Sequence of Event
April 25
1. 1:06am-the scheduled shutdown of the reactor started, power
level gradually lowered.
2. 3:47am-reactor power halted at 1600 MW (t).
April 26
3. 0:05am-power level decreased to 720 MW (t) and continued
decreasing. [the safe operating level for a pre-accident
configuration RMBK was about 700 MW(t)
4. 0:28am-power level reduced to 500 MW (t).
5. 0:32am-due to an unexpected fall in power to about 30 MW
(t), the operator withdraw a number of control rods, in order to restore the power level.
6. 1:00am-power level rose to 200 MW (t).
7. 1:19am-some manual [control rods] were withdrawn to
increase power, raise the temperature and pressure in the
steam separator.
8. 1:21am-the operator reduced the feed normal flow rate to
below normal to stabilise the steam separator water level,
decreasing heat removal from the core.
9. 1:22am-spontaneous formation of steam in the core began.
10. 1:23am-The beginning of the actual test was marked by the
closing of the turbine feed valves, which initiated turbine
coasting. Automatic control rods were withdrawn from the
core.
11. 1:23:35am-steam in the core began to increase
uncontrollably.
12. 1:23:40am-the operator pressed the emergency button,
control rods started to enter the core. This entry of rods
from the top concentrated all of the reactivity in the bottom
of the core.
13. 1:23:45am-fuel pellets broke and reacted with the cooling
water to form a pulse of high pressure in the fuel channels.
14. 1:23:49am-fuel channels ruptured.
15. 1:24am-two explosions occurred.
*back* (C) 1999 ThinkQuest Team 27954