Systems and methods for determining an amount of fissile material in a reactor

Patent metadata

Field	Value
Publication number	US-2016358679-A1
Application number	US-201615171740-A
Country	US
Kind code	A1
Filing date	Jun 2, 2016
Priority date	Jun 5, 2015
Publication date	Dec 8, 2016
Grant date	—

Abstract

A method of determining an amount of fissile material in a reactor includes sensing neutrons or photons emitted from the reactor before and after a change in a reactor operating parameter and determining a mass of fissile material responsive to a difference between the intensities of the radiation. A system for determining an amount of fissile material includes a radiation detector and a computing system. The radiation detector may be configured to detect neutrons or photons. The computing system may be configured for calculating mass of the fissile material based at least in part on a change in the power output from the reactor as a function of time. Some methods include collecting radiation emitted by a reactor, generating an electrical signal responsive to the collected radiation, and evaluating mass of the fissile material responsive to the magnitude and response of the electrical signal after a change in the reactor.

First claim

What is claimed is:

1 . A method of determining an amount of fissile material in a reactor, the method comprising:
sensing, with a radiation detector, a first intensity of at least one of neutrons or photons emitted from a reactor; sensing, with the radiation detector, a second intensity of at least one of neutrons or photons emitted from the reactor after a change in an operating parameter of the reactor; and determining a mass of fissile material within the reactor responsive to a difference between the first intensity and the second intensity.

2 . The method of claim 1 , further comprising:
determining a first composition of the fissile material within the reactor responsive to the first intensity of the at least one of neutrons or photons emitted therefrom; and determining a second composition of the fissile material within the reactor responsive to the second intensity of the at least one of neutrons or photons emitted therefrom after the change in the operating parameter of the reactor.

3 . The method of claim 1 , further comprising comparing the determined mass of the fissile material within the reactor with a mass of fissile material reported by an operator of the reactor.

4 . The method of claim 1 , further comprising initiating the change in the operating parameter by purposefully perturbing the reactor from a steady state.

5 . The method of claim 4 , wherein purposefully perturbing the reactor from a steady state comprises at least one of inserting a control rod to the reactor and removing a control rod from the reactor.

6 . The method of claim 1 , wherein each of sensing the first intensity of at least one of neutrons or photons and sensing the second intensity of at least one of neutrons or photons comprises sensing at least one of neutrons or photons within a fluid in which the fissile material and the radiation detector are immersed.

7 . The method of claim 1 , wherein each of sensing the first intensity of at least one of neutrons or photons and sensing the second intensity of at least one of neutrons or photons comprises sensing at least one of neutrons or photons emitted from a single fuel element of the reactor.

8 . The method of claim 1 , further comprising continuously measuring at least one of neutrons or photons as a function of time during the change in the operating parameter of the reactor.

9 . The method of claim 8 , wherein determining a mass of the fissile material within the reactor responsive to a difference between the first intensity and the second intensity comprises measuring a time between the change in the operating parameter of the reactor and a change in the at least one of neutrons or photons emitted therefrom.

10 . The method of claim 1 , further comprising identifying relative amounts of radioisotopes in the fissile material.

11 . The method of claim 10 , wherein identifying relative amounts of radioisotopes in the fissile material comprises identifying relative amounts of radioisotopes in the fissile material based at least in part on delayed neutron fraction and prompt neutron lifetime.

12 . The method of claim 1 , wherein determining a mass of the fissile material within the reactor comprises determining a mass of plutonium within the reactor.

13 . The method of claim 1 , wherein each of sensing the first intensity of at least one of neutrons or photons and sensing the second intensity of at least one of neutrons or photons comprises sensing Cherenkov radiation emitted from the reactor.

14 . The method of claim 1 , wherein each of sensing the first intensity of at least one of neutrons or photons and sensing the second intensity of at least one of neutrons or photons comprises sensing the first intensity and the second intensity emitted from each of a plurality of locations within the reactor.

15 . The method of claim 1 , wherein each of sensing the first intensity of at least one of neutrons or photons and sensing the second intensity of at least one of neutrons or photons comprises detecting a change in at least one of the first intensity and the second intensity over a period of time.

16 . A system for determining an amount of fissile material in a reactor, the system comprising:
a radiation detector configured to detect at least one of neutrons or photons emitted from a reactor; a computing system configured for operable communication with the radiation detector to receive a measurement corresponding to an intensity of the at least one of neutrons or photons, the computing system comprising:
a memory configured for storing computing instructions; and
a processor operably coupled to the memory and configured for executing the computing instructions to calculate a power output from the reactor based at least in part on the intensity of the at least one of neutrons or photons, wherein the processor is further configured for calculating a mass of fissile material within the reactor based at least in part on a change in the power output from the reactor as a function of time.

17 . The system of claim 16 , wherein the processor is configured for calculating relative amounts of radioisotopes in the fissile material based at least in part on the change in the power output from the reactor as a function of time.

18 . The system of claim 16 , wherein the processor is configured to compare the power output from the reactor to a theoretical power output based at least in part on a known composition and quantity of the fissile material.

19 . The system of claim 16 , wherein the radiation detector has a response time of less than about 1 millisecond.

20 . The system of claim 16 , wherein the radiation detector comprises at least one device selected from the group consisting of a photon flux monitor, an ionization chamber, a proportional counter, a neutron flux monitor, a fission chamber, a self-powered photon detector, a photodiode, a photomultiplier tube, a charge-coupled device, and a camera.

21 . The system of claim 16 , wherein the radiation detector comprises a plurality of sensors configured to detect at least one of neutrons or photons emitted from different locations within the reactor.

22 . A method, comprising:
collecting an initial radiation measurement of emissions by a reactor; generating a baseline electrical signal responsive to the collected initial radiation measurement; changing a reactivity of the reactor; sensing a change in radiation emitted by the reactor; generating a second electrical signal responsive to the change in radiation during the change in the reactivity of the reactor; and evaluating a mass of fissile material within the reactor responsive to a magnitude and response of the second electrical signal.

23 . The method of claim 22 , wherein evaluating a mass of the fissile material within the reactor comprises evaluating a variance of the second electrical signal as a function of time for a time period within 20 milliseconds after the change in reactivity of the reactor.

24 . The method of claim 22 , further comprising evaluating a composition of the fissile material within the reactor responsive to the magnitude and response of the second electrical signal.

25 . The method of claim 22 , wherein generating a second electrical signal responsive to the change in radiation during the change in the reactivity of the reactor comprises continuously generating the second electrical signal at least unt

Assignees

• Battelle Energy Alliance Llc
• Univ Oregon State

Inventors

• Morrell Sean R
• Holschuh Thomas V
• Marcum Wade R
• Chichester David L

Classifications

• G21C17/108

  Measuring reactor flux · CPC title

• G21Y2002/204

  Physics · mapped topic

• G21C17/06 Primary

  Devices or arrangements for monitoring or testing fuel or fuel elements outside the reactor core, e.g. for burn-up, for contamination (G21C17/08, G21C17/10 take precedence; detecting leaking fuel elements during reactor operation G21C17/04) · CPC title

• Y02E30/00

  Energy generation of nuclear origin · CPC title

• G21D1/02 Primary

  Arrangements of auxiliary equipment · CPC title