This is a step-by-step startup guide for the RBMK Simulator on how to bring it up to full power. Note that this is work in progress, you might want to come back to this manual and check for updates.
The simulation starts in a full shutdown state after some maintenance was done. The reactor is cooled by natural circulation and the decay heat is removed by the Blowdown/Cooldown system.
Preparations
To allow the reactor to be operated, the reactor protection system needs to be reset. This is possible with pressure on feedwater pumps as well as pressure on condensate system pumps and a sufficient flow through the reactor. During startup, main ejectors are not available so they need to be bypassed.
Make yourself familiar with the Blowdown/Cooldown system. To prevent high flow through the cooldown system, shut off the blowdown pump by closing the discharge valve and turning off the pump (all pumps are shut down like this). Use the bypass for passive flow through the aftercooler. Alternatively, you could also completely close the Blowdown system, this will, however, result in immediate heat up of the core and less controlled heatup.
The MCP get their water from the bottom of the steam drum with the cold feedwater mixed into the steam drum outlet. During operation, the water mixture is cooled down and cavitation is avoided. You can see a cooldown value in Kelvin on the MCP control panel, this refers to the boiling point of water on given pressure. As we can not add cold water when no steam leaves the steam drum, we have to trim the MCP flow by closing the trim valve to about 40 %.
Switch on one MCP per side and close the reactor bypass afterwards. You might want to watch the levels in the steam drums as with only one pump on one side and no pump on the other side, the water will be taken from only one side but returned to both sides. You can switch on the “balance control” on the blowdown system, it will automatically adjust the return valves. After one MCP per side is running, switch on a total of 3 MCP per side.
3 Pumps with 40 % trim will still throw a LOW1 flow warning, which is acceptable during startup.
Heatup and first steam generation
With 3 MCP running, bring the Blowdown system in operation with the regenerator in use and the water taken from the MCP. The aftercooler flow can be reduced to 400 kg/s or less as there is much less flow after the water is pushed through the polishers now. With the regenerator in place, less heat will now be removed and the core will start to heat up. At this point, you can decide to either wait for steam or speed up the progress by making your reactor critical.
As no condenser vacuum is available, we use the auxiliary steam condensers to remove steam from the drums and have a pressure regulation. Use the auxiliary condensers to control the pressure automatically and have a flow cycle back via hotwell, condensation and feedwater pumps.
[to be continued…]
Turbine Warmup
The Turbine has 4 predefined hold points on which the warming up can be done. It is recommended to not operate the turbine on different speeds for a long period of time as vibrations outside those hold points will occur. There is a recommendation for steam parameters for each hold points. With the steam pressure setpoint from reactor thermal power output in use, each steam parameter can be achieved with a certain power level of the reactor.
| Speed (1/min) | Pressure | Reactor Power | Neutron Setpoint |
|---|---|---|---|
| 750 1/min | 15 bar | 140 MWth | 4.7 %N |
| 1500 1/min | 27 bar | 206 MWth | 7.0 %N |
| 2250 1/min | 38 bar | 263 MWth | 8.8 %N |
| 3000 1/min | 50 bar | 326 MWth | 10.9 %N |
Note that the pressure setpoint is generated from actual reactor thermal power output, not from neutron setpoint. It is not necessary to exactly have the given values, they are only a recommendation.