International Atomic Energy Agency

IñEñ/RL/

gust 1984

Report on Intercomparisons IñEñ/S-17, S-18, and S-19

of the Determination of Uranium in Uranium Phosphate Ores

by

L. Pszonicki, A.N. Hanna and O. Suschny

II/

Report on Xntercomparisons IAKA/S-17, S-18, and S-19

of the Determination of Uranium in Uranium Phosphate Ores

by

L. Pszonicki, A.If. Hanna and 0. Suschny

International Atomic Energy Agency

Vienna, August 1984

Content

page

1. Introduction

2. Scop* of the intercomparison

3. Description of the metería!

4. Evaluation of results

5. Discussion and conclusions

1

1

1

3

4

Acknowledgement

Note

References

List of participants

5

5

5

6

Appendix 1:

Data handling and statistical evaluation

Appendix 2:

Terms used in tables

10

Appendix 3:

Description of figures

12 Tables

3 Figures

1. Introduction

The aim of the reportad intercomparisons, similar as that of all

other exercise* organised by the IAEA's Analytical Quality Control

Service, was to provide an opportunity to the participating laboratories

to check the reliability of their results by comparing them with the

results obtained by other laboratories. The intercompared materials were

three Brasilian uranium phosphate ores containing uranium of a low, a

medium, and a large concentration, respectively. An additional aim was

to establish the concentrations of uranium in these ores and to certify

the latter.as reference materials.

2. Scope of the intercomparison

The participants were requested to determine the concentration of

uranium in three samples of uranium ores provided to them. 24

laboratories from 19 countries returned results.

The evaluation was based on the following numbers of laboratory

means: 34 for the ore with a low concentration of uranium (S-17), 35 for

that with an intermediate concentration (S-18), and 33 for that with a

large concentration (S-19). Seven laboratory means were rejected as

outliers. The number of laboratory means exceeds the number of

laboratories because some of the latter provided groups of results

obtained by different methods.

3. Description of materials

Three batches of phosphate matrix uranium ores containing different

uranium concentration were prepared in the form of fine powder (grain

size below 0.1 sm) by NUCLEBRAS, Empresas Nucleares Brasileiras SA,

Centro de Desenvolvimiento da Tecnología Nuclear, Cidade Universitaria -

Pampulha in Belo Horizonte, Brazil. Each batch of ore was provided to

the IAEA in three separate 20 kg bags containing materials of slightly

- 2 -

different uranium concentrations. The contents of these bass were put

together tad carefully homogenized by mixing in a rotating plastic drum

for 100 hours in the lACá/s Laboratory. Three homogeneous batches of the

ores S-17, S-18, and S-19 were obtained in this way. Aliquots of them

(25 g) were distributed into plastic bottles.

The homogeneity of the materials was checked by determining the

concentration of uranium by instrumental neutron activation analysis in

several sub-samples taken from various bottles chosen at random. By

applying F and t, tests it was found that the results did not differ

significantly and that these materials could be considered homogeneous at

a confidence, level of 95%, at least for a sample weight equal to or

larger than 100 mg.

The approximate general composition of the materials, according to

data provided by C.D.T.N.-NUCLEBRAS, is as follows:

ComponentS-17

Concentration in %S-18 S-19

CaO

P

F.2O

K2°HgO

P2°5sio2SrO

Loss on ignition (900*C)

2

50

0.5

2

0.4

0.7

0.4

9

7

0.2

0.1

30

11

21

0.6

2

0.5

0.2

10

14

38

0.2

0.1

4

5

33

1

2

0.2

0.1

0.4

25

26

0.2

0.2

5

The water content of the materials determined by drying at 105*C was

found to be 0.29% in S-17, 0.51% in S-18, and 0.23% in S-19. Since the

moisture content can vary with changes in the ambient humidity and

- 3 -

temperature, the participants in the intercomperisons were advised to

determine this parameter in separate sub-samples by drying at 105*C to a

constant weight and report their results on a dry-weight basis.

Ко information on the degree of radioactive equilibrium was provided

to the participants.

