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1、INTERNATIONAL STANDARD IS0 12184 First edition 1994-08-I 5 Determination of solubility in nitric acid of plutonium in unirradiated mixed oxide fuel pellets (U,Pu)02 D M is the average atomic weights of the metals, in grams per mole; C is the concentration of the uranium and plutonium in the solution
2、, in moles per litre (c = 1 mol/l). Make up the solution resulting from the treatment of the undissolved residue to a known volume. Take samples and analyze their plutonium content by a suitable method. The method shall have an uncer- tainty of 10 % or better, even in the presence of higher level of
3、 impurities contained in the dissolved material. The method described in IS0 9463 is ade- quate. Other methods should first be qualified with representative samples. 7.5 Repeat solubility test If visible pellet fragments are observed in the residue of the first dissolution test, perform a new test o
4、n a fresh sample. For such a repeat, the test duration (up to 18 h), concentration of nitric acid (up to 10 mol/l and (U + Pu) concentration (down to 0,9 mol/l) shall be defined prior to carrying out the test. The con- ditions of each test and its results should be reported. 2 Copyright Internationa
5、l Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/27/2007 20:59:46 MDTNo reproduction or networking permitted without license from IHS -,-,- 0 IS0 IS0 12184:1994(E) 8 Expression of results 8.1 Method of calcula
6、tion The plutonium solubility, L, expressed as a mass fraction in percent, can be calculated from the fol- lowing equation: L= (I-+) x 100 For a mass fraction of plutonium less than 5 %, a minimum sample size of 45 g is needed to obtain a standard deviation of the repeatability smaller than 0.1 %. I
7、n order to avoid waste of material, the sample size may be reduced to between 18 g and 22 g with a mass fraction of plutonium less than 5 %. Then the standard deviation of the repeatability can be as large as 0,2 %. 9 Test report where ml is the mass of the sample, in grams; The test report shall in
8、clude the following information: - date and place of the test carried out; m, is the mass of the plutonium in the resi- due, in grams; - identification of the sample; W is the mass fraction of the plutonium in the - the reference of the analytical method used; sample. 8.2 Repeatability - the method
9、of calculation of the results including the boiling time; The repeatability of the results depends upon the mass fraction of the plutonium W, and the sample size. For a material with a mass fraction of plutonium greater than 5 56 and a sample size of 25 g, the Stan- dard deviation of the repeatabili
10、ty is smaller than 0.1 %. - the results and their units; _ any unusual features observed during the test; - any operation regarded as optional. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resal
11、e, 04/27/2007 20:59:46 MDTNo reproduction or networking permitted without license from IHS -,-,- IS0 12184:1994(E) CJ IS0 ICS 27.120.30 Descriptors: nuclear energy, nuclear fuels, fide materials, pelletized materials. fuel pellets, plutonium, tests, determination, solubility. Price based on 3 pages Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/27/2007 20:59:46 MDTNo reproduction or networking permitted without license from IHS -,-,-
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