Safety comparative margins, various

Guidance to date supports the risk assessment principles for general chemical substances already published by the Commission (1996). Consequently, the risk characterisation simply involves a quantitative comparison of the outcome of the hazard/effects assessment with the exposure assessment. For human risk this involves the calculation of the TER (Toxicity Exposure Ratio) and comparing it with the MOS (Margin Of Safety). For environmental risk the PEC/PNEC ratio (Predicted Environmental Concentration versus the Predicted No-Effect Concentration) for the various environmental compartments. 

From the results, most of the extracts tested were relatively non-cytotoxic, which could be an indicator of some safety aspects of the tested plants, hence justifying the generational uses of these plants in traditional medicine. This information could be a basis for development of safe herbal therapies with fewer or no side effects compared to conventional medicines most of which have been reported to have many side effects. Since only a preliminary screening was done for the reported extracts, there would be a need to carry out further studies on their toxicity and safety margins, and develop standardized herbal formulations based on this. There would also be a need to screen the extracts against a panel of more than one cell line as different cell lines exhibit different sensitivities towards various extracts or compounds. 

The tear gas CS has a much higher safety margin compared to the incapacitating chemicals under investigation by various militaries today. CS therefore qualifies as a riot control agent under the CWC. 

The exposure assessment (left hand side of Figure 1) and the effects assessment (right hand side of Figure 1) taken together lead to a risk assessment that determines the likelihood and severity of adverse effects in the exposed population (human, animal or the environment). This is conducted by comparing the Risk Characterisation Ratios (RCR) such as Predicted Environmental Concentration (PEC)/Predicted No Effect Concentration (PNEC) - PEC/PNEC for the various ecosystems to be protected or the margin of safety (MOS) for exposed human populations. 

Thermal Hydraulics. The proposed reactor will have a low power density (10-30 MW/m ) and be cooled by water with a low flow velocity. Appendix E discusses these passive safety features and the thermal hydraulics of the INEL concept. As a result of the low-power densities, the reactor pressures and temperatures are very low compared to a commercial LWR. This enhances safety by reducing stresses on various components and by providing wider margins between steady-state fuel temperature and maximum allowable fuel temperature. Low coolant velocities, low pressures, and low temperatures also reduce capital costs as discussed in Appendix G. With low pressure coolant, a thick pressure vessel is not needed, and the core can be quite... 

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