4. Evaluation of results

The data provided by laboratories participating in the reported

intercomparison were edited and processed by a statistical computer

programme equal to that used in previous intercomparisons . This

programme is based on the assumption of a non-parametric distribution of

the data. Any outlying data were eliminated by a procedure proposed by

Veglia1 ' and slightly modified by the authors. The medians and their

confidence intervals were accepted as the most robust estimations of the

true values. The confidence intervals of the medians were estimated from

a table given by Remington and Short . A short description of the

evaluation procedure used is given in Appendix 1.

The numerical values of the results of evaluation are presented in

tables as follows:

- Tables 1 to 5 provide general information on the intercomparison;

- Tables б to 8 give information on reported data;

- Tables 9 to 11 provide a summary of the results.

The meaning of the terms used in the tables is described in Appendix 2.

A graphical presentation of the results showing their distribution in

the form of local density functions is shown in Fig's 1 to 3. The figures

also show the medians, means, and modes together with their confidence

intervals. A description of the figures and the procedures used for

their preparation is given in Appendix 3.

- 4 -

Mote: Since the data, on uranium concentration in the three materials were

processed by a computer programme and printed together in the tables,

instead of element symbols a special notation must be used, e.g. U-S17

means uranium in the material S-17, etc.

S. Discussion and conclusions

More than 40% oí all determinations in these exercises were carried

out without any pretreatment of the samples, or after simple pretreatment

as briquetting or mixing with other powder (Table 3). This category

includes samples which were analysed by activation analysis, by radio-

metry of natural isotopes or by Z-ray fluorescence. For fluorimetric or

spectrophotometric determinations uranium was usually separated from the

matrix by extraction or ion-exchange.

The analytical method most frequently used was radiometry of natural

isotopes (23.9% of all determinations; Code No. .2, Table S), followed by

neutron activation analysis (19.3%), fluorimetry (18.3%), X-ray

fluorescence (18.3%) and spectrophotometry (18.3%). One laboratory

provided results obtained by isotope dilution mass spectrometry.

A total of seven outlying results (below 7%) was found and it may be

considered as moderate for this concentration level. Four of these

outliers were produced for the lowest uranium concentration (S-17). Six

of the outliers were produced by fluorimetric method. Fluorimetry,

although very sensitive, is effected by many parameters which are

difficult to standardize, and therefore its results are more dispersed

than those of other methods. Three of these outliers were provided by

one laboratory (Code No. 3) and this laboratory should revise its

fluorimetric procedure.

In general, the results can be considered as satisfactory. Their

overall medians pass all qualification criteria formulated in previous

intercomparisons .

V- 5 -

The relative confidence intervals (relative uncertainty) of these

medians extend in the range from -3% to +5% (Table 11). Although they

may be considered too large for some purposes, they correspond, in fact,

to the real precision at the method used at the given concentration

levels.

The two peaks (360 yg/g and 395 pg/g), which are observed in the

distribution of results of S-17 (fig. 1), can not be correlated with any

pretreatment or analytical methods used (compare Table 6 and Fig. 1} and

they can be considered as a result of statistical fluctuation of random

data.

The overall medians of all materials were accepted as reliable for

certification. They are listed with their confidence intervals in

Table 12.

Acknowledgements

The authors of this report are thankful to Ms. Katalin Lewis-Goettler

of the IAB1 Computer Section for computation of the results, and to

Mr. Robert Oekner of the IAEA Laboratory Seibersdcrf for assistance in

the preparation and distribution of the intercomparison samples.

Note

The authors will appreciate all remarks and comments from analysts

using the reference materials IAEA/S-17, S-18, and S-19 which are

certified on the basis of the intercomparisons reported here. Additional

results received will be held for use in a conceivable future revision of

recommended values.

References

[1] L. Pszonicki, A.M. Hanna and 0. Suschny, International Atomic EnergyAgency, Report No. IAKA/RL/97, March 1983.

[2] A. Veglia, International Atomic Energy Agency, Report No. IASA/SL/84,August 1981.

[3] S.O. Remington, M.A. Schork, "Statistic» with Application to theBiological and Health Sciences", Prentice Hall, Inc., Engelwood,Cliffs, N.J. 1970.

