Seismic Qualification of Secondary Devices for Differential Pressure TransmittersUsed in WWER-440 Reactors at Kozloduy NPP

摘要

Prototype tests of the safety related equipment under accident conditions were performed under PHARE programrnproject. Empresarios Agrupados (Spain) as a leading company of the Consortium, formed by Spanish and Bulgarianrncompanies, was responsible for performance of the study. One main part of this project was in the field of seismicrnqualification of the safety-related equipment. The special attention was paid to electrical and C&I components. In this respectrnfour groups of equipment were selected for seismic qualification by prototypes test. One of these groups comprises secondaryrndevices.rnThe secondary devices in WWER-440 units at Kozloduy NPP are used for two purposes. First- to ensure actuationrnof safety systems by interlock contacts integrated in their design. Second - to support the operators in the main control roomrnwith visual information about flow rates, levels and pressures in various systems.rnThe main objective of the study was to qualify the secondary devices used at Kozloduy NPP, units 1-4 for seismicrnevent. Because of the lack of proper information and corresponding technical data about seismic vulnerability of thernequipment, the only reasonable approach was qualification by seismic tests. The paper is dedicated to the seismicrnqualification tests of selected four types of secondary devices. The following activities have been carried out:rn? Review of the safety related secondary devices and selection of the types to be qualified;rn? Development of specification for the Seismic Qualification Test;rn? Development of test procedure, including functional tests of the secondary devices before, during and after the seismicrnexcitations;rn? Performance of the specified Seismic Qualification Tests;rn? Analyses of the results, conclusions and proposals.rnThe Required Response Spectra (RRS) were developed on the bases of the Review Level Earthquake (RLE) for thernsite of NPP Kozloduy. The Amplified Response Spectra (ARS) were based on Floor Response Spectra taking into accountrnlocal amplification effects induced by control panels. The RRS were developed for two levels of excitation: an upper level,rncorresponding to a Safe Shutdown Earthquake (SSE) and a lower level corresponding to Operating Basis Earthquake (OBE).rnThe functional performance of the tested equipment during the seismic excitation was monitored by a datarnacquisition system in steady state and transition mode of operation.rnThe test results are satisfactory. No single failure of the signal from safety related contacts was registered duringrnapplied seismic excitations. In general, the functional performance of the tested secondary devices remained unchanged afterrncompletion of the testing program.