IE58952B1 - Absorber for nuclear radiations - Google Patents

Absorber for nuclear radiations

Info

Publication number
IE58952B1
IE58952B1 IE185186A IE185186A IE58952B1 IE 58952 B1 IE58952 B1 IE 58952B1 IE 185186 A IE185186 A IE 185186A IE 185186 A IE185186 A IE 185186A IE 58952 B1 IE58952 B1 IE 58952B1
Authority
IE
Ireland
Prior art keywords
aluminium
absorber
absorber according
gadolinium
alloyed
Prior art date
Application number
IE185186A
Other versions
IE861851L (en
Original Assignee
Montupet Fonderies
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Montupet Fonderies filed Critical Montupet Fonderies
Publication of IE861851L publication Critical patent/IE861851L/en
Publication of IE58952B1 publication Critical patent/IE58952B1/en

Links

Classifications

    • GPHYSICS
    • G21NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21FPROTECTION AGAINST X-RADIATION, GAMMA RADIATION, CORPUSCULAR RADIATION OR PARTICLE BOMBARDMENT; TREATING RADIOACTIVELY CONTAMINATED MATERIAL; DECONTAMINATION ARRANGEMENTS THEREFOR
    • G21F1/00Shielding characterised by the composition of the materials
    • G21F1/02Selection of uniform shielding materials
    • G21F1/08Metals; Alloys; Cermets, i.e. sintered mixtures of ceramics and metals

Abstract

1. An absorber for nuclear radiations characterised in that it is formed by an alloy of gadolinium with an aluminium selected from the group comprising pure aluminium, alloyed aluminium and pure or alloyed aluminium containing a dispersed phase.

