IEC 60532 Edition 3 0 2010 08 INTERNATIONAL STANDARD NORME INTERNATIONALE Radiation protection instrumentation – Installed dose rate meters, warning assemblies and monitors – X and gamma radiation of[.]
General characteristics
Overview
Equipment may be designed as a single assembly (monitoring assembly) with the detector assembly adjacent to or contained within the monitoring assembly or the detector remote from the remaining equipment
The detector assembly (detector and associated electronics) may be located remotely from any processing assembly (electronics) and the indication and alarm assembly
A unified equipment design is essential to offer all these options, enabling the use of various detector types while maintaining consistent indication and alarm systems.
Measurement range
The equipment must measure the dose rate from X or gamma rays within an energy range of at least 80 keV to 1.5 MeV, with potential specifications for effective response to energies as low as 50 keV and as high as 7 MeV Additionally, the equipment should cover a dose rate range of at least three orders of magnitude, with some applications requiring five or more orders of magnitude.
Safety classification
This standard addresses equipment designed for radiological protection, as outlined in section 5.3 of IEC 61226:2009 Such equipment is applicable in environments like nuclear power plants and nuclear fuel storage and processing facilities, contributing significantly to the safety and operational integrity of nuclear power plants.
Signals that trigger protective actions to reduce the impact of structural, system, or component malfunctions are classified as integral to safety-related or protection systems.
In this case, it shall meet the requirements of the respective system
When a safety classification is relevant, specific requirements must be established for the specification, design, manufacturing, installation, and operation of the equipment, focusing on the quality of both hardware and software These requirements should be mutually agreed upon by the manufacturer and the purchaser Notably, the purchaser is responsible for determining the applicable safety standard for the operational site, choosing between IEC 61513 or the IEC 61508 series.
Compliance with IEC 61513 is required for monitors used in nuclear power plants
The IEC 61508 safety standards, tailored for the nuclear industry, can be applied based on mutual agreement between manufacturers and purchasers When these standards are chosen, the relevant requirements must align with the specified safety integrity level (SIL) for the system.
In safety-related protection system applications, it is essential that equipment meets environmental qualification standards as outlined in IEC 60780 Furthermore, when relevant, equipment must also comply with seismic qualification requirements.
NOTE 1 It is anticipated that the SIL for equipment intended for the purpose of general area radiological protection will be SIL 1 In cases where the equipment is intended to act as an interlock in a safety related protection system(s), such as personnel access control systems which prevent human access to areas which can be subject to very high radiation fields, it is anticipated that the SIL for equipment will be SIL 2 or 3
NOTE 2 The final choice between IEC 61513 and the IEC 61508 series will be agreed between purchaser and manufacturer As an indication, the following correspondence is given:
Detailed characteristics
Equipment configuration
The type of equipment defined in this standard generally comprises up to four types of assemblies, which may be interconnected in a number of configurations
The equipment design must consider the practical application of assemblies, ensuring they can effectively measure radiation fields from multiple angles in relation to their position.
Where detector assemblies are to be used in high neutron radiation fields, the detector assembly should be constructed of materials which will minimize the effects of neutron activation
The detector assembly should be constructed from smooth, nonporous materials to reduce the possibility of contamination and designed to facilitate decontamination.
Equipment reliability
The reliability shall be managed either by IEC 61513 and associated series, or by IEC 61508 according to the required SIL
When intended being used in NPP/NF, the equipment shall comply with IEC 61513
The required reliability of the functions shall be specified either quantitatively (mean time between failures) or qualitatively (compliance with the single failure criterion)
For any part of the equipment (including sampling assembly if any), subject to appropriate planned maintenance, the following requirements shall be reached:
– MTBF (mean time between failure): > 20 000 h (with preventive maintenance)
A failure modes and effects analysis (FMEA) shall be performed in addition to the MTBF calculation in the case of equipment classified in accordance with IEC 61226
For particular designated safety applications, by agreement between the manufacturer and the purchaser, the equipment may be designed to meet the IEC 61508 series to the applicable
SIL (Safety Integrity Level) is crucial for safety applications, particularly when equipment incorporates safety functions through software (firmware), classifying it as a programmable electronic system (SMART) Compliance with standards such as IEC 61508 and IEC 60880 is essential for ensuring the reliability and safety of these systems.
IEC 62138, or evidence that the equipment meets the required SIL, shall be provided by the manufacturer
To ensure compliance with IEC 60987 or IEC 61508-2 standards, manufacturers must provide evidence through assessments like failure modes, effects, and diagnostic analysis (FMEDA), demonstrate the safe failure fraction (SFF), and conduct appropriate statistical testing.
This shall include evidence of how the manufacturer has met the lifecycle requirements of
IEC 61508-3 to meet the required SIL
The equipment shall be designed to be fail-safe and have a minimum safe failure fraction of
60 % for SIL 1 applications, 90 % for SIL 2, and 99 % for SIL 3
Diagnostic systems must be implemented to identify component and software failures that could compromise the safety functions of the equipment These systems should ensure the activation of all necessary trip, interlock, and alarm functions.
Equipment indication
The processing unit must provide local indications along with audible and visual alarms, as specified by the agreement between the manufacturer and purchaser Additionally, it should be equipped to transmit these indications and alarms to remote locations Importantly, the equipment's performance should remain consistent across all operational modes and should not be impacted by any failures in the remote location's equipment.
Additionally, a facility to allow the connection of a local chart recorder may be provided
In multi-monitor setups, the remote location may serve as a centralizer, and it is essential that the facility meets the IEC 61559 series standards The ideal processing unit display should feature an analog logarithmic scale meter with a minimum scale length of 20 mm per decade, complete with clear divisional marks Alternatively, a digital display is acceptable if it clearly indicates the scales For processing units with linear scales, the indication ratio between adjacent scales must not exceed a factor of 10.
The effective range of measurement of the equipment shall be as follows:
– For processing units with linear scales, the effective range shall be between 10 % and
– For processing units with logarithmic scale, the effective range shall be between 1,5 times the lowest significant dose rate marked and full scale
For digital indication processing units, the effective range extends from the beginning of the second least significant order of magnitude scale, which corresponds to two indicated digits, up to the complete range of available indications.
