diff --git a/coordinator/iocontrol.lua b/coordinator/iocontrol.lua
index 0a42038..26ef62b 100644
--- a/coordinator/iocontrol.lua
+++ b/coordinator/iocontrol.lua
@@ -112,7 +112,8 @@ function iocontrol.record_builds(builds)
                     unit.reactor_ps.publish(key, val)
                 end
 
-                if unit.reactor_data.mek_struct.length ~= 0 and unit.reactor_data.mek_struct.width ~= 0 then
+                if (type(unit.reactor_data.mek_struct.length) == "number") and (unit.reactor_data.mek_struct.length ~= 0) and
+                   (type(unit.reactor_data.mek_struct.width) == "number")  and (unit.reactor_data.mek_struct.width ~= 0) then
                     unit.reactor_ps.publish("size", { unit.reactor_data.mek_struct.length, unit.reactor_data.mek_struct.width })
                 end
             end
diff --git a/coordinator/startup.lua b/coordinator/startup.lua
index 5416262..b4f3db4 100644
--- a/coordinator/startup.lua
+++ b/coordinator/startup.lua
@@ -16,7 +16,7 @@ local config       = require("coordinator.config")
 local coordinator  = require("coordinator.coordinator")
 local renderer     = require("coordinator.renderer")
 
-local COORDINATOR_VERSION = "alpha-v0.5.12"
+local COORDINATOR_VERSION = "alpha-v0.6.0"
 
 local print = util.print
 local println = util.println
diff --git a/coordinator/ui/components/unit_detail.lua b/coordinator/ui/components/unit_detail.lua
index df79a00..182b773 100644
--- a/coordinator/ui/components/unit_detail.lua
+++ b/coordinator/ui/components/unit_detail.lua
@@ -141,6 +141,7 @@ local function init(parent, id)
     local rps_noc = IndicatorLight{parent=annunciator,label="No Coolant",colors=cpair(colors.yellow,colors.gray)}
     local rps_flt = IndicatorLight{parent=annunciator,label="PPM Fault",colors=cpair(colors.yellow,colors.gray),flash=true,period=period.BLINK_500_MS}
     local rps_tmo = IndicatorLight{parent=annunciator,label="Timeout",colors=cpair(colors.yellow,colors.gray),flash=true,period=period.BLINK_500_MS}
+    local rps_sfl = IndicatorLight{parent=annunciator,label="System Failure",colors=cpair(colors.orange,colors.gray),flash=true,period=period.BLINK_500_MS}
 
     r_ps.subscribe("rps_tripped", rps_trp.update)
     r_ps.subscribe("dmg_crit", rps_dmg.update)
@@ -151,6 +152,7 @@ local function init(parent, id)
     r_ps.subscribe("no_cool", rps_noc.update)
     r_ps.subscribe("fault", rps_flt.update)
     r_ps.subscribe("timeout", rps_tmo.update)
+    r_ps.subscribe("sys_fail", rps_sfl.update)
 
     annunciator.line_break()
 
@@ -171,7 +173,7 @@ local function init(parent, id)
 
     -- machine-specific indicators
     if unit.num_boilers > 0 then
-        TextBox{parent=main,x=32,y=34,text="B1",width=2,height=1,fg_bg=cpair(colors.black, colors.white)}
+        TextBox{parent=main,x=32,y=35,text="B1",width=2,height=1,fg_bg=cpair(colors.black, colors.white)}
         local b1_hr = IndicatorLight{parent=annunciator,label="Heating Rate Low",colors=cpair(colors.yellow,colors.gray)}
         b_ps[1].subscribe("HeatingRateLow", b1_hr.update)
     end
diff --git a/supervisor/session/plc.lua b/supervisor/session/plc.lua
index 079d8e9..6b066ef 100644
--- a/supervisor/session/plc.lua
+++ b/supervisor/session/plc.lua
@@ -304,7 +304,7 @@ function plc.new_session(id, for_reactor, in_queue, out_queue)
                     self.sDB.formed = pkt.data[5]
 
                     if not self.sDB.no_reactor and self.sDB.formed then
-                        self.sDB.mek_status.heating_rate = pkt.data[6]
+                        self.sDB.mek_status.heating_rate = pkt.data[6] or 0.0
 
                         -- attempt to read mek_data table
                         if pkt.data[7] ~= nil then
@@ -471,7 +471,7 @@ function plc.new_session(id, for_reactor, in_queue, out_queue)
         if self.received_struct then
             return self.sDB.mek_struct
         else
-            return nil
+            return {}
         end
     end
 
@@ -480,7 +480,7 @@ function plc.new_session(id, for_reactor, in_queue, out_queue)
         if self.received_status_cache then
             return self.sDB.mek_status
         else
-            return nil
+            return {}
         end
     end
 
diff --git a/supervisor/startup.lua b/supervisor/startup.lua
index adf6437..2b3412d 100644
--- a/supervisor/startup.lua
+++ b/supervisor/startup.lua
@@ -13,7 +13,7 @@ local svsessions = require("supervisor.session.svsessions")
 local config     = require("supervisor.config")
 local supervisor = require("supervisor.supervisor")
 
-local SUPERVISOR_VERSION = "beta-v0.6.6"
+local SUPERVISOR_VERSION = "beta-v0.6.7"
 
 local print = util.print
 local println = util.println