instrumentation and control

08:19 Aug 7, 2016 

In the case of the Fukushima Daiichi NPP, considering the fact that safety related items for removing the reactor decay heat (linked to the ultimate heat sink) and for cooling the emergency diesel generators (EDGs) for emergency power supply are located at the plant area at OP +4.00 m, which would be flooded in case of the newly reassessed tsunami flood level of OP +5.70–6.10 m, TEPCO mentioned during the IAEA Fact Finding mission in 2011 [6] that the motors of the safety related pumps (residual heat removal (RHR) system) were accordingly elevated to avoid disruption of function. However, no additional details were provided about the adequacy of these measures to cope with such an event for the protection of all related mechanical, electrical and instrumentation and control (I&C) components of the RHR system. Table 2.1–12 shows that TEPCO raised the pumps. Whether all the pumps or the pump motors were elevated was not clear.