US4034599A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Device for locating defective fuel
Assignee: General Electric Co
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Filing: 1975-06-18
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Granted: 1977-07-12
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Expires: 1995-06-18
Abstract
Abstract A method and apparatus for locating defective nuclear fuel elements is disclosed. Fuel elements that are to be tested are enclosed in a test chamber, filled with water. Air is pumped or pulled into the chamber, entering through a gas sparger at the bottom of the chamber and displacing a portion of the water above the fuel element. This reduces the pressure in the vessel, forms an air pocket above the fuel element and purges the water surrounding the fuel element of fission gases released from defective fuel elements. The activity of sample gas drawn from the chamber is continuously monitored to indicate fission gas content. In subsequent steps the pressure in the chamber is further reduced with a vacuum pump and gas drawn from the air pocket above the fuel for testing is recirculated and allowed to continuously purge the water surrounding the fuel elements of fission gases released from defective fuel elements.
Inventors
- 👤 Robert N. Osborne
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 07:43
CPC Classifications
G; G21; G21C; G21C17/00; G21C17/06; G21C17/07; Y; Y02; Y02E; Y02E30/00; Y02E30/30
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
197 words
Apparatus for detecting defective nuclear fuel elements comprising: a. a test chamber filled with water for individually enclosing and sealing the fuel element to be tested, said test chamber having a gas sparger disposed at the bottom of said test chamber, b. a reservoir connected to said test chamber for receiving water displaced from above the fuel element to effect a reduction in pressure in said test chamber and for receiving sample gas from said test chamber, c. a pump for drawing sample gas from said reservoir, d. a radiation monitor receiving sample gas from said pump, and e. a two-way receiving sample gas from said monitor for selectively directing said sample gas back to said test chamber through said gas sparger to displace the water above the fuel element to effect a reduction in pressure in said test chamber and to simultaneously purge the water surrounding said fuel element of any fission gases pulled therefrom, and for selectively venting said sample gas to further reduce the pressure in said test chamber to a vacuum by means of said pump and to simultaneously purge the water surrounding the fuel element of any further fission gases pulled therefrom.
Claim 2
Dependent Claim
197 words
Apparatus for detecting defective nuclear fuel elements comprising: a. a test chamber filled with water for individually enclosing and sealing the fuel element to be tested, said test chamber having a gas sparger disposed at the bottom of said test chamber, b. a reservoir connected to said test chamber for receiving water displaced from above the fuel element to effect a reduction in pressure in said test chamber and for receiving sample gas from said test chamber, c. a pump for drawing sample gas from said reservoir, d. a radiation monitor receiving sample gas from said pump, and e. a two-way receiving sample gas from said monitor for selectively directing said sample gas back to said test chamber through said gas sparger to displace the water above the fuel element to effect a reduction in pressure in said test chamber and to simultaneously purge the water surrounding said fuel element of any fission gases pulled therefrom, and for selectively venting said sample gas to further reduce the pressure in said test chamber to a vacuum by means of said pump and to simultaneously purge the water surrounding the fuel element of any further fission gases pulled therefrom.
Claim 3
Dependent Claim
73 words
The apparatus of claim 1 wherein said test chamber comprises: a. a sipping can including a sipping can head, b. a gas sparger at the bottom of said sipping can, c. a return line connected to said gas sparger for returning sample gas from said two-way valve to said gas sparger, and d. a drain line and a sample line connected to the top of said sipping can head leading to said reservoir.
Claim 4
Dependent Claim
65 words
The apparatus of claim 2 further including: a. ventilation system, b. vent line connected between said reservoir and said ventilation system, and c. a vent valve in said vent line and a drain valve in said drain line, said valves being normally closed to seal said reservoir and prevent water displaced from said test chamber, during the purging operation, from returning to said test chamber.
Claim 5
Dependent Claim
38 words
The apparatus of claim 3 further including a gas chiller connected to receive sample gas from said reservoir and remove moisture from said sample gas for preventing the condensation of water in the rest of the test apparatus.
Claim 6
Dependent Claim
72 words
The apparatus of claim 4 including: a. means for preventing accidental flooding of the apparatus, said means comprising a water trap for receiving sample gas from said gas chiller, b. a spring-loaded platform having said water trap mounted thereon and switch contacts mounted on said spring loaded platform for turning said pump off and opening the valve in said vent line when said water trap fills to a predetermined level with water.
Claim 7
Dependent Claim
12 words
The apparatus of claim 5 wherein said pump is a diaphragm-type pump.
Claim 8
Dependent Claim
65 words
The apparatus of claim 6 further including: a second water trap for receiving sample gas from said pump, said radiation monitor receiving sample gas from said second water trap, said radiation monitor including amplifier-discriminator circuitry for preferentially measuring the activity of Kr 85 in the presence of Xe 133 , or selectively for measuring the activity of Kr 85 and Xe 133 with equal efficiency.
Claim 9
Independent Claim
127 words
A method for locating defective nuclear fuel elements comprising the steps of: a. individually enclosing and sealing the fuel element to be tested in a test chamber filled with water; b. reducing the pressure in said chamber by introducing sample gas to said chamber to displace the water above said fuel element thereby removing the pressure head due to the water above said fuel element; c. simultaneously introducing sample gas to the bottom of said chamber for purging the water surrounding the fuel element of any fission gases pulled therefrom as a result of said reduction of pressure; and d. simultaneously monitoring the radiological activity of sample gas from said chamber, sample gas activity indicating the presence of fission gases pulled through defects in said fuel element.
Claim 10
Independent Claim
127 words
A method for locating defective nuclear fuel elements comprising the steps of: a. individually enclosing and sealing the fuel element to be tested in a test chamber filled with water; b. reducing the pressure in said chamber by introducing sample gas to said chamber to displace the water above said fuel element thereby removing the pressure head due to the water above said fuel element; c. simultaneously introducing sample gas to the bottom of said chamber for purging the water surrounding the fuel element of any fission gases pulled therefrom as a result of said reduction of pressure; and d. simultaneously monitoring the radiological activity of sample gas from said chamber, sample gas activity indicating the presence of fission gases pulled through defects in said fuel element.
Claim 11
Dependent Claim
31 words
The method of claim 8 wherein the pressure in said test chamber is further reduced to about 15 inches of mercury vacuum, while the activity of said sample gas is monitored.
Claim 12
Dependent Claim
30 words
The method of claim 9 wherein sample gas drawn from said test chamber is recirculated to continuously purge the water surrounding said fuel element of any fission gases pulled therefrom.
Claim 13
Dependent Claim
71 words
The method of claim 10 wherein said sample gas is monitored preferentially for the presence of Kr 85 when a relatively long period of time has passed since said fuel element has been used for power generation and said sample gas is monitored preferentially or equally for the presence of Xe 133 when a relatively short period of time has passed since the fuel element has been used for power generation.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-07-11 | 1981-01-10 | 1981-07-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-07-11 | 1985-01-10 | 1985-07-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-07-11 | 1989-01-10 | 1989-07-12 | $7700.00 | Window Closed / Lapsed |