US 11,430,578 B2 · Subcritical reactivity monitor utilizing prompt self-powered in-core detectors

Abstract

A subcritical reactivity monitor that utilizes one or more primarily gamma sensitive (prompt responding) self-powered detector style radiation measurement devices located within the core of a nuclear reactor to determine the amount that the reactor multiplication factor (Keff) is below the reactivity required to achieve or maintain a self-sustaining nuclear chain reaction. This invention utilizes measured changes in the self-powered detectors' current(s) to allow a reactor operator to measure the value of Keff at essentially any desired interval while the reactor is shutdown with a Keff value less than the critical value of 1.0. This invention will enable integration of the output of the value of Keff directly into the Reactor Protection System, which will enable the elimination of the operational and core design analysis constraint costs associated with the current Boron Dilution Accident prevention methodology and enable automatic control of the Chemical Volume Control System.

Claims12

Dependent claims

A method for monitoring a nuclear reactor for a shutdown condition, the method comprising:

detecting gamma radiation within a core of the nuclear reactor utilizing one or more self-powered detectors located within the core of the nuclear reactor;
outputting, by the one or more self-powered detectors, a current based on the detected gamma radiation;
generating a current value of Keff based on the outputted current in accordance with the following equation;
K
eff
⁡
(
t
)
=
1
-
f
⁡
(
t
Ref
)
⁢
I
Ref
f
⁡
(
t
)
⁢
I
⁡
(
t
)
⁢
(
1
-
K
Ref
)
wherein tRef is a time after shutdown of the nuclear reactor, t is a time after tRef, wherein a ratio of f(tRef)/f(t) is a fission product correction factor based on a time dependent fission product gamma decay relation, I(t) is an output current of the one or more self-powered detectors at time t, IRef is an output current of the one or more self-powered detectors at time tRef, and KRef is a neutron multiplication factor at time tRef;
monitoring the current value of Keff;
and based on the monitoring of the current value of Keff, adding Boron to coolant in the nuclear reactor when an undesirable change in Keff is detected.

39 more elements

Dependencies are inferred from the claim text.

Subcritical reactivity monitor utilizing prompt self-powered in-core detectors

Life of this patent

Subcritical reactivity monitor utilizing prompt self-powered in-core detectors

Life of this patent

Abstract

Claims12