# US 4,751,040 A · Means and techniques useful in the monitoring and accountability of radioactive materials

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- Number: US 4,751,040 A
- Document ID: US4751040A
- Status: Granted
- Kind: A
- Application number: 06/350,304
- Filed: 1982-02-19
- Granted: 1988-06-14
- Earliest claimed: 1982-02-19
- Assignees: Geoscience Ltd.
- Inventors: Heinz F. Poppendiek
- Web page: https://patentgrep.com/patent/US4751040A

## CPC

- G21F 5/12: Closures for containers; Sealing arrangements
- G21F: PROTECTION AGAINST X-RADIATION, GAMMA RADIATION, CORPUSCULAR RADIATION OR PARTICLE BOMBARDMENT; TREATING RADIOACTIVELY CONTAMINATED MATERIAL; DECONTAMINATION ARRANGEMENTS THEREFOR (radiation protection by pharmaceutical means A61K8/00, A61Q17/04; in cosmonautic vehicles B64G1/54; combined with a reactor G21C11/00; combined with X-ray tubes H01J35/16; combined with X-ray apparatus H05G1/02)

## Abstract

Afterheat being released from a radioactive storage system is measured and monitored. Changes in heat release with respect to time is related to expected radioactive decay processes of the confined radioactive materials. Material leakage from storage is detected and defined by deviations from the normal expected heat release-time function being monitored. Such deviations or lack of deviations, as the case may be, provide the desired accountability of the radioactive materials.

## Claims

### Claim 1

A radioactive material storage system, and a heat flux sensor system positioned on said storage system to surround the same in (a) the path of all anticipated heat flow being developed by radioactive materials while still in said storage system, said heat flow path being in a direction outwardly of said storage system and through said sensor system, said sensor system producing an output representative of the quantity of said heat flow.

### Claim 2

In a system for determining information related to the presence of radioactive materials in a radioactive storage system, the step of measuring (the) a quantity representative of the flow of all heat being produced in (a direction0 all directions out of said storage system by said materials in said storage system.

### Claim 3 (depends on 1)

In an arrangement as set forth in claim 1 including a system for calibrating said sensor system, said calibrating system including means for producing additional heat sensed by said sensor system.

### Claim 4 (depends on 2)

A system as set forth in claim 2 including the step of producing heat for calibration purposes such that measuring of both the heat flow from the radioactive materials and the produced heat results.

### Claim 5 (depends on 1)

A radioactive storage system as set forth in claim 1 on which a series of heat flux sensing means is circumferentially disposed, and heat producing means is circumferentially disposed about said system for producing a source of calibration heat sensed by said flux sensing means.

### Claim 6 (depends on 5)

An arrangement as set forth in claim 5 in which said heat producing means is spaced from said heat flux sensing means.

### Claim 7 (depends on 4)

A system as set forth in claim 4 including measuring a characteristic of the produced heat.

### Claim 8 (depends on 3)

a system as set forth in claim 3 in which said heat producing means includes electrical heating means, and means for measuring the amount of power being supplied to said electrical heating means.

### Claim 9 (depends on 4)

A system as set forth in claim 4 in which the heat produced by said radioactive materials alone is measured to achieve a first measurement, then the heat produced by said radioactive materials together with the heat produced by said calibrating system is measured to achieve a second measurement, and subtracting said first measurement from said second measurement.