fi

Ohje _ __ Direktiv Sl 4.2 Guide

&*£&%•?'•• V..

Säteilyturvakeskus Strälsäkerhetscentralen Finnish Centre for Radiation and Nuclear Safety FINNISH CENTRE FOR RADIATION AND NUCLEAR SAFETY ST 4.2 6 June 1991

Radiation Meters for Civil Defence

1 General 3

2 Universal Survey Meter 3

3 Basic Survey Meter 4

4 Dosimeters 5

4.1 Quartz Fiber Dosimeter 5 4.2 Electronic Dosimeter 5

5 Installed Meters for Environmental Monitoring 5

6 Bibliography 6

Appendix A Radiation Characteristics of Ambient Dose Equivalent (Rate) Meters Appendix B Electrical, Mechanical and Environmental Characteristics of Ambient Dose Equivalent (Rate) Meters Appendix C Electromagnetic Susceptibility

This ST Guide takes effect on 1 January 1992 and will remain in force until further notice.

Helsinki 1994 Erweko Painotuote ISBN 951-47-9513-X ISSN 0789-4511 Authorization

The Finnish Centre for Radiation and Nuclear Safety (STUK) issues general guides according to § 70 paragraph 2 of the Radiation Act (592/91) in order to achieve the safety levei mentioned in the Act.

Translation. Original text in Finnish. FINNISH CENTRE FOR RADIATION ST 4.2 AND NUCLEAR SAFETY

Table 1. General requirements for the uni­ 1 General versal survey meter.

Because of their specific application, radia­ tion meteis used in civil defence must meet Characteristics Requirement technical requirements that are slightly dif­ ferent from the present standards of radiation Lower limit of the meters. The aim of the requirements is to range of dose rates < 0.1 uSv/b guarantee sufficient measurement accuracy and reliable operation even in extreme en­ Upper limit of Ute vironmental conditions. Whenever possible range of dose rates >10 Sv/h the requirements laid down in this guide are based on the following international stand­ Lower limit of the ards: range of doses < 1 MSV Upper limit of the IEC 846 "Beta, X and Gamma Radia­ range of doses >10 Sv tion Dose Equivalent and Dose Equivalent Rate Meters for Use in Sealing IP 65* Radiation Protection" 1} Standard SFS 2972 with the interpre­ IEC 1017-1 "Portable, Transportable tation that there shall be no water or Installed X or Gamma Radiation inside the enclosure after the test. Ratemeters for Environmental Moni­ toring. Part 1: Ratemeters"

and on the draft standard Additional requirements:

IEC 45 B (Secretariat) 104 "Direct The meter must be easy to use. It must Reading, Personal Dose Equivalent be applicable for outdoor use (for and/or Dose Equivalent Rate Monitors cold, damp or dark environments). It for X, Gamma and High Energy Beta must be well protected against electro­ Radiation". magnetic interference and easy to decontamine with soap and water. The Ministry of the Interior confirms the applicability of the meters for use in civil The meter must be equipped with a defence. plug-in unit for a probe intended for the measurement of surface con­ tamination. The sensitivity (the lowest 2 Universal Survey detectable surface activity) for high- energy beta emitters (^Y/^Sr) must be Meter 4 Bq/cm2. The detection threshold is considered to be exceeded if the in­ The measurement quantities are the ambient crease in indication caused by the sur­ 2 dose equivalent rate (in short, dose rate) and face activity 4 Bq/cm is at least three the ambient dose equivalent (in short, dose). times higher than the standard devia­ The universal >urvey meter is intended for tion of background readings at the many measurement purposes and for a wide dose rate of 0.2 uSv/h. range of dose rates. General requirements for the universal survey meter are given in The batteries must be of a type that is Table 1. listed to be kept in stock for emer­ gencies.

3 FINNISH CENTRE FOR RADIATION ANO NUCLEAR SAFETY ST 4.2

There must be a continuous audio an analogous display for the rapid signal in the meter for easy observa­ observation of changes in dose rate or tion of dumges in dose rate or in sur­ in surface activity. face activity. The accessories must be designed for long- The range of dose rates for which the term storage and outdoor transportation. meter is intended must be clearly marked on the meter. The unit (e.g. Tables on performance characteristics and uSv/h or mSv/h) must be clearly seen performance testing are presented in Appen­ either from the switchboard or from dices A to C the display.

