Irish Sea seawater was sampled at the surface at location 54°23,579'N, 03°56,377'W on 12 December 2019 and acidified to pH 2. A total quantity of 4200 L of water was sampled in 7 containers of 600 L each. After receiving the samples in Monaco, the water was filtered using 1 micron filter cartridges and was spiked with defined activities of 3H, 90Sr and 137Cs. The water was mixed for 2x2 hours using an air pump. The water was transferred to polyethylene containers, sealed with a screw top and coded as IAEA-484.
- Reference date for all specified radionuclides: 01 January 2020.
Certified values for activity concentration
| Radionuclide | Certified value⁽ᵃ⁾ [Bq kg⁻¹] | Uncertainty⁽ᵇ⁾ [Bq kg⁻¹] | Half-life[¹] | Remark(c) |
3H | 42.36 | 3.56 | 12.312 (25) years | (N) |
90Sr | 0.549 | 0.038 | 28.80 (7) years | (N) |
137Cs | 1.081 | 0.032 | 30.018 (22) years | |
234U | 0.0428 | 0.0015 | 245.5 (6) 103 years | (N) |
235U | 0.00153 | 0.00021 | 704 (1) 106 years | (N) |
238U | 0.0374 | 0.0018 | 4.468 (5) 109 years | (N) |
239+240Pu | 0.00131 | 0.00007 | - | (N) |
241Am | 0.00132 | 0.00008 | 432.6 (6) years | (N) |
(a) Certified values are calculated from the accepted data sets, reported for each radionuclide by the laboratories participating in the characterization study, following ISO 33405 [2].
(b) The uncertainty is expressed as a combined standard uncertainty (coverage factor k = 1).
(c) The property values annotated (N) are not within the scope of accreditation.
References
[1] BNM – CEA/LABORATOIRE NATIONAL HENRI BECQUEREL, Table de Radionucleides, http://www.lnhb.fr/nuclear-data/nuclear-data-table/ (date accessed 2024-08-27).
[2] INTERNATIONAL ORGANIZATION FOR STANDARDIZATION, Reference materials — Guidance for characterization and assessment of homogeneity and stability, ISO 33405:2024, ISO, Geneva (2024).
[3] JOINT COMMITTEE FOR GUIDES IN METROLOGY (JCGM), Evaluation of Measurement data - Guide to the Expression of Uncertainty in Measurement, JCGM 100:2008 (GUM 1995 with minor corrections), (2008). http://www.bipm.org/utils/common/documents/jcgm/JCGM_100_2008_E.pdf (date accessed 2024-08-27).
[4] INTERNATIONAL ATOMIC ENERGY AGENCY, Certification of Massic Activities of Radionuclides in IAEA-484 Certified Reference Material (Irish Sea Seawater). IAEA Analytical Quality in Nuclear Applications Series No. xx (IAEA/AQ/xx), IAEA, Vienna (202x).
