Strålningsskydd

Ämnesområden: Specialavfall; Strålningsskydd
Kommittébeteckning: SIS/TK 405 (Kärnenergi)
Källa: ISO
Svarsdatum: den 3 mar 2020
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This document focuses on monitoring the activity concentrations of radioactive gases, from which the activity released are calculated, in the gaseous effluent discharge from facilities producing positron emitting radionuclides and radiopharmaceuticals. Such facilities produce short half-life radionuclides used for medical purposes or research and may release gases typically including, but not limited to 18F, 11C, 15O, 13N. These facilities include accelerators, radiopharmacies, hospitals and universities. This document provides performance-based criteria for the design and use of air monitoring equipment including probes, transport lines, sample monitoring instruments, and gas flow measuring methods. This document also provides information covering monitoring program objectives, quality assurance, developing air monitoring control action levels, system optimisation, and system performance verification.

The goal of achieving an unbiased measurement is accomplished either by direct (in-line) measurement on the exhaust stream or with samples which are extracted (bypass) from the exhaust stream, in which the radioactive gases are well mixed in the airstream. This document sets forth performance criteria and recommendations to assist in obtaining valid measurements.

The criteria and recommendations of this document are aimed at monitoring which is conducted for regulatory compliance and system control. If existing air monitoring systems were not designed to the performance criteria and recommendations of this document, an evaluation of the performance of the system is advised. If deficiencies are discovered, it should be determined if retrofit is needed and practicable.

The criteria and recommendations of this document apply under both normal and off-normal operating conditions, provided that normal and off-normal conditions do not include production of aerosols or vapours. If the normal and/or off-normal conditions produce aerosols and vapours, then the aerosol collection principles of ISO 2889 also apply.

Kommittébeteckning: SIS/TK 405 (Kärnenergi)
Källa: ISO
Svarsdatum: den 23 mar 2020
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This document specifies requirements for the ice plug technique with liquid nitrogen or dry ice as refrigerant (cryogenic medium) on metal pipes of nuclear power plants. The freezing liquid can be water or water mixture (e.g. boric acid mixture).

This document specifies technical requirements of ice plug generation, formation judgment and removal, measures before, during and after ice plugging and requirements for personnel and non-destructive testing.

This document is applicable for maintenance work, modification work and test inspections work when no other locking opportunity than ice plugging is available.

The application of the ice plug isolation technique is principally not allowed on cladded pipes or pipes with internal coatings. The application for pressure test is not in the scope of this document and should be qualified separate.

Kommittébeteckning: SIS/TK 405 (Kärnenergi)
Källa: ISO
Svarsdatum: den 30 mar 2020
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ISO 20041-1 presents the methods and provisions for sampling tritium and carbon-14 in the gaseous effluents generated by nuclear facilities during operation and decommissioning. Specifically included are sample withdrawal location, extraction, transport flow measurement, and collection for later analysis.

This document doesn’t address to real time measurements of tritium activity and carbon-14 activity in the effluent air of stacks and ducts. Information about real time measurements can be found in the informative annex H of ISO 2889.

Sample processing, analysis and calculations of tritium and carbon-14 emissions are addressed in ISO 20041-2 and ISO 20041-3 respectively.

Ämnesområden: Strålningsskydd
Kommittébeteckning: SIS/TK 405 (Kärnenergi)
Källa: ISO
Svarsdatum: den 14 apr 2020
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This document provides performance and test requirements for determining the acceptability of neutron dosimetry systems to be used for the measurement of personal dose equivalent, Hp(10), for neutrons ranging in energy from thermal to 20 MeV 1). No distinction between the different techniques available in the market place is made in the description of the tests. Only generic distinctions, for instance, as disposable or reusable dosemeters, are considered.

This document gives information for extremity dosimetry in the Annex A, based on recommendations given by ICRU Report 66. This document addresses only neutron personal monitoring and not neutron criticality accident conditions.

Ämnesområden: Strålningsskydd
Kommittébeteckning: SIS/TK 405 (Kärnenergi)
Källa: ISO
Svarsdatum: den 14 apr 2020
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No qualification or correction of the dosimetry system at a workplace is required if the dosimetry system fulfils the criteria of ISO 21909-1. However, methodologies described in this document can be used to improve the quality of individual monitoring in specific workplace fields for all dosimetry systems.

As specified in ISO 21909-1, the Individual Monitoring Service (IMS) shall specify clearly in its documentation the energy range (as described in ISO 21909-1) for which the dosemeter is qualified.

This document provides methodology and criteria to qualify the dosimetry system at workplaces where it is used. The criteria in this document apply to dosimetry systems which do not meet the criteria with regard to energy and direction dependent responses described in ISO 21909-1. That means that this document shall be systematically used to qualify at workplaces a dosimetry system that does not fulfil the criteria of ISO 21909-1 on the dependence of the response on neutron energy and direction of incidence.

The qualification of the dosimetry system at workplace aims to demonstrate that:

— either, the non-compliance of the dosimetry system to some of the requirements on the energy or direction dependent responses defined in ISO 21909-1 will not lead to significant discrepancies in the dose determination for a certain workplace field;

— or, that the correction factor or function used for this specific studied workplace enables the dosimetry system to accurately determine the conventional dose value with uncertainties similar to the ones given in ISO 21909-1.

Methodologies to characterize the workplace field are also described in the normative annex A, to help performing the qualification of the dosimetry system.

This document is directed at all stakeholders who are involved: IMSs, accreditation or regulatory bodies, and users of the particular dosimetry systems (the user is meant as the entity which assigns the dosimetry system to the radiation worker and records the assigned dose.)

The provider of the dosimetry system shall provide the type test results corresponding to ISO 21909-1. However, in the case when the dosimetry system to qualify will not comply with all the criteria of ISO 21909-1 dealing with the energy and angle dependence of the response, some tests of the ISO 21909-1 can be not performed. In that case, the requirements in accordance of the part 2 (see 6.3) shall be fulfilled instead.

This document only addresses neutron personal monitoring and not neutron criticality accident conditions.