In the years 1997-1999, studies on the periods of A. lusitanicus development and on the occurrence of its developmental stages were carried out. Dates of overwintering, mating, egg-laying, hatching and population peaks of the slug were observed on six sites located in horticultural habitats, as well as in the isolation cage, where slugs were reared. It was ascertained that A. lusitanicus has a year-long life cycle. The slug overwinters in the form of eggs or juvenile stages and rarely as adult individuals. Young slugs leave their winter shelters by the end of February. The mating period starts in the second half of July and lasts from 6 to IO weeks. Eggs are laid from mid-August till late autumn. Slug hatching occurs in spring and autumn at the time of plant sprouting.

Evaluation of palatability of 20 plant species as a food source for slugs Deroceras reticulatum (Mi.iller), Arion lusitanicus (Mabille) and Arion ruf us (Linnaeus) was performed under laboratory conditions in tests with multiple choices and without choice. Rate and degree of damage of seedlings and leaves of matured plants of herbs and winter oilseed rape were calculated. Based on conducted experiments, plant species preferred and rejected by particular slug species were defined. Plants that were preferred by all examined slug species were the following: Brassica napus, Conium maculatum and Lamium amplexicaule. Rejected plants were Polygonum nodosum and Plantago lanceolata. Slugs have showed differentiated preferences towards the remaining plant species.

Studies on palatability of some commom weed species, herbaceous plants and oilseed rape to D. reticulatum, A. lusitanicus and A. rufus slugs have been carried out under laboratory conditions. In food choice trials the rate and degree of damage to seedlings and leaf disks were determined for 20 plant species. The conducted experiments have also permitted to establish, which plant species were preferred or were not accepted by particular slug species. It was found that the studied slug species preferred seedlings and leaves of Brassica napus and Papaver rhoeas, but showed no preference for Epilobium hirsutum, Geranium sanguineum and Saponaria officinalis plants. As to the remaining plant species under study, the preferences exhibited by particular slug species were quite diverse.

U-10wt.%Zr-5wt.%RE fuel slugs for a sodium-cooled fast reactor (SFR) were conventionally prepared by a modified injection casting method, which had the drawback of a low fabrication yield rate of approximately 60% because of the formation of many metallic fuel scraps, such as melt residue and unsuitable fuel slug butts. Moreover, the metallic fuel scraps were classified as a radioactive waste and stored in temporary storage without recycling. It is necessary to develop a recycling process technology for scrap wastes in order to reduce the radioactive wastes of the fuel scraps and improve the fabrication yield of the fuel slugs. In this study, the additive recycling process of the metallic fuel scraps was introduced to re-fabricate the U-10wt.%Zr-5wt.%RE fuel slugs. The U-10wt.%Zr-5wt.%RE fuel scraps were cleaned on the surface impurity layers with a mechanical treatment that used an electric brush under an Ar atmosphere. The U-10wt.%Zr-5wt.%RE fuel slugs were soundly re-fabricated and examined to evaluate the feasibility of the additive process compared with the metallic fuel slugs that used pure metals.