Background technology
Plutonium is a kind of important metallic element, and its multiple isotope has very important application in military, economic dispatch field, and exposed plutonium metal at room temperature can react with airborne oxygen and form the oxide of plutonium, and its chemical reaction is:
Pu (s)+O
2(g) → PuO
2(s)+Δ H (Δ H is-1056kJ/mol)
Be easy to the characteristic of oxidation due to plutonium metal in air, even taked the technical matters of overlay coating (nickel-copper-nickel coating), can not guarantee definitely that plutonium metal is not oxidized.Therefore, to the differentiation of plutonium degree of oxidation with determine just to become important.
Oxygen has multiple isotope, but stable isotope only has three kinds:
16O,
17O,
18O, it is respectively 99.757%, 0.038% in natural abundance, and 0.205%.Oxygen in the plutonium material is subject to the irradiation of α particle and neutron, and following physical process will occur:
17O(n,n′γ)
17O(871keV);
17O(α,α′γ)
17O(871keV);
18O(n,n′γ)
18O(1982.2keV);
18O(α,α′γ)
18O(1982.2keV);
17O (α, n)
20Ne
*(1634keV); Or
18O(α,n)
21Ne
*(350.7,1396,2438,2788.5,2794keV)
These physical processes for
16O, due to
16The excitation energy of O is higher, so in the plutonium material
16The probability that O is activated can be ignored.
17The 871keV feature gamma-rays of O is 1.24/10 being subject to the reaction probability of α when particle excitated
6, and be 622/10 under neutron excites
6, due under the natural radiation condition, in the plutonium metal material, the quantity of α particle is approximately 10 of number of neutrons
8Doubly, so the feature gamma-rays of the 871keV in plutonium oxide mainly is subject to the particle excitated generation of α, that is:
17(α, α ' γ) for O
17O (871keV).
In the interim article " Plutonium oxide attribute Research on measuring technique " of Nuclear Technology magazine volume the 12nd Dec the 29th in 2006, the author has provided and has proposed study qualitatively and discuss whether plutonium metal is oxidized by measuring 871keV feature gamma-rays.
But following problem but ignored in above-mentioned article, that is, due to
14N (α, p)
17O (871keV) reaction also can produce the feature gamma-rays of 871keV, and in the production run of plutonium metal material, inevitably can introduce the N element,
14The abundance of N also can be higher, so in the gamma-rays of measuring,
14N (α, p)
17The gamma-rays that O (871keV) reaction produces also than
17(α, α ' γ) for O
17O (871keV) is higher, therefore directly utilizes
17The 871keV feature gamma-rays of O judges that the existence of plutonium oxide easily is subject to
14The interference of N.
For example, be numbered article " the The 871keV gamma ray from of " Nuclear Instruments and Methods in Physics ResearchA 474 (2001) 285-293 " at article
17O and theidentification of plutonium oxide " and article be numbered article " the THE 870.8keV GAMMA RAY FORMPuO of " Nuclear Instruments andMethods 193 (1982) 383-385 "
2" in think afterwards by analysis, only depend on 871keV feature gamma-rays proof plutonium oxide exist larger error, directly utilization
17The 871keV feature gamma-rays of O also is difficult to quantitative test is carried out in the existence of plutonium oxide.
Summary of the invention
The invention provides a kind of method of measuring the plutonium metal degree of oxidation, especially a kind of method of measuring oxidation percentage of metal plutonium, the method can reduce or avoid problem noted earlier.
