A REVIEW ON OPERATING EXPERIENCES OF CONTAINMENT ISOLATION SYSTEMS INKOREA

Authors
Citation
Ig. Kim et Hj. Kim, A REVIEW ON OPERATING EXPERIENCES OF CONTAINMENT ISOLATION SYSTEMS INKOREA, Nuclear Engineering and Design, 145(3), 1993, pp. 431-438
Citations number
10
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Nuclear Sciences & Tecnology
ISSN journal
0029-5493
Volume
145
Issue
3
Year of publication
1993
Pages
431 - 438
Database
ISI
SICI code
0029-5493(1993)145:3<431:AROOEO>2.0.ZU;2-0
Abstract
Wide experience, on the order of 50 reactor-years, in operating contai nment isolation systems has been accumulated in Korea since 1978, nece ssitating a review of the operating data to confirm the integrity of c ontainments and to establish the future direction to the containment t est program. The objectives of the present work are to collect, consol idate and assess the operational data relevant to containment isolatio n systems, and then to identify types of isolation valve failures, dom inant leakage paths and factors affecting integrated leakage rate test . Leakage is observed to be the most frequent type of isolation valve failure. The causes of the valve leakage are packing leakage, seat dam age due to foreign material, and misadjustment of torque switches. Mal function and deterioration are also observed to be frequent failure mo des. General leakage trends show that more careful surveillance during preoperational test can reduce the containment leakage. Significant l eakage paths are found to be through air locks and large valves of six -inch or greater nominal diameter, so that weighted surveillance and i nspection on these dominant leakage paths can considerably reduce the containment leakage. Atmospheric stabilization is found to be the most important factor to obtain the reliable integrated leakage rate. In o rder to achieve a well stabilized atmosphere, temperature and flow rat e of compressed air should be kept constant and it is preferable not t o operate fan coolers during pressurizing the containment for test. Th ese results are expected to be a guidance for improving the operation of containment system.