ABL and ABH samples

NPL Environmental Radioactivity Comparison Workshop

Arvic Harms

21 February 2006

Radionuclides in ABL and ABH

• 7 nuclides:

55Fe, 89Sr, 90Sr, 238U, 238Pu, 239Pu and 241Am

• Two concentration levels:

ABL 1 – 20 Bq kg-1

ABH 1 – 20 Bq g-1

ABL and ABH composition

ABL (Bq kg-1) ABH (Bq g-1)

55Fe 15.8(3) 6.89(12)89Sr 17.8(3) 12.83(20)90Sr 8.900(19) 10.189(16)238U 1.24(3) 1.059(24)238Pu 15.28(5) 2.607(9)239Pu 13.29(6) 6.06(3)241Am 11.99(4) 3.691(13)

Treatment of data

(i) Deviation D from NPL value (%)

(ii) u-test (P = 0.01) and relative uncertainty ratio RR

u < 2.58 ‘in agreement’

u < 2.58 but RR is an outlier ‘possibly in agreement’

u > 2.58 ‘discrepant’

−=

−= 1100100

N

L

N

NLD

N

L

R2

N

2

LuL

uNR

uu

NLu =

+

−

=

Uncertainty ratio outlier

Relative uncertainty ratio U-238 ABL

0

5

10

15

20

Lab

8 MS

Lab

35La

b 8 A

S

Lab

56La

b 47

MS

Lab

29

Lab

34

Lab

40

Lab

17

Lab

13

Lab

4

Lab

22La

b 47

AS

Lab

25

Lab

28R

el.

un

cert

ain

ty r

ati

o

Fe-55 results

ABL

4 results

75% of the results ‘in agreement’

Deviation mean: (10 ± 29) % Deviation median: 13%

ABH

7 results

100% of the results ‘in agreement’

Deviation mean: (-1 ± 20) % Deviation median: 2%

Fe-55 ABL

Deviation Fe-55 ABL

-50

0

50

Lab

34

Lab

7

Lab

21

Lab

28

Devia

tio

n (

%)

Fe-55 ABH

Deviation Fe-55 ABH

-50

0

50

Lab

7

Lab

38

Lab

60

Lab

55

Lab

59

Lab

32

Lab

21

Devia

tio

n (

%)

Sr-89 results

ABL

5 results

60% of the results ‘in agreement’

Deviation mean: (-27 ± 71) % Deviation median: -10%

ABH

6 results

50% of the results ‘in agreement’

Deviation mean: (-8 ± 27) % Deviation median: -6%

Sr-89 ABL

Deviation Sr-89 ABL

-50

0

50

Lab

56

Lab

35

Lab

22 3M

Lab

22 Eic

h

Lab

21

Devia

tio

n (

%)

Sr-89 ABH

Deviation Sr-89 ABH

-50

0

50

Lab

22 3M

Lab

55

Lab

38

Lab

22 Eic

h

Lab

60

Lab

32

Devia

tio

n (

%)

Sr-90 results

ABL

13 results

46% of the results ‘in agreement’

Deviation mean: (1 ± 39) % Deviation median: -5%

ABH

13 results

54% of the results ‘in agreement’

Deviation mean: (3 ± 11) % Deviation median: 0%

Sr-90 ABL

Deviation Sr-90 ABL

-50

0

50

Lab

56

Lab

35

Lab

62

Lab

25La

b 22

3MLa

b 22

Eich

Lab

8

Lab

28

Lab

29

Lab

21

Lab

40

Lab

13

Lab

7D

evia

tio

n (

%)

Sr-90 ABH

Deviation Sr-90 ABH

-50

0

50

Lab

49La

b 22

Eich

Lab

22 3M

Lab

38

Lab

55

Lab

32

Lab

60

Lab

28

Lab

36

Lab

14

Lab

8

Lab

59

Lab

7

Devia

tio

n (

%)

U-238 results

ABL

15 results

80% of the results ‘in agreement’

Deviation mean: (0 ± 7) % Deviation median: -3%

ABH

13 results

85% of the results ‘in agreement’

Deviation mean: (-2 ± 6) % Deviation median: -3%

U-238 ABL

Deviation U-238 ABL

-50

0

50

Lab

29

Lab

22

Lab

13La

b 47

MS

Lab

56La

b 47

AS

Lab

17

Lab

34La

b 8 A

S

Lab

4

Lab

40

Lab

35La

b 8 M

S

Lab

25

Lab

28D

evia

tio

n (

%)

U-238 ABH

Deviation U-238 ABH

-50

0

50

Lab

28

Lab

47

Lab

60

Lab

17

Lab

55

Lab

38

Lab

21

Lab

22

Lab

59

Lab

32La

b 8 A

S

Lab

4La

b 8 M

SD

evia

tio

n (

%)

Pu-238 results

ABL

16 results

88% of the results ‘in agreement’

Deviation mean: (-5 ± 7) % Deviation median: -3%

ABH

14 results

79% of the results ‘in agreement’

Deviation mean: (5 ± 10) % Deviation median: 3%

Pu-238 ABL

Deviation Pu-238 ABL

-50

0

50

Lab

62

Lab

19

Lab

28

Lab

29

Lab

25

Lab

56

Lab

41

Lab

35La

b 40

Lab

4

Lab

22

Lab

13

Lab

8

Lab

34

Lab

47

Lab

17D

evia

tio

n (

%)

Pu-238 ABH

Deviation Pu-238 ABH

-50

0

50

Lab

49

Lab

28

Lab

55

Lab

60

Lab

59

Lab

47

Lab

22

Lab

38

Lab

4

Lab

32

Lab

17

Lab

8

Lab

14

Lab

21D

evia

tio

n (

%)

Pu-239 results

ABL

17 results

82% of the results ‘in agreement’

Deviation mean: (-0.5 ± 2.8) % Deviation median: 0%

ABH

13 results

92% of the results ‘in agreement’

Deviation mean: (-2 ± 10) % Deviation median: -1%

Pu-239 ABL

Deviation Pu-239 ABL

-50

0

50

Lab

62La

b 19

Lab

25La

b 40

Lab

56La

b 22

Lab

29La

b 47

Lab

41

Lab

8

Lab

4La

b 13

Lab

34La

b 26

Lab

35La

b 17

Lab

28D

evia

tio

n (

%)

Pu-239 ABH

Deviation Pu-239 ABH

-50

0

50

Lab

49

Lab

28

Lab

22

Lab

14

Lab

60

Lab

59

Lab

55

Lab

47

Lab

4

Lab

38

Lab

32

Lab

17

Lab

8D

evia

tio

n (

%)

Am-241 results

ABL

14 results

86% of the results ‘in agreement’

Deviation mean: (3.5 ± 3.8) % Deviation median: 3%

ABH

16 results

88% of the results ‘in agreement’

Deviation mean: (2.3 ± 4.4) % Deviation median: 1%

Am-241 ABL

Deviation Am-241 ABL

-50

0

50

Lab

47

Lab

41

Lab

25

Lab

22

Lab

13

Lab

17

Lab

28

Lab

21

Lab

42

Lab

4

Lab

40

Lab

29

Lab

34

Lab

26D

evia

tio

n (

%)

Am-241 ABH

Deviation Am-241 ABH

-50

0

50

Lab

14

Lab

60

Lab

38La

b 8 X

R2

Lab

32

Lab

59

Lab

22La

b 8 L

EPLa

b 8 X

R1

Lab

28

Lab

17

Lab

21

Lab

55

Lab

47

Lab

4La

b 8 A

SD

evia

tio

n (

%)

ABL summary

Results

76% ‘in agreement’

4% ‘probably in agreement’

20% ‘discrepant’

Problematic nuclides: 89Sr and 90Sr

Less problematic: 55Fe, 238U, 238Pu, 239Pu and 241Am

ABH summary

Results

79% ‘in agreement’

1% ‘probably in agreement’

20% ‘discrepant’

Problematic nuclides: 89Sr and 90Sr

Less problematic: 55Fe, 238U, 238Pu, 239Pu and 241Am

Mean deviation ABL and ABH with 99% confidence limits

Mean deviation ABL and ABH with 99% confidence limits

-50

0

50

Sr-89

L

Sr-89

HPu-

238 L

U-2

38 H

Pu-23

9 H

Fe-55

H

U-2

38 L

Pu-23

9 L

Sr-90

LAm

-241

H

Sr-90

HAm

-241

LPu-

238 H

Fe-55

LD

evia

tio

n (

%)

Median deviation ABL and ABH

Median deviation ABL and ABH

-50

0

50

Sr-89

L

Sr-89

H

Sr-90

LPu-

238 L

U-2

38 H

U-2

38 L

Pu-23

9 HPu-

239 L

Sr-90

HAm

-241

H

Fe-55

HPu-

238 H

Am-2

41 L

Fe-55

LD

evia

tio

n (

%)

Naji plot

Square of the absolute uncertainty ratio versus the z-score

The parabolae represent u-test values of 1.64, 1.96 and 2.58, (P = 0.10, 0.05 and 0.01, respectively)

Data points outside the area bounded by the u = 2.58

parabola are discrepant

2

2

=

−=

N

L

Nu

uR

u

NLz

A

Naji plot ABL

ABL

0

500

1000

-100 -50 0 50 100

z test value

(Ra)2

Naji Plot ABH

ABH

0

500

1000

-100 -50 0 50 100

z test value

(Ra)2

Pu-238 / Pu-239 ratio ABL

Pu-238 / Pu-239 ratio ABL

0.80

0.90

1.00

1.10

1.20

1.30

1.40

Lab

28La

b 35

Lab

29La

b 41

Lab

56La

b 25

Lab

4La

b 40

NPL

Lab

34La

b 13

Lab

17

Lab

8La

b 22

Lab

47La

b 62

Lab

19R

ati

o

Pu-238 / Pu-239 ratio ABH

Pu-238 / Pu-239 ratio ABH

0.30

0.35

0.40

0.45

0.50

0.55

0.60

Lab

49

Lab

55

Lab

47

Lab

17

Lab

60

Lab

59

NPL

Lab

8

Lab

38

Lab

32

Lab

22

Lab

4

Lab

28

Lab

14R

ati

o

Sr-90 2000-2005

Sr-90 2000-2005

-50

0

50

Devia

tio

n (

%)

2000-2003

2005

Pu-238 2000-2005

Pu-238 2000-2005

-50

0

50

Devia

tio

n (

%)

2000-2003

2005

Pu-239 2000-2005

Pu-239 2000-2005

-50

0

50

Devia

tio

n (

%)

2000-2003

2005

Am-241 2000-2005

Am-241 2000-2005

-50

0

50

Devia

tio

n (

%)

2000-2003

2005

Thank you