US3949460A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of manufacturing nuclear fuel elements
Assignee: SAES Getters SpA
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Filing: 1974-04-30
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Granted: 1976-04-13
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Expires: 1994-04-30
Abstract
Abstract A method of manufacturing a nuclear fuel element which contains a pre-activated non-evaporable getter material such that the getter material starts to sorb gas at a temperature lower than the temperature at which the fuel element walls start to sorb gas which getter action at least partially takes place at subatmospheric pressure.
Inventors
- 👤 Paolo della Porta
- 👤 Tiziano Anselmo Giorgi
- 👤 Livio Rosai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 23:12
CPC Classifications
G; G21; G21C; G21C3/00; G21C3/02; G21C3/04; G21C3/16; G21C3/17; G21C21/00; G21C21/02; G21C3/06; G21C3/10; Y; Y02; Y02E; Y02E30/00; Y02E30/30; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49826
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
90 words
A method of manufacturing a nuclear fuel element comprising a metallic container having walls forming a fuel containing chamber and a plenum chamber, a body of fissionable material within the fuel containing chamber comprising the steps of A. pumping the fuel element to sub-atmospheric pressure B. inserting a non-evaporable activated getter material into the plenum chamber C. heating the fuel element and getter material to a temperature below that at which the fuel element walls commence to sorb gas D. filling the fuel element with helium to super atmospheric pressure.
Claim 2
Independent Claim
90 words
A method of manufacturing a nuclear fuel element comprising a metallic container having walls forming a fuel containing chamber and a plenum chamber, a body of fissionable material within the fuel containing chamber comprising the steps of A. pumping the fuel element to sub-atmospheric pressure B. inserting a non-evaporable activated getter material into the plenum chamber C. heating the fuel element and getter material to a temperature below that at which the fuel element walls commence to sorb gas D. filling the fuel element with helium to super atmospheric pressure.
Claim 3
Independent Claim
126 words
A method of manufacturing a nuclear fuel element comprising a metallic container having walls forming a fuel containing chamber and a plenum chamber, a body of fissionable material within the fuel containing chamber comprising the steps of A. pumping the fuel element to sub-atmospheric pressure B. heating the fuel element to a temperature below that at which the fuel element walls commence to sorb gas C. filling the fuel element with a washing gas D. pumping the fuel element to sub-atmospheric pressure E. inserting a non-evaporable activated getter material into the plenum chamber F. heating the fuel element and getter material to a temperature below that at which the fuel element walls commence to sorb gas G. filling the fuel element with helium to super-atmospheric pressure.
Claim 4
Independent Claim
126 words
A method of manufacturing a nuclear fuel element comprising a metallic container having walls forming a fuel containing chamber and a plenum chamber, a body of fissionable material within the fuel containing chamber comprising the steps of A. pumping the fuel element to sub-atmospheric pressure B. heating the fuel element to a temperature below that at which the fuel element walls commence to sorb gas C. filling the fuel element with a washing gas D. pumping the fuel element to sub-atmospheric pressure E. inserting a non-evaporable activated getter material into the plenum chamber F. heating the fuel element and getter material to a temperature below that at which the fuel element walls commence to sorb gas G. filling the fuel element with helium to super-atmospheric pressure.
Claim 5
Dependent Claim
17 words
A method of claim 2 in which steps A to D are performed two or more times.
Claim 6
Dependent Claim
12 words
A method of claim 2 in which the washing gas is nitrogen.
Claim 7
Dependent Claim
14 words
A method of claim 2 in which the washing gas is a rare gas.
Claim 8
Dependent Claim
12 words
A method of claim 5 in which the washing gas is helium.
Claim 9
Dependent Claim
17 words
A method of claim 1 in which the sub-atmospheric pressure is less than 10 - 1 torr.
Claim 10
Dependent Claim
20 words
A method of claim 2 in which the sub-atmospheric pressure of step D is less than 10 - 1 torr.
Claim 11
Dependent Claim
18 words
A method of claim 1 in which the temperature of step C is between 120° and 250° C.
Claim 12
Dependent Claim
18 words
A method of claim 2 in which the temperature of step B is between 150° and 250° C.
Claim 13
Dependent Claim
18 words
A method of claim 2 in which the temperature of step F is between 120° and 250° C.
Claim 14
Dependent Claim
23 words
A method of claim 1 or 2 in which the last step is followed by a further step of sealing the fuel element.
Claim 15
Dependent Claim
22 words
A method of claim 1 or 2 in which the nuclear fuel element is temporarily sealed after insertion of the getter material.