- б -

List of Participants

(in alphabetical order by countries)

Иг. H.B.L. Do NaseimentoNUCLSBRA3 - Laboratorio d» Procesaos - Labpr. EM, Caixa Postal, 913 -Pocos de Caldas, MG, Brasil

Mr. J.Tai-PowRadiation Protection Laboratory, Ontario Ministry of Labour, 81 ResourcesRoad, Weston, Ontario, Canada M9P 3T1

Messrs. J. Krtil, V. KuvikNuclear Research Institute, Central Control Laboratory, 250 68 Rez,Czechoslovak!a

Dr. L. Ltfvborg

Rise National Laboratory, DK-4000 Roskilde, Denmark

Mr. P. HolligerService d*Etudes Analytiques, Centre d'Etudes Nucleaires de Saclay,91191 Gif-Sur-Yvette Cedez, France

Dr. F. Moldenbawer, Mr. J. ThieleStaatliches Amt f. Atoasicherheit und Strahlenschutz, DDR-1157 Berlin,Waldowallee 117, German Democratic Republic

Dr. T.S. Bant, A.G. Hegde, S. ChandramouliEnvironmental Survey Laboratory, Tarapur Atomic Power Station, TAPSColony, Tapp-Post., PIX 401-S04, Xhana District, India

Messrs. E. Giomo, R. Magarini, L. RaglioSimur S.p.A. - Lab. Geominerario, Via Miniera di Novazza, 24020 YalgoglioBergamo, Italy

Messrs. M.A. Valdovinos Taran, H. A. Silva JimenezLaboratorio de Monitoreo y Dosimetría Ambiental, Comisión Federal deElectricidad/PNLV, Mexico

Messrs. I.H. Qureshi, M.S. Chaudhary, I. Fatima, A. Mannan, S. VaheedPakistan Institute of Nuclear Science and Technology, P.O. Nilore,Rawalpindi, Pakistan

Messrs. A. Baranski, A. Pawlak, A. Pietruszewski, Z. WoloazynCentral Laboratory for Radiological Protection, 03-194 Warsaw, Konwaliowa7, Poland

Dr. L. DinescuInstitute of Physics and Nuclear Engineering, Section 6, P.O.Box 5206,Bucharest, Romania

Mr. R. Dumitrescu, Dr. V. Mateiciuc, Ms. M. Constantinescu, Ms. APantelica, Ms. M. Salagean, Ms. S. SpiridonInstitute of Physics and Nuclear Engineering, P.O.Box 5206, Bucharest,Romania

- 7 -

Dr. S.J.N. Brits, Mi. B.W. MoolmanNuclear Development Corporation of SA (Pty) Ltd., Private Big X256,Pretoria 0001, Republic of South Africa

Dr. A.S. ColePhosphate Development Corporation, P.O.Box 1, Phalaburwa 1390, Republicof South Africa

Messrs. A. Faanhof, M.C.B. SuitNuclear Development Corporation of SA (Pty) Ltd., Private Bag X256,Pretoria 0001, Republic of South Africa

Ms. B. Crigorova, Mr. R. Murray-Smith, Mr. W.C. LenahanAnglo American Research Laboratories, 8 Schotlland Street, Theta,Johannesburg 2001, P.O.Box 106, Crown Mines, Transvaal 2025, Republic ofSouth Africa

Mr. ¿. BayonJunta de Bnergia Nuclear, Av. Complutense 22, Madrid, Spain

Messrs. I. Alkan, A. BassariCekmece Nuclear Research and Training Center, P.R.I, Havaalani, Istanbul,Turkey

Dr. J.M. Matuszek, Mr. J.A. HutchinaonRadiological Sciences Laboratory, Center for Labs & Research, NY StateDept. of Health, Efe$lra State Plaza, Albany, NY 12201, USA

Dr. Pham Duy HienNational Institute for Nuclear Reseach of SRVietnam, 67 Nguyen Du, Hanoi,Vietnam

Dr. V. Valkoviclestitut "Ruder BoskovicN, Laboratory for Nuclear Microanalysis,Yugoslavia

Dr. t. Chitumbo, Dr. M.B. Zaman, Mr. P. Kalebwe, Mr. V.M. MwandoRadioisotopes Research Unit, national Council for Scientific Research,P.O.Box CH:1S8,, Chelston, Lusaka, Zambia

Mr. W. MpukuGeological Survey Department, P.O.Box SO135, Lusaka, Zambia

- 8 -

APPENDIX 1

Data handling and statistical evaluation

The participants were requested to make at least three, preferablysix separate determinations of each radionuclide and to report theresults of all determinations as net values, i.e. after correcting forthe blanks. Some laboratories, however, sent in the results of only oneor two determinations.

