Feasibility Of Long-term Storage Research Articles

Cryopreservation of potato microtubers: the critical roles of sucrose and desiccation

Microtubers are an important source of tissues for conservation and exchange of germplasm. An efficient method for cryopreservation of whole microtubers that will ensure a safe and long-term storage was developed in this study. Potato cultivars (Climax, Avon and Ceza) were evaluated for responses to in vitro tuberization and cryopreservation. Treatments include pretreatment on medium with sucrose (30–100 g l−1) and desiccation in silica gel (0, 3 and 6 h) followed by rapid plunging into liquid nitrogen (LN). There were significantly higher number of microtubers produced on the medium with 80–100 g l−1 sucrose (8–11.33) compared to 30 g l−1 sucrose (0.7–1.7). The microtuber fresh weights varied among genotypes on sucrose (80–100 g l−1) with ‘Climax’ showing the highest value followed by ‘Avon’ and ‘Ceza’. The microtuber moisture content ranged from 26 to 36 % after 3 h of desiccation and from 17 to 28 % after 6 h of desiccation for all three cultivars. After cryopreservation, the percentage of surviving (green) microtubers of ‘Climax’ increased with an increase in sucrose concentration, and was significantly higher than the control. For ‘Avon’, the percentage of green microtubers produced on sucrose (80–100 g l−1) was significantly higher than other treatments. Also, ‘Ceza’ produced significantly more green microtubers with 100 g l−1 sucrose compared to other sucrose treatments, similar to the control. Cryopreserved microtubers produced the most shoots on medium with 100 g l−1 sucrose. This study demonstrates the feasibility of long term storage of microtubers in LN for conservation purposes.

Corrosion issues in nuclear waste disposal

This paper summarized some corrosion issues specific to nuclear waste disposal and illustrates them by the French geological clay concept for the reliable prediction of container degradation rate and engineering barrier integrity over extended periods, up to several thousands years. Among the items, the following are included: • The importance of the underground repository conditions. • The necessity of developing comprehensive semi-empirical models and also predictive models that must be based on the mechanisms of corrosion phenomena. • The use of archaeological artefacts to demonstrate the feasibility of long term storage and to provide a database for testing and validating the models.

Prediction of Long Term Corrosion Behaviour in Nuclear Waste Systems

ABSTRACTThe corrosion resistance of container materials in underground repositories is an important issue for the safe disposal of High Level Nuclear Waste (HLNW). The reliable prediction of container degradation rate and engineering barrier integrity over extended periods, up to several thousands years or even several hundreds of thousands of years, represents one of the greatest scientific and technical challenges. The first and the second International Workshops on Prediction of Long Term Corrosion Behaviour in Nuclear Waste Systems, which were held in 2001 (Cadarache) and 2004 (Nice), sought to compare the scientific and experimental approaches that are being developed in various organisations worldwide for predicting long term corrosion phenomena, including corrosion strategies for interim storage and geological disposal. The lessons learned during these Workshops, include the necessity of developing two approaches based on semi-empiricism and determinism in a complementary manner for effective prediction. The use of archaeological artefacts to demonstrate the feasibility of long term storage and to provide a database for testing and validating modelling work was also emphasized.