Alarm/trip/interlock facilities
Processing units responsible for trip and interlock safety functions must be designed to ensure fail-safe operation in the event of power supply interruption or failure These units should activate all selected alarm, trip, and interlock functions to maintain safety.
The outputs for genuine alarms, instrument faults, or power failures will remain in an activated state until the unsafe condition is resolved and a reset control function is specifically initiated.
The alarm unit (AU) for equipment configured to provide area radiological protection shall produce both audible and visual alarms on interruption or failure of the power supply
Alarm circuits must remain functional to maintain alarm conditions until they are manually reset, regardless of whether the activation is due to a genuine alarm, instrument failure, or power failure The audible alarm can be silenced using a push button on the unit, while the visual alarm will persist until a reset is performed.
In all cases, an indication of power supply failure shall be provided on the processing unit
NOTE The suggested alarm hierarchy is as follows: high alarm (4.2.4.2), low alarm (warning level) (4.2.4.3, instrument fault alarm (4.2.4.4)
A minimum of one high-level alarm must be implemented, with the option for fixed or adjustable set points Each alarm is required to activate within one second of the displayed value reaching the designated set point.
Other (alert level) alarms may be provided to operate on increasing dose rates but at a level below the alarm level
Adjustable alarms should cover at least 10 % to 100 % of scale reading (linear scales), from
50 % of the lowest order of magnitude scale to 100 % highest order of magnitude scale
(logarithmic scales) and over all but the least significant decade for digital displays
A low level alarm facility should be provided These shall be adjustable as defined in 4.2.4.2
These are to operate on decreasing dose rate and generally act as an additional fault alarm but could be used for process control
Diagnostic facilities must be implemented to effectively identify failures in electronic components, inter-unit communication, and processing firmware that could compromise equipment safety functions These facilities should provide fault indications or alarms, with a preference for separate identification of the fault source.
The fault alarm should be configured to trigger at a level below the minimum effective measurement range, ensuring that it activates in the event of a detector assembly failure.
There will generally be an interrelationship between the time for the alarm to operate, the frequency of false alarms and the margin between background level and alarm level
The low-level alarm can be configured to function above an enhanced background, utilizing a priming source to elevate the existing background for improved detection capabilities This setup is designed to optimize measurement statistics, effectively reducing the likelihood of false alarms.
Radioactive sources used in detector assemblies must comply with relevant international and national regulations concerning radioactive materials, although their activity typically falls below regulatory concern Manufacturers should specify that these sources remain effective for at least five years, and adjustments to the source's position or equivalent changes in the operating firmware should not be necessary more than once a year.
The displayed information must consider all priming sources to ensure accurate readings for all dose rates throughout the source's specified lifespan, while also accounting for permissible inaccuracies.
4.2.4.6 Interrelationship between response time and statistical fluctuations
The response time and the coefficient of variation of the statistical fluctuations are interdependent characteristics for which acceptable limits are given in 6.9 and 6.10
For high dose rates, it is advisable to minimize response times whenever feasible, adhering to the limits set by this standard Response times shorter than 1 second provide minimal benefits, making it more effective to focus on reducing statistical fluctuations.
For low dose rates, the manufacturer must specify the suitable values for the coefficient of variation and response time, which may exceed the limits outlined in sections 6.9 and 6.10, subject to the purchaser's agreement.
Nature of tests
All tests listed in this standard are classified as "type tests" unless stated otherwise in specific clauses However, with mutual agreement between the manufacturer and the purchaser, certain tests may be designated as acceptance tests.
Tests performed under standard test conditions
Table 4 presents the tests conducted under standard conditions, detailing the requirements for each characteristic tested as specified in the relevant clauses of the corresponding test methods.
Tests performed with variation of influence quantities
To assess the effects of the variations in the influence quantities listed in Tables 5 and 6, all other influence quantities must remain within the standard test conditions specified in Table 3, unless the test procedure indicates otherwise.
Statistical fluctuations
In tests involving radiation, if the statistical fluctuations from radiation are a significant portion of the allowed variation, it is essential to take enough readings This ensures that the mean value of these readings can be accurately estimated to confirm compliance with the test requirements.
The interval between such readings shall be sufficient to ensure that the readings are statistically independent.
Consideration of natural background radiation
To accurately measure low dose equivalent rates, it is essential to consider the contribution of natural background radiation This involves taking multiple readings of background radiation and calculating their mean value This average must then be subtracted from the dose rate indicated by the detector assembly being tested Additionally, if the detector assembly includes a priming source, its effect must also be factored into the measurements.
False alarm test
Requirements
No unexplained alarms shall occur over a period of 100 h with the monitor operating in a stable background Repeat if explained alarms occur.
Method of test
With the monitor operating normally in a stable background, observe the monitor to verify that no alarms occur for a period of 100 h.
Point of test
The test point for determining the gamma dose rate must be selected to ensure that the distance between the radiation source and the detection assembly is sufficiently large, minimizing any potential error from detector irradiation non-uniformity to within ±5%.
Linearity
Requirements
The linearity of an instrument's measurement range is crucial, as it defines the relationship between the measured values and the actual radiation quantity the equipment is intended to assess Establishing the instrument's error is essential for accurate measurements.
Under standard test conditions, the response linearity of the detector assembly, when exposed to either of the reference radiations shall not exceed ±30 %, over the effective measurement range
NOTE This uncertainty is additional to the uncertainty in the value of the conventional true dose rate.
Test source of gamma radiation
The test shall be performed with a source of 137 Cs or 60 Co.The use of 60 Co is subject to the requirements of 5.6
The conventional true dose rate shall be known and the uncertainty stated (see NOTE in
A type test shall be performed on monitoring units comprised of at least one of each type of processing, alarm, and detector assemblies
Routine tests shall be carried out on each combination of processing units, alarm units and detector assemblies
All tests shall be carried out using a radiation field unless otherwise agreed between manufacturer and purchaser
Type testing for assemblies equipped with linear scales must be conducted across all ranges, with evaluations performed at a minimum of three points on each range, specifically at approximately 25%, 50%, and 75% of the scale range.
For assemblies featuring a single range and logarithmic graduation, or digital displays, type testing must be conducted across all order of magnitude scales of dose rate and on a minimum of
Each order of magnitude scale consists of two key points, where the higher value must be at least three times greater than the lower value and at least 70% of the maximum for that scale Additionally, if a detector includes a priming source, this factor must be considered in the evaluation.