The computer programme in its present form accepts a maximum of óindividual results for a given radionuclide from one laboratory. If thenumber of reported results obtained by the same analytical procedure waslarger, only six results chaos«n at random were included, the others wereignored.

The results supplied in the form "less than" were tabulated only asadditional information values but not used for statistical evaluation.

Results described as doubtful by the laboratory itself were notincluded.

The main stages of the general statistical procedure used forevaluation of data were as follows:

1. Laboratory means were calculated on the basis of the reportedindividual determinations.

2. All laboratory means for one element were treated as a set of datapoints and arranged by their ascending values (see tables 6 to 8).

3. The set of data was tested for outlying results and the outlierswere rejected, using the followng procedure:

the data points most distant from the mean of the set weretested sequentially one after the other;

for every tested point an h-value was calculated:

n—iwhere: Xj - value of the point to be tested

xn-l ~ Arithmetic mean of the set without XjSn_i - standard deviation of the set without xjn - total number of the data points in the set

if the h-value was found to be larger than 3.162, then XJ wasrejected as an outlier at the significance level of 0.05, andthe testing procedure wa3 continued for the next most distantpoint;

- 9 -

4.

if h was smaller than 3.162, then the point was provisionallyexcluded from the set of data and the next point was tested.If for this next point the h-v*lue was also smaller than 3.162,both points were Accepted, and the procedure was finished,however, if for the second point h was larger than 3.162, bothpoints were rejected as outliers and the testing was continuedfor the next data points of the sot.

- results rejected as outliers are indicated in Tables 6 to 9 byan asterisk put next to a laboratory mean

The overall «radian was calculated in the usual way and its confi-dence limits were found in the table given by Remington andSchorl3*.

5. For comparison, the arithmetic mean and its confidence limits(assuming a normal distribution of data) and the mode (seeAppendix 3) are also calculated.

6. The distribution of the results for each element was plotted as afunction of local density of the data (see Appendix 3).

- 10 -

APPENDIX 2

Inscription of terms ttitd in the tables

Tables 1 to 5

Method Code Mo. t The main features of the analytical methods used by in-dividual laboratories are shown in the form of code numbers. The codenumbers appearing before the point refer to sample pretreatment methodssuch as dissolution, separation and/or preconcentration, the key to whichis given in Table 1. The use of two digits before the point means that acombination of two different pretreatment methods was applied, e.g. aciddigestion and solvent extraction.

The coi» number appearing after the point refers to the method used forth<* »i»iaotitative determination of an element/radionuclide. The firstdigit after the point characterizes the type of method, e.g. neutronactivation analysis, atomic absorption spectroscopy, or spectrometry ofthe daughter radionudide. The second digit gives more exact informationabout the analytical procedure used, e.g. neutron activation with radio-chemical separation, flameless atomic absorption, or gamma-spectrometryof the daughter radionuclide with a scintillation detector.

If in the method code only one digit after the point is used, e.g.: .1,this code number refers to all analytical procedures indicated by the twodigits code number in which the first digit is the same, e.g.: .10, .11,.12, etc.

Method Abbreviation: The combination of capital letters corresponding tothe first letters of the name of the analytical method. Each methodabbreviation referes to the first digit after the point in the methodcode.

Frequency of the Application of Pretreatment Methods: The relative numberof results, which were obtained by a single procedure using the pretreat-ment method indicated by «Method Code Mo." (figures before the point),calculated as percent of all results reported for a given element in-cluding "less than"-results. Because sometimes the combination of morethan one pretreatment method was used, the sum of the frequencies for oneelement/radionuclide may exceed 100%.

Frequency of the Application of Analytical Methods: The relative numberof results, which were obtained by the analytical method indicated by"Method Code No.** (figures after the point), calculated as percent of allresults reported for a given element including "less thanH-results.

Two different types of frequencies are listed in Table 4: frequencies ofexactly specified methods (two digits code no.) and frequencies of thegroup of methods (one digit code no.). The frequencies of the secondtype were calculated as the sum of the frequencies of all methods of thegroup concerned.

