US3969077A
Expired / Lapsed
US
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Alkali metal leak detection method and apparatus
Assignee: Varian Medical Systems Inc
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Filing: 1974-03-13
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Granted: 1976-07-13
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Expires: 1994-03-13
Abstract
Abstract A method and apparatus for detecting a leak of an alkali metal in liquid form in a structure such as the heat transfer system of a nuclear reactor. When alkali metal leaks from its containment structure and thereupon comes into contact with a compound containing hydrogen which can be displaced by the alkali metal, a chemical reaction occurs by which hydrogen gas is generated. The hydrogen gas so generated will diffuse very rapidly throughout the region proximate to the sodium leak. The hydrogen compound can be present in a variety of physical forms. The compound barium hydroxide is especially suitable as a source for the generation of hydrogen gas. Water vapor in air or in an inert gas also provides a suitable hydrogen source. A sensor located within the region of the alkali metal leak will sense the presence of hydrogen gas and will thereupon activate an alarm or recording device. The efficiency of the leak detection system can be evaluated and periodically tested by simply introducing a measured quantity of hydrogen gas into the region proximate to the alkali containment structure. This obviates the necessity of effecting a controlled alkali metal leak in order to test the leak detection system.
Inventors
- 👤 Eugene F. Hill
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 22:54
CPC Classifications
G; G01; G01N; G01N7/00; G01N7/10; G01M; G01M3/00; G01M3/02; G01M3/04; G01M3/20; G01M3/202; G21; G21C; G21C17/00; G21C17/002; Y; Y02; Y02E; Y02E30/00; Y02E30/30
Claims Analysis
Total Claims: 29
Claim 1
Independent Claim
87 words
A method of determining whether or not an alkali metal leak exists in a structure confining the alkali metal comprising the steps of: exposing the exterior of said structure to a substance including hydrogen in a form chemically replaceable by said alkali metal to form hydrogen gas; detecting any of said formed hydrogen gas exterior to said structure with a hydrogen gas detection apparatus which provides a signal when said hydrogen is detected; and evaluating said signal to determine whether or not said alkali metal leak exists.
Claim 2
Independent Claim
87 words
A method of determining whether or not an alkali metal leak exists in a structure confining the alkali metal comprising the steps of: exposing the exterior of said structure to a substance including hydrogen in a form chemically replaceable by said alkali metal to form hydrogen gas; detecting any of said formed hydrogen gas exterior to said structure with a hydrogen gas detection apparatus which provides a signal when said hydrogen is detected; and evaluating said signal to determine whether or not said alkali metal leak exists.
Claim 3
Dependent Claim
118 words
In a containment structure containing a liquid alkali metal heat exchange fluid circulating in said structure, a method of detecting whether or not there is a leak of the alkali metal to the exterior of said structure comprising the steps of: supplying a substance containing hydrogen in a form chemically replaceable by said alkali metal outside of and in proximity to said structure; combining any leaking alkali metal with said substance to generate hydrogen gas; detecting the presence or absence of any generated hydrogen gas outside said structure; generating an output signal indicative of the presence or absence of said generated hydrogen gas; and evaluating said output signal to determine whether or not said alkali metal leak exists.
Claim 4
Dependent Claim
118 words
In a containment structure containing a liquid alkali metal heat exchange fluid circulating in said structure, a method of detecting whether or not there is a leak of the alkali metal to the exterior of said structure comprising the steps of: supplying a substance containing hydrogen in a form chemically replaceable by said alkali metal outside of and in proximity to said structure; combining any leaking alkali metal with said substance to generate hydrogen gas; detecting the presence or absence of any generated hydrogen gas outside said structure; generating an output signal indicative of the presence or absence of said generated hydrogen gas; and evaluating said output signal to determine whether or not said alkali metal leak exists.
Claim 5
Dependent Claim
16 words
The method of claim 2 wherein said hydrogen including substance is a gas containing water vapor.
Claim 6
Dependent Claim
83 words
The method of claim 2 wherein a hydrogen gas detector is provided to detect the formed hydrogen gas, said step of detecting further including the steps of measuring the temperature of a hydrogen gas permeable wall portion of the hydrogen gas detector, the detector producing an indication as a function of the temperature of the wall portion, and compensating the hydrogen gas detector in accordance with said measured temperature so that the indication is substantially independent of the temperature of the wall portion.
Claim 7
Dependent Claim
14 words
The method of claim 2 wherein said formed and detected hydrogen gas is deuterium.
Claim 8
Dependent Claim
20 words
The method of claim 5 including the step of measuring the presence of said formed deuterium with a mass spectrometer.
Claim 9
Dependent Claim
28 words
The method of claim 2 wherein said step of detecting further includes the step of heating a hydrogen gas permeable wall portion of a hydrogen gas detecting apparatus.
Claim 10
Dependent Claim
31 words
The method of claim 7 wherein the step of heating further includes the step of maintaining the temperature of said hydrogen gas permeable wall portion at a substantially constant, desired temperature.
