Expected Safety Criticality Model

This model estimates the safety criticality per unit time of the equipment when it is inspected with a periodicity of T (Pillay (2001), Pillay et al. (2001a, b)). If b(t) is the probability of a defect arising as a breakdown failure k then, Cr is the safety criticality of the said failure and Crk is the operational safety criticality when the defect does not arise and/or is not a breakdown failure. The estimation of and is given by Equations (8.22) and (23) 

Cr = safety criticality associated with failure k. safety gjjgjy Severity for the m effect for failure k. 

The safety criticality and operational safety criticality of a failure can be identified by performing an FMEA study on the system. The values of these two parameters can be estimated subjectively using a scale of 0 tolO (0 being least critical and 10 being most critical). The values are assigned based on the probability of occurrence and severity, and are considered for four categories (personnel, environment, equipment and catch). All the other variables in Equations (8.22) and (23) will have the same values as defined in Equation (8.13) of Section 8.5.2. 

Maintaining the assumptions and notations presented in Section 8.5.1, the expected safety criticality is given by Equation (8.24). 

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With the expected growth of puhhc transport volmnes within the next years, the simulation of pedestrian flows to design new and assess existing pedestrian walking facilities becomes of increasing importance. To get meaningful simulation results, accurate pedestrian flow models are required. These models include the appropriate description of the pedestrian behaviour in normal as well as safety-critical conditions (e.g. evacuations). Furthermore, planners and engineers require tools, which allow for fast and reliable simulations of real-world problems. 

VII. 14. The SAR should provide sufficient information or references to demonstrate that the computer code, nuclear cross-section data and technique used to complete the criticality safety assessment are adequate. The computer codes used in the safety assessment should be identified and described in the SAR, or adequate references should be included. Verification that the software is performing as expected is important. The SAR should identify or reference all hardware and software (titles, versions, etc.) used in the calculations as weU as pertinent version control information. Correct installation and operation of the computer code and associated data (e.g. cross-sections) should be demonstrated by performing and reporting the results of the sample problems or general validation problems provided with the software package. CapabiUties and limitations of the software that are pertinent to the calculational models should be discussed, with particular attention to discussing limitations that may affect the calculations. 

This body of experience and data will be critical as the industry begins mass production and infrastructure expansion over the next several years, and the next phase of JHFC is expected to continue to support this process. Priorities for future work include developing an infrastructure model for commercialization, development of a process to validate infrastructure from a safety perspective, and continuing to lower costs for both vehicles and stations [22]. 

Reactivity insertion accident (RIA) since the innovative hydraulic control drive for the FSS and the adjust and control system is located inside the RPV, the control rod ejection accident is avoided only inadvertent control rod withdrawal transients are postulated. Two scenarios considering FSS success and FSS failure with SSS actuation were modelled, assuming a conservative hypothesis. The results of simulation show that safety margins are well above critical values (DNBR and CPR - critical power ratio) and no core damage is expected. Moreover, as there is no boron in the coolant, boron dilution as a reactivity-initiating event is precluded. 

However, CCSM, in the described formulation, is not adequate for the continuous monitoring of the extern situation and of the performance of the workers in a Behaviour-Based Safety perspective. The main limitation is that the model does not provide an estimation of the risk related to the non-conforming behaviours. The method distinguishes between conforming and non-conforming behaviours, without any further clarification on the criticality or on the expected consequences of the behaviours themselves. In fact, different at-risk behaviours are characterized by different criticalities. 

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