Search - Number 22 - JUSTIFICATION OF RELIABILITY OF THE SYSTEM DECAY HEAT REMOVAL OF A NUCLEAR REACTOR FROM THE POINT OF VIEW OF NPP SAFETY

JUSTIFICATION OF RELIABILITY OF THE SYSTEM DECAY HEAT REMOVAL OF A NUCLEAR REACTOR FROM THE POINT OF VIEW OF NPP SAFETY
Cover not present JUSTIFICATION OF RELIABILITY OF THE SYSTEM DECAY HEAT REMOVAL OF A NUCLEAR REACTOR FROM THE POINT OF VIEW OF NPP SAFETY
Category: Number 22
Publication: 22
Summary

The article describes the methodology for determining the reliability of the systems decay heat removal (SDHR) of VVER-1000. Reliability analysis of the SDHR made for the case to ensure continuous operation for decay heat removal for about 100 days. Also, under the following assumptions: the limit of damage to the fuel elements in the absence of heat removal is 3,0•1011 J, the minimum time to reach the limit of damage to the fuel elements is 2 hours, while the inclusion of back-channel SDHR is 60 seconds. In this case, it was found that the average time between failures SDHR more plant life, and therefore, can not be verified on the basis of operational statistics and, therefore, can not be controlled of reliability system. Therefore, control of system reliability should be done through the control of reliability of its channels. In this case, the required uptime channel (Time Between Failures) is 720 hours. Because the existing requirements for the running time of the channel is limited SDHR 240 hours, to ensure the reliability required to ensure maintainability of the SDHR channels. SDHR also required reliability can be achieved if the reactor system retrofit passive heat removal systems, which initially have a high reliability and not require rehabilitation for a long time (30 - 100 days) following a postulated accident with a blackout of the VVER-1000. Keywords: decay heat, heat removal system, reliability, availability factor, time to failure, passive heat removal system.

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