Description

The present invention relates to an absorber for nuclear Ί radiationsWith the development in nuclear processes, a great deal of i*esearch has been carried out on a world-wide basis, for the purpose of devising ardproducing effective and competitive radiation absorbers. To achieve that aim, the materials used for producing them must comply with the following criteria; - they must have particular nuclear properties: a large effective capture section, a lew level of secondary emission and good stability in respect of time with respect to the radiation; - they must have a high melting point in order to withstand the heating effect generate! by the absorption of radiation, in particular neutron rays; - they must be good conductors of heat in order to provide 15 for rapid removal of the heat generated; - they must have mechanical characteristics which permit them easily to be shaped; - they must resist corrosion in the atmosphere or in the working medium; and - they must be of the lowest possible cost.
Among all the materials used for absorbing neutrons, the most widely known are cadmium, samarium, europium, boron and gadolinium.
Cadmium suffers from the disadvantage of being a highly toxic substance and having a very low melting point (321°C) and a very lew > boil:ng point (765°C). Samarium and europium have given rise to pre^ti-cally no industrial development because of their excessively high cost. - 2 The most widespread among such materials is boron which is used in different forms: elementary boron, borides, boron carbide, boric acid, etc. Moreover, a large number of patents have been filed cm that subject. However, this material suffers from very poor mechanical properties and it must be highly diluted in a metal matrix such as aluminium for example in order to acquire the qualities necessary for it to be able to assure the form required for each type of absorber. In that case however, its absorption capacity is greatly reduced and must be compensated by an increase in the volume of material used, and that, in short, substantially increases the cost of the absorber, At any event, boron being virtually insoluble in aluminium, the material obtained is a composite product, and the production thereof makes it necessary to have recourse to highly complicated production processes if regular distribution of the boron in the aluminium matrix is to be achieved and if heterogeneity in the absorption capacity is to be avoided.
Gadolinium and its oxide have already been used for a number of years new, in various nuclear installations in which, mixed with the fuel, they perform the function of moderators. However, the application thereof to the production of radiation absorbers gives rise to problems.
As regards the oxide, which is generally available in powder form, it must be mixed with other substances, which involves the use of highly complicated technologies, and its very poor mechanical properties make the use thereof for the production of absorbers of complex shape, both a delicate and an expensive matter. In addition, this oxide suffers fron a poor level of thermal conductivity and its absorption capacity is relatively low in comparison with that of elementary gadolinium.
As regards the metal itself, the cost hereof is still high and it is difficult to use because of its very high level of oxidizability. - 3 ~ However, in the spectrum of sick? neutrons, gadolinium has the highest effective capture section of all the known absorbers.
In particular, in comparison with boron,, its section for thermal neutrons of an energy level of 10 eV is one hundred times greater. As regards fast neutrons, its effectiveness in regard thereto is as good as that of boron.
It is for that reason that the present applicants,, being aware of the attraction of gadolinium bit also the disadvantages involved therewith, sought and discovered a way of making therefrom attractive nuclear radiation absorbers.
The absorber is characterised in that it is formed by an alloy of gadolinium with an aluminium selected from the group ccraprising pure aluminium,. allayed aluninitan, and pure or alloyed aluminium containing a dispersed phase.
This therefore involves an alloy based on gadolinium and aluminium in which the proportion of gadolinium is between 0.05% and 70% by weight. Below a value of 0.05%, the absorption effect is found to be excessively reduced while above a value of 70%, difficulties occur in regard to producing the alloy. Preferably, the above-indicated range is between 0.1 and 15% and depends on the nature and the flux of radiations to be absorbed.
The aluminiian used may be pure, whether it has bean refined by any method such as three-layer electrolysis or fractional crystallization or is simply such that it is collected at the discharge of electrolysis tanks with its usual impurities such as iron and silicon.
However, the aluminium may also be a conventional alloy such as those denoted by numbers 1000 , 5000 and 6000 in the Aluminium Association standards, which makes it possible to enhance the ' . mechanical properties of the absorbers produced, or alternatively an - 4 alloy of aluminium with at least one other metal which also has absorbent qualities such as cadmium, samarium, europium, lithium, < hafnium and tantalum, which latter alloys may also he produced from alloy of types 1CCO,· 5000 and 6000« In addition, the aluminium which may or may not be alloyed nay contain a dispersed phase such as carbon fibres or other fibres which are intended to enhance the mechanical strength of the absorbers or alternatively, whether combined with such fibres or not, a product which absorbs radiation such as for example boron. and its derivatives, which may represent up to 30% of the mass of aluminium used.
The gadolinium-aluminium alloys which are produced in that way, by virtue of their good mechanical properties, cssn be easily transformed into absorbers of any shape whatever by one at least of the production processes selected from casting, whether in sand, in a chill mould, or under high or low pressure, hot or cold rolling, extrusion and forging.
Such alloys give perfectly homogenous structures with very regular effective capture sections. In addition, their specific gravity which is variable in dependence on the percentage of Gd gives a value close to that of aluminium, with proportions of Gd of up to 30% fay weight, which makes it possible to produce very light neutron barriers. Table I below gives values in respect of specific gravity for two binary alloys Al-Gd, ons containing 11% of Gd and the other containing 23% of Gd.
TABLE I : SPECIFIC GRAVITIES OF BINARY ALLOYS Al-Gd % by weight of Gd Specific gravity 1 11 2.92 » 25 3.12 Tbs aluminium matrix gives the finished products an excellent level of thermal conductivity if ran 120 to 180 W/m K-> depending on the aluminium matrix selected), which thus makes it possible rapidly to remove the heat generated by absorption, to external cooling systems.
Ihe point at which the alloys Al-Gd begin to melt is very high, toeing in most cases higher than 62O°C; that characteristic permits the neutron barriers which axe produced in that way easily to withstand the heating effect caused by the absorption of neutrons or other rays.
The atomic mass of Gd being very high (156.9 g), % and X-rays in particular are absorbed to a very substantial extent.
Resistance to corrosion generally speaking, is not affects! or only little affected by the presence of gadolinium, ani the corrosion properties are close to those of the aluminium matrices used. Alloys of series 1COO, 5GQ0 and 6000 enjoy excellent resistance to corrosion in respect of atmospheric agents or in a marine atmosphere. That resistance to corrosion may be further enhanced by suitable surface treatments (anodization, alcdine, painting, plastics coatings etc.).
The mechanical properties are high and depend on the aluminium matrix selecasd .. In the csss of binary aluminiua-gadoliniun alloys, mechanical properties vary with the amount of gadolinium; Table II sets out results obtained with cast alloys, one with a proportion of Gd of 12% by weight and the other with a percentage by weight of 25%. iz TABLE II - MECHANICAL PROPERTIES OF BINARY Al-Gd ALLOYS % by weight of Gd Rm £ffi>A Rp 0.2 MPA A % HB 12% 140 60 17 40 25% . 80 55 0.8 54 Table III sets forth the results obtained with rolled alloys containing 11% by weight of Gd.
TABLE_III - MECHANTCAT, TENSILE CHARACTERISTICS IN A ROLLED Al-Gd ALLOY % by weight of Gd lengthwise direction lengthwise transverse direction IE HB Rm MPA Rp 0.2 MPA A % Rm MPA Rp 0.2 MPA A % 11 - - 130 110 15 '130 110 10 42 Rm Rp 0.2 Ά % By using aluminium matrices which are doped with elements 15 such as ccpper, silicon, zinc, magnesium, etc., the level of strength and the elastic limit can be greatly increased to attain the following values: 280 to 320 MPA 220 to 260 MPA iron 3 to 10% The higher values set out hereinbefore are not limiting it . 7 . being appreciated that ternary, quaternary, quinary, etc alloy compositions comprising gadolinium could give values much higher than those indicated above.
Machining of those metal alloys dees not give rise to 5 any problem, the parameters and the operating speeds to be taken into account being the same as chose which are generally used for aluninium alloys.
There are many uses for this invention and they all ccrcsrn areas in which there is a problem in regard to the absorption of radiation (neutrons, ’/-rays. X-rays), whether such areas are military or civil.
The following nay be mentioned ac examples of use: flasks for transporting and storing nuclear waste, swimming-pool racks for storing nuclear reactor fuel elements, decontamination installation shielding, shielding or armouring for military vehicles, fall-out shelters, nuclear reactor elements, shielding for monitoring apparatuses using radiation or radioactive sources, etc. That list would not be intended in any way to be limitative.
( I

