The high level sensor for the Meson Hall Hot Cell Lab Active Sump was tested today and worked as expected.  When the sensor is tilted (as occurs when the water level rises above it) an audible alarm sounds in the hot cell lab, and the Safety Panel in the MCR also alarms with "MHESA B1 RCR1 RM 6 WARN" displaying NOT OK.  This alarm sounds every 3 minutes in the MCR until the PLC outside of the RCR lab is reset.  When the sensor was tested on the RCR lab PLC there was a message indicating that the MH Hot Cell Lab Active Sump is full.

It is still unclear why the operators did not receive this alarm when the sump filled and overflowed last night (or possibly they did receive it, but it was ignored or silenced).  The operators from that shift are currently off until this Saturday, so they will be contacted next week to try to learn more.

UPDATE (Sept 8, 2016):  Further testing revealed that the electronics for the high level switch were wired incorrectly which resulted in the RCR PLC only seeing sump level high when the "silence" button on the electronics box for the switch was pushed.  This was not discovered during previous tests because the "silence" button was pushed each time shortly after triggering the switch.  The new electronics for the switch will address this issue.