(ANSI and ISO TEST CHART No. 2)

- 11 -

Laboratory Mean: The arithmetic mean computed from «11 individual re-sults supplied by a given laboratory. An asterisk next to a laboratorymean denotes that this swan was classified as an outlier and Mas nottaken into account when computing the overall swan and Median.

Outlier: A laboratory mean classified as an outlying value in the set ofall laboratory swans obtained for the eleswnt/radionuclide concerned (seeAppendix 1).

"less than"-Result <**<"-result); A result reported by a laboratory as"less than". If a laboratory supplied sosw different "less than"-resultsfor an elenwnt/radionudide, then only one, viz. the highest, wasaccepted. -

Total Number of Laboratory Means: The total number of all laboratoryswans and "less than"-results obtained for all elements/radionuclideswhich were to be determined ia the intercoaparison run.

Total H"pfrt7 nf Otttliers; The sum of outliers obtained in the intercom-

par i son run for all elements/radionudides which were to be determined.Its relative number was calculated as percent of the "Total Number ofLaboratory Heans".

Total М"**Ьег of "less th**!"—Results: The sum of all "less than"—resultsreported in this intercomparison. Its relative value is calculated as apercentage of the total number of laboratory means.

number of Laboratory Means. Outliers, and "less than"-Results bv theMethod: Numbers corresponding to the above defined "total numbers" butconcerning the results obtained by one analytical method indicated in thetable by "code no." and "abbreviation". Their relative values werecalculated as percentage of "Number of Laboratory Means by the Method".

Tables 6 to S

Method Code No.: )Laboratory Mean: )"less than"-Result: .)

See description of Tables 1 to 5

Input Value: Known concentration of an element/radionuclide put in andhomogeneously distributed in the bulk of the material to be analysed.(Not applicable in the reported intercomparison).

Units: Units in which the concentration of an element/radionuclide to bedetermined is expressed.

Laboratory Code No.; Each laboratory is represented by a code number,which remains unchanged throughout the tables. These numbers, however,do not correspond to the sequence of laboratories in the list of partici-pants given at the end of this report, so that anonymity is secured.When a laboratory has used more than one analytical procedure for the

- 12 -

determination of tbe I I M element/radionuclide, then the results «re dis-tinguished as different set of data by different capital letters added totbe code nuaber.

Мишоег of Determinations: The number of individual determinations per-formed by the laboratory using the seme analytical procedure (

Nless than"

-results excluded).

Laboratory Standard Deviation: The absolute and relative laboratory stan-dard deviations are calculated in the usual way only if at least tworesults were reported by a laboratory.

Estimated Laboratory Error: The participants' own estimate of the rela-tive standard deviation expressed in percent. The figure before thepoint refers to the error due to counting statistics (only for radio-metric methods),, and that after the point to the error due to a completeanalytical procedure.

Deviation from Input Value: Not applicable in the reported intercompari-son.

R-Value: Not applicable in the reported intercomparison.

Tables 9 to 11

Method Code No.: )Method Abbreviation; )Laboratory Mean; )Outliers: )•

Pnit:

Input Value;

See descriptionof Tables 1 to 5.

See descriptionof Tables 6 to 8.

j j ^ p of Reported Results: Laboratory Means: Number of laboratory means(excluding "less than

n-results) reported for an element/radionrelide.

af Reported Results; Individual Determinations: Number of indivi-dual determinations (excluding "less than"-results) reported by alllaboratories for an element/radionuclide.

Number of Accepted Results; Individual Determinations: Number of indivi-dual determinations (excluding "less than"-results and outliers) reportedby all laboratories for an element/radionuclide.

Total Ranite of Laboratory Means: The range between the lowest and thehighest of the "Reported Results".

Range of Accepted Laboratory Means: The range between the lowest and thehighest of the "Accepted Results".

- 13 -

Percentage of OutlTJmt Laboratories; Relative number of laboratorieswhich have supplied outlying results given in percent of the total numberof laboratories which have reported results.

Percentage of Outliers: Percentage of "Outlying Laboratories".

Percentage of Laboratories with an R-Value larger than 1: Mot applicablein the reported intercomparison.

Percentage of Laboratories with no R-Value; Mot applicable in thereported intercomparison.

Overall mean; Non-weighted mean of all accepted "Laboratory Means", afterelimination of outliers.

Confidence Limits of the Overall meant Calculated on the assumption ofnormal distribution of laboratory means. If for an element/radionuclidethe calculated lower confidence limit was found to be negative, then itwas taken to be equal to zero.

Relative Uncertainty of the Mean; The differences between the overallmean and its confidence limits expressed as percent of this overall mean.

Overall Median; The median i'alue of all(after elimination of outliers).

•accepted" laboratory means

Confidence Limits of the Overall Median; Values of the data points(overall means) which were found in the table given by Remington andSchorl^] for tn# significance level of 0.0S.

Relative Uncertainty of the Overall Median; the differences between theoverall median and its confidence limits expressed as percent of thevalue of this median. Notice that the confidence interval can be dis-tributed asymmetrically around the median.

Overall Mode: The concentration value corresponding to the maximum localdensity of laboratory means (see Appendix 3).

Relative Deviation from the Input Value; Not applicable in the reportedintercomparison.

Mean Value by the Method; The arithmetic mean of results (laboratorymeans) obtained by the method referred to by the "code no".

Median Value bv the Method; The median of results (laboratory means)obtained by the method referred to by the "code no".

- 14 -

APPENDIX 3

Description of fitcures

Th« data distribution is presented graphically in the form of rela-tive local density of data points as a function of corrected values ofthese points. Because the data represent the values of a. random variablethey may form small clusters with a very high local density which doesnot result from the distribution of the total set. The plotted values,therefore, were calculated by using the following smoothing procedure:

1. For every data point a new corrected value was calculated as theaverage value of this point and of two neighbouring points. Thisoperation was repeated O.ln times, where "n" is the total number ofaccepted data points rounded to full tens.

2. The absolute local density values in the nearest vicinity of everycorrected point were calculated as the reciprocal values of the meandistance between this point and two neighbouring points.

3. The function obtained in this way was smoothed by calculation foreach point of a mean value of this point and 0.2n neighbouringpoints. This operation was also repeated O.ln times (

nn

n-value see

para 1). Finally, the function was transformed into the relativelocal density function by normalizing its maximum to 100.

The relative local density functions Ф (Xj) plotted against thecorrected values of results are shown in Figures 1 - 3 as the con-tinuous lines with small circles. They represent only the distributionof experimental data, not the shape of the general distribution in astatistical sense. The modal values were estimated as values of thecorrected points corresponding to the maximum of the density functions.The values of original results (laboratory means) are indicated directlyabove the abscissa. The values of the overall means and mediansaccompanied by their confidence limits and values of the modes areindicated in the plots by vertical arrows. The values of outliers arelisted on both sides of the plots with horizontal arrows indicating thedirection of their position.

For multimodal curve (more than one maximum) the function Ф(Х|) wasprocessed further by the same procedure as given in para 3. Theoperation was repeated until a unimodal plot was achieved.

The transformed unimodal function was plotted as a continuous linewithout circles, e.g. figure 1. The modal value was estimated for thisfunction.

Table 1

Cod» numbers of the» pretreataent methodsused in intercomparison S-17, 3-18, and S-19

(not including radiochemical separation after neutron activation)

MethodCod* Mo.

•

0.

1.

2.

3.

4.

S.

6.

7.

8.

Method

not coHMinicated or not clearly indicate*

no prttreatnent

briquet ting, pellets formation orfoil formation

dry dilution (by mixing of powders)

digestion

fusion

extraction

Ion-exchange

combined treatment involving more thantwo pretreatment methods

electroplating

Tiblt 2

Cod* numbers and abbreviations of analytical methodsused in the intercomparison* S-17, S-18, and S-19

Cod*No.

Abbre-viation

Method

not communicated or not clearly indicated

.1 NAA Neutron activation analysis - general

.10 NAA - no additional information provided

.11 Instrumental NAA - spectrometry

.12 Instrumental NAA - delayed neutron method

.14 NAA - epithermal neutron

.2 RAD Radiómetrie analysis

.21 Gamma-spectrometry

.22 Alpha-spectrometry

.3 XRF X-ray fluorescence

.30 XRF - no addtional information provided

.31 XRF - energy dispersive

.4 F Fluor imetry

.S SP Spectrometry

.6 MS Isotope dilution mass spectrometry

TABLE NO.3

FREQUENCY OF THE APPLICATION OF PRETREATMENT

METHODS USED IN INTERCOMPARISON FOR IAEA/RUNS S-t7.S-18.S-19. 1983(NOT INCLUDING RADIOCHEMICAL SEPARATION AFTERNEUTRON ACTIVATION).

% OF USE IN THE RUN FOR ELEMENT

METHOD

ELEMENT

U-S17U-S18U-S19

CODES:

181617

.4

.2

.6

О

313235

.6

.4

.3

1

782

#

.9

.1

.9

2

22

#

.6

. 7

3 -

1 8 .1 8 .2 0 .

496

4

655

m

.3

.4

.9

5

181820

.4

.9

.6

7.

2 1 .2 1 .20.

166

3

s55

.3

.4

.9

(METHOD CODE NUMBERS AS IN TABLE 1 )

J

TABLE N0.4

FREQUENCY OF THE APPLICATION OF ANALYTICALMETHODS USED FOR THE DETERMINATION OFELEMENTS IN INTERCOMPARISON IAEA/RUNS S-17.S-18.S-19, 1983

METHODCODE ABBR.

• •

. 1

.11

.12

.2

.21

.22

.3

.30

.31

.4

.5

.6

NAA

RAD

XRF

F

SP

MS

U-S 17

2.6

18.4

10.57.9

23.7

18.45.3

18.4

15.82.6

18.4

15.8

2.6

% OF USE

U-S 18

2.7

18.9

10.88.1

24.3

18.95.4

16.2

13.52.7

18.9

16.2

2.7

IN T

U-S

2.9

20.6

11.88.8

23.5

17.65.9

14.7

11.82.9

17.6

17.6

2.9

(METHOD CODE NUMBERS AS IN TABLE 2 )

TABLE NO, 5

GENERAL FREQUENCY OF THE APPLICATION OFANALYTICAL METHODS USED FOR DETERMINATIONOF ELEMENTS IN INTERCOMPARISON IAEA/RUNS S-17.S-18.S-19, 19B3

TOTAL NUMBEA TOTAL NUMBER ABS 7OF LAB MEANS 1O9 OF OUTLIERS REL(X) 6.4

METHOD CODE NO.:

METHOD ABBREVIATION

NUMBER OF LAB.MEANSBY THE METHOD

PERCENTAGE OF LAB.MEANS BY THE METHOD

NUMBER OF OUTLIERSBY THE METHOD

PERCENTAGE OF OUT-LIERS BY THE METHOD

•

3

2.В

1

33.3

.1

NAA

21

19.3

.2

RAD

26

23.9

.3

XRF

18

16.5

.4

F

20

18.3

6

30.0

.5

SP

18

16.5

.6

MS

3

2.8

(METHOD CODE NUMBERS AS IN TABLE 2

СО ЫСОСОСО СО СО С О О М М Ю М М М М М Ю М -

а ю д с о м о ю а ^ е л д с о м о с

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TABLE NO. 9

SUMMARY OF THE RESULTS OF THE INTERCOMPARISON IAEA/RUNS S-17.S-18.S-19, 1983

ELEMENTSDETERMINED

UNIT

INPUT VALUE

NUMBER OFREPORTEDRESULTS

NUMBER OFACCEPTEDRESULTS

TOTAL RANGELABORATORY

LABORATORYMEANSINDIVIDUALDETERMINATIONS

LABORATORYMEANSINDIVIDUALDETERMINATIONS

OFMEANS

RANGE OF ACCEPTEDLABORATORY MEANS

PERCENTAGE OF OUTLYING

U-S17

MICROG/G

•

38

159

34

143

195.000 - 460.000

313.333 - 410.000

11LABORATORIES

PERCENTAGE OF LABORATORIESWITH THE R VALUE > 1

PERCENTAGE OF LABORATORIESWITH NO R VALUE

OVERALL MEAN OF ACCEPTEDLABORATORY MEANS

CONFIDENCE LIMITS OF THEOVERALL MEAN AT.05 SIGN. LEVEL

OVERALL MEDIAN OF ACCEPTEDLABORATORY MEANS

CONFIDENCE LIMITS OF THEOVERALL MEDIAN AT.05 SIGN. LEVEL

362

356

OVERALL MODE OF ACCEPTEDLABORATORY MEANS

RELATIVE DEVIATION % MEANFROM THE MEDIANINPUT VALUE MODE

370.710

.37f - 379.O48

365.250

.000 - 385.000

357.963

U-S18

MICROG/G

37

161

35

149

U-S19

MICROG/G

34

140

33

134

599.500 - 880.000 1295.000 - 2880.000

691.OOO - 880.000 1713.333 - 288O.00O

5 3

778.339 2277.563

761.778 - 794.900 219!.OO8 - 2364.1Í9

766.667 2283.333

750.000 - 791.000 2210.000 - 2387.750

761.663 2292.133

TABLE NO. 10

COMPARISON OF THE OVERALL MEANS WITH THE MEAN VALUES OBTAINED BY VARIOUSANALYTICAL METHODS IN INTERCOMPARISON IAEA/RUNS S-17.S-18.S-19. 1983

NUMBER PERCEN-ELEMENT OF TAGE OF

ACCEPTEO OUTLIERSRESULTS ( * )

UNITО V

VALUEE R A L LCONFIDENCELIMITS(0.05)

M E A NRELATIVEUNCERTAINTY

(X)

ANALYTICALMETHODS USEDCODE NO. ABBREV.

OBTAINED BY THE METHODMEAN VALUE NUMBER OF NUMBER

ACCEPTEO OFRESULTS OUTLIERS

U-S17 34 11 MICROG/G 370.71 362.37 - 379.05 +-2.1.2.3.4.5.6

NAARADXRFFSPMS

371.13370.30376.74364.2537O.22358.00

797461

U-S18 35 MICROG/G 778.34 761.78 - 794.9O +-2.1.2.3.4.5.6

NAARADXRFFSPMS

880.00761.38772.67785.17784.33782.97747.70

179656

U-S19 33 MICROG/G 2277.86 2101.01 - 2364.12+-4.1.2.3.4.5.6

NAARAOXRFFSPMS

1933.332350.312232.052250.602392.902236.942278.50

1

85561

TABLE N 0 . 1 1

COMPARISON OF THE OVERALL MEDIANS WITH THE MEDIAN VALUES OBTAINED BY VARIOUSANALYTICAL METHODS IN INTERCOMPARISON IAEA/RUNS S - 1 7 . S - 1 8 . S - 1 9 . 1983

NUMBER PERCEN-ELEMENT OF TAGE OF

ACCEPTED OUTLIERSRESULTS (%)

O V E R A L L M EUNIT VALUE CONFIDENCE

LIMITS(0.05)

D I A N ANALYTICAL OBTAINED BY THE METHODRELATIVE METHODS USED MEDIAN VALUE NUMBER OF NUMBER.UNCERTAINTY CODE NO. ABBREV. ACCEPTED OF

«) RESULTS OUTLIERS

U-S17 34 11 MICROG/G 365.25 356.00 - 385.00 -3; +5

U-S18 35 MICROG/G 766.67 750.00 - 791.Op -2; +3

U-S19 33 MICROG/G 2283.33 2210.OO - 2387.75 -3; 45

123456

123456

123456

NAARADXRFFSPMS

NAARADXRFFSPMS

NAARADXRFFSPMS

365.50360.00398.00358.33368.33358.00

880.00763.33766.67791.67765.00773.67747.70

1933.332336.672227.502458.002220.002260.OO2278.50

797461

1796561

1785561

Tabla 12

Concentration of uraniua in the materials IAEA/S-I7, S-18, and S-19,

phosphate uraniua ores, which can be recosnended

with a satisfactory degree of confidence

Material Units Concentration* Confidence limits**

XAE&/S-17

IAEA/S-18

IAKA/S-19

Wt.%

wt.%

wt.%

0.037

0.077

0.228

0.036

0.075

0.221

- 0.039

- 0.079

- 0.239

* on dry-weight basis (constant weight at 105*C)** at a significance level of 0.0S