Claims (12)

1. An absorber for nuclear radiations wherein it is formal by an alloy of gadolinium with an aluminium selected from the group comprising pure aluminium, alloyed aluminiun and pure or alloyed aluminium containing a dispersed phase.
2. An absorber according to claim 1 wherein the proportion of gadolinium is from 0,.,05¾ to 70% by weight.
3. An absorber according to claim 2 wherein the proportion of gadolinium is from 0.1 to 15%.
4. An absorber according to claim, 1 wherein the alloyed aluminium is selected from the alloys denoted by the numbers loco, 5000 and 6000 in the Aluminium Association standards.
5. An absorber according to claim 1 wherein the alloyed aluminium con tains at least one nuclear radiation absorber metal.
6. An absorber according to claim 5 wherein the metal belongs to the group formed by cadmium, samarium, europium, lithium, hafnium and tantalum.
7. An absorber according to claim 1 wherein the dispersed phase contains at least one nuclear radiation absorber product.
8. » An absorber according to claim 7 wherein the dispersed phase is formed by boron or one of the derivatives thereof. S.
9.An absorber according to claim 8 wherein the boron represents up to 30% by weight of the aluminium.
10. An absorber according to claim 1 wherein the dispersed phase is in the form of fibres. - 9
11. An absorber according to claim 1 wherein it is produced by one at least of the production precesses selected from casting, rolling, extrusion and forging.
12. An absorber for nuclear radiations as claimed in claim 1 substantially as hereinbefore described by way of Example.
IE185186A 1985-07-11 1986-07-10 Absorber for nuclear radiations IE58952B1 (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR8510983A FR2584852B1 (en) 1985-07-11 1985-07-11 NUCLEAR RADIATION ABSORBER

Publications (2)

Publication Number Publication Date
IE861851L IE861851L (en) 1987-01-11
IE58952B1 true IE58952B1 (en) 1993-12-01

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Family Applications (1)

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IE185186A IE58952B1 (en) 1985-07-11 1986-07-10 Absorber for nuclear radiations

Country Status (19)

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EP (1) EP0211779B1 (en)
JP (1) JPS6270799A (en)
KR (1) KR910007461B1 (en)
AT (1) ATE40763T1 (en)
AU (1) AU580177B2 (en)
BR (1) BR8603239A (en)
CA (1) CA1268031A (en)
DE (1) DE3662078D1 (en)
DK (1) DK327786A (en)
ES (1) ES2001015A6 (en)
FI (1) FI85923C (en)
FR (1) FR2584852B1 (en)
GR (1) GR861792B (en)
IE (1) IE58952B1 (en)
IL (1) IL79385A0 (en)
NO (1) NO169035C (en)
NZ (1) NZ216802A (en)
PT (1) PT82958B (en)
ZA (1) ZA865168B (en)