For addressing the above problem, the present invention proposes a kind of method of measuring oxidation percentage of metal plutonium, said method comprising the steps of:
A, pure zirconia plutonium powder and simple metal plutonium powder are mixed into 100 gram standard testing samples, carry out 871keV feature gamma-rays peak position count value and measure, obtain having the plutonium metal 871keV feature gamma-rays peak position count value w1 of this plutonium oxide of determining percentage by weight;
B, the described 100 gram standard testing samples in steps A are added outer source irradiates, carry out simultaneously 871keV feature gamma-rays peak position count value and measure, obtain having the plutonium metal of this plutonium oxide of determining percentage by weight at the 871keV feature gamma-rays peak position count value w2 that adds under outer source irradiates condition;
C, the 871keV feature gamma-rays peak position count value w1 that obtains during the 871keV feature gamma-rays peak position count value w2 under adding outer source irradiates condition that obtains in step B is deducted steps A, can obtain having this determine percentage by weight the plutonium metal of plutonium oxide in
17(n, n ' γ) for O
17The 871keV feature gamma-rays peak position count value w3 that O (871keV) reaction occurs;
D, with reference to steps A-C, measure in the plutonium metal of plutonium oxide of Different Weight number percent
17(n, n ' γ) for O
17The 871keV feature gamma-rays peak position count value w3 that O (871keV) reaction occurs simulates plutonium oxide percentage by weight 0-100%'s in 100 gram standard testing sample plutonium metals
17(n, n ' γ) for O
17O (871keV) reaction 871keV feature gamma-rays peak position count value typical curve;
E, get the plutonium metal sample of 100 gram degree of oxidations to be measured, carry out 871keV feature gamma-rays peak position count value and measure, obtain its 871keV feature gamma-rays peak position count value w1 ';
F, the plutonium metal sample of the described 100 gram degree of oxidations to be measured in step e is added the source irradiates described in outer above-mentioned step B, carry out simultaneously 871keV feature gamma-rays peak position count value and measure, obtain the plutonium metal sample of described 100 gram degree of oxidations to be measured at the 871keV feature gamma-rays peak position count value w2 ' that adds under outer source irradiates condition;
G, the 871keV feature gamma-rays peak position count value w1 ' that obtains during the 871keV feature gamma-rays peak position count value w2 ' under adding outer source irradiates condition that obtains in step F is deducted step e can obtain in the plutonium metal sample of described 100 gram degree of oxidations to be measured
17(n, n ' γ) for O
17The 871keV feature gamma-rays peak position count value w3 ' that O (871keV) reaction occurs;
H, the described count value w3 ' that obtains in step G is compared with the typical curve described in step D, can obtain the plutonium oxide percentage by weight in the plutonium metal sample of described 100 gram degree of oxidations to be measured.
Preferably, the pure zirconia plutonium powder in 100 gram standard testing samples described in step D was respectively 1: 9,2: 8,3: 7,4: 6,5: 5,6: 4,7: 3,8: 2,9: 1 with simple metal plutonium powder weight ratio.
Preferably, described outer neutron source is the 5MKev ra-Be neutron source.
A kind of method of measuring oxidation percentage of metal plutonium provided by the present invention is first measured under oxidized plutonium metal sample natural radiation condition
17(α, α ' γ) for O
17O (871keV) and
14N (α, p)
17Then the 871keV feature gamma-rays peak position count value that occurs of O (871keV) reaction is utilized
17(n, n ' γ) for O
17O (871keV) reaction by adding outer source irradiates, strengthens in tested plutonium metal sample
17(n, n ' γ) for O
17The ability of O (871keV) reaction, record and adding the 871keV feature gamma-rays peak position count value of plutonium metal sample oxidized under outer source irradiates condition, to deduct 871keV feature gamma-rays peak position count value measured under the natural radiation condition adding 871keV feature gamma-rays peak position count value measured under outer source irradiates condition, can obtain in oxidized plutonium metal sample
17The 871keV feature gamma-rays peak position count value that O contributes so just can effectively be avoided
14N (α, p)
17The gamma-ray interference of 871keV feature that O (871keV) reaction produces, the plutonium metal sample that also just can treat the oxygen determination degree carries out quantitative test.
Embodiment
Understand for technical characterictic of the present invention, purpose and effect being had more clearly, now contrast description of drawings the specific embodiment of the present invention.Wherein, identical parts adopt identical label.
Describe with reference to the accompanying drawings according to a kind of method of measuring the plutonium metal degree of oxidation of the present invention especially a kind of implementation step and principle thereof of measuring the method for oxidation percentage of metal plutonium in detail.
A kind of method of measuring oxidation percentage of metal plutonium provided by the present invention said method comprising the steps of:
A, pure zirconia plutonium powder and simple metal plutonium powder are mixed into 100 gram standard testing samples, carry out 871keV feature gamma-rays peak position count value and measure, obtain having the plutonium metal 871keV feature gamma-rays peak position count value w1 of this plutonium oxide of determining percentage by weight;
B, the described 100 gram standard testing samples in steps A are added outer source irradiates, carry out simultaneously 871keV feature gamma-rays peak position count value and measure, obtain having the plutonium metal of this plutonium oxide of determining percentage by weight at the 871keV feature gamma-rays peak position count value w2 that adds under outer source irradiates condition;
C, the 871keV feature gamma-rays peak position count value w1 that obtains during the 871keV feature gamma-rays peak position count value w2 under adding outer source irradiates condition that obtains in step B is deducted steps A, can obtain having this determine percentage by weight the plutonium metal of plutonium oxide in
17(n, n ' γ) for O
17The 871keV feature gamma-rays peak position count value w3 that O (871keV) reaction occurs;
D, with reference to steps A-C, measure in the plutonium metal of plutonium oxide of Different Weight number percent
17(n, n ' γ) for O
17The 871keV feature gamma-rays peak position count value w3 that O (871keV) reaction occurs simulates plutonium oxide percentage by weight 0-100%'s in 100 gram standard testing sample plutonium metals
17(n, n ' γ) for O
17O (871keV) reaction 871keV feature gamma-rays peak position count value typical curve;
E, get the plutonium metal sample of 100 gram degree of oxidations to be measured, carry out 871keV feature gamma-rays peak position count value and measure, obtain its 871keV feature gamma-rays peak position count value w1 ';
F, the plutonium metal sample of the described 100 gram degree of oxidations to be measured in step e is added the source irradiates described in outer above-mentioned step B, carry out simultaneously 871keV feature gamma-rays peak position count value and measure, obtain the plutonium metal sample of described 100 gram degree of oxidations to be measured at the 871keV feature gamma-rays peak position count value w2 ' that adds under outer source irradiates condition;
G, the 871keV feature gamma-rays peak position count value w1 ' that obtains during the 871keV feature gamma-rays peak position count value w2 ' under adding outer source irradiates condition that obtains in step F is deducted step e can obtain in the plutonium metal sample of described 100 gram degree of oxidations to be measured
17(n, n ' γ) for O
17The 871keV feature gamma-rays peak position count value w3 ' that O (871keV) reaction occurs;
H, the described count value w3 ' that obtains in step G is compared with the typical curve described in step D, can obtain the plutonium oxide percentage by weight in the plutonium metal sample of described 100 gram degree of oxidations to be measured.