Claim 16
Dependent Claim
33 words
A method of claim 1 or 2 in which the non-evaporable getter material is chosen from the group Zr and Zr--Al alloys either alone or in mixture between themselves or mixed with graphite.
Claim 17
Dependent Claim
36 words
A method of claim 14 in which the non-evaporable getter material comprises A. particulate zirconium and B. a particulate alloy of zirconium and aluminium in which the weight ratio of A:B is between 19:1 and 2:3.
Claim 18
Dependent Claim
18 words
A method of claim 15 in which the zirconium-aluminium alloy is of 16 weight percent aluminium balance zirconium.
Claim 19
Independent Claim
134 words
A method of manufacturing a nuclear fuel element comprising a zircalloy container having walls forming a fuel containing chamber and a plenum chamber, a body of fissionable material within the fuel containing chamber comprising the steps of A. pumping the fuel element to sub-atmospheric pressure B. heating the fuel element to a temperature between 150° and 250° C C. filling the fuel element with nitrogen D. pumping the fuel element to a pressure below 10 - 1 torr E. inserting a non-evaporable activated getter material into the plenum chamber F. temporarily sealing of the fuel element G. heating the temporarily sealed fuel element and getter material to a temperature between 120° and 250° C H. breaking the temporary seal I. filling the fuel element with helium to super-atmospheric pressure J. sealing the fuel element
Claim 20
Independent Claim
134 words
A method of manufacturing a nuclear fuel element comprising a zircalloy container having walls forming a fuel containing chamber and a plenum chamber, a body of fissionable material within the fuel containing chamber comprising the steps of A. pumping the fuel element to sub-atmospheric pressure B. heating the fuel element to a temperature between 150° and 250° C C. filling the fuel element with nitrogen D. pumping the fuel element to a pressure below 10 - 1 torr E. inserting a non-evaporable activated getter material into the plenum chamber F. temporarily sealing of the fuel element G. heating the temporarily sealed fuel element and getter material to a temperature between 120° and 250° C H. breaking the temporary seal I. filling the fuel element with helium to super-atmospheric pressure J. sealing the fuel element
Claim 21
Independent Claim
88 words
A method of manufacturing the nuclear fuel element comprising a metallic container having walls forming a fuel containing chamber and a plenum chamber, a body of fissionable material within the fuel containing chamber comprising the steps of: I. inserting a non-evaporable activated getter material into the plenum chamber; Ii. maintaining the fuel element at a temperature between 120° and 250° C and at a pressure less than 10 - 1 torr for a period of time and then; Iii. filling the container with helium at a super-atomospheric pressure.
Claim 22
Independent Claim
88 words
A method of manufacturing the nuclear fuel element comprising a metallic container having walls forming a fuel containing chamber and a plenum chamber, a body of fissionable material within the fuel containing chamber comprising the steps of: I. inserting a non-evaporable activated getter material into the plenum chamber; Ii. maintaining the fuel element at a temperature between 120° and 250° C and at a pressure less than 10 - 1 torr for a period of time and then; Iii. filling the container with helium at a super-atomospheric pressure.
Claim 23
Independent Claim
123 words
A method of manufacturing a nuclear fuel element comprising a metallic container having walls forming a fuel containing chamber and a plenum chamber, a body of fissionable material within the fuel containing chamber, one end of the container being closed by a first end cap, the other end of the container being adapted to be closed by a second end cap, said method comprising the steps of: I. inserting a non-evaporable activated getter material into the plenum chamber; Ii. hermetically sealing the second end cap while maintaining the pressure within the chamber at less than 10 - 1 torr, and then; Iii. storing the fuel element at 175° for 4 weeks, and then; Iv. filling the chamber with helium at a super-atmospheric pressure.
Claim 24
Independent Claim
123 words
A method of manufacturing a nuclear fuel element comprising a metallic container having walls forming a fuel containing chamber and a plenum chamber, a body of fissionable material within the fuel containing chamber, one end of the container being closed by a first end cap, the other end of the container being adapted to be closed by a second end cap, said method comprising the steps of: I. inserting a non-evaporable activated getter material into the plenum chamber; Ii. hermetically sealing the second end cap while maintaining the pressure within the chamber at less than 10 - 1 torr, and then; Iii. storing the fuel element at 175° for 4 weeks, and then; Iv. filling the chamber with helium at a super-atmospheric pressure.
References Cited (Backward Citations)
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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) | 1979-04-13 | 1979-10-13 | 1980-04-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-04-13 | 1983-10-13 | 1984-04-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-04-13 | 1987-10-13 | 1988-04-13 | $7700.00 | Window Closed / Lapsed |