La dosimétrie individuelle des neutrons constitue une des difficultés actuelles de la radioprotection des travailleurs. La dosimétrie dite active (opérationnelle) est réglementaire depuis mars 1999 ; les valeurs des seuils recommandées par la CIPR 60 applicables en mai 2000 rendent nécessaire la mise en place d'une nouvelle génération de dosimètresneutrons. L'Institut de protection et de sûreté nucléaire (IPSN) a mené, au cours de ces dernières années, l'étude d'un dosimètre électronique individuel pour les neutrons satisfaisant aux spécifications d'un cahier des charges défini par le groupe de travail " dosimétrie neutrons " réunissant les principaux acteurs du cycle nucléaire français. Courant1998, l'IPSN a engagé un transfert de technologie vers la société Saphymo ; celle-ci commercialisera fin 2000 le premier dosimètre individuel électronique pour les neutrons, le Saphydose-n, répondant à la norme CEI 1323. Ce dosimètre,d'un encombrement réduit, permettra d'évaluer l'équivalent de dose individuel Hp(10) dans des champs mixtes neutron-gamma. Il pourra être utilisé dans toutes les installations du cycle électronucléaire, sans connaissance préalable de l'énergie moyenne du spectre des neutrons et du rapport neutron-gamma. Le dosimètre Saphydose-n pourra être raccordé aux bornes existantes des dosimètres gamma pour la lecture des informations et pour la charge des accumulateurs.

Effect of organic acids on 241 americium and 237 neptunium desorption from an acidic cultivated soil.Naturally occurring organic substances have been recognised as one important factor affecting the behaviour in the environment of transuranic actinides. This experimental study aims at evaluating if some naturally occurring carboxylic acids (vanillic, citric, lactic, oxalic) would affect 241Am or237Np availability in an acidic agricultural soil. Data show that these acids enhance the desorptionof americium and neptunium from the soil, with a noticeable effect of citric acid. The fraction desorbedis multiplied by more than 10 for 0.1 M citric acid, and by 3 or 4 with other acids, in relation withthe complexation of radionuclides with these acids. The desorption increases with molar concentration ofthe acids because of the decrease of pH in acidified soils, except for oxalic acid. The soil moistureconditions seem to affect the desorption results: the percentage desorbed is approximately 10 times lowerfor batch experiments (saturated conditions) than for centrifugation corresponding to unsaturated soilconditions. These preliminary data are mainly qualitative, but they show that it could be interesting totake into account more realistic physico-chemical conditions when measuring desorption ratios forcultivated soils.

“ CALLIOPE " est une base de données sous forme de cédérom destinée à la formation de la dosimétrie interne. Cet outil est une aide pour l'interprétation des mesures de surveillance des travailleurs ou du poste de travail réalisées en routine ou après incident. Il contient des informations issues des sept principales Publications de la CIPR sur la dosimétrie interne et permet l'accès aux données nucléaires du logiciel NUCLEIDE. Cet utilitaire facilite la mise en application des réglementations extraites de la Directive européenne 96/29 dans le respect des nouvelles limites. Il est une aide à la validation par l'utilisateur des démarches et des estimations des doses consécutives à l'expositioninterne.

Irradiation of unknown pregnancy: review of 17 cases.The article summarizes the analysis of 47 cases of pregnant women who did not know their pregnancy and had undergone one or more diagnostic radiological examinations. We distinguished two groups. The firstgroup G1 consisting of 12 women whose exposure to radiation had been focused under diaphragmatic regionand occurred during the critical period of organogenesis with a gonadal dose estimated to range 12 to 52mGy. A therapeutic abortion had been recommended to these women. The second group G2 consisting of 35women whose exposure to radiation interested directly or indirectly the above diaphragmatic region withdose lower than 10 mGy. To these women, a recommendation to continue their pregnancy had been given. Weinvestigated only 17 pregnant women issues; 7 from G1 et 10 from G2. We noted that there were nospontaneous abortion or major abnormalities or malignant diseases. However, 4 minor abnormalities wereidentified among the examined children sample: facial dysmorphism, anus atresia, hypospadias and harelip.These anomalies could not be attributed to the irradiation effects because the conceptus received verylow doses during the minimal risk gestation period. We believe that the malformations observed may beattributed to congenital malformation risk.

1999 occupational dosimetry in EDF's nuclear power plants: comments and analyse.The year 1999 ended with rather positive results concerning worker dosimetry, which is constantly decreasing. The targeted objective for the year 2000 (1.2 man.Sv per reactor) was already attained in 1999(1.17 man.Sv). However, even though the 1 300 MWe level still continues to progress, the 900 MWe level seems to marking time. In the case ofindividual dosimetry, even though it remained stable on the whole, nonetheless the number of workers themost strongly exposed decreased very much. These advancements should be considered as a part of theactions committed not only within the scope of optimization, but also in the reduction of shutdown periodsfor refueling, the extension of the fuel cycle (loading 1/4 of a core) and the revision of the maintenancepolicy (implementation of the optimization of reliability oriented maintenance). 1999 was the year whenthe initial effects of the "cleanliness"plan launched in 1998 were noted. This plan has already allowedimproving notably the situation in terms of contamination in the transport of spent fuel. However, theexposure incident which occurred at Tricastin, as well as other minor malfunctions, incite in us prudenceand more rigor in the performance of operations related to radiation protection.