Patent Number: 042499941
Section: claims

1. A method for cleaning an electro-magnetic filter containing a magnetizable packing located in a water circulatory loop of a nuclear reactor by subjecting the packing to a series of washing and draining cycles of wash water withdrawn from said circulatory loop, said method comprising the steps of: (a) isolating the filter from the water circulatory loop of the reactor and draining the water so as to empty the filter which contains then only steam;  (b) withdrawing a fraction of the water being circulated in the isolated circulatory loop for use as wash water for said filter;  (c) introducing said wash water into said filter at a temperature within the range of 200.degree. C. to 300.degree. C. and at a pressure within the range of 100 to 160 bar so that a sudden expansion of said water occurs in the filter;  (d) completely draining the wash water introduced into the filter through a bottom portion of the filter, so as to empty the filter which contains then only steam;  (e) repeating the withdrawing, introducing and draining steps several times in succession so as to subject the packing of said filter to a series of washing and draining cycles in order to completely clean said filter.