TimeLine of Events at the Three Mile Island
TimeLine of Events at the Three Mile Island
March 28, 1979
4am Problems Begin 00:00:00 (hrs, minutes, seconds) Pumps that were feeding water into the secondary loop shut down
00:00:01
Alarm is sounds in the TMI control room- Ignored by its operators because rise in temperature is considered a normal part of the plants process.
00:00:02
Water pressure and temperature of the reactors core begin to rise- secondary loop pump has stopped transferring heat from the first loop to the second.
00:00:03
The Pressure Relief Valve opens- the pressure in the reactors core had surpassed safe limits, which automatically opens the Relief Valve. This released steam into a containment tank.
00:00:04
Back up Pumps turn on- Lights on the control panel indicated to the operators that the secondary loop water pumps have been turned on. They are unaware that the pumps are disengaged and not performing.
00:00:09
Boron and Silver rods are lowered into the reactor. Control Panel Light Goes out which indicates the valve is closed- the lowering of the rods slows down the reaction rate and the amount of heat produced. With the panel light going out the operators assume that the valve has closed without physically checking.
00:02:00
Emergency Injection Water activated- this causes water to flow to the reactors core to keep the core at a safe level.
00:04:30
Water level appears to be increasing in first system while pressure decreases- the water level is really dropping and the EIW is shut off by the operators. EIW increases the amount of steam that is produced. Now water and steam are being released by through the Pressure Release Valve.
00:08:00
Operators notice that the value is secondary back up pumps are closed- so they turn it back on the Secondary Water Loop, now the system is functioning correctly. Primary Loop’s water level continues to drop.
00:45:00
Loss of Cooling agent has not been checked by operators- the device used to check radiation has not registered an alarm.
March 28, 1979
4am Problems Begin 00:00:00 (hrs, minutes, seconds) Pumps that were feeding water into the secondary loop shut down
00:00:01
Alarm is sounds in the TMI control room- Ignored by its operators because rise in temperature is considered a normal part of the plants process.
00:00:02
Water pressure and temperature of the reactors core begin to rise- secondary loop pump has stopped transferring heat from the first loop to the second.
00:00:03
The Pressure Relief Valve opens- the pressure in the reactors core had surpassed safe limits, which automatically opens the Relief Valve. This released steam into a containment tank.
00:00:04
Back up Pumps turn on- Lights on the control panel indicated to the operators that the secondary loop water pumps have been turned on. They are unaware that the pumps are disengaged and not performing.
00:00:09
Boron and Silver rods are lowered into the reactor. Control Panel Light Goes out which indicates the valve is closed- the lowering of the rods slows down the reaction rate and the amount of heat produced. With the panel light going out the operators assume that the valve has closed without physically checking.
00:02:00
Emergency Injection Water activated- this causes water to flow to the reactors core to keep the core at a safe level.
00:04:30
Water level appears to be increasing in first system while pressure decreases- the water level is really dropping and the EIW is shut off by the operators. EIW increases the amount of steam that is produced. Now water and steam are being released by through the Pressure Release Valve.
00:08:00
Operators notice that the value is secondary back up pumps are closed- so they turn it back on the Secondary Water Loop, now the system is functioning correctly. Primary Loop’s water level continues to drop.
00:45:00
Loss of Cooling agent has not been checked by operators- the device used to check radiation has not registered an alarm.