Wherein, for the measurement of gamma-rays peak position count value, can use low background HpGe gamma ray spectrometer to measure, such as, can measure as testing tool with GEM-30185-P detector and the DESPEC numeral multichannel analyzer of ORTEC company.
Described outer neutron source can be that gamma ray that the decay of radium or other metals is sent comes the irradiation beryllium to produce neutron or directly by californium source given-ioff neutron.
In a preferred embodiment, described outer neutron source is the 5MKev ra-Be neutron source.
By above-mentioned steps A-D, can obtain having the 871keV feature gamma-rays peak position count value typical curve without 100 gram plutonium metal specimen of the plutonium oxide of percentage by weight.
In a preferred embodiment, the pure zirconia plutonium powder in 100 gram standard testing samples described in step D was respectively 1: 9,2: 8,3: 7,4: 6,5: 5,6: 4,7: 3,8: 2,9: 1 with simple metal plutonium powder weight ratio.
Such as, be 1: 9 preparation 100 gram standard testing sample according to pure zirconia plutonium powder and simple metal plutonium powder weight ratio, that is to say and use 10 gram pure zirconia plutonium powder and 90 gram simple metal plutonium powder, after it is fully mixed in beaker, put into low background HpGe gamma ray spectrometer, it is carried out 871keV feature gamma-rays peak position count value mensuration under the natural radiation condition, and Fig. 1 is a kind of 871keV feature gamma-rays peak position count value test result schematic diagram of measuring the method for plutonium metal degree of oxidation according to a specific embodiment of the present invention.As shown in Figure 1, by described low background HpGe gamma ray spectrometer, can record pure zirconia plutonium powder is the 871keV feature gamma-rays peak position count value w1 of 100 gram standard testing samples under the natural radiation condition of preparation in 1: 9 with simple metal plutonium powder weight ratio, and this 871keV feature gamma-rays peak position count value w1 has comprised under the natural radiation condition
17(α, α ' γ) for O
17O (871keV) reaction and
14N (α, p)
17The 871keV feature gamma-rays peak position count value that O (871keV) reaction occurs.
After under the natural radiation condition, 871keV feature gamma-rays peak position count value mensuration is completed, by adding the 100 gram standard testing samples that outer neutron source is preparation in 1: 9 to described pure zirconia plutonium powder and simple metal plutonium powder weight ratio to shine at low background HpGe gamma ray spectrometer.
Adding under outer source irradiates condition, by described low background HpGe gamma ray spectrometer, can record pure zirconia plutonium powder is the 871keV feature gamma-rays peak position count value w2 of 100 gram standard testing samples of preparation in 1: 9 with simple metal plutonium powder weight ratio, and this 871keV feature gamma-rays peak position count value w2 had both comprised under the natural radiation condition
17(α, α ' γ) for O
17O (871keV) reaction and
14N (α, p)
17The 871keV feature gamma-rays peak position count value that O (871keV) reaction occurs is after also having comprised neutron irradiation
17(n, n ' γ) for O
17The 871keV feature gamma-rays peak position count value that O (871keV) reaction occurs, wherein, neutron irradiation excites the gamma-rays peak position count value of lower generation can not produce any impact for α under the natural radiation condition, and
14N can not excite the extra 871keV feature gamma-rays peak position count value of lower generation at neutron yet.
