Patent EP0312247A2 successfully refreshed from Google Patents.
EP0312247A2
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Nuclear power generating station equipment qualification method and apparatus
Assignee: Westinghouse Electric Corp
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Filing: 1988-10-05
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Granted: —
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Expires: 2008-10-05
Abstract
Abstract Apparatus for monitoring the life and degradation of an object piece in a nuclear power plant includes passive means for detecting a total integrated dose of radiation received by the object piece, means for projecting a thermal history of the object piece, and means for housing the passive detection means and projection means in close proximity to the object piece. In order to generate and maintain evidence to assure that the object piece will operate on demand, the passive detection means and projection means mounted in close proximity to the object piece are exposed to the environment of a normally operating power plant and periodically analyzed to determine whether the estimated life of the object piece may be extended.
Inventors
- 👤 Arnold Hill Fero
- 👤 Ronald William Riling
- 👤 Lawrence Martin Potochnik
- 👤 Kenneth Frances Semethy
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-30 22:28
CPC Classifications
G; G21; G21C; G21C17/00; Y; Y02; Y02E; Y02E30/00; Y02E30/30
Claims Analysis
Total Claims: 36
Claim 1
Independent Claim
94 words
Apparatus for monitoring degradation of the life of an object piece (4, 50) of equipment in a nuclear power plant owing to radiation and service aging of the object piece, without removing the object piece from service, said apparatus characterized by: passive means (10, 54) for detecting a total integrated dose of radiation received by the object piece; means for projecting (12, 14, 56) a thermal history of the object piece; and means for housing (16, 52) said passive detection means and said projection means in close proximity to the object piece (4, 50).
Claim 2
Dependent Claim
94 words
Apparatus for monitoring degradation of the life of an object piece (4, 50) of equipment in a nuclear power plant owing to radiation and service aging of the object piece, without removing the object piece from service, said apparatus characterized by: passive means (10, 54) for detecting a total integrated dose of radiation received by the object piece; means for projecting (12, 14, 56) a thermal history of the object piece; and means for housing (16, 52) said passive detection means and said projection means in close proximity to the object piece (4, 50).
Claim 3
Dependent Claim
33 words
The apparatus according to claim 1, wherein said passive detection means (10, 54) comprises: first dosimetry means for measuring a gamma ray dose; and second dosimetry means for measuring a beta ray dose.
Claim 4
Dependent Claim
14 words
The apparatus according to claim 2, further comprising means (2) for detecting neutron-induced fission.
Claim 5
Dependent Claim
21 words
The apparatus according to claim 3, wherein said neutron-induced fission detection means comprises at least one solid state track recorder (SSTR).
Claim 6
Dependent Claim
36 words
The apparatus according to claim 4, wherein said SSTR comprises: a nickel backing disc; a reusable deposit of a selected fissionable material on said backing disc; and replaceable mica in surface contact with said reusable deposit.
Claim 7
Dependent Claim
21 words
The apparatus according to claim 5, wherein said fissionable material is selected from the group of U-235, U-238, Np-239 and Pu-239.
Claim 8
Dependent Claim
11 words
The apparatus according to claim 6, wherein said SSTR is cadmium-shielded.
Claim 9
Dependent Claim
11 words
The apparatus according to claim 7, wherein said SSTR is bare.
Claim 10
Dependent Claim
87 words
The apparatus according to claim 2, wherein said first dosimetry means comprises: color-center formation means for measuring said gamma ray dose in a range of from approximately 10³ rads to 1010 rads; thermoluminescent dosimetry means for measuring said gamma ray dose in a range of from 10 rads to approximately 10⁵ rads; and means for holding said color-center formation means and said thermoluminescent dosimetry means within said housing means, said holding means being adapted to establish an electron equilibrium condition which satisfies requirements of Bragg-Gray small cavities.
Claim 11
Dependent Claim
19 words
The apparatus according to claim 9, wherein said color-center formation means comprises a plurality of lithium fluoride optical crystals.
Claim 12
Dependent Claim
20 words
The apparatus according to claim 9, wherein said thermoluminescent dosimetry means comprises at least one manganese-activated calcium fluoride thermoluminescent dosimeter.
Claim 13
Dependent Claim
59 words
The apparatus according to claim 9, wherein said holding means comprises: a generally rectangular base portion having formed therein a longitudinal groove of a predetermined cross-section; a slide portion having formed therein a plurality of slots adapted to contain said color-center formation means and said thermoluminescent dosimetry means, said slide portion having a cross-section complementary to said predetermined cross-section.
Claim 14
Dependent Claim
35 words
The apparatus according to claim 2, wherein second dosimetry means comprises: a pair of lithium fluoride optical crystals; and means for retaining said pair of optical crystals upon an exterior portion of said housing means.
Claim 15
Dependent Claim
118 words
The apparatus according to claim 13, wherein said retaining means comprises: a cover plate having formed therein a groove to contain said pair of optical crystals; means for protecting said pair of optical crystals from environmental hazards due to temperature and radiation, said protection means having a predetermined low mass thickness in order to minimize attenuation of beta rays; and a retainer plate having formed therein a beta window comprised of a slot of dimensions corresponding generally to said groove formed in said cover plate, wherein said retainer plate is connected through said protection means to said cover plate in such a manner as to register said beta window with said groove containing said pair of optical crystals.
Claim 16
Dependent Claim
64 words
The apparatus according to claim 14, wherein said protection means comprises: a polyimide film disk sealing said pair of optical crystals contained in said groove; and a stainless steel foil disk retained between said film disk and said retainer plate; wherein said predetermined low mass thickness of said film disk and said foil disk is less than thirty milligrams per square centimeter (30 mg/cm²).