The dose memory must not become empty when the meter is switched off 3 Basic Survey Meter or its batteries are changed. The measurement quantities are the ambient There must be a clear logic in the dose equivalent rate (in short, dose rate) and setting of various operations. The the ambient dose equivalent (in short, dose). change of a probe or any similar General requirements for the basic survey measure shall not cause operational meter are given in Table 2. errors which could endanger safety. It must be possible to switch the alarm Table 2. General requirements for the basic thresholds off when the continuous survey meter. audio signal is in use.

In addition to the above requirements, it is Characteristics Requirement recommended that the meter should be Lower limit of the equipped with: range of dose rates < 0.1 uSv/h

a long-stemmed probe to measure Upper limit of the high dose rates from a distance range of dose rates >10 mSv/h"

a sensitive probe to search for low- Lower limit of the activity radiation sources distributed on range of doses <1 uSv a wide area Upper limit of the a sensitive probe to measure volume range of doses >1 Sv activity from food samples etc. (may be the same probe as above). Sealing IP 54* >} The limit is based on technical Further, it is recommended that there should points of view. A wider range up be in the meter: to higher doses is recommendable. 2) Standard SFS 2972 with the in­ a connection plug to the power net terpretation that there shall be no water inside the enclosure after a clear alarm signal which is switched the test. on when the dose rate or the dose exceeds a preset threshold, and

4 FINNISH CENTRE FOR RADIATION ST 4.2 AND NUCLEAR SAFETY

h addition: The sealing class must be at least IP 54, according to standard SFS 2972 with the The batteries must be of a type that is interpretation that there shall be no water listed to be kept in stock for emerg­ inside the enclosure after the test. encies. The temperature dependence of the meter There must be a continuous audio response shall not exceed ± 20 % in the signal in the meter for easy obser­ temperature range -30 to +55 °C. vation of changes in dose rate. The requirements concerning performance Tables on performance characteristics and characteristics and performance testing are performance testing are presented in Appen­ presented in the draft standard IEC 45 B dices A to C. (Secretariat) 104. The requirements are available from the Finnish Centre for Radia­ tion and Nuclear Safety, on request. Dosimeters

Quartz Fiber Dosimeter 5 Installed Meters

The measurement quantity is the personal for Environmental dose equivalent* (in short, dose). The range Monitoring of doses shall be 0 to 500 mSv. The measurement quantities are the ambient The relative intrinsic error shall not exceed dose equivalent rate (in short, dose rate) and + 20 %. The increase in indication caused the ambient dose equivalent (in short, dose). by leakage current shall not be more than General requirements for the installed meters SO mSv, when the dosimeter is stored for for environmental monitoring are given in seven days at room temperature. Table 3.

Other quality tests specified in standard In addition to the above requirements, the ISO 4071** can also be carried out for the instruments should comply with the follow­ quartz fiber dosimeter. The user's manuals of ing recommendations: the dosimeters should specify at which values of the ambient quantities (temperature, hu­ There should be a plug-in unit in the midity, etc.) the meters will pass the tests. central part of the system to control an air sampler which starts when the dose Electronic Dosimeter rate exceeds a preset value.

The measurement quantity is the personal The central parts of the system (e.g. dose equivalent* (in short, dose). A suitable a microcomputer) should meet the range of doses is 1 \iSv to 10 Sv. requirements of standard EEC 950.

Tables on performance characteristics and * The quantities intended for pocket and portable performance testing are presented in Appen­ radiation meters differ because of the attenuation dices A to C. and backscatter of radiation in the body (see items 2, 3 and 5). The difference is insignificant in typical radiation measurements for civil defence. ** Under revicing, will be replaced by ISO 11934.

5 FINNISH CENTRE FOR RADIATION AND NUCLEAR SAFETY ST 4.2

Table 3. General requirements for the in­ 3 ISO 4071. Exposure Meters and Dosi­ stalled meters for environmental monitoring. meters - General Methods for Testing.

4 IEC 1017-1. Portable, Transportable or Characteristics Requirement Installed X or Gamma Radiation Rate- meters for Environmental Monitoring. Part Lower limit of the 1: Ratemeters. range of dose rates < 0.1 nSv/h 5 IEC 45 B (Central Office) 103 (draft, Upper limit of the later DEC 1017-2). Portable or Installed X range of dose rates >10 Sv/h or Gamma Radiation Equipment for Envi­ ronmental Monitoring. Part II: Integrating Lower limit of the Assemblies. iange of doses < 0.1 nSv 6 IEC 68 - 2. Part 2: Basic Environmental Upper 'imit of the Testing ProceoVes. Tests: 68-2-1 CoM, range of doses >10 Sv 68-2-2 Dry heat 68-2-3 Damp Heat Steady State, 68-2-6 Vibration, 68-2-27 Sealing of the probe IP65W Shock.

