Accident consequences

The calculation follows the procedure of Sect. 10.2.6.1. It is assumed that the released gas ignites after 10 s. Hence a total mass of W = 3,151.2 kg/s 10 s = 31,512 kg is available for the fireball (thereafter a jet fire might occur at the aperture). 

Assuming an SEP of q ,., = 350 kW/m the procedure of Example 10.23 gives the distance-dependent heat flux density and the conditional probability of death shown in Fig. 10.44. 

In case of a leakage from a high pressure pipeline the usual relationships for flame dimensions of Sect. 10.6.1.1 cannot be applied, since they are only valid for pool fires (low initial momentum). 

According to [82] the flame length for a flame assumed as cylindrical is 

The best agreement with experimental values is reached, if the cylinder length is calculated with Jm = 13 voI% and its diameter with Jm = 5 voI%. 

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Analyses and experimental results used to assess the consequences of a severe potential accident have resulted in substantially reduced estimates of severe accident consequences. Comparing estimates made by the U.S. Atomic Energy Agency (27) in 1977 with those reported by the U.S. NRC (18,28) in 1990 shows that improved knowledge and plant modifications have reduced the cote damage frequency by a factor of 3—15, depending on reactor type. Additionally, the fractions of radioactive species that would be released are lower by a factor of 10—100,000, depending on the radioactive species. 

The Rohm and Haas Major Accident Prevention Program (Ren-shaw, 1990 Berger and Lantzy, 1996 Hendershot, 1991a) is based on potential accident consequence analysis and uses checklists based on inherently safer design principles to identify ways to eliminate or reduce hazards. 

At this point, following the chapters, the objectives have been defined, the effect of government regulations and standards are known, accidents have been identified and analyzed by various methods to determine the probability of an accident, and the accident consequences have been calculated. These parts must be assembled to present the risk and the analysis of the risk according to its various contributors. 

Meihem, G., et al. 1997, Explosions and Energetic Events (EEE) Modeling Guidance for Accident Consequence Mid Safety Analysis, Draft Report, A.D. Little Inc., January. 

Reg. Guide 1.145, 1983, Atmospheric Dispersion Models for Potential Accident Consequence Assessments at Nuclear Power Plants, USNRC, February. 

Risk iuialysis of accidents serves a dual purpose. It estimates tlie probability tliat iui accident will occur and also assesses the severity of the consequences of an accident. Consequences may include dmnage to tlie surrounding enviromnent, financial loss, injury to life and/or deatli. This Part of the book (Part IV) is primarily concerned witli tlie metliods used to identify liazards and causes and consequences of accidents. Issues dealing witli healtli risks have been explored in die previous Part (III). Risk assessment of accidents provides an effective way to help ensure eidier diat a mishap will not occur or reduces the likelihood of an accident. The result of die risk assessment also allows concerned parties to take precautions to prevent an accident before it happens. 

Chapter 14 Introduction to Hazard Risk Assessiiiciit Chapter 15 Evcnt/Haaird Identification Chapter 16 Accident Causes and Probability Chapter 17 Accident Consequences and Evaluation Chapter 18 Hazard Risk Analysis... 

Cause-consequence risk evaluation combines event tree and fault tree analysis to relate specific accident consequences to causes. Tlie process of cause-consequence evaluation usually proceeds as follows ... 

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