Therefore described 871keV feature gamma-rays peak position count value w2 is deducted described 871keV feature gamma-rays peak position count value w1, can be with under natural conditions
17(α, α ' γ) for O
17O (871keV) reaction and
14N (α, p)
17The 871keV feature gamma-rays peak position count value that O (871keV) reaction occurs balances out, after only obtaining neutron irradiation
17(n, n ' γ) for O
17The 871keV feature gamma-rays peak position count value w3 that O (871keV) reaction occurs.
Fig. 2 is for plutonium oxide percentage by weight 0-100%'s in 100 gram standard testing sample plutonium metals of a kind of measure the plutonium metal degree of oxidation according to a specific embodiment of the present invention method
17(n, n ' γ) for O
17O (871keV) reaction 871keV feature gamma-rays peak position count value typical curve schematic diagram.In figure, transverse axis represents plutonium oxide percentage by weight in 100 gram standard testing sample plutonium metals, and the longitudinal axis is illustrated in and adds 871keV feature gamma-rays peak position count value under outer source irradiates condition.
With reference to Fig. 2, corresponding pure zirconia plutonium powder is 100 gram standard testing samples of preparation in 1: 9 with simple metal plutonium powder weight ratio, that is to say when on transverse axis, in 100 gram standard testing sample plutonium metals, the plutonium oxide percentage by weight is 10%, its
17(n, n ' γ) for O
17O (871keV) reaction 871keV feature gamma-rays peak position count value is the 871keV feature gamma-rays peak position count value w3 that uses preceding method to calculate.
Equally, be respectively 2: 8,3: 7,4: 6,5: 5,6: 4,7: 3,8: 2,9: 1 o'clock corresponding to the pure zirconia plutonium powder in 100 gram standard testing samples and simple metal plutonium powder weight ratio
17(n, n ' γ) for O
17O (871keV) reaction 871keV feature gamma-rays peak position count value also available said method test draws, and just can obtain also therefore in Fig. 2 on transverse axis that in 100 gram standard testing sample plutonium metals, the plutonium oxide percentage by weight is when being respectively 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%
17(n, n ' γ) for O
17O (871keV) reaction 871keV feature gamma-rays peak position count value.Therefore (n, n ' γ) 17O (871keV) react 871keV feature gamma-rays peak position count value typical curve also just can to simulate the 17O of plutonium oxide percentage by weight 0-100% in 100 gram standard testing sample plutonium metals shown in Figure 2.
In the time need to testing the plutonium metal of unknown degree of oxidation, can take out the plutonium metal sample of 100 gram degree of oxidations to be measured, record the plutonium metal sample of described degree of oxidation to be measured according to the method for step e-G
17(n, n ' γ) for O
17The 871keV feature gamma-rays peak position count value w3 ' that O (871keV) reaction occurs, described 871keV feature gamma-rays peak position count value w3 ' is compared with described typical curve, can find corresponding plutonium oxide percentage by weight, namely obtain the transverse axis coordinate on the corresponding described typical curve of ordinate of orthogonal axes w3 ', this transverse axis coordinate is the plutonium oxide percentage by weight of the plutonium metal of described unknown degree of oxidation namely.
A kind of method of measuring the plutonium metal degree of oxidation provided by the present invention is first measured under oxidized plutonium metal sample natural radiation condition
17(α, α ' γ) for O
17O (871keV) and
14N (α, p)
17Then the 871keV feature gamma-rays peak position count value that occurs of O (871keV) reaction is utilized
17(n, n ' γ) for O
17O (871keV) reaction by adding outer source irradiates, strengthens in tested plutonium metal sample
17(n, n ' γ) for O
17The ability of O (871keV) reaction, record and adding the 871keV feature gamma-rays peak position count value of plutonium metal sample oxidized under outer source irradiates condition, to deduct 871keV feature gamma-rays peak position count value measured under the natural radiation condition adding 871keV feature gamma-rays peak position count value measured under outer source irradiates condition, can obtain in oxidized plutonium metal sample
17The 871keV feature gamma-rays peak position count value that O contributes so just can effectively be avoided
14N (α, p)
17The gamma-ray interference of 871keV feature that O (871keV) reaction produces, the plutonium metal sample that also just can treat the oxygen determination degree carries out quantitative test.
Although it will be appreciated by those skilled in the art that the present invention is that mode according to a plurality of embodiment is described, be not that each embodiment only comprises an independently technical scheme.In instructions, narration like this is only for the sake of clarity; those skilled in the art should make instructions as a wholely to be understood, and regard technical scheme related in each embodiment as the mode that can mutually be combined into different embodiment understand protection scope of the present invention.
The above only is the schematic embodiment of the present invention, is not to limit scope of the present invention.Any those skilled in the art, the equivalent variations of doing under the prerequisite that does not break away from design of the present invention and principle, modification and combination all should belong to the scope of protection of the invention.