Approximate Event Frequency Determination

The rate constant denotes the activation frequency per chain, that is, the number of aaivation events occurring on a chain per unit time, which, in the quasi-equilibrium state, is approximately equal to the deactivation frequency per chain. This frequency determines the polydispersity of the product. In the ideal case with constant concentrations of monomer and all other components along with negligible fractions of dead and conventionally initiated chains, the PDI of the LRP product maybe given by (see Section 3.05.4.1.1)... 

To determine maximum individual risk, generic frequency data are required for explosion events for Process Units 1 and 2. For Process Unit 1, incident data were available from the unit licenser identifying three explosions in approximately 15,000 operating years, for an explosion frequency of 2.0 x 10-4 per year. For Process Unit 2, a fault tree analysis of the nitrogen vessel brittle fracture event had been conducted as part of an unrelated project. That study concluded that the frequency of brittle fracture failure of the nitrogen vapor storage vessel was 5x10"4 per year. 

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