For assemblies equipped with a linear scale, routine testing must be conducted at a single point within the range where the highest alarm is set, specifically at a value between 50% and 75%.
For assemblies featuring a single range and logarithmic graduation, or digital displays, testing must be conducted at a value between 10% and 90% of the range where the highest alarm is configured Additionally, if a detector includes a priming source, this factor must be considered during the test.
For routine testing, it is permissible to use current or pulse injection in the processing assembly, provided that this method is aligned with the results of radiation type tests.
Variation of response with photon radiation energy
Requirements
The response in reference direction to photon energy between 80 keV and 1,5 MeV shall be within –25 % to +40 %
For assemblies intended for use in energies between 50 keV and 80 keV and/or higher than
1,5 MeV, the variation shall be subject to agreement between the purchaser and manufacturer
When utilizing an ambient dosemeter near nuclear power facilities, it is essential that its response up to 7 MeV meets the specified requirements, as determined by mutual agreement between the purchaser and the manufacturer.
This test ideally requires a consistent dose rate for each radiation energy However, if this is not feasible in practice, adjustments must be made to the indicated dose rate for each radiation energy These adjustments should account for non-linearity and may require interpolation, ensuring alignment with the reference gamma radiation.
In the case of multiple detectors covering different dose rate ranges, the test should be performed for each detector at the appropriate dose rate and energy.
Method of test
The following energies should be used for low air kerma rates (taken from the ISO 4037 series):
– mean energy (keV): quality (tube voltage, kV);
When the instrument is intended for use in other energies:
– 65 keV(N-80) or 60 keV(L-70) or 59,5 keV(Am-241)
For 6,61 MeV the following alternatives may be used:
– verification by Monte Carlo simulation especially for this energy
The test for this energy shall be agreed between the purchaser and manufacturer
The results will be presented as a ratio comparing the indication per unit dose rate of each radiation source used to the response per unit dose rate of the reference gamma radiation, specifically \(^{137}\text{Cs}\).
Variation of response with angle of incidence
Requirements
The response with angle of incidence against the direction of calibration for more than one plane of response shall be within following variation (see Figure 1):
For the range 80 keV to 1,5 MeV:
– for 83 keV 0°, ±15°, ±30°, ±45°, ±60° to be defined by the manufacturer;
The manufacturer shall state the relative variation of the response for ±90°
The results should be presented as a ratio comparing the response per unit dose rate for each radiation source to the response per unit dose rate at a zero-degree angle of incidence.
In general, detector assemblies are designed to be installed on a flat surface such as a wall
The angles to be tested are restricted to ±60° from the normal to the mounting surface, as specified in section 6.5.2 If a different angle range is necessary, it must be determined through mutual agreement between the manufacturer and the purchaser.
The need for additional angles in testing X-ray or gamma ray exposures will be established based on the agreement between the manufacturer and the purchaser Radiation direction should be adjusted in 15° increments within a plane that includes the manufacturer's specified calibration direction, with response measurements taken across the angles outlined in section 6.5.1 This procedure must then be repeated in a plane that is perpendicular to the first, while still incorporating the calibration direction.
Method of test
The assembly shall be mounted so as to most conveniently enable measurements to be made at the required angle
For this test, the detector assembly's reference point must be positioned at a location where the dose rate is established It is recommended to utilize the photon radiation qualities from the narrow spectrum series, along with gamma sources 137 Cs and 241 Am, as outlined in the ISO 4037 series, whenever feasible.
Calibration direction and direction of radiation
2) Plane perpendicular to 1) and including calibration direction Calibration marking
Figure 1 – Example of the rotation of the detection assembly
Response to beta radiation
Requirements
When measuring gamma radiation doses in the presence of beta radiation, the detector assembly may be affected by more energetic particles that penetrate its sensitive volume This results in a response from the detector assembly to beta radiation emitted from strontium-90 (Sr-90).
90/Y-90 source shall be stated by the manufacturer, if the detector assembly is intended to be used in the present of beta radiation.
Method of test
Expose the detector assembly at 0° angle of radiation incidence to beta reference radiation specified in ISO 6980: Parts 1 to 3 of the following quality:
The indicated dose rate value shall be less than 10 % of the exposed dose rate value.
Response to neutron radiation
Requirements
Manufacturers must specify the detector assembly's response to neutron radiation if it is designed for use in environments with neutron radiation.
By agreement between the purchaser and the manufacturer, tests can be omitted if documented analysis demonstrates that the instrument is not sensitive to neutron radiation.
Method of test
When a test is required the following procedure is recommended
The detector assembly must be oriented in the reference calibration direction and exposed to radiation from a 252 Cf or 241 Am/Be source, ensuring that the reading reaches 70% of the maximum value.
IEC 2041/10 second most sensitive order of magnitude scale If this is not practically achievable, a limit of
The indication (n+ γ ) from the neutron source shall be noted
The photon dose rate H&*(10)γ at the detector assembly must be calculated or measured using a reference instrument The indication I(γ) is derived from the equation I(γ) = Rγ × H&*(10)γ, considering the photon response to radiation from 60 Co For 252 Cf, the ratio of photon to neutron dose rate is typically around 0.04.
NOTE 1 The energy of photons emitted from a 252 Cf source is similar to the energy emitted from a 60 Co source
Similarly the neutron dose rate, H&*(10)n shall be determined
The neutron response shall be expressed as: n
Neutron radiation qualities are specified in the ISO 8529 series: Parts 1 to 3
NOTE 2 Encasing the 252 Cf source in 1 mm of lead would reduce the gamma (photon) emissions
NOTE 3 The dose rate quantity is chosen to H&*(10) as this quantity is equivalently defined for neutron and photon radiation.
Overload characteristics
Requirements
For dose rates exceeding the maximum limit of a scale, the detector assembly or monitoring unit will indicate an off-scale reading at the upper end and will consistently remain in that state This requirement is applicable to every switchable scale range.
Method of test
Prior to the overload test, reference readings shall be established The readings shall be obtained from the each scale
The detector assembly will be subjected to a 5-minute exposure at a dose rate that is 10 times the maximum scale During this time, the indication will consistently remain off scale at the upper limit.