Claim 11
Dependent Claim
74 words
In combination: a containment structure; a heat exchange, alkali metal fluid circulating in said structure; and a detector mounted outside of and in proximity to the exterior of said structure for detecting a reaction of any of said fluid leaking through said structure with a substance including hydrogen in a form chemically replaceable by said alkali metal, said substance being in proximity to said detector and in communication with the exterior of said structure.
Claim 12
Dependent Claim
74 words
In combination: a containment structure; a heat exchange, alkali metal fluid circulating in said structure; and a detector mounted outside of and in proximity to the exterior of said structure for detecting a reaction of any of said fluid leaking through said structure with a substance including hydrogen in a form chemically replaceable by said alkali metal, said substance being in proximity to said detector and in communication with the exterior of said structure.
Claim 13
Dependent Claim
22 words
The combination of claim 9 including alarm means responsive to said detector for indicating a presence of said leak to be detected.
Claim 14
Dependent Claim
13 words
The combination of claim 9 wherein said hydrogen including substance is water vapor.
Claim 15
Dependent Claim
22 words
The combination of claim 9 wherein said formed and detected hydrogen gas is deuterium, and said detecting means includes a mass spectrometer.
Claim 16
Dependent Claim
43 words
The combination of claim 9 wherein said containment structure is surrounded by a thermal insulation pipe, a space being formed between said containment structure and said pipe, said space containing said hydrogen including substance, said hydrogen gas detector being supported by said pipe.
Claim 17
Dependent Claim
12 words
The combination of claim 9 wherein said detector includes a sputter-ion pump.
Claim 18
Dependent Claim
43 words
The combination of claim 14 wherein said hydrogen gas detector comprises a sealed chamber, a wall portion of said chamber being permeable to hydrogen gas, and means for indicating the presence of said hydrogen gas permeating into said chamber through said wall portion.
Claim 19
Dependent Claim
93 words
The combination of claim 15 wherein said hydrogen gas detector includes means for sensing the temperature of said hydrogen gas permeable wall portion and for generating a signal indicative of said temperature; means for generating a signal indicative of the pressure of said hydrogen gas in said chamber, said last named means deriving the pressure indicative signal as a function of the temperature of the wall portion, and compensating means responsive to said temperature indicative signal for compensating the pressure indicative signal generating means so that the pressure indicative signal is temperature corrected.
Claim 20
Dependent Claim
21 words
The combination of claim 15 wherein said hydrogen gas detector further includes means for heating said hydrogen gas permeable wall portion.
Claim 21
Dependent Claim
26 words
The combination of claim 17 wherein said hydrogen gas detector further includes means for maintaining said hydrogen gas permeable wall portion at a constant desired temperature.
Claim 22
Dependent Claim
112 words
Apparatus for detecting a liquid alkali metal leak, comprising a containment structure containing an alkali metal fluid circulating in said structure, the exterior of said structure being in communication with a substance including hydrogen in a form chemically replaceable by said alkali metal, whereby in the event of the leak, hydrogen gas is formed externally of said structure; means for detecting the presence or absence of any of said formed gas, said detecting means being positioned outside of and in proximity to said structure for determining the presence or absence of the leak; and means responsive to the detecting means for enabling the presence or absence of said leak to be detected.
Claim 23
Dependent Claim
112 words
Apparatus for detecting a liquid alkali metal leak, comprising a containment structure containing an alkali metal fluid circulating in said structure, the exterior of said structure being in communication with a substance including hydrogen in a form chemically replaceable by said alkali metal, whereby in the event of the leak, hydrogen gas is formed externally of said structure; means for detecting the presence or absence of any of said formed gas, said detecting means being positioned outside of and in proximity to said structure for determining the presence or absence of the leak; and means responsive to the detecting means for enabling the presence or absence of said leak to be detected.
Claim 24
Dependent Claim
43 words
The apparatus of claim 19 further including a thermal insulation pipe surrounding said containment structure, a space being provided between said containment structure and said pipe, said space containing said hydrogen including substance therein, said hydrogen gas detector being supported by said pipe.
Claim 25
Dependent Claim
65 words
The apparatus of claim 19 wherein said hydrogen gas detector includes means for sensing the temperature of said hydrogen gas permeable wall portion and for generating a signal indicative of said temperature; means for generating a signal indicative of the pressure of said hydrogen gas in said chamber; and compensating means for receiving said temperature and pressure indicative signals to provide a temperature-corrected output signal.
Claim 26
Dependent Claim
21 words
The apparatus of claim 19 wherein said detecting means comprises a sputter-ion pump in gaseous communication with said hydrogen forming substance.
Claim 27
Dependent Claim
26 words
The apparatus of claim 19 wherein said detecting means comprises a sealed chamber, a wall portion of said chamber being permeable to said formed hydrogen gas.
Claim 28
Dependent Claim
17 words
The apparatus of claim 23 including means for heating said hydrogen permeable wall portion of said chamber.
Claim 29
Dependent Claim
23 words
The apparatus of claim 24 further including means for maintaining said hydrogen permeable wall portion of said chamber at a constant desired temperature.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-07-13 | 1980-01-12 | 1980-07-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-07-13 | 1984-01-12 | 1984-07-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-07-13 | 1988-01-12 | 1988-07-13 | $7700.00 | Window Closed / Lapsed |