title: Optimization of Routine Monitoring of Workers Exposed to Plutonium Aerosols.
abstract: In case of incidental confinement failure, mixed oxide (MOX) fuel preparation may expose workers to plutonium aerosols. Due to its potential toxicity, occupational exposure to plutonium compounds should be kept as low as reasonably achievable. To ensure the absence of significant intake of radionuclides, workers at risk of internal contamination are monitored by periodic bioassay planned in a routine monitoring programme. From bioassay results, internal dose may be estimated. However, accurate dose calculation relies on known exposure conditions, which are rarely available when the exposure is demonstrated by routine monitoring only. Therefore, internal dose calculation is subject to uncertainty from unknown exposure conditions and from activity measurement variability. The present study calculates the minimum detectable dose (MDD) for a routine monitoring programme by considering all plausible conditions of exposure and measurement uncertainty. The MDD evaluates the monitoring quality and can be used for optimization. Here, MDDs were calculated for the monitoring of workers preparing MOX fuel. Uncertain parameters were modelled by probability distributions defined according to information provided by experts of routine monitoring, of workplace radiological protection and of bioassay analysis. Results show that the current monitoring is well adapted to potential exposure. A sensitivity study of MDD highlights high dependence on exposure condition modelling. Integrating all expert knowledge is therefore crucial to obtain reliable MDD estimates, stressing the value of a holistic approach to worker monitoring.
authors.affiliation: 1.Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-HOM, SDI, Laboratoire d'Evaluation de la Dose Interne, Fontenay-aux-Roses 92262 France; estelle.davesne@irsn.fr.
authors.forename: Estelle
authors.initials: E
authors.lastname: Davesne
authors.affiliation: 2.AREVA MELOX, Service de Santé au Travail, Bagnols-sur-Cèze 30207 France;
authors.forename: Benoit
authors.initials: B
authors.lastname: Quesne
authors.affiliation: 3.AREVA MELOX, Service de Radioprotection et Environnement, Bagnols-sur-Cèze 30207 France;
authors.forename: Antoine
authors.initials: A
authors.lastname: De Vita
authors.affiliation: 4.Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PSN-RES, SEMIA, Laboratoire Incertitude et Modélisation des Accidents de Refroidissement, Cadarache, Saint-Paul-Lez-Durance 13115 France.
authors.forename: Eric
authors.initials: E
authors.lastname: Chojnacki
authors.affiliation: 1.Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-HOM, SDI, Laboratoire d'Evaluation de la Dose Interne, Fontenay-aux-Roses 92262 France;
authors.forename: Eric
authors.initials: E
authors.lastname: Blanchardon
authors.affiliation: 1.Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-HOM, SDI, Laboratoire d'Evaluation de la Dose Interne, Fontenay-aux-Roses 92262 France;
authors.forename: Didier
authors.initials: D
authors.lastname: Franck
mesh_terms: D000336:Aerosols / Q000032:analysis*; D001822:Body Burden; D006801:Humans; D015233:Models, Statistical; D016273:Occupational Exposure / Q000032:analysis / Q000517:prevention & control*; D011005:Plutonium / Q000032:analysis*; D011835:Radiation Protection / Q000295:instrumentation / Q000379:methods*; D018570:Risk Assessment; D035501:Uncertainty
chemical_list: D000336:Aerosols; D011005:Plutonium
keywords: internal dosimetry; minimum detectable dose; optimization; plutonium; uncertainty