A probabilistic model of environmental safety of ship power plant

In the paper a probabilistic model of environmental risk of ship power plant is presented. This is a linear strategy model with an additional restraint. It can be usedfor assessing risk to marine environment, which results from ship power plant operation. The risk is a sum of component probabilities of exceedance of the limits assigned - by MARPOL convention to particular kinds of pollution discharged from ships, multiplied by weight factors. The factors determine a degree of harmfulness of a discharge for the environment. The restraint concerns the case of exceedance of the limits assumed unacceptable by the convention. A risk value is be contained within (0,1) interval. Moreover a criterion for environmental safety of ship power plant was propsed. This is the criterion of the ALARP class, in which an intolerable risk level and acceptable one is distinguished. Suggestions concerning determination of the levels are submitted. The considerations are illustrated by results of example computer investigations of influence of reliability oftechnical elements of the systems responsible for environmental safety of a hypothetical ship power plant on environmental risk value. Three qualification levels of ship:s. crew were accounted for: high, average and low.