Alarm level settings Set by the com­ 7 SFS 2972. Electrical Equipment Classifi­ petent authority cation of Degrees of Protection Provided by Enclosures. l) Standard SFS 2972 with the interpreta­ tion that there shall be no water inside 8 IEC 529. Degrees of Protection Provided the enclosure after the test. by Enclosures (IP Code). 9 Alternative methods to protect the probe against damage caused by con­ 9 IEC 950. Safety of Information Techno­ densed water (e.g. ventilation or heat­ logy Equipment Including Electrical Busi­ ing) are acceptable. ness Equipment Amendment 1. 10 ISO 7503-1. Evaluation of Surface Con­ tamination - Part 1: Beta Emitters (Maxi­ mum beta energy grwier than 0.15 Mev) and Alpha-Emitters. 6 Bibliography 11 SFS 5101. General Requirements for the 1 IEC 846. Beta, X and Gamma Radiation Technical Competence of Testing Labora­ Dose Equivalent and Dose Equivalent Rate tories. Meters fc; Use in Radiation Protection. 12 EN 45001. General Criteria for the Op­ 2 IEC45B (Secretariat) 104 (draft). Direct eration of Testing Laboratories. Reading, Personal Dose Equivalent and/or Dose Equivalent Rate Monitors for X, Gamma and High Energy Beta Radiation.

6 RADIATION CHARACTERISTICS OF AMBIENT DOSE EQUIVALENT (RATE) METERS

Characteristic Range of values of Limits of variation Description of the Differences from the under test or influence quantity test international standards influence quantity

Relative intrinsic Effective range of ±15% IEC 846 subclause error - X and gamma measurement 12.1 radiation X and gamma radiation 10 keV to 80 keV To be stated by the IEC 846 subclause In the energy range 80 keV to 1.0 MeV energy manufacturer 12.3 the requirement is nearly the same with 80 keV to 0.2 MeV ±35% and IEC 846. At other energies the require­ 0.2 MeV to 1.0 MeV ±20% 1EC 1017-1 ment is less stringent. 1.0 MeV to 1.3 MeV ±35% In the energy range 0.2 to 1.0 MeV the 1.3 MeV to 10 MeV To be stated by the requirement is more stringent compared manufacturer with IEC 1017-1. At other energies the requirement is less stringent. Beta radiation energy Beta radiation up to To be stated by the IEC 846 subclause The requirement of ± 50 % (IEC 846) E^» of 4 MeV manufacturer 12.4 and nigged construction required in civil defence are in contradiction. Angle of incidence Portable instrument X and gamma radiation 0" IO 45° from ± 35 % (for 83 keV) IEC 846 subclause The requirements are less stringent reference direction 12.5 compared with IEC 846. 45° to 180° from To be stated by the reference direction manufacturer Probe of the installed instrument 0° to 45° from ± 35 % (for 83 keV) IEC 1017-1 The requirements of the installed instru­ reference direction ments are less stringent compared with 45° to 60° from ± 50 % (for 83 keV) IEC 1017-1. Note that the requirements reference direction differ essentially from IEC 846 because 60° to 180° from To be stated by the the radiation incidence is from half space. reference direction manufacturer 00

Characteristic Range of values of Limits of variation Description of the Differences from the under test or influence quantity test international standards influence quantity

Portable instrument

Overload 100 times the range maximum Indication to be off- IEC 846 subclause 12.6 for range maxima up to and scale on the high side or Installed instrument including 0.1 Sv/h assembly to indicate overload (for 5 min)1 IEC 1017-1

10 times the range maximum or 10 Sv/h, whichever is larger, for range maxima more than 0.1 Sv/h

Effects of neutron To be stated by the IEC 846 subclause radiation manufacturer 12.7

l) Note that manufacturer shall state both the time taken by the assembly to reach the off-scale reading and the time to return to the on scale reading following the beginning or end of over exposure. ELECTRICAL, MECHANICAL AND ENVIRONMENTAL CHARACTERISTICS OF AMBIENT DOSE EQUIVALENT (RATE) METERS

Characteristic Range of values of Limits of variation Description of the Differences from the under test or influence quantity test international standards influence quantity

Statistical fluctuations Coefficient of IEC 846 subclause variation < 15 % 13.1 Response time Dose rate H Portable instrument

H > 10 raSv/h < 2 s to indicate IEC 846 subclause For portable instruments the 90 % of change 13.2 requirements comply with IEC 846 10 mSv/h > H > 20 uSv/h <10s at dose rates greater than 20 uSv/h. For installed instruments the H < 20 nSv/h To be stated by the requirement is less stringent com­ manufacturer pared with IEC 1017-1.

