocatoria de propuestas Data not available Régimen de financiación Data not available Coordinador BETRIEBSFORSCHUNGSINSTITUT Verein Deutscher Eisenhuettenleute Aportación de la UE Sin datos Dirección Sohnstrasse, 65 40237 Duesseldorf Alemania Ver en el mapa Coste total Sin datos
