US3612873A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Neutron flux recorder utilizing a continuous web of track-registration material
Assignee: General Electric Co
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Filing: 1968-12-23
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Granted: 1971-10-12
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Expires: 1988-12-23
Abstract
Abstract A neutron flux recorder is disclosed which is capable of continuously monitoring the neutron flux level of a nuclear reactor over an extended period of time. This recorder utilizes a continuous web of track-registration material which is slowly passed adjacent a slit containing a source material which emits charged particles such as fission fragments or alpha particles when irradiated with neutrons. The rate of charged particle emission by the source material is directly proportional to the neutron flux. The charged particles which strike the trackregistration material form damage tracks therein. These tracks may be etched by treatment with a suitable etchant. The resulting etched tracks are visible and may be counted or otherwise measured. This produces a permanent record of the neutron flux level adjacent the recorder. These recorders can be made tamperproof and are capable of recording flux levels for periods on the order of a year.
Inventors
- 👤 Henry Ward Alter
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 17:57
CPC Classifications
G; G21; G21C; G21C17/00; G21C17/10; G21C17/108; G01; G01T; G01T5/00; G01T5/10; Y; Y02; Y02E; Y02E30/00; Y02E30/30
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
88 words
A neutron flux recorder comprising: a. an elongated tape of track-registration material, said material being capable of forming tracks of altered material along the trajectories of charged particles in said material; b. adjacent said tape a quantity of a source material which emits charged particles upon neutron irradiation; c. means to move said tape past said source material at a uniform rate over long periods of time; and d. a tamper-resistant closed container permitting the passage of neutrons therethrough and surrounding said tape, source material and drive means.
Claim 2
Dependent Claim
88 words
A neutron flux recorder comprising: a. an elongated tape of track-registration material, said material being capable of forming tracks of altered material along the trajectories of charged particles in said material; b. adjacent said tape a quantity of a source material which emits charged particles upon neutron irradiation; c. means to move said tape past said source material at a uniform rate over long periods of time; and d. a tamper-resistant closed container permitting the passage of neutrons therethrough and surrounding said tape, source material and drive means.
Claim 3
Dependent Claim
27 words
The neutron flux recorder according to claim 1 further including a marking means positioned adjacent said tape, adapted to visibly mark said tape at selected time intervals.
Claim 4
Dependent Claim
31 words
The neutron flux recorder according to claim 1 wherein at least that portion of said tamper-resistant closed container adjacent said source material consists of a low neutron absorption cross section material.
Claim 5
Dependent Claim
61 words
The neutron flux recorder according to claim 1 wherein said source material extends adjacent substantially the entire width of said tape with the quantity adjacent one edge of said tape being greater than the quantity adjacent the other edge of said tape, whereby the number of tracks formed by a given neutron flux will vary across the width of said tape.
Claim 6
Dependent Claim
54 words
The neutron flux recorder according to claim 1 wherein said means to move said tape past said source material includes at least one drive roller in operative engagement with said tape; with said marking means mounted on said roller so as to engage and mark said tape once during each revolution of said roller.
Claim 7
Dependent Claim
59 words
The neutron flux recorder according to claim 1 further including a small amount of a spontaneously fissioning isotope adjacent said tape whereby a continuous Uniform line of tracks in said tape is formed by charged particles from said spontaneously fissioning isotope and stoppages of said tape may be detected by locally higher track densities adjacent said spontaneously fissioning isotope.
Claim 8
Dependent Claim
35 words
The neutron flux recorder according to claim 1 wherein the quantity of source material is sufficient to produce at least about 104 tracks per square millimeter at the maximum anticipated flux level to be recorded.
Claim 9
Dependent Claim
31 words
The neutron flux recorder according to claim 1 wherein said source material is selected from the group consisting of uranium-235, plutonium-239, and mixtures thereof; and said tape comprises a polycarbonate resin.
Claim 10
Dependent Claim
31 words
The neutron flux recorder according to claim 1 wherein said source material is selected from the group consisting of lithium-6, boron-10 and mixtures thereof; and said tape comprises a cellulosic resin.
Claim 11
Dependent Claim
25 words
The neutron flux recorder according to claim 1 wherein said means to move said tape past said source material includes a battery-driven uniform speed motor.
Claim 12
Independent Claim
133 words
A method for monitoring the flux level of a nuclear reactor over a long period of time which comprises the steps of: a. providing adjacent the reactor to be monitored a quantity of a source material which emits charged particles upon irradiation with neutrons; b. slowly moving a tape of track-registration material past said source material in close proximity thereto, said track-registration material being capable of forming tracks of altered material along the trajectories of charged particles in said track-registration material; and c. treating said tape with an etching solution which preferentially attacks and dissolves said altered material, making said tracks visible, whereby the number of tracks at a given location along said tape is indicative of the power level of said reactor at the time said location was adjacent said source material.
Claim 13
Independent Claim
133 words
A method for monitoring the flux level of a nuclear reactor over a long period of time which comprises the steps of: a. providing adjacent the reactor to be monitored a quantity of a source material which emits charged particles upon irradiation with neutrons; b. slowly moving a tape of track-registration material past said source material in close proximity thereto, said track-registration material being capable of forming tracks of altered material along the trajectories of charged particles in said track-registration material; and c. treating said tape with an etching solution which preferentially attacks and dissolves said altered material, making said tracks visible, whereby the number of tracks at a given location along said tape is indicative of the power level of said reactor at the time said location was adjacent said source material.
Claim 14
Dependent Claim
19 words
The flux-monitoring method of claim 11 further including forming a visible mark on said tape at regular time intervals.
Claim 15
Dependent Claim
50 words
The method of flux monitoring according to claim 11 wherein said tape is moved by at least one drive roller in engagement therewith, and a pin mounted on said drive roller contacts said tape once during each revolution of said drive roller to form a visible mark on said tape.
Claim 16
Dependent Claim
59 words
The flux-monitoring method according to claim 11 further including providing a small amount of a spontaneously fissioning isotope adjacent said tape whereby charged particles emitted by said spontaneously fissioning isotope produce a continuous uniform line of tracks along said tape so that any stoppage of said tape will be indicated by a locally higher track density along said line.
Claim 17
Dependent Claim
30 words
The flux-monitoring method according to claim 11 wherein said source material is selected from the group consisting of uranium-235, plutonium-239 and mixtures thereof; and said tape comprises a polycarbonate resin.
Claim 18
Dependent Claim
32 words
The flux-monitoring method according to claim 11 wherein said source material comprises a material selected from the group consisting of lithium-6, boron-10, and mixtures thereof; and said tape comprises a cellulosic register.
References Cited (Backward Citations)
US3457408A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-10-11 | 1975-04-12 | 1975-10-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-10-11 | 1979-04-12 | 1979-10-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-10-11 | 1983-04-12 | 1983-10-12 | $7700.00 | Window Closed / Lapsed |