Installed instrument

To be stated by the I manufacturer. Power supplies CO a) Primary batteries For 40 h intermittent use ±10% IEC 846 subclause 13.7 b) Secondary batteries For 12 h continuous use + 10% c) A.C. mains voltage From 88% to 110% of ±10% IEC 846 subclause (if applicable) nominal supply voltage 13.7 Characteristic Range of values of Limits of variation Description of the Differences from the under test or influence quantity test uiifmational standards influence quantity

Mechanical shock All instruments No damage IEC 846 subclause 14.1 300 m2/s, 18 ms

Portable instrument or A simple drop test has been included Drop from 1 meter onto IEC 68-2-27 because it demonstrates well the a concrete surface, a drop ruggedness of the instrument. onto each face

Orientation of assembly Any ± 2 % of full scale IEC 846 subclause maximum angular 14.2 deflection Vibration + 3 mm or 10 m/s No damage IEC 68-2-6 The test has been included because it 5.150 Hz, 3 x 2 h demonstrates well the quality of circuit board and components.

Portable instrument Ambient temperature -30 °C to +55 °C ±20% IEC 846 subclause The requirements are more stringent 15.1 or compared with IEC 846 and with Probe of installed IEC 68-2-1 and IEC 1017-1. instrument IEC 68-2-2 Test time at each of the -40 «C to +70 °C ±20% extreme temperature values shall be at least 16 h I Characteristic Range of values of Limits of variation Description of the Differences from the 1 under test or influence quantity test international standards } influence quantity

Relative humidity Up to 90 % relative ±10% 1EC 846 subclause The requirement is »ore stringent humidity at 35 °C 15.2 or compered with IEC 846 and with IEC 68-2-3 IEC 1017-1. Test time 96 h in the extreme temperature value External electro­ Principles for preparation Very stringent susceptibility tests magnetic fields of the test program are are necessary for instruments which given in appendix C are intended for use in civil de­ fence.

External magnetic fields *.**»

EMP protection _ M

Storage -40 °C, 72 h No damage IEC 68-2-1 and The tests suit better for extreme •70 «C, 72 h No damage IEC 68-2-2 climatic conditions and are more practical compared with the test presented in IEC 846 FINNISH CENTRE FDR RADIATION ANO NUCLEAR SAFETY ST 4.2

APPENDIX C

ELECTROMAGNETIC SUSCEPTIBILITY

The construction and operating principle of the radiation meter, and the length and protection of cables must be taken into account in choosing disturbance levels for the tests. Sufficient test programs can in most cases be prepared by using the following standards:

MIL-STD-462, Notice 3 (CS01): Electromagnetic interference characteristics, measurement of conducted susceptibility, power leads, 30 Hz to SO kHz.

MIL-STD-462, Notice 3 (CS02): Electromagnetic interference characteristics, measurement of conducted susceptibility, power leads ISO kHz to 65 MHz. LISN Method.

MIL-STD-462, Notice 3 (RS01): Electromagnetic interference characteristics, measurement of radiated susceptibility, 30 Hz to 30 kHz, magnetic field.

SFS S1S8: Interference immunity of electronic equipment for professional use. Im­ munity to electrostatic discharge. Testing method. Based on international standard EC 801-2 (see below).

IEC-801-1...5. Electromagnetic compatibility for industrial - process measurement and control requirements: Parti General introduction. Part 2 Electrostatic discharge requirement. Part 3 Radiated electromagnetic field requirements. Part 4: Electrical fast transient requirements (Draft). Part 5 Surge voltage immunity requirements (Draft).

A suitable simulator shall be used for testing the EMP-protection. The pulses induced in the cable connecting the probe and the central part of the system shall be taken into account in evaluating whether the EMP-protecticn is sufficient.

12 FINNISH CENTRE FOR RADIATION ST 4.2 AND NUCLEAR SAFETY

ST(SS) GUIDES (14.6.1994)

General Guides ST 3.4 Quality Control of Image Intensifier - Television Chains, 24 October 1991 (in ST 1 2 Application of Maximum Radiation Ex­ English, Finnish and Swedish) posure Values and Monitoring of Radia­ ST 3.5 Quality Control of Diagnostic X-ray tion Exposure, 31 March 1992(in English, Equipment and Film Processing, 3 De­ Finnish and Swedish) cember 1991 (in English, Finnish and ST 13 Safety Signs Denoting Radiation Sources, Swedish) 9 April 1992 (in Fiiursh and Swedish) ST 3.6 Radiation Shielding of X-ray Examin­ ST 1.4 Organization for the Use of Radiation, ation Rooms, 20 December 1991 (in 24 October 1991 (in English, Finnish and English, Finnish and Swedish) Swedish) ST 1.5 Maximum Values and Classification of Measurement of Radiation Radionuclides, 26 November 1991 (in English, Finnish and Swedish) ST 4._ Radiation Meters for Civil Defence, ST 1.6 Monitoring of Radiation Exposure and 6 June 1991 (in English and Finnish) Registration of Doses, 16 December 1992 (in English, Finnish and Swedish) Industry, Research, Education and ST 1.7 Health Surveillance of Persons Engaged Commerce in Radiation Work, 19 December 1991 (in English, Finnish and Swedish) ST 5.1 Radiation Safety of Sealed Sources and Equipment Containing Them, 27 August Radiation Therapy 1992 (in English, Finnish and Swedish) ST 5.3 Use of Ionizing Radiation in the ST 2.1 Quality Assurance for Radiotherapy Teaching of Physics and Chemistry, 14 Equipment, 13 January 1993 (in English, December 1992 (in English, Finnish and Finnish and Swedish) Swedish) SS 2.8 Radiation Protection Requirements for SS 5.4 Import and Export of and Trade with Radiotherapy Equipment and Rooms. Radioactive Materials and Equipment High-energy Radiotherapy Equipment, Containing Them, 9 January 1989 (in 21 December 1989 (in English, Finnish English, Finnish and Swedish) and Swedish) SS5.6 Radiation Safety in Industrial Radi­ SS 2.9 Radiation Protection Requirements for ography, 6 January 1989 (in English, Radiotherapy Equipment and Rooms. Finnish and Swedish) X-ray Therapy Equipment (25 kV... 400 SS 5.8 Installation, Repair and Maintenance of kV), 21 December 1989 (in Finnish and Radiological Equipment Used for Swedish) Medical Purposes, 28 March 1988 (in SS 2.10 Radiation Protection Requirements for English, Finnish and Swedish) Radiotherapy Equipment and Rooms. SS5.9 Transport of Radioactive Materials, Afterloading Therapy Equipment, 21 16 May 1989 (in Finnish) December 1989 (in Finnish and Swedish) Unsealed Sources and Radioactive Diagnostic Radiology Wastes

SS 3.1 Dental X-ray Equipment: Type In­ ST 6.1 Radiation Safety Requirements for spection and Technical Requirements, 25 Radionuclide Laboratories, 30 May 1991 February 1987 (in English, Finnish and (in English, Finnish and Swedish) Swedish) ST 6.2 Radioactive Wastes and Discharges, SS 3.2 Radiation Safety Requirements for 20 December 1991 (in English, Finnish Mammographic Equipment, 17 February and Swedish) 1987 (in English, Finnish and Swedish) ST 3.3 Diagnostic X-ray Equipment and its Use, 27 August 1992 (in English, Finnish and Swedish) FINNISH CENTRE FOR RADIATION ANO NUCLEAR SAFETY ST 4.2

Non-Ionizing Radiation Natural Radiation

SS 9.1 Radiation Safety Requirements aad Type ST 12.1 Radiation Safety in Mining and Inspection of Solarium Equipment and Sun Excavation Work, 27 August 1992 Lamps, 1 September 1989 (in Finnish and (in English, Finnish and Swedish) Swedish) ST 12.2 Radioactivity of Building Materials, ST 9.2 Radiation Safety of Pulsed Radars, Fuel Peat and Peat Ash, 2 February 11 December 1991 (in Finnish) 1993 (in English, Finnish and Swedish) ST 93 Radiation Safety During Work on Masts ST 123 Radioactivity of Household Water, at FM and TV Stations, 9 April 1992 (in 9 August 1993 (in English, Finnish and Finnish) Swedish) ST 9.4 Radiation Safety of High Power Display Lasers, 8 October 1993 (in Finnish) SS Guides will be converted into ST Guides wherever necessary.

Finnish Centre for Radiation and Nuclear Safety P.O.BOX 14, FIN-00881 HELSINKI Tel. +358 0 759 881