The monitor must return to normal within 10 minutes after the dose rate is reverted to the pre-exposure level, and the post-test reading should fall within ±10% of the pre-test or reference readings.
Statistical fluctuations
Requirements
The coefficient of variation of the dose rate due to random fluctuations shall be less than
20 % for the most sensitive scale and 10 % for all other scales.
Method of test
The detector assembly must be subjected to a radiation source that produces a dose rate indicating between one-third and one-half of the maximum scale on the most sensitive range (linear) or decade (logarithmic scale), or the second least significant decade in digital indication.
Sufficient readings shall be taken to ensure that the mean value of such readings and coefficient of variation can be determined.
Response time
Requirements
The response time shall be such that, if there is a sudden increase or decrease in the dose rate, the indication will reach the following value:
I i + 0,9 (I f – I i ) where I i is the initial indication and I f is the final indication
The response time shall be less than:
– for a dose rate lower than 60 μGy/h (μSv/h): 60 s;
– for a dose rate between 60 μGy/h (μSv/h) and 1 000 μGy/h (μSv/h) s μSv/h) 50
(or μGy/h 940 μSv/h) (or μGy/h – 60
– for a dose rate higher than 1 000 μGy/h (μSv/h): 10 s
The number of tests to be performed shall be agreed between the purchaser and the manufacturer
The response time shall be stated by the manufacturer.
Method of test
The test will be conducted using an appropriate radiation source or by injecting a suitable electrical signal into the input of the dose rate meter assembly.
The initial and final dose rates must vary by a factor of 10 or greater, with measurements taken for both increases and decreases in the dose rate by this factor.
Measurements must be conducted across all orders of magnitude for dose rate indications on dose rate meter detector assemblies with digital or logarithmic displays, as well as on each scale range for those equipped with linear displays.
Linear scale dose rate meters define the lower dose rate as either zero or background, while the upper dose rate should correspond to at least 80% of the maximum scale across all ranges.
For dose rate meters with switchable ranges, the response time shall be tested on each scale range
If the electrical method of test is employed, this shall be stated in the accompanying documents The injected signals shall correspond to the above requirements
In the increasing dose equivalent rate test, the dose rate meter detector assembly is first exposed to a higher dose rate, and the indication \( I_f \) is recorded Next, the assembly is subjected to a lower dose equivalent rate for a sufficient duration until the indication \( I_i \) stabilizes, at which point this value is noted The dose rate is then rapidly adjusted to match the indication \( I_f \), and the time taken to reach the specified value, as outlined in formula 6.10.1, is measured.
The decreasing dose equivalent rate test is performed to the same way.
Zero drift
Requirements
For linear scaled detector assemblies, the zero point of the meter indication must remain stable within ±2% of the scale maximum after 30 minutes of operation under standard test conditions, and this stability should be maintained for the next 24 hours of continuous use In contrast, for logarithmic scales and digital displays, the acceptable drift is less than 5% after 8 hours, 25% after 24 hours, and 50% after 20 days for the most sensitive order of magnitude scale or the second least significant order of magnitude scale.
Method of test
To begin, activate the detector assembly and, if applicable, adjust the zero set control to achieve a zero indication after 30 minutes For detector assemblies featuring a non-linear scale, this control is utilized to set the indication to a specific reference value instead of zero In such instances, adjust the indication to the reference value, switch to the appropriate reading range, wait for 30 minutes, and then reset to zero.
Leave the detector assembly switched to a reading range Note the indication hourly for the first 8 h, then again after 24 h
Unless otherwise agreed between the manufacturer and the purchaser, the test shall continue for a total of 20 days with indications noted every four days.
Alarm requirements
Requirements
The range of settings shall conform to the requirements of 4.2.4.2 and 4.2.4.3.
Method of test
The test will be conducted on the detector assembly and processing unit, excluding the detector itself Appropriate signal injection equipment will simulate the detector output range Alarms will be calibrated to within 10% of their lowest setting, and the input signal will be increased until the alarms activate, with the equipment's indications recorded The alarm settings will then be adjusted to their maximum levels, and the procedure will be repeated.
For alarms intended to operate on decreasing signals, operate as above, but slowly decrease the level of the input signal.
Equipment fault alarms
The instrument fault alarm shall normally be tested in accordance with 4.2.4.4
Tests of failure alarms against appropriate equipment malfunctions shall be carried out.
Alarm response time and stability
Requirements
Radiation alarm thresholds (low or high level) shall not deviate by more than ±10 % from the selected alarm set point and shall conform to the requirements of 4.2.4.2 and 4.2.4.3.
Method of test
The low level alarm threshold should be set to an appropriate dose rate to allow the test to continue Ensure that the detection assembly is exposed to a dose rate that is 90% of the low threshold.
The alarm shall not activate for the duration of the exposure (1 min) Increase the dose rate level to twice the low threshold The alarm shall activate immediately
Perform the same test for the high level alarm
To verify stability, repeat the low and high level alarm test after a period of 24 h of continuous use.
Warm-up
Requirements
The manufacturer shall state the warm up time The warm up time used to reach standard test conditions is indicated in Table 3.
Method of test
To test the detector assembly, first ensure it is turned off and then expose it to a suitable radiation source that indicates at least half of the maximum scale After switching on the assembly, record the readings every 30 seconds until the specified warm-up time is reached.
After allowing the device to warm up for thirty minutes, take a minimum of ten readings and calculate the mean value to determine the “final value” of the indication Plot these readings on a graph with indication as a function of time, and draw a smooth curve that best fits the data The warm-up time is defined as the duration required to reach 90% of this final value.
7 Electrical, mechanical and environmental characteristics
Mains operation
Requirements
Assemblies should be designed to operate from single-phase a.c supply voltage in one of the following categories in accordance with IEC 60038:
– series III: 120 V and/or 240 V AC
Nominal single-phase power in the United States of America and Canada is 117 V and/or
234 V, 60 Hz Nominal single-phase power of 110 V, 50 Hz is also used in the United
Nevertheless, the assemblies may be designed to operate from 24 V d.c (series IV) Line operated assemblies should be designed to operate from single-phase AC supply voltage of
100 V to 240 V and from 47 Hz to 63 Hz The equipment shall operate with a variation in supply of ±10 %.
Method of test
Place a 137 Cs source as defined in 5.6 adjacent to the detection assembly With the supply voltage at its nominal value, determine and record the mean reading from each detector
To ensure accurate measurements, conduct sufficient readings with the supply voltage set 10% above and 10% below the nominal value The average results obtained should not deviate by more than 10% from those measured at the nominal supply voltage.
