Radioactive sources for nuclear facilities

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Hundreds of radioactive sources are used in nuclear facilities to control and calibrate equipment. This brochure addresses 4 key application fields :

Health Physics: Detection of radioactive contamination and exposure of nuclear facilities’ workers
Radiation Monitoring Systems: Monitoring of radiation levels in ambient air and released effluents
Laboratories: Detection and characterization of radionuclides in process or environment samples
Waste characterization: radiological characterization of solid wastes for storage purpose

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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 :

	Radiation Moniors	Dosimeters	Anthropo-radiametry
Nuclides	α, β & γ emitters ²³⁹Pu, ²⁴¹Am, ¹⁴C, ⁶⁰Co, ¹³⁷Cs, ⁹⁰Sr	γ emitters ⁶⁰Co, ¹³⁷Cs	γ emitters ⁶⁰Co, ¹³³Ba, ¹³⁷Cs
Activities	From 50 Bq to 10 kBq	From 10 to 500 MBq	From 100 Bq to 2 kBq
Geometries	Wide sources From 3 to 120 mm diameter or 100 x 100 mm and 100 x 150 mm	Capsules From 5 to 8 mm diameter and 5 to 15 height	Linear sources 5 mm diameter x 160 mm de height

Radiation monitors

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.

Mobile systems

Immediately nearby workplaces, portable polyradiameters are widely used to screen the most likely contamination locations (hands, feet, head, respiratory tract protection device, tools,…)

Fixed systems

Between workplaces and radiological uncontrolled zones, several automatic measurement devices are used to detect contamination on objects, tools or workers.

Objects or tools monitor © MIRION TECHNOLOGIES

Hand-Foot Monitor © MIRION TECHNOLOGIES

Whole body monitors © MIRION TECHNOLOGIES

Here are the most adapted sources:

Types		Radionuclides	Activities
Disc	α	²³⁹Pu, ²⁴¹Am	0.05 – 0.1 – 0.4 – 0.5 kBq
Disc	β	¹⁴C, ⁶⁰Co, ¹³⁷Cs, ⁹⁰Sr	1 – 2 - 4 – 6 – 8 kBq
Square	α	²⁴¹Am	0.4 – 1kBq
Square	β	⁶⁰Co, ¹³⁷Cs, ⁹⁰Sr	4kBq

Wide Disc Source © LEA - Cyril Delestrade

Wide Square Source © LEA - Cyril Crespeau

Dosimeters

Like radiation protection devices for contamination monitoring, active gamma dosimeters need to be periodically checked.

These calibrations can be performed with small gamma and neutron irradiators, powered by a radioactive capsule (typically in the range of hundreds of MBq or GBq of ⁶⁰Co,¹³⁷Cs,²⁵²Cf, AmBe). Probes and radiameters or radiation beacons can also be checked with such a device.

Anthropo-radiametry

BOMAB – BOttle Mannikin ABsorber – and IGOR phantoms are used to calibrate whole body counting systems. These mannikins are filled with radioactive sources in order to simulate internal contaminations.

The BOMAB phantom is composed of 10 polyethylene cylindrical or elliptical bottles, filled with a radioactive liquid.

The IGOR phantom is composed of 70 right-angled polyethylene blocs, filled with linear sealed sources. For each IGOR, LEA produces hundreds of linear sources, composed of gamma emitters – ⁶⁰Co, ¹³³Ba, ¹³⁷Cs, ¹⁵²Eu – alone or mixed.

IGOR © RADEK 2et3

Linear sources © LEA - Cyril Crespeau

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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.

Equipments

Mobile airborne monitors © BERTIN ludlium

Fixed airborne monitors © LUDLUM

Mobile airborne monitors © MIRION TECHNOLOGIES Balise ICAM

Fixed airborne monitors © MIRION TECHNOLOGIES

Sources

Needle sources © LEA - Cyril Crespeau Carte

Card sources © LEA - Cyril Crespeau

Filter sources © LEA - Cyril Crespeau Source Tiroir

Drawer Sources © LEA - Cyril Crespeau

Types		Radionuclides	Activities
Filter	Mix of α, β, γ	⁵⁷Co, ⁶⁰Co, ⁶⁵Zn, ⁸⁵Sr, ⁸⁸Y, ¹⁰⁹Cd, ¹³⁷Cs, ¹³⁹Ce, ²⁴¹Am	10 – 20- 40 kBq
Needle	α	²³⁹Pu	2 kBq
Needle	βγ	¹³⁷Cs	2 kBq
Card	α	²⁴¹Am	0.3 – 0.6 kBq

Area monitors

équipement de mesure utilisant source capsule

Fixed area monitors © CEA GIM-203k

Fixed area monitors © MIRION TECHNOLOGIES

Capsule sources © LEA

Types	Radionuclides	Activities
Capsules γ	⁶⁰Co, ¹³⁷Cs, ²⁴¹Am	50 – 100 – 370 - 700 kBq

Liquid and gaseous effluents release monitoring

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.

Equipments

In-line liquid effluent monitors © MIRION TECHNOLOGIES

In-line gaseous effluent monitor © MIRION TECHNOLOGIES

In-line gaseous monitors © CAEN

Sources

Capsule sources © LEA

Charcoal sources © LEA - Cyril Crespeau

Gas bulb © LEA - Cyril Crespeau Conteneur-métallique-gaz (1)

Gas container (SG50 or SG3000) © LEA - Cyril Delestrade

Gas bottle (500 liters) © LEA - Cyril Crespeau

Types		Radionuclides	Activities
Capsules	γ	⁶⁰Co, ¹³⁷Cs, ²⁴¹Am	50 – 100 – 370 - 700 kBq
Gas	γ	⁸⁵Kr	240 kBq – 100 MBq
Charcoal	γ	²⁴¹Am	4 kBq
Charcoal	Mix of α, β, γ	⁵¹Cr, ⁵⁴Mn, ⁵⁷Co, ⁶⁰Co, ⁶⁵Zn, ⁸⁵Sr, ⁸⁸Y, ¹⁰⁹Cd, ¹¹³Sn, ¹³⁷Cs, ¹³⁹Ce, ²⁴¹Am	20 kBq total

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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:

Single or mixed α, β, γ emitters • Multiple geometries and matrices (solid, liquid, resin…)
Activities from 80 Bq to 1 GBq

Typical applications

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,…).

Alpha analyst © MIRION TECHNOLOGIES EASA (2)

Punctual α source © LEA - Cyril Crespeau

Liquid scintillation counters © PERKIN ELMER Pack Liquides (1)

β liquid source © LEA

Germanium © CANBERRA Pack Résine

γ or multi γ resin source © LEA

punctual α

punctual β

punctual γ

Liquids and Resins

Frequently purchased sources

Types		Radionuclides	Activities
Ponctual	α	²³⁸Pu, ²³⁹Pu, ²⁴¹Am, ²⁴⁴Cm	0.3 – 3 kBq
	β	¹⁴C, ³⁶Cl, ⁶⁰Co, ¹³⁷Cs, ¹⁴⁷Pm, ⁹⁰Sr	0.08 – 3 kBq
	γ	⁶⁰Co, ¹³³Ba, ¹³⁷Cs, ¹⁵²Eu	4 -40 – 80 – 400 – 3.500 kBq
Resin	γ	⁶⁰Co, ¹³⁷Cs, ¹⁵²Eu	5 – 37 – 100 – 420 kBq
Liquid	α	²⁴¹Am, ²⁴³Am, ²⁴⁴Cm	0.8 – 4 – 200 kBq
	β	³H, ¹⁴C, ⁵⁵Fe	200 – 400 – 4.000 kBq
	γ	⁶⁰Co, ¹³⁴Cs, ¹³⁷Cs, ¹⁵²Eu	20 – 200 – 4.000 kBq

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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: