Hundreds of radioactive sources are used in nuclear facilities to control and calibrate equipment. This brochure addresses 4 key application fields :
Hundreds of probes and detectors - generally Geiger Muller probes and scintillation detectors – are extensively used in Nuclear Facilities for contamination monitoring of hand-foot, whole body and tools, as well as radiologic surveys and workers' dose rate monitoring.
All these systems must be calibrated and periodically checked with adequate radioactive sources : wide sources for radiation monitors, capsules for dosimeters, linear sources for anthropomorphic phantoms.Typical sources provided for such equipment are :
α, β & γ emitters
239Pu, 241Am, 14C, 60Co, 137Cs, 90Sr
60Co, 133Ba, 137Cs
From 50 Bq to 10 kBq
From 10 to 500 MBq
From 100 Bq to 2 kBq
From 3 to 120 mm diameter or 100 x 100 mm and 100 x 150 mm
From 5 to 8 mm diameter and 5 to 15 height
5 mm diameter x 160 mm de height
Nuclear workers are often screened or scan themselves in several locations inside radiological controlled zones, to ensure that they have not been contaminated during operations.
Immediately nearby workplaces, portable polyradiameters are widely used to screen the most likely contamination locations (hands, feet, head, respiratory tract protection device, tools,…)
Here are the most adapted sources:
0.05 – 0.1 – 0.4 – 0.5 kBq
14C, 60Co, 137Cs, 90Sr
1 – 2 - 4 – 6 – 8 kBq
0.4 – 1kBq
60Co, 137Cs, 90Sr
Radiation Monitoring Systems are used in nuclear facilities to measure radioactivity of liquid or gaseous effluents, and airborne or area radioactivity.
Liquid and gaseous effluents are continuously generated by operating Nuclear Power Plants (for instance the radioactivity potentially released in the environment must be controlled and monitored).
Airborne and area radioactivity are continuously monitored inside radiological controlled zones with fixed systems, to ensure that workers are not exposed to internal contamination. In addition to this collective protection, mobile systems are deployed immediately nearby workplaces.
These systems are calibrated and periodically checked with appropriated radioactive sources : needles or filters for airborne monitors, capsules, charcoals or gas containers for effluents monitors.
60Co, 137Cs, 241Am
50 – 100 – 370 - 700 kBq
Monitoring any release of liquid or gaseous effluents is crucial to protect people and the environment around nuclear facilities. Most frequently measured radionuclides around NPPs are 3H, 14C and iodines.
These measurements are performed with in-line or off-line systems which are calibrated and periodically checked with appropriate standard, sealed (capsules, charcoals) or unsealed (gas) sources.
60Co, 137Cs, 241Am
50 – 100 – 370 - 700 kBq
240 kBq – 100 MBq
Mix of α, β, γ
51Cr, 54Mn, 57Co, 60Co,
65Zn, 85Sr, 88Y, 109Cd,
113Sn, 137Cs, 139Ce, 241Am
20 kBq total
A wide variety of radioactive sources is used in Radiochemistry and Environment laboratories in order to calibrate and check potential deviation of equipment, mainly on Alpha & Gamma counters and spectrometers, as well as Liquid scintillators:
Alpha counters used for identification and quantification of alpha emitters through gross count or spectrometry α measurements.
Liquid scintillation counters for quantification of pure beta emitters such as 3H, 14C, 90Sr in liquid samples.
Gamma ray detectors made with HPGe (High Purity Germanium) crystal for quantification of γ emitters ( 137mBa, 110mAg,…) or αγ emitters ( 239Pu, 241Am,…) or βγ emitters ( 137Cs, 60Co, 152Eu, 133Ba,…).
238Pu, 239Pu, 241Am, 244Cm
0.3 – 3 kBq
14C, 36Cl, 60Co, 137Cs, 147Pm, 90Sr
0.08 – 3 kBq
60Co, 133Ba, 137Cs, 152Eu
4 -40 – 80 – 400 – 3.500 kBq
60Co, 137Cs, 152Eu
5 – 37 – 100 – 420 kBq
241Am, 243Am, 244Cm
0.8 – 4 – 200 kBq
3H, 14C, 55Fe
200 – 400 – 4.000 kBq
60Co, 134Cs, 137Cs, 152Eu
20 – 200 – 4.000 kBq
Before leaving nuclear facilities for storage or disposal, nuclear wastes are characterized with several Non Destructive Assay (NDA) systems. One purpose of these NDA technics is to sort out waste according to AIEA thresholds : HLW (High Level Waste), ILW (Intermediate Level Waste), LLW ( Low Level Waste) and VLLW (Very Low Level Waste).
Most of the NDA systems are composed of gamma ray spectrometers and passive neutron systems. NDA systems are often linked to a modeling software to calculate the efficiency curve of the drum to be assayed but radioactive sources are still required for calibration and periodical checks of detectors’ efficiencies.
The most common radioactive sources (tens kBq to several MBq) are as follows:
60Co, 133Ba, 137Cs, 152Eu, 241Am
40 – 400 – 700 – 3.500 kBq
70 – 370 – 700 – 1.800 kBq