Variance in Apparent Elemental Concentrations observed for Packard PPO 21-634 after Ion Exchange



Zelimir Djurcic1, Andreas Piepke1 and Bryan Tipton2
1University of Alabama
2California Institute of Technology
(Status 7/2/2001)
(Updated 7/27/2001)
(Updated 9/7/2001)


We describe here the variance of activities observed at UA in different activated Packard (all from batch 21-634) PPO samples. Such comparison tests the consistency and reproducibility of the entire analysis procedure, from sample preparation, post irradiation chemistry to counting. Data taken with four different samples activated on 3/22/2001 (UA22-24), 6/10/2001 (UA34 and UA36spiked), and 7/13/2001 (UA45) at MITR are presented. UA22-24 and UA45 were prepared at UA, while for UA34 and UA36 the pre-irradiation sample preparations were performed at CIT.
The following table lists apparent element concentrations derived from the measured activities, sample mass and neutron flux data, assuming 100% extraction efficiency (for Th/U too). The error listed are the quadratic sum of the statistical and a 10% systematic error.


Sanple Description

UA22-24: PPO mass: 3.4303 g,
irradiation time: 5 hours,
neutron flux: [5·1013 cm-2s-1]therm, [3.3·1012 cm-2s-1]epi,
activities reported for delay of: 49.8168 hours after end of irradiation.

UA34: PPO mass: 0.71 g,
irradiation time: 12.8 hours,
neutron flux: [4.7·1013 cm-2s-1]therm, [1.2·1012 cm-2s-1]epi,
activities reported for delay of: 84.0 hours after end of irradiation.

UA36spiked: PPO mass: 1.0332 g,
irradiation time: 12.8 hours,
neutron flux: [4.7·1013 cm-2s-1]therm, [1.2·1012 cm-2s-1]epi,
activities reported for delay of: 84.0 hours after end of irradiation.

UA45: PPO mass: 1.2638 g,
irradiation time: 1.0 hours,
neutron flux (not yet analyzed): [4.1·1013 cm-2s-1]therm, [9.5·1011 cm-2s-1]epi,
activities reported for delay of: 84.0 hours after end of irradiation.



Clean UA22-24 (Packard 21-634)
3/22/2001 		Clean UA34 (Packard 21-634)
6/10/2001 		Th/U spiked UA36 (Packard 21-634)
6/10/2001 		Clean UA45 (Packard 21-634)
7/13/2001
Activity [Bq] Conc. [g/g] Activity [Bq] Conc. [g/g] Activity [Bq] Conc. [g/g] Activity [Bq] Conc. [g/g]
Na 137±14 (3.3±0.3)·10-9 5.7±0.6 (1.6±0.16)·10-9 24±2.3 (4.7±0.5)·10-9 -3.1±0.37 (-5.6±0.67)·10-9
K 1.1±0.33 (3.9±1.2)·10-9 -10.6±4.1 (-324±125)·10-9
Sc 0.96±0.09 (9.9±1)·10-12 0.59±0.06 (12.7±1.3)·10-12 1.2±0.36 (17.7±5.3)·10-12 0.069±0.007 (12.2±1.3)·10-12
Cr 0.17±0.04 (29±3)·10-12 0.32±0.05 (118±19)·10-12 0.29±0.08 (73±20)·10-12 -0.039±0.045 (-118±136)·10-12
Fe 2.9±0.3 (159±16)·10-9 4.5±0.45 (539±54)·10-9 9.3±0.9 (766±77)·10-9 (0.28±0.028) (300±30)·10-9
Zn 0.036±0.004 (109±13)·10-12 0.09±0.014 (602±94)·10-12 0.11±0.016 (507±74)·10-12 (0.027±0.004) (1494±238)·10-12
Br 229±23 (1.8±0.2)·10-9 41±4 (2.2±0.22)·10-9 66±7 (2.5±0.25)·10-9 (6.4±0.65) (2.6±0.27)·10-9
Hf 0.061±0.010 0.26±0.03 0.38±0.04 (0.0029±0.0034)
Au 3.4±0.3 (1.1±0.1)·10-12 13±1.3 (20±2)·10-12 7.1±0.7 (7.6±0.7)·10-12 (0.23±0.04) (2.8±0.5)·10-12
Th 0.05±0.013 (1.9±0.49)·10-12 0.097±0.020 (10.9±2.2)·10-12 0.22±0.03 (17±2.3)·10-12 (0.017±0.009) (15.9±8.2)·10-12
U 0.032±0.20 (0.11±0.69)·10-12 1.8±0.23 (45±6)·10-12 4.6±0.48 (78.4±8.1)·10-12 (0.29±0.20) (58±40)·10-12


Comparison of UA and Caltech Results

In the next table we compare UA analysis results to those obtained at Caltech for Packard PPO batch 21-634. As in the table above apparent concentrations are given. Please note that the high level of observed U/Th in CIT22-24 was not confirmed by neither UA's data nor Caltech parallel analysis using TBP extraction. We therefore attributed it to a contamination introduced during the post-irradiation sample preparation on CIT's end. For completeness this result is listed too.


Clean PPO
3/22/2001 		Clean PPO
6/10/2001 		Th/U spiked PPO
6/10/2001 		Clean PPO
7/13/2001
UA22-24
Conc. [g/g] 		CIT22-24
Conc. [g/g] 		UA34
Conc. [g/g] 		UA36
Conc. [g/g] 		CIT36
Conc. [g/g] 		UA45
Conc. [g/g] 		CIT45
Conc. [g/g]
Na (3.3±0.3)·10-9 (1.22±0.1)·10-9 (1.6±0.16)·10-9 (4.7±0.5)·10-9 (63±6)·10-9 (-5.6±0.67)·10-9 <3.98·10-9
K (1.95±1.3)·10-9 (1.1±0.33)·10-9 (43±6)·10-9 (-324±125)·10-9 <2.02·10-6
Sc (9.9±1)·10-12 (11±1)·10-12 (12.7±1.3)·10-12 (17.7±5.3)·10-12 (12±1)·10-12 (12.2±1.3)·10-12 (22±1.7)·10-12
Cr (29±3)·10-12 (39±5)·10-12 (118±19)·10-12 (73±20)·10-12 (21±2)·10-12 (-118±136)·10-12 (22±14)·10-12
Fe (159±16)·10-9 (150±15)·10-9 (539±54)·10-9 (766±77)·10-9 (170±17)·10-9 (300±30)·10-9 (263±16)·10-9
Zn (109±13)·10-12 (110±38)·10-12 (602±94)·10-12 (507±74)·10-12 (2600±20)·10-12 (1494±238)·10-12 <700·10-12
Br (1.8±0.2)·10-9 (2.6±0.3)·10-9 (2.2±0.22)·10-9 (2.5±0.25)·10-9 (2.0±0.2)·10-9 (2.6±0.27)·10-9 (2.85±0.055)·10-9
Hf
Au (1.1±0.1)·10-12 (0.2±0.04)·10-12 (20±2)·10-12 (7.7±0.7)·10-12 (2.5±0.1)·10-12 (2.8±0.5)·10-12 <0.406·10-12
Th (1.9±0.49)·10-12 (38±5)·10-12(?) (11±2.2)·10-12 (17±2.3)·10-12 (0.7±0.2)·10-12 (15.9±8.2)·10-12 <15.7·10-12
U (0.11±0.69)·10-12 (72±10)·10-12(?) (45±6)·10-12 (78.4±8)·10-12 (20±2)·10-12 (58±40)·10-12 <24.9·10-12
This page is maintained by A. Piepke
Last update September 7, 2001