04.02.2013 Views

Regional Basic Professional Training Course in Korea

Regional Basic Professional Training Course in Korea

Regional Basic Professional Training Course in Korea

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

❙ 571 ❙<br />

9. Probabilistic Safety Analysis<br />

crashes, etc. External hazards <strong>in</strong>clude <strong>in</strong>ternal fires and floods for which the process<strong>in</strong>g<br />

methods are analogous to those of external events.<br />

Moreover IEs (<strong>in</strong>ternal and/or external) can be considered either only when the plant is at<br />

full power, or for all the plant operat<strong>in</strong>g modes.<br />

The m<strong>in</strong>imum scope of a level 1 PSA is to cover <strong>in</strong>ternal IEs dur<strong>in</strong>g full power operation.<br />

More recent PSAs cover all the possible IEs, s<strong>in</strong>ce a more complete scope allows for<br />

more complete and <strong>in</strong>terest<strong>in</strong>g applications [9.6, 9.11].<br />

9.2.3.1. Identification of Initiat<strong>in</strong>g Events<br />

In the identification of <strong>in</strong>itiat<strong>in</strong>g events, every effort must be made to ensure<br />

completeness. However, there is no method that can be systematically applied to<br />

demonstrate completeness. The best method of mak<strong>in</strong>g sure that the <strong>in</strong>vestigation is as<br />

complete as possible is to use all the available sources of <strong>in</strong>formation. The pr<strong>in</strong>cipal<br />

sources of <strong>in</strong>formation that can be used for identify<strong>in</strong>g the <strong>in</strong>itiat<strong>in</strong>g events are:<br />

Similar probabilistic assessments;<br />

Specific and worldwide experience feedback;<br />

The safety analysis report (design situations);<br />

Ad hoc studies carried out <strong>in</strong> the field of safety (for example post Chernobyl studies).<br />

Moreover, <strong>in</strong> order to complete the list of IEs, it is possible to use deductive analysis, for<br />

example, the master logic diagram.<br />

An important aspect is that IEs have to be considered <strong>in</strong> all the plant operat<strong>in</strong>g modes that<br />

are covered <strong>in</strong> the PSA. Especially <strong>in</strong> case of non-full power analysis, IEs specific to each<br />

situation have to be <strong>in</strong>vestigated.

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!