Accreditation of the “ACTIVA-N” Laboratory Accreditation of the “ACTIVA-N” Laboratory and and

participation in ILC’s and PT’s exercisesparticipation in ILC’s and PT’s exercises

EmanuelaEmanuela CincuCincu

Ioana ManeaIoana Manea

Manu Valentin, Sibila Brancovici, Alexandru RusuManu Valentin, Sibila Brancovici, Alexandru Rusu

{IFIN-HH}{IFIN-HH}, , Lab ‘ACTIVA-N’ Lab ‘ACTIVA-N’ <cincue@ifin.nipne.ro><cincue@ifin.nipne.ro>

………………………………………………………………………………………………………………………………………….. “ “IWIRAD 2005”, Bucharest, 20-21 June, 2005IWIRAD 2005”, Bucharest, 20-21 June, 2005

“HORIA HULUBEI” NATIONAL INSTITUTE FOR PHYSICS AND NUCLEAR ENGINEERING

IFIN - HH Bucharest

Str. Atomistilor 407, Com. Mãgurele, jud.Ilfov, P.O.Box MG-6, code R-077125Tel. : (0040 21) 404.23.00, Fax : (0040 21) 457.44.32 / 457.44.40

IFIN-HH

PRESENTATION OF LABORATORY

‚ACTIVA-N’ is a young Laboratory, created in 2001 within the frame of the Quality Programme INFRAS put in force by the Ministry of Education & Research.

Its objective is to develop performant analytical measurements by using nuclear techniques, both for research and advanced applications ; in order to be able to provide valid services to industry, medicine, and to other fields we implemented in our activity the quality criteria /requirements given in the Standard SR EN ISO/IEC 17025 :2000*.

Two analytical nuclear techniques are currently employed in the Laboratory activity:

1/ Gamma -ray spectrometry for evaluating activities of the gamma-ray nuclides in various types of samples ; 2/ Instrumental Neutron Activation Analysis (INAA) for identifying elements present in the investigated materials and evaluating their concentrations (for beginning, we got accreditation for metallic alloys, namely for stainless steels).

In May 2004 the Laboratory got the RENAR (the Romanian Accreditation body) Accreditation Certificate (presented in the next slide); the International Atomic Energy Agency was also mentioned, as the IAEA expert in Radionuclide Metrology joined the RENAR team during Audits.

‚ACTIVA-N’ is thus the first nuclear Romanian Laboratory whose accreditation relies on the Romanian and international expertise. *General requirements for competence of the calibration and testing laboratories’

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IWIRAD 2005, Bucharest, 20-21 June, 2006 Dr. Em. Cincu, Ioana Manea – IFIN-HH, Romania

IWIRAD 2005 Dr. Em. Cincu, Ioana Manea, IFIN-HH, ROMANIAIWIRAD 2005 Dr. Em. Cincu, Ioana Manea, IFIN-HH, ROMANIA

Testing performance of the ‚ACTIVA-N’ Laboratory by ILC and PT exercises

After getting accreditation in 2004 we asked for participation in the ILC exercise launched by NPL (UK) in the field of the ionising radiation, which included use of the gamma -ray spectrometry technique, and in the PT exercise launched by the ‚Swedish Institute for Metals Research’(SIMR) on elemental analysis of a special high alloy Stainless Steel{SS1} they specially prepared; the ‚ACTIVA-N Laboratory’ had thus the chance to test its performance in application of the INAA technique in steel materials.

The first exercise envisaged identification of eight β / radionuclides in an aqueous mixture of radionuclides of low activity (from a list of 30 possible), and evaluation of their activity concentrations. According to Standards {ISO GUM2 and ISO.17025: ...} the numerical values of the activity and –respectively- of the element concentrations must be accompanied by their overall uncertainty values that should include the Summing and Coincidence factors, as indicated in the Standard for use of Ge detectors3, , and any other correction considered necessary, that could correct for an error . .............................................................................................……………………….......… 2 Guide to the Expression of Uncertainty :1993; corrected version: 1995 3 IEC Standard no. 1452:1995 ‘Calibration and use of Germanium spectrometers ”

................................................................................................................................................................................................................................................ IWIRAD 2005, Bucharest, 20-21 June, 2005 Dr. Em. Cincu, Ioana Manea, IFIN –HH, Romania

By the above mentioned participations we aimed to comply to the Standard ISO/IEC 17025:

2000 requirements, which states that the analytical performance of every accredited Laboratory

should be validated by participation in International Laboratory Comparison (ILC) or

Proficiency Tests (PT) exercises launched / organized by authorized Laboratories, before,

during and after getting Accreditation.