Claim 17
Dependent Claim
38 words
The apparatus according to claim 1, wherein said projection means comprises: first monitor means for determining a peak temperature experienced by the object piece; and second monitor means for determining an integrated thermal exposure to the object piece.
Claim 18
Dependent Claim
16 words
The apparatus according to claim 16, wherein said first monitor means comprises a non-reversible temperature label.
Claim 19
Dependent Claim
59 words
The apparatus according to claim 16, wherein said second monitor means comprises a plurality of solid state track recorders (SSTR), each said SSTR having been pre-exposed to a fission source to produce a predetermined number of fission fragment tracks which upon subsequent exposure to an elevated temperature are annealed at a rate corresponding to an Arrhenius function of temperature.
Claim 20
Dependent Claim
101 words
The apparatus according to claim 1, wherein said housing means comprises: a tubular portion; an end plate portion sealing said tubular portion at one end thereof; a flange portion attached to the other end of said tubular portion; and means for sealing said passive detection means and said projection means within said tubular portion, said tubular portion, end plate portion and said flange portion being adapted to provide a thermal inertia for reducing monitor sensitivity to brief excursions of temperature which would not affect the object piece, to provide a beta radiation shielding, and to provide protection from an accident environment.
Claim 21
Dependent Claim
48 words
The apparatus according to claim 1, wherein said passive detection means comprises: first mimic means representative of the object piece, said first mimic means being preaged through exposure to a selected amount of radiation thereby establishing a first predetermined baseline; and means for monitoring an operational radiation rate.
Claim 22
Dependent Claim
23 words
The apparatus according to claim 20, wherein said first predetermined baseline further comprises said artificial age and exposure to a selected nuclear accident.
Claim 23
Dependent Claim
16 words
The apparatus according to claim 20, wherein said selected amount of radiation comprises approximately 160 megarads.
Claim 24
Dependent Claim
14 words
The apparatus according to claim 20, wherein said monitoring means comprise a thermoluminescent dosimeter.
Claim 25
Dependent Claim
46 words
The apparatus according to claim 1, wherein said projection means comprises: second mimic means representative of the object piece, said second mimic means being preaged through exposure to a selected amount of heat thereby establishing a second predetermined baseline; and means for monitoring a service temperature.
Claim 26
Dependent Claim
26 words
The apparatus according to claim 24, wherein said second predetermined baseline comprises an artificial age of six years exposure to a service temperature comprising approximately 120°F.
Claim 27
Dependent Claim
18 words
The apparatus according to claim 1, further comprising means for predicting a seismic failure of the object piece.
Claim 28
Independent Claim
64 words
A method of monitoring an object piece of qualified equipment in a nuclear power plant, comprising the steps of: providing passive means for detecting a total integrated dose of radiation received by the object piece; providing a means for projecting a thermal history of the object piece; and housing said passive detection means and said projection means in close proximity to the object piece.
Claim 29
Independent Claim
64 words
A method of monitoring an object piece of qualified equipment in a nuclear power plant, comprising the steps of: providing passive means for detecting a total integrated dose of radiation received by the object piece; providing a means for projecting a thermal history of the object piece; and housing said passive detection means and said projection means in close proximity to the object piece.
Claim 30
Dependent Claim
124 words
The method according to claim 27, wherein said first providing step comprises the steps of: measuring a gamma ray dose with first dosimetry means including color-center formation means for measuring said gamma ray dose in a first predetermined range, thermoluminescent dosimetry means of or measuring said gamma ray dose in a second predetermined range; and means for holding said color-center formation means and said thermoluminescent dosimetry means within said housing means, said holding means being adapted to establish an electron equilibrium condition which satisfies requirements of Bragg-Gray small cavities; and measuring a beta ray dose with second dosimetry means including a pair of lithium fluoride optical crystals and means for retaining said pair of optical crystals upon an exterior portion of said housing means.
Claim 31
Dependent Claim
30 words
The method according to claim 28, wherein said first predetermined range comprises from 10³ rads to 10¹⁰ rads, and said second predetermined range comprises from 10 rads to 10⁵ rads.
Claim 32
Dependent Claim
22 words
The method according to claim 27, further comprising the step of detecting neutron-induced fission with at least one solid state track recorder.
Claim 33
Dependent Claim
55 words
The method according to claim 27, wherein said second providing step comprises: determining a peak temperature experienced by the object piece with first monitor means including at least one non-reversible temperature label; and determining an integrated thermal exposure to the object piece with second monitor means including a plurality of solid state track recorders (SSTR).
Claim 34
Dependent Claim
49 words
The method according to claim 31, wherein said second determining step further comprises pre-exposing said SSTRs to a fission source to produce a predetermined number of fission fragment tracks which upon subsequent exposure to an elevated temperature are annealed at a rate corresponding to an Arrhenius function of temperature.
Claim 35
Dependent Claim
56 words
The method according to claim 27, wherein said first providing step comprises the steps of: mimicking the object piece with first means representative thereof; preaging said first mimic means being through exposure to a selected amount of radiation thereby establishing a first predetermined baseline; and monitoring an operational radiation rate with at least one thermoluminescent dosimeter.
Claim 36
Dependent Claim
48 words
The method according to claim 27, wherein said second providing step comprises the steps of: mimicking the object piece with second means representative thereof; preaging said second mimic means through exposure to a selected amount of heat thereby establishing a second predetermined baseline; and monitoring a service temperature.
References Cited (Backward Citations)
No citation records indexed.
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