**6.6. Case study 3 – gas-tanker accident**

144 Nuclear Power – Practical Aspects

The MCS depends on a sequence of single events:

width of street 1 and street 2 (Table 3).

 Wind-direction φ: empirical-distributed (Figure 7). Wind-speed vW: empirical-distributed (Figure 8). Time τ to ignition: Exp(0.01 s-1)-distributed.

Development of explosive gas mixture: fixed probability (0.3).

Accident (x, y)-coordinate: uniformly-distributed depending on the length and the

Different ranges of conditional explosion-probability PE are depicted in Figure 12. The denotation of the different ranges of the explosion event probability PE, which is normalised on 1m2, is as follows: red area (> 1E-07/m2), orange area (≤ 1E-07/m2), yellow area (≤ 5E-08/m2), green area (≤ 1E-08/m2). The methods, number of trials, the simulation time and the

results like mean value, variance and figure of merit (fom) are listed in Table 5.

**Figure 12.** Tank-lorry accident - ranges of conditional explosion event probability PE/1m2

**method trials time [s] mean variance fom** 

MCS-lee 1E05 6.86 5.40E-04 5.0E-04 2.70E07

biased 1E05 26.69 7.78E-04 6.25E-06 5.99E08

MCS-ffe 1E05 7.04 7.50E-04 8.20E-05 1.73E08

biased 1E05 27.72 7.70E-04 5.16E-06 6.99E08

**Table 5.** Tank-lorry accident - conditional probability of an explosion event within the plant area with

*6.5.1. Analysis* 

*6.5.2. Results* 

MCS-lee

MCS-ffe

radius rP

The third case study (Figure 13) deals with a gas-tanker accident on the river. The river is subdivided into 6 subsections; each subsection is characterised by an individual length, width and gas-tanker accident frequency. It is assumed, that the accident frequency is higher in sections with confluences or curves than in straight river-sections. The accidentcoordinate (xi, yi) is uniformly distributed depending on the river-section i.

The vertical distances between the plant and the river are between 440m (dR-1) and 780m (dR-2). In the given application ships can reach every location at the river. Further relevant application parameters of Figure 13 are given in Table 2 and Table 3.

**Figure 13.** Gas-tanker accident on the river

### *6.6.1. Analysis*

The MCS depends on a sequence of single events:

