Claims
- 1. A method of starting up a boiling water nuclear reactor with a reactor core having a plurality of control rods distributed about a cross section of the reactor core in a two-color checkerboard pattern in which each square is assigned a control rod, and wherein the control rods are moved into the reactor core in a shutdown state of the reactor and are moved at least partially out of the reactor core during a start-up of the reactor, the method which comprises:
defining a first configuration, in which simultaneously moved control rods are assigned to squares of different color in the checkerboard pattern, and/or a second configuration, in which virtually half the control rods are moved completely or partially out of the reactor core and fully moved-in control rods are assigned to squares of different color; and moving the control rods out of the reactor core under the following restrictions in order to reach a reactor power output upper limit limiting a start-up range: a) move a given control rod completely or partially out of the reactor core only when all directly or diagonally adjacent control rods remain at rest; and b) as long as the reactor power output upper limit is not yet reached and a predetermined minimum number of the control rods are not yet moved virtually completely out of the reactor core, all the control rods which in each case are directly adjacent to a completely or at least partially moved-out control rod remain moved in completely.
- 2. The method according to claim 1, which comprises, upon receiving a command to move out a control rod disposed directly or diagonally adjacent to a control rod being moved out at the moment, suppressing the command and interrupting a movement of all control rods.
- 3. The method according to claim 1, which comprises, upon receiving a command to move out a control rod disposed directly adjacent to a control rod moved at least partially out of the reactor core, suppressing the command and interrupting a movement of all control rods.
- 4. The method according to claim 1, which comprises setting the minimum number to below half the total number of control rods.
- 5. The method according to claim 1, which comprises canceling at least one of the restriction a) and b) no later than when the upper limit is reached.
- 6. The method according to claim 1, which comprises setting the upper limit is approximately 5% of a rated power output of the reactor.
- 7. The method according to claim 1, which comprises canceling the restriction b) no later than as soon as at least the minimum number of control rods have moved substantially completely out of the reactor core.
- 8. The method according to claim 1, which comprises moving the control rods out in groups.
- 9. The method according to claim 1, which comprises considering only those control rods to be partially or completely moved out that are moved more than approximately 5 cm out of an initial position defining the moved-in state.
- 10. A method of monitoring an operation of a boiling water reactor with a reactor core, the reactor core having control rods distributed about a cross section thereof in a pattern corresponding to a two-color checkerboard with squares each assigned a control rod, the checkerboard representing a regular grid with square meshes, each of the control rods being movable via a respective control rod drive from an initial position, in which the control rod is moved completely in the reactor core, into a final position, in which the control rod is moved completely out of the reactor core, and the method comprises:
during start-up, activating at most some control rod drives and interlocking other control rod drives, and wherein, in the interlocking of the control rod drives, permitting one of a first configuration, in which simultaneously moved control rods are assigned to squares of different color in the checkerboard pattern, and a second configuration, in which substantially half the control rods are moved at least partially out of the reactor core and fully moved-in control rods are assigned to squares of different color, and thereby monitoring the following rules: a) the control rod drives of the control rods which are directly or diagonally adjacent to one another should not be activated simultaneously; b) for each control rod no longer in the initial position, the drives of the directly adjacent control rods should not be activated before a predetermined minimum number of control rods are in the final position or the reactor power output reaches an upper limit predetermined for the start-up operation.
- 11. The method according to claim 10, which comprises blocking all the control rod drives upon an infringement of at least one of the rules a) and b).
- 12. The method according to claim 10, which comprises setting the minimum number to no more than half the total number of all the control rods.
- 13. The method according to claim 10, which comprises, during start-up, monitoring a region of the reactor core comprising at least a plurality of control rods such that the control rods are assigned to two groups, the groups being distributed over the region according to the differently colored squares of a checkerboard, and monitoring the drives of the control rods to ensure that the drives of one group remain interlocked and only selected drives of the other group are activated.
- 14. The method according to claim 10, which comprises enabling the control rod drives in groups.
- 15. The method according to claim 10, which comprises setting the upper limit to approximately 5% of a rated power output of the reactor.
- 16. The method according to claim 10, which comprises, upon an occurrence of criterion b), interlocking the directly adjacent control rods only in the event of a displacement of a control rod of more than approximately 5 cm in relation to an initial position thereof.
- 17. An apparatus for controlling a boiling water nuclear reactor, comprising:
a plurality of control rods distributed over a reactor core of the reactor in a pattern corresponding to a two-color checkerboard, wherein each square of the checkerboard is assigned a control rod; each control rod having a control rod drive for moving the control rod between an initial position and a final position; a control rod movement computer connected to said control rod drives for controlling an outward movement of said control rods; and a monitoring stage connected to said computer, said monitoring stage permitting one of a configuration in which simultaneously moved control rods are assigned to squares of different color in the checkerboard pattern, and a core configuration in which virtually half the control rods are moved completely or partially out of the reactor core and still fully moved-in control rods are assigned to squares of different color, said monitoring stage being programmed to: a) define for each said control rod selected to be moved out a first blocking zone in which all said drives for said control rods directly or diagonally adjacent to a selected said control rod cannot be activated; and b) define, for each control rod no longer in the initial position, a second blocking zone in which all drives of said control rods directly adjacent to the respective said control rod that is already no longer in the initial position cannot be activated during a start-up mode.
- 18. The apparatus according to claim 17, wherein each f said control rod drives is controllable and activatable via a selection signal, and, whenever selection signals for another control rod located in the first blocking zone of the respective said control rod are generated simultaneously, said drives of said two control rods are interlocked by said monitoring stage.
- 19. The apparatus according to claim 18, wherein said monitoring stage is configured to cancel the selection signals of all said drives simultaneously with the interlocking of said two drives.
- 20. The apparatus according to claim 17, wherein an automatically running program for selecting and activating said drives during the start-up of the reactor are activatable in said control rod movement computer, and wherein, if two of said drives are selected simultaneously, said control rod of one of said selected drives being located in said first blocking zone of said control rod capable of being moved out by the other said selected drive, the selection of said two drives, and the already activated program can be canceled by said monitoring stage.
- 21. The apparatus according to claim 20, wherein, upon a cancellation of the selection of a given said drive, said given drive is also blocked against a movement thereof towards a final position.
- 22. The apparatus according to claim 17, wherein monitoring of every first blocking zone and/or of every second blocking zone can be canceled with a power output signal indicating that the reactor has reached a power output above an upper limit for the start-up range.
- 23. The apparatus according to claim 17, wherein monitoring of every first blocking zone and/or of every second blocking zone can be canceled with a power output signal indicating that the reactor has reached a power above 5% of the rated power output.
- 24. The apparatus according to claim 17, wherein monitoring of every second blocking zone can be canceled with move-out length signals indicating that a predetermined minimum number of control rods have substantially reached their final position.
- 25. The apparatus according to claim 24, wherein the minimum number is at most equal to half a total number of said control rods.
- 26. The apparatus according to claim 24, wherein the minimum number lies just below half the total number of said control rods.
Priority Claims (1)
Number |
Date |
Country |
Kind |
198 27 443.2 |
Jun 1998 |
DE |
|
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This is a continuation of copending international application PCT/EP99/04082, filed Jun. 14, 1999, which designated the United States.
Continuations (1)
|
Number |
Date |
Country |
Parent |
PCT/EP99/04082 |
Jun 1999 |
US |
Child |
09740691 |
Dec 2000 |
US |