The background of the ILCs and PTs exercises was established in the international Standard ISO/

IEC Guide 43 :1997– Part 1 ”Development and operations of PT Schemes”. …………………………………………………………………………………………………….……………………………………………… IWIRAD 2005, Bucharest, 20-21 June, 2005 Dr. Em. Cincu, Ioana Manea, IFIN-HH, Romania

Exercise 1 - Performance Test in using the gamma-ray spectrometry Experimental

A reference standard was prepared by the Radionuclide Metrology Laboratory of IFIN-HH, in order to absolutely calibrate the Laboratory gamma -ray spectrometer, as a mixture of 4 aqueous solutions of the standard radionuclides 60Co, 134Cs, 137Cs, and 133Ba.

Trying to minimize the measurement uncertainty and avoid uncontrolled error sources: we used identical ampoules for the NPL sample and for the Standard solution, the measurement location was kept unchanged and similar quantities from each solution were measured; the optimum distance sample - detector was established 6 cm so that to get reasonable intensities for the full- energy -ray peak areas and minimising –at the same time- the Summing and Coincidence (S-C) correction values*.

The -ray spectra evidenced some delicate analytical problems due to the interference of both characteristic - rays of 95Zr with two specific - rays of 134Cs; the evaluation of 95Zr activity became difficult, and also the evaluation of 95Nb, as this last one is generated by 95Zr decay.

Thus, it appeared very difficult to determine the amount of 95Nb radioactivity introduced in the sample when it was prepared, as required. During work we established a practical procedure allowing to evaluate 95Zr and 95Nb activities in conditions of interference.

...................................................................................................................................................................................................................... *the S-C correction factors were evaluated by using the GESPECOR package of codes, detailed in the reference: O. Sima et al., ‘GESPECOR – a versatile tool in gamma-ray spectrometry’, J.R.N.C. , 248 (2001) 359.

....................................................................................................................................................................................................... .................................................... IWIRAD 2005, Bucharest, 20-21 June, 2005 Dr. Em. Cincu, Ioana Manea - IFIN-HH, Romania

Discussion /Comments

The NPL evaluation based on the ‚ u –score criterion’ evidenced quite good results, but, at the same time, the existence of a not high but systematic error, as all results had a negative relative deviation.

By revising the calculation chain the ‚source of error’ was identified as the mass correction (4.8 %) between the NPL sample and our standard, that had been twice applied, by mistake.

After correction, the results got plus (+) and minus (-) deviations by comparison with the NPL reference values. The Report, re-evaluated by NPL - the organizer of the ILC exercise, is presented in Table 1* .

The results are very good, as all of them are less than 1.64, excepting the value for 95Nb (2.22) obtained for the most ‚delicate case’, above described.

The values of the ‚u-score’parameter, used for evaluating performance of the participating laboratories in the ILC exercise, are below indicated:

u-score < 1.64 the values (reference and experimental ones) do not differ significantly;

1.64 < u-score < 1.96 the values probably do not differ significantly, but more data are required;

1.96 < u-score < 2.58 one cannot say whether there is a significant difference without further data;

2.58 < u-score < 3.29 the values probably differ significantly but more data are required; 3.29 < u-score the values differ significantly

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*the line of 106Ru was withdrawn later by NPL ......................................................................................................................... ..................................................................................................................... ........... IWIRad 2005, Bucharest, 20-21 June, 2005 Dr. Em. Cincu, Ioana Manea - IFIN-HH, Romania

Table 1Table 1 – – Results obtained in the NPL ILC Exercise (2004)Results obtained in the NPL ILC Exercise (2004)

IWIRAD 2005, Bucharest, 20-21 June, 2005IWIRAD 2005, Bucharest, 20-21 June, 2005 Dr. Em. Cincu, Ioana Manea,IFIN-HH, Romania Dr. Em. Cincu, Ioana Manea,IFIN-HH, Romania

Exercise 2 - Performance Test in elemental analysis of metallic alloy materials by the INAA nuclear analytical technique

Our Laboratory took part in the Proficiency Test (PT) exercise launched by the Swedish Institute for

Metals Researches {SIMR} in 2004, for establishing the elemental composition of a high alloy

Stainless Steel material {SS 1} they recently produced.

Among the initial 19 laboratories that registered for participation, only ‚ACTIVA-N’ Laboratory was

dealing with the nuclear INAA analytical technique; the other Labs. employed atomic spectrometry

techniques (XRF, OES, GDS).

Our results after the first and after the second evaluation, as established by the organizer experts

using statistical criteria are illustrated in the next slides. In the first our Report we presented 8 elements,

and in the second one the 9th element - Sb - was added.

One may notice that all our results are good, as they are within 1.5 value of the Standard deviation of

the mean value for each element.

A detailed discussion of the NAA performance, based on results of ours and of other 4 NAA Labs. from Romania, Belgium, Hungary and Poland (which later took part in a NAA network) is given in a special session dedicated to this subject scheduled on June 21.

…………………………………………………………………………………………………………………………….…………….……………….………………… IWIRAD 2005, Bucharest, 20-21 June, 2006 Dr. Em. Cincu, Ioana Manea, IFIN-H, Romania

IWIRAD 2005, Bucharest, 20-21 June, 2005 Dr. Em. IWIRAD 2005, Bucharest, 20-21 June, 2005 Dr. Em. Cincu, Ioana Manea, IFIN-HH, Romania Cincu, Ioana Manea, IFIN-HH, Romania

IWIRAD 2005, Bucharest, 20-21 June, 2005 Dr. Em. IWIRAD 2005, Bucharest, 20-21 June, 2005 Dr. Em. Cincu, Ioana Manea, IFIN-HH, Romania Cincu, Ioana Manea, IFIN-HH, Romania

ConclusionsConclusions

Our first conclusion is that the relative Standardization method employed, basedOur first conclusion is that the relative Standardization method employed, based on Certified Reference Materials (also a Stainless Steel material) and on a on Certified Reference Materials (also a Stainless Steel material) and on a certified radioactive Sources (for calibrating the certified radioactive Sources (for calibrating the -ray spectrometer), assures a-ray spectrometer), assures agood analytical performance in establishing the elemental composition of angood analytical performance in establishing the elemental composition of anunknown material. unknown material.

Limitations:Limitations: In our case, as the nuclear reactor TRIGA is located quite far fromIn our case, as the nuclear reactor TRIGA is located quite far from Bucharest, the performance of our Laboratory is limited to elements that generateBucharest, the performance of our Laboratory is limited to elements that generate

by neutron activation radionuclides emitting delayed gamma-rays (with Tby neutron activation radionuclides emitting delayed gamma-rays (with T½½ 2 h). 2 h).

One may also appreciate that implementation of the One may also appreciate that implementation of the Quality ManagementQuality Management System Systemaccording to the Standard ISO/IEC 17025:2000 is a very helpful tool in assuring according to the Standard ISO/IEC 17025:2000 is a very helpful tool in assuring valid results, but it must be valid results, but it must be often often demonstrated by participation in ILCdemonstrated by participation in ILC//PTPT exercises. exercises.

However, one has to be aware that participation in any ILC /PT exercises pretends time and money.However, one has to be aware that participation in any ILC /PT exercises pretends time and money.

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IWIRAD 2005, Bucharest, 20-21 June, 2005 Dr. Em. IWIRAD 2005, Bucharest, 20-21 June, 2005 Dr. Em. Cincu, Ioana Manea, IFIN-HH, RomaniaCincu, Ioana Manea, IFIN-HH, Romania

Acknowledgements:

Thank you for your attention !!!

We thank Eng. Marin Preda - Chief Manager of We thank Eng. Marin Preda - Chief Manager of

the   Reactor TRIGA for his help in performing irradiation, and the   Reactor TRIGA for his help in performing irradiation, and 

Drd. Dumitru Barbos for his skills in characterizing the Drd. Dumitru Barbos for his skills in characterizing the

neutron irradiation fieldneutron irradiation field..