IEC 61468:2021 pdf free download

IEC 61468:2021 pdf free download Nuclear power plants – Instrumentation systems important to safety – In-core instrumentation: Characteristics and test methods of self-powered neutron detectors
1Scope
This document applies to in-core neutron detectors，viz. self-powered neutron detectors(SPNDs),which are intended for application in systems important for nuclear reactor safety:protection，instrumentation and control. This document contains SPND characteristics andtest methods. ln this document, the main sources of errors,and the possibilities for theirminimization are also considered.
Self-powered neutron detectors can be used for measurement of neutron fluence rate andassociated parameters in nuclear reactors. Most popular for the indicated applications aredetectors with rhodium emitters.
In this document dynamic characteristics， emitter burn-up，identity and other factorsinfluencing operational characteristics of detectors are considered.
Besides SPNDs with hodium emitters，SPNDs with emitters from other materials and theirmain characteristics are also considered in this document.
This document contains requirements, recommendations and instructions concerningselection of SPND type and characteristics for various possible applications. This documentabout SPNDs uses the basic requirements of IEC 61513 and lEC 60568 and complementsthem with more specific provisions in compliance with lAEA Safety Guides.
2Normative references
The following documents are referred to in the text in such a way that some or all of theircontent constitutes requirements of this document. For dated references，only the editioncited applies.For undated references, the latest edition of the referenced