Subcritical reactivity measurement method
AssigneeWestinghouse Electric Corp.
InventorsMichael D. Heibel, Patrick J. Sebastiani, Stanwood L. Anderson
Life of this patent
Estimating the term…
Abstract
A method of determining the spatially corrected inverse count ratio (SCICR) used to determine reactor criticality, which subtracts a background noise signal from the source range detector output. The method monitors the source range detector signal at two different core temperature levels during a transient portion of the detector output as the power output of the reactor is increased in the source range. This information is employed to analytically determine the background noise signal, which is then subtracted from the detector outputs to obtain the SCICR reactivity measurement.
Claims7
A method of determining the nearness to criticality of a nuclear reactor having a control rod configuration in a core region of a nuclear reactor vessel and a coolant moderator circulating therethrough, comprising the steps of:
- Monitoring a first source range detector signal (CMC) during a transient portion of the detector signal to obtain a neutron radiation level of the core when the coolant moderator is at a density corresponding to a first temperature;
- Raising the temperature of the core to a second temperature;
- Monitoring a second source range detector signal (CMH) during a transient portion of the detector signal to obtain a neutron radiation level of the core when the coolant moderator is at a density corresponding to the second temperature, the monitored first source range detector signal and the monitored second source range detector signal each having a background non-neutron signal component (N);
- Determining the background non-neutron signal component based upon the monitored first and second source range detector signals in accordance with the relationship
- N
- =
- {
- K
- eff
- H
- -
- K
- eff
- C
- 1
- -
- K
- eff
- H
- +
- R
-
- (
- T
- H
- )
- R
-
- (
- T
- C
- )
- +
- F
- H
- F
- C
- -
- 1
- }
-
- C
- MC
- -
- C
- MH
- {
- K
- eff
- H
- -
- K
- eff
- C
- 1
- -
- K
- eff
- H
- +
- R
-
- (
- T
- H
- )
- R
-
- (
- T
- C
- )
- +
- F
- H
- F
- C
- -
- 1
- }
- -
- 1
- Removing the background non-neutron signal component from the monitored neutron radiation level obtained at the second temperature to obtain an background adjusted neutron radiation level;
- and
- Determining the nearness to criticality based upon the background adjusted neutron radiation level.
Dependencies are inferred from the claim text.