N. Blanchin et al.: Radioprotection 2026, 61( 2), 171 – 177 173
Table 2. Control bioassay results of the involved worker.
URINES |
U 238( mBq) |
U 235( mBq) |
U 234( mBq) |
Total( mBq) |
Isotopic ratio U 234 / U 238 |
Urinary creatinine( g / L) |
20 / 04 / 2015 |
2 |
< 0.2 |
2.5 |
4.5 |
1.3 |
0.9 |
24 / 07 / 2015 |
< 0.6 |
< 0.1 |
< 0.6 |
< LOD |
– |
1.2 |
12 / 02 / 2016 |
2 |
< 0.4 |
3 |
5 |
1.5 |
1.13 |
11 / 04 / 2016 |
< 0.4 |
< 0.1 |
< 0.4 |
< LOD |
– |
0.86 |
26 / 07 / 2016 |
4.9 |
< 0.5 |
6.1 |
11 |
1.2 |
1 |
31 / 08 / 2016 |
3.7 |
< 0.4 |
7 |
10.7 |
1.9 |
1.02 |
31 / 01 / 2017 |
1.5 |
< 0.1 |
2.4 |
3.9 |
1.6 |
1.4 |
10 / 07 / 2017 |
3.5 |
0.3 |
4.4 |
7.9 |
1.3 |
1.6 |
12 / 09 / 2017 |
2.9 |
< 0.2 |
4.1 |
7 |
1.4 |
1.47 |
07 / 11 / 2017 |
3.1 |
0.2 |
4.1 |
7.2 |
1.3 |
1.07 |
11 / 12 / 2017 |
5.8 |
< 0.5 |
6.5 |
12.3 |
1.1 |
0.7 |
30 / 01 / 2018 |
2.6 |
< 0.2 |
3 |
5.6 |
1.2 |
1.83 |
24 / 03 / 2018 |
2 |
< LOD |
3.6 |
5.6 |
1.8 |
1.37 |
FECES |
U 238( mBq) |
U 235( mBq) |
U 234( mBq) |
Total( mBq) |
Isotopic ratio U 234 / U 238 |
Feces ash weight( g) |
11 / 02 / 2016 |
12.9 |
< 0.9 |
10.2 |
23.1 |
0.8 |
3.75 |
11 / 04 / 2016 |
9.5 |
0.9 |
9.9 |
20.3 |
1.0 |
1.9 |
31 / 08 / 2016 |
18.5 |
1 |
28.8 |
48.3 |
1.6 |
2.6 |
30 / 01 / 2017 |
19.5 |
0.9 |
18.6 |
39.0 |
1.0 |
2.7 |
07 / 07 / 2017 |
16.7 |
0.5 |
21 |
38.2 |
1.3 |
3.3 |
12 / 09 / 2017 |
11.1 |
< 0.6 |
13 |
24.1 |
1.2 |
2 |
07 / 11 / 2017 |
25.7 |
1.5 |
31.2 |
58.4 |
1.2 |
5.1 |
11 / 12 / 2017 |
13.7 |
0.9 |
17.6 |
32.2 |
1.3 |
3.7 |
30 / 01 / 2018 |
10 |
< 0.9 |
14.2 |
24.2 |
1.4 |
2 |
Fig. 1. Graphical representation of urinary measurements compared to predicted values with the ICRP 78 biokinetic model for inhalation( IMBA).
recommends using an SF value of 1.1 for 24-hour urine samples and 3 for 24-hour feces samples. The SF is represented by the uncertainty bars around the data points.
– The green curves correspond to the biokinetic model from ICRP Publication 78( ICRP, 1997) used as the hypothesis( acute inhalation).
In this first scenario, there is good correlation, confirmed by the chi-squared test, between the measurement results and the theoretical curves of the ICRP model used as the hypothesis( acute inhalation).
In this scenario, the intake is estimated at approximately 3000 Bq, corresponding to a committed effective dose of 18.5 mSv. It should be noted that this hypothesis � which assumes the potential incorporation date as the day after the previous urine analysis < LOD � represents a worst-case assumption. Additionally, the dietary background contribution was not subtracted from the feces results, as advised in Good Practice Recommendation 54( SFMT, 2011).
Nevertheless, this initial estimate provides an order of magnitude for the committed effective dose, which approaches the annual regulatory limit set in France( 20 mSv for category A employees) aligned with ICRP recommendations for radiation workers.
Consequently, meticulous investigations will be conducted by the radioprotection service to determine the possible origin of the contamination. Specifically, all of Mr CC’ s activities in radiological areas since 12 / 04 / 2016 have been tracked, along with any potential contamination incidents that occurred during this period. All nasal mucus samples, atmospheric contamination measurements, and surface contamination measurements during this timeframe returned " negative " results.
Finally, all facilities where Mr. CC worked had mixed radioactive spectra, primarily containing plutonium and americium, combined with uranium. Mr. CC never worked in facilities where the source term consisted exclusively of uranium. None of the radiotoxicological analyses performed detected the presence of transuranic elements.
Although the interpretation of results relative to the ICRP theoretical models( 8) supports an occupational inhalation