The tests will be conducted again, this time varying the frequency instead of the voltage For a 60 Hz supply voltage, the frequency will be adjusted from 54 Hz to 66 Hz, while for a 50 Hz supply voltage, it will change from 45 Hz to 55 Hz.
Electromagnetic compatibility (EMC)
General
Special precautions shall be taken in the design of the monitoring units to ensure proper operation in the presence of electromagnetic disturbances, particularly radio-frequency fields
According to IEC 61000-4-3, electromagnetic disturbances can lead to fluctuations in radiation readings and may trigger functional changes in monitoring systems, such as alarm activations For the EMC tests outlined in sections 7.2.3 to 7.2.10, the detector assembly must be configured to its most sensitive range and exposed to radiation at five times the lower limit of its measuring range.
Emission of electromagnetic radiation
The emission limits, when measured at 30 m, shall be less than what is shown below:
To ensure accurate testing, position the monitoring assembly in a radio frequency shielded room Conduct the test according to IEC 61000-6-4 standards First, with the assemblies powered off, gather a background spectrum using a scanning bandwidth of 50 kHz Then, power on the assemblies and carry out an RF scan to measure the field strength.
Electrostatic discharge
The monitoring assembly must remain unaffected by electrostatic discharges as specified in Table 6, ensuring that readings stay within ±15% of those taken without exposure to such discharges Additionally, no alarms should be triggered, and no functional changes should occur solely due to the discharges.
Place a 137 Cs source as defined in 5.6 adjacent to the detection assembly Determine and record the mean reading
To ensure compliance with performance requirements, it is essential to observe and record the display indications and data output terminals while using a suitable test generator as outlined in IEC 61000-4-2 This should be conducted at least five times on various external parts of the equipment that operators may touch during normal measurements The dose equivalent (rate) detector assembly and processing unit must be powered on and, if applicable, set to its most sensitive range.
Electrostatic discharge testing must adhere to IEC 61000-4-2 standards, utilizing a voltage of 4 kV For dose equivalent (rate) meter detector assemblies featuring insulated surfaces, the air discharge method at a voltage of 8 kV, corresponding to severity level 3, is required for testing.
General radiated electromagnetic fields
The monitoring assembly shall not be affected by exposure to radio frequency fields from
The RF field intensity ranges from 80 MHz to 1,000 MHz and 1.4 GHz to 2.5 GHz at 10 V/m It is essential that the readings stay within ± 15% of those recorded without RF field exposure, ensuring that no alarms are triggered and no functional changes occur solely due to the RF field.
Place a 137 Cs source as defined in 5.6 adjacent to the detection assembly Determine and record the mean reading
To ensure compliance with performance requirements, it is essential to monitor and document the readings from the display and data output terminals of the processing assembly, utilizing the dose equivalent (rate) detection assembly in its most sensitive range.
The electromagnetic field strength shall be 10 V/m in the frequency range of 80 MHz to
1 000 MHz and 1,4 GHz to 2,5 GHz in steps of 1 % (see IEC 61000-4-3)
To minimize the number of measurements required for compliance, testing can be conducted at a field strength of 20 V/m in a single orientation If any signs of susceptibility are detected, further tests must be performed within a ± 5% frequency range at a field strength of 10 V/m, utilizing the dose equivalent (rate) meter detection assembly in all three orientations as specified in IEC 61000-4-3.
Conducted disturbances induced by fast transients or bursts
The monitoring assembly must remain unaffected by conducted disturbances caused by fast transients or bursts, as specified in Table 6 It is essential that the readings stay within ±15% of the values recorded without disturbances, ensuring that no alarms are triggered and no functional changes occur solely due to these disturbances.
Place a 137 Cs source as defined in 5.6 adjacent to the detection assembly Determine and record the mean reading
Fast transients or bursts must be introduced to the mains supply terminals through a coupling/decoupling network or similar equipment, with a maximum repetition rate of once per minute To ensure compliance with this requirement, it is essential to monitor and document the display indications and data output from the processing assembly, using the dose equivalent (rate) detection assembly set to its most sensitive range.
The tests shall be performed as described in IEC 61000-4-4 with a peak voltage of ±2 kV
The severity of the test shall be as follows:
• for equipment installed in protected room: level 2;
Conducted disturbances induced by surges
The monitoring assembly must remain unaffected by conducted disturbances caused by surges, as specified in Table 6 It is essential that the readings stay within ± 15% of the baseline values obtained without disturbances, ensuring that no alarms are triggered and no functional changes occur solely due to these disturbances.
Place a 137 Cs source as defined in 5.6 adjacent to the detection assembly Determine and record the mean reading
Pulses must be applied to the mains supply terminals through a coupling/decoupling network or similar equipment, with a maximum repetition rate of once per minute To ensure compliance with this requirement, the display and data output terminals of the processing assembly should be monitored and recorded while the dose equivalent (rate) detection assembly is set to its most sensitive range Testing should follow the guidelines outlined in IEC 61000-4-5, utilizing a voltage of ±2 kV or ±1 kV as specified in Table 4.
Conducted disturbances induced by radio-frequencies
The monitoring assembly must remain unaffected by radio-frequency disturbances listed in Table 6, ensuring that readings stay within ±15% of those obtained without exposure to these disturbances Consequently, no alarms will be triggered, and no functional changes will occur solely due to the disturbances.
Place a 137 Cs source as defined in 5.6 adjacent to the detection assembly Determine and record the mean reading
To ensure compliance with performance requirements, the display indications of the processing unit will be monitored and recorded using the dosemeter detector assembly set to its most sensitive range.
The voltage shall be equivalent to 10 V in the frequency range of 150 kHz to 80 MHz in steps of 1 % according to IEC 61000-4-6.