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6338553A (en) * 1986-08-01 1988-02-19 Kobe Steel Ltd Aluminum alloy having superior thermal neutron absorbing power
DE19706758A1 (en) * 1997-02-20 1998-05-07 Siemens Ag Apparatus used to store spent fuel elements from nuclear power stations
JP3122436B1 (en) 1999-09-09 2001-01-09 三菱重工業株式会社 Aluminum composite material, method for producing the same, and basket and cask using the same
EP1737992A1 (en) * 2004-04-22 2007-01-03 Alcan International Limited Improved neutron absorption effectiveness for boron content aluminum materials
EP3011066B1 (en) 2013-06-19 2019-05-08 Rio Tinto Alcan International Limited Aluminum alloy composition with improved elevated temperature mechanical properties
JP2017214652A (en) * 2016-05-30 2017-12-07 株式会社フジクラ Gadolinium wire, method for producing the same, metal-coated gadolinium wire prepared therewith, heat exchanger and magnetic refrigeration device
WO2017209038A1 (en) * 2016-05-30 2017-12-07 株式会社フジクラ Gadolinium wire material, method for manufacturing same, metal-coated gadolinium wire material using same, heat exchanger, and magnetic refrigeration device

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS583001B2 (en) * 1977-12-16 1983-01-19 財団法人特殊無機材料研究所 Neutron absorbing material and its manufacturing method
DE3024892A1 (en) * 1979-08-18 1982-02-11 Thyssen Industrie Ag, 4300 Essen Steel castings which can be hardened and tempered - contain lanthanide so they can be used as neutron absorbing shields
JPS6055460B2 (en) * 1980-08-12 1985-12-05 東芝セラミツクス株式会社 Alumina sintered pellets for neutron absorption
CA1183613A (en) * 1980-12-27 1985-03-05 Koichiro Inomata Neutron absorber, neutron absorber assembly utilizing the same, and other uses thereof
FR2533943B1 (en) * 1982-10-05 1987-04-30 Montupet Fonderies PROCESS FOR THE MANUFACTURE OF COMPOSITE ALLOYS BASED ON ALUMINUM AND BORON AND ITS APPLICATION
DE3335888A1 (en) * 1983-10-03 1985-04-18 Kernforschungsanlage Jülich GmbH, 5170 Jülich METHOD FOR REDUCING THE REACTIVITY OF A GAS-COOLED BULLET HEAD REACTOR AND SHUT-OFF ELEMENT
JPS6212895A (en) * 1985-07-10 1987-01-21 株式会社神戸製鋼所 Aluminum alloy having excellent neutron absorptivity

Also Published As

Publication number Publication date
ATE40763T1 (en) 1989-02-15
FI85923B (en) 1992-02-28
FI862902A (en) 1987-01-12
NO862793D0 (en) 1986-07-10
IL79385A0 (en) 1986-10-31
DK327786D0 (en) 1986-07-10
KR910007461B1 (en) 1991-09-26
FI862902A0 (en) 1986-07-10
EP0211779A1 (en) 1987-02-25
AU580177B2 (en) 1989-01-05
FR2584852A1 (en) 1987-01-16
IE861851L (en) 1987-01-11
NZ216802A (en) 1989-06-28
JPS6270799A (en) 1987-04-01
FI85923C (en) 1992-06-10
FR2584852B1 (en) 1987-10-16
NO169035C (en) 1992-04-29
PT82958A (en) 1986-08-01
AU6004886A (en) 1987-01-15
CA1268031A (en) 1990-04-24
ZA865168B (en) 1987-03-25
DK327786A (en) 1987-01-12
NO169035B (en) 1992-01-20
NO862793L (en) 1987-01-12
DE3662078D1 (en) 1989-03-16
GR861792B (en) 1986-11-04
EP0211779B1 (en) 1989-02-08
BR8603239A (en) 1987-02-24
KR870001611A (en) 1987-03-14
ES2001015A6 (en) 1988-04-16
PT82958B (en) 1993-03-31

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