once a leak event is confirmed the second step practiced is to determine its location in order to determine whether a leak is present in the boiler the concept of universal leak sensitive variables ulsv is introduced ulsvs are process variables which respond to most leak events which occur in the several different locations of a boiler the list of ulsvs is given in table 2 below referring now more specifically to fig2 it may be appreciated that the ulsvs will be used as input to an ann based detector called a tube ulds and identified at block 211 the output of ulds block 211 is zero when no leak is present in the boiler and one whenever a leak is present more detailed information relating to such ulds is found in t zhong a t alouani and r a smoak u201c ann based tube leak detection system u201d proc 29th ieee southeastern symposium on systems theory cookeville tenn march 1997 as noted above once a leak event is declared the second step for practice of the instant invention is to determine its location in the boiler for this reason the concept of local leak sensitive variable llsv has been introduced into the teachings practice and operation of the instant new and novel invention a llsv is a variable whose response to a leak in a given location is much higher than in any other location for each and every location in a boiler which has been determined and identified in the practice of the instant invention to be a likely location where a tube.