Ring wave immunity
The monitoring assembly shall not be affected by oscillatory waves injected shown in Table 6
The readings must stay within ±15% of those recorded without disturbances, ensuring that no alarms are triggered and no functional changes occur solely due to the oscillatory waves.
The test procedures are defined in IEC 61000-4-12, with the following details concerning the dampened oscillatory wave:
• mains supply frequency between 50 Hz and 400 Hz and non-synchronized on the network frequency
Place a 137 Cs source as defined in 5.6 adjacent to the detection assembly Determine and record the mean reading
Injection occurs in common mode through the coupling/uncoupling network If the manufacturer's guidelines indicate that an earth connection is necessary for a circuit conductor, the testing of this circuit must be conducted in differential mode while applying the specified common mode severities.
The severity of the test shall be as follows:
• circuits connecting the protected room: level 1;
• circuits exiting other place: level 3
On completion of this test, the performances of the system shall comply with the performances stipulated by the manufacturer
The monitoring assembly is designed to remain unaffected by 50 Hz or 60 Hz magnetic fields, ensuring that readings stay within ±15% of those taken without magnetic exposure Consequently, no alarms will be triggered, and no functional changes will occur solely due to the presence of the magnetic field.
Compliance is verified by monitoring the display and data output of the processing unit during measurements in the most sensitive range The dose equivalent rate meter detector assembly must be subjected to continuous fields of 30 A/m at either 50 Hz or 60 Hz Additionally, the detector assembly should be tested in at least two orientations, specifically at 0° and 90° relative to the field lines.
Voltage dips and short interruptions
The monitoring assembly must remain unaffected by voltage dips and short interruptions, ensuring that readings stay within ±15% of those recorded under stable voltage conditions During such events, no alarms should be triggered, and no functional changes should occur solely due to the voltage fluctuations.
To ensure compliance for mains-operated dose equivalent (rate) detector assemblies, it is essential to observe and record the display indications and data output from the processing unit during measurements on the most sensitive range Testing must follow the guidelines outlined in IEC 61000-4-11, incorporating the specified voltage reductions.
Mechanical characteristics
Areas of application
Indoor equipment generally avoids mechanical stresses like shock and vibration, except during shipping However, monitoring units intended for installation on devices like cranes or vehicles may experience slight shock and vibration during operation.
Detection assemblies mounted on cranes may have additional requirements that are not addressed by this standard.
Microphonics/impact
The monitoring assembly must remain unaffected by microphonic conditions, such as low-intensity impacts with hard surfaces It should maintain readings within ±15% of those obtained in stable conditions, ensuring that no alarms are triggered and no functional changes occur due to these microphonic influences.
The test can be performed either according to IEC 60068-2-75 or IEC 62262
To begin the testing process, power on the assemblies and let them warm up as per standard procedure Utilize a suitable testing device, such as a spring hammer, to deliver three impacts of 1.0 joules (J) to the detection assembly case Ensure that the test is conducted on both sides of the detection assembly while carefully monitoring the response.
The monitoring unit response shall be unaffected (remain within ±15 % of the pre-test values) by the impacts.
Environmental characteristics
Ambient temperature
The monitoring assembly shall be able to operate over an ambient temperature range from a) +10 °C to +50 °C for indoor use; b) –25 °C to +40 °C (or +55 °C) for outdoor use
When installing equipment in enclosed cabinets, it is crucial to account for potential temperature increases Therefore, testing should be conducted across a temperature range of –25 °C to +55 °C The measured values must stay within 15% of the values recorded at +20 °C throughout this temperature range.
–25 °C to +40 °C Over the temperature range of +40 to +55 °C, the indicated value shall be within 25 % of the value obtained at +20 °C
The test will measure the dose rate from ambient background and gamma radiation sources as specified in section 6.3.2, while maintaining consistent geometry throughout the test cycle.
The temperature must be held at its extreme values for at least 16 hours, with measurements taken every 60 minutes Humidity should remain below 50% to avoid condensation Additionally, the temperature change rate must not exceed 10°C per hour, and the variation limits of the measurements should align with the values specified in Table 4.
Portions of the system that are intended for installation in a controlled environment may be excluded from this test
Monitoring assemblies with temperature control devices must be tested as complete units In contrast, for assemblies lacking internal temperature control, testing can be conducted on each assembly as grouped components.
Relative humidity
The monitoring assembly is designed to function effectively in environments with relative humidity levels reaching 93% and ambient temperatures of +35 °C Acceptable performance is demonstrated by a change in detector count rate of less than 15% compared to measurements taken at +20 °C and 65% humidity.
RH both during and after exposure There shall be no observable effects from the exposure to high humidity
Higher humidity limit (93 % RH at +40 °C) may be required in accordance with the agreement between purchaser and manufacturer In such a case, a test shall be conducted for such expanded conditions
The test shall be carried out a single temperature of 35 °C using an environmental chamber
The monitoring unit, including the detector assembly, must be activated and exposed to the reference gamma radiation as outlined in section 6.3.2 Humidity levels should be maintained at their extreme values for at least 24 hours, with the assembly's readings recorded every 2 hours throughout this duration The allowable variation in these readings is specified in the guidelines.
Table 5 is additional to the permitted variations due to temperature alone Following exposure, each assembly shall be inspected for corrosion or other humidity caused affects
There shall be no observable effects from the exposure
Portions of the system that are intended for installation in a controlled environment may be excluded from this test.
Sealing
The monitoring assembly must be engineered to prevent moisture ingress, with the manufacturer required to specify the measures implemented for this protection Additionally, the manufacturer should provide the unit's IP rating in accordance with IEC 60529 standards.
This test is required if the unit does not comply with IEC 60529 and when agreed between manufacturer and purchaser
All outdoor components must undergo a rain test, which involves exposure to 10 liters per square meter based on the component's area The testing duration is set at 3 minutes per square meter, with a minimum exposure time of 15 minutes, in accordance with IEC 60068-2-18 standards.
The spray nozzle should be approximately 2 m from the monitor After exposure, each component shall be inspected to determine if moisture penetrated the installed seals
Type test report
The manufacturer shall make available, at the request of the purchaser, the report on the type tests performed to the requirements of this standard.
