Concentration ratios for chemical analogues of key nuclides for different vegetation types at the Olkiluoto site

Olkiluoto Island on the western coast of Finland has been selected as a repository site for spent nuclear fuel in Finland. This study aimed at identifying differences in concentration ratios (CR), and their distributions, for the elements analysed on soil and vegetation samples taken on the island (Al, B, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Ni, P, S, Zn). Many of the elements can be considered to be chemically analogous to radionuclides that, potentially, can be released from the repository. Differences between the soil and vegetation in different tree age, tree species and site fertility classes typical of the forest ecosystems in Olkiluoto were investigated. Lognormal distributions were fitted to the different groupings of the CR data calculated on the basis of the results from 94 sampling plots. In most cases no significant differences were found between the different groupings for a specific element when the 95% confidence intervals were applied. According to the results based on real site data for CRs in forest ecosystems on Olkiluoto, it appears that the current CR-based approach to radionuclide modelling in forest ecosystems is problematic due to the large variation in parameter values and in their practical definition

On real and abstracted geometries of boreal forest plants

In Finland, Olkiluoto Island on the western coast has been selected as a repository site for spent nuclear fuel disposal. A safety criterion is that typical exposures (dose rates) to flora and fauna should be demonstrated to be lower than those that according to best available knowledge could cause detrimental effect. To increase the confidence of dose assessment to flora, some selected plant species were measured in field conditions. This paper presents the results of the field campaign and discusses on the realism of the common assumption of ellipsoidal geometry applied to the plants in dose assessments of the other biota

Crops and garden products near Olkiluoto repository site

In Finland, Olkiluoto Island on the western coast has been selected as a repository site for spent nuclear fuel disposal. With approaching licensing steps, the biosphere assessment demonstrating the long-term safety of the repository is developed into more and more site specific. As the literature data on site-relevant crops and garden products on site-relevant soils are sparse or in some cases lacking for the elements of a high relevance to the biosphere assessment of the Olkiluoto spent fuel repository, crops and garden products were collected from farms nearby the site. The samples were then analysed for stable elements for initial contribution to the site-specific database in respect of these edibles

Assessing doses to humans in the Posiva safety case

In Finland, Olkiluoto Island has been selected for constructing a spent nuclear fuel disposal facility. With the approaching licensing step, submitting the application for nuclear construction licence in 2012, all components of the safety case are becoming more site-specific. In order to assess compliance with regulatory requirements, a prospective deterministic dose assessment methodology based on the ICRP concept of assessing doses to the representative person was developed and implemented in the interim safety case 2009, to be further refined for the safety case 2012. To facilitate the assessment of doses to the most exposed people and other people at the evolving site, full dose distributions are derived, comprising the dose to each potentially exposed person in each generation