Certificate
A certificate shall be provided with each monitoring unit and detector assembly, including at least the following information in accordance to IEC 61187:
– manufacturer's name or registered trademark;
– type of assembly and serial number;
– types of radiation the assembly is intended to measure;
– where tested for operation in pulsed radiation fields, the dose rates, pulse duration times and pulse repetition rates;
– reference point of the assembly;
– declaration of conformity with respect to this standard.
Operation and maintenance manual
An operation and maintenance manual containing at least the following information in accordance with IEC 61187 shall be supplied:
– schematic electrical diagrams including spare parts list;
– operational details, maintenance and testing procedures
The maintenance manual user instructions must be clear and consistent across all components of the type test, ensuring they address routine usage effectively.
Table 3 – Reference conditions and standard test conditions
Reference conditions (unless otherwise indicated by the manufacturer)
Standard test conditions (unless otherwise indicated by the manufacturer)
Reference gamma radiation source 137 Cs 137 Cs
Warm-up time 30 min > 30 min
Atmospheric pressure 101,3 kPa 70 kPa to 106 kPa
Power supply voltage Nominal power supply voltage Nominal power supply voltage ± 1 %
Power supply frequency Nominal frequency Nominal frequency ± 2 %
Power supply waveform Sinusoidal Sinusoidal with total harmonic distortion lower than 5 %
Gamma radiation background Air kerma rate 0,1 μ Gy ⋅ h –1 Less than air kerma rate of
Angle of incidence of radiation Calibration direction given by the manufacturer Direction given ± 10°
Electromagnetic field of external origin Negligible Less than the lowest value that causes interference
The magnetic induction from external sources is minimal, measuring less than twice the induction caused by the Earth's magnetic field Additionally, the manufacturer specifies the orientation of the assembly, which is allowed a tolerance of ± 10˚.
Assembly controls Set up for normal operation Set up for normal operation
Table 4 – Tests performed under standard test conditions
Characteristics under test Requirements subclause Method of test subclause
Background effects and false alarm 6.1.1 6.1.2
6.3.2.3 6.3.2.4 Variation of response with photon radiation energy
Variation of response with angle incidence
Alarm response time and stability 6.13.1 6.13.2
Table 5 – Tests performed with variations of influence quantities
Characteristic under test or influence quantity
Range of values of influence quantities
Limits of variation of indications or of the responses
Mains operation – From 100 V to 240 V power supply voltage – From 45 Hz to 66 Hz ± 10 % 7.1.2
Microphonics/impact Trois impacts at an intensity of 1,0 joules at different locations on the detection assembly
Response shall be unaffected by exposure ± 15 %
Ambient temperature +10 °C to +55 °C for indoor use –25°C to +40°C (or +55°C) for outdoor use ± 15 % and ± 25 % 7.4.1.2
Relative humidity 40 % to 93 % at +35 ºC ± 15 % 7.4.2.2
Sealing 3 mm per min/m 2 for a minimum of 15 min
Table 6 – Maximum values of additional indications due to electromagnetic disturbances
Influence quantity or instrument parameter
Minimum rated range of influence quantity
Test according to IEC standard
Allowed change of response at five times the lower end of the measuring range
230 MHz to 1 000 MHz 61000-6-4 Less than 30 dB
0 kV to ± 8 kV air discharge
0 kV to ± 4 kV contact discharge
Radiated electromagnetic fields, field strength and modulation
80 MHz to 1 000 MHz and 1,4 GHz 2,5 GHz
Conducted disturbances induced by fast transients / burst, peak voltage
0 kV to ± 2 kV Signal ports:
0 kV to ± 1 kV 5/50 ns (tr/th)
Conducted disturbances induced by surges, peak voltage and rise time
AC power ports, line-to- earth:
AC power ports, line-to- line:
0 kV to ± 1 kV Signal ports, line-to-earth:
0 kV to ± 2 kV 1,2/50 (8/20) μ s (tr/th)
Conducted disturbances induced by radio- frequencies, frequency and voltage
1 MHz + 10 %, mains supply frequency between
50 Hz and 400 Hz and non-synchronized on the network frequency
50 Hz/60 Hz magnetic field, field strength
Voltage dips/ short interruptions, duration
Voltage dips/ short interruptions, duration
* Criteria A, B, and C according to IEC 61000-6-2:
– A: The apparatus shall continue to operate as intended during and after the test
– B: The apparatus shall continue to operate as intended after the test
– C: Temporary loss of function is allowed, provided the function is self-recoverable or can be restored by the operation of the controls
Monitoring of pulsed ionizing radiation
Certain dose and dose equivalent detector assemblies may provide inaccurate readings when monitoring pulsed radiation fields, including those from medical x-ray machines, various x-ray devices, linear accelerators (LINACs), and cyclotrons.
LINACs emit radiation in bursts lasting approximately 1 μs, occurring at a frequency of around 400 bursts per second During these pulses, the dose rate is approximately 2,500 times higher than the average dose rate.
Pulse counting detectors, including Geiger counters, scintillation counters, and semiconductors, can generate only a single pulse during their operational time due to the dead time of the detector or its electronics, which may match or exceed the duration of the radiation burst Consequently, the maximum count rate is capped at 400 pulses per second, regardless of the actual dose rate, translating to approximately a few microsieverts per hour in practical scenarios Similarly, dosemeters exhibit a slower increase in dose readings compared to the actual dose received.
Detector assemblies that do not depend on pulse counting, like ionization chambers and current-mode scintillation and semiconductor detectors, can effectively measure dose and dose rate from pulsed sources However, saturation issues may arise at extremely high dose rates To prevent this, it is essential to compare results with ionization chambers operating at various voltages.
To ensure the monitor's effectiveness in pulsed fields, it is essential to conduct tests at the maximum dose rate specified by the manufacturer for proper operation The radiation pulse's duration and repetition rate should closely resemble the conditions anticipated during actual use, and these parameters must be clearly detailed in the test report.
To evaluate the performance of the dose rate meter, expose it to the radiation conditions outlined in section 5.6.1 Subsequently, compare the readings obtained with those from a reliable dose rate meter that operates effectively at the specified mean dose rates, pulse dose rates, pulse durations, dose per pulse, and repetition frequencies.
The difference between the readings shall be provided
To ensure accurate comparisons, the dose rate meter's performance must be validated against an ionization chamber instrument This validation is crucial to avoid saturation effects, as the dose rate indication should not exceed a 5% increase when the polarizing voltage applied to the ionization chamber is raised.
50 % with dose rates equal to or in excess of those applied in this test
IEC 60068-2-2, Environmental testing – Part 2-2: Tests – Test B: Dry heat
IEC 60359:2001, Electrical and electronic measurement equipment – Expression of performance
IEC 60761 (all parts), Equipment for continuous monitoring of radioactivity in gaseous effluents
IEC 60768, Nuclear power plants – Instrumentation important to safety – Equipment for continuous in-line or on-line monitoring of radioactivity in process streams for normal and incident conditions
IEC 60861, Equipment for monitoring of radionuclides in liquid effluents and surface waters
IEC 60951-1, Nuclear power plants – Instrumentation important to safety – Radiation monitoring for accident and post-accident conditions – Part 1: General requirements
IEC 60951-2 outlines the standards for radiation monitoring equipment essential for safety in nuclear power plants It specifically focuses on the continuous off-line monitoring of radioactivity in gaseous effluents and ventilation air during both accident and post-accident conditions This standard ensures that nuclear facilities maintain effective monitoring systems to safeguard against radiation hazards.
IEC 60951-3, Nuclear power plants – Instrumentation important to safety – Radiation monitoring for accident and post-accident conditions – Part 3: Equipment for continuous high range area gamma monitoring
IEC 60951-4 outlines the standards for radiation monitoring equipment essential for safety in nuclear power plants It focuses on the continuous in-line or on-line monitoring of radioactivity in process streams, particularly during accident and post-accident conditions This standard ensures that the instrumentation used is reliable and effective in maintaining safety protocols in nuclear facilities.
IEC 60980:1989, Recommended practices for seismic qualification of electrical equipment of the safety system for nuclear generating stations
IEC 61000-4-14:1999, Electromagnetic compatibility (EMC) – Part 4-14: Testing and measurement techniques – Voltage fluctuation immunity test
IEC 61000-4-28:1999, Electromagnetic compatibility (EMC) – Part 4-28: Testing and measurement techniques – Variation of power frequency immunity test
IEC 61508-1, Functional safety of electrical/electronic/programmable electronic safety-related systems – Part 1: General requirements
IEC 61508-2, Functional safety of electrical/electronic/programmable electronic safety-related systems – Part 2: Requirements for electrical/electronic/programmable electronic safety- related systems
IEC 61508-3, Functional safety of electrical/electronic/programmable electronic safety-related systems – Part 3: Software requirements
IEC 61508-4, Functional safety of electrical/electronic/programmable electronic safety-related systems – Part 4: Definitions and abbreviations
IEC 61508-5, Functional safety of electrical/electronic/programmable electronic safety-related systems – Part 5: Examples of methods for the determination of safety integrity levels
IEC 61508-6, Functional safety of electrical/electronic/programmable electronic safety-related systems – Part 6: Guidelines on the application of IEC 61508-2 and IEC 61508-3
IEC 61508-7, Functional safety of electrical/electronic/programmable electronic safety-related systems – Part 7: Overview of techniques and measures
IEC 61559-1:2009, Radiation protection instrumentation in nuclear facilities –Centralized systems for continuous monitoring of radiation and/or levels of radioactivity – Part 1: General requirements
IEC 61559-2:2002, Instrumentation in nuclear facilities – Centralized systems for continuous monitoring of radiation and/or levels of radioactivity – Part 2: Requirements for discharge, environmental, accident, or post-accident monitoring functions
IEC 62003:2009, Nuclear power plants – Instrumentation and control important to safety –
Requirements for electromagnetic compatibility testing
International Atomic Energy Agency (IAEA), Safety Series No 50-C/SG-Q:1996, Quality
Assurance for Safety in Nuclear Power Plants and other Nuclear Installations, Code and
International Atomic Energy Agency (IAEA), Safety Series No NS-R-1, Safety of Nuclear
Power Plants: Design Safety Requirements
International Atomic Energy Agency (IAEA), Safety Series No NS-G-1.3, Instrumentation and
Control Systems Important to Safety in Nuclear Power Plants Safety Guide – IAEA Safety
ICRU Report 51, Quantities and units in radiation protection dosimetry
ICRP Publication 57, Radiological Protection of The Worker In Medicine And Dentistry
5.2 Conditions de référence et conditions normales d'essai 60
5.3 Essais exécutés dans les conditions normales d'essai 60
5.4 Essais exécutés avec variation des grandeurs d'influence 60
5.7 Prise en compte du rayonnement naturel du fond 61
6.3.2 Source de rayonnement gamma d'essai 62
6.4 Variation de la réponse avec l'énergie du rayonnement photonique 63
6.5 Variation de la réponse avec l'angle d'incidence 64
6.13 Temps de réponse et stabilité de l'alarme 69
7 Caractéristiques électriques, mécaniques et environnementales 69
7.2.5 Perturbations conduites induites par les transitoires rapides ou salves 72 7.2.6 Perturbations conduites induites par des ondes de choc 72
7.2.7 Perturbations conduites induites par les fréquences radioélectriques 72
7.2.9 Champ magnétique de 50 Hz/60 Hz 73
7.2.10 Creux de tension et coupures brèves 74
8.3 Manuel d'exploitation et de maintenance 77
Annexe A (informative) Surveillance du rayonnement ionisant pulsé 81
Figure 1 – Exemple de rotation de l'ensemble de détection 65
Tableau 1 – Série de normes des sous-comités SC 45A / SC 45B de la CEI 48
Tableau 2 – Bande de fréquences des émissions 70
Tableau 3 – Conditions de référence et conditions normales d'essai 77
Tableau 4 – Essais exécutés dans les conditions normales d'essai 78
Tableau 5 – Essais exécutés avec variations de grandeurs d'influence 78
Tableau 6 – Valeurs maximales des indications additionnelles dues à des perturbations électromagnétiques 79
INSTRUMENTATION POUR LA RADIOPROTECTION – DÉBITMÈTRES À POSTE FIXE, ENSEMBLES D'ALARMES
ET MONITEURS – RAYONNEMENTS X ET GAMMA D'ÉNERGIE COMPRISE ENTRE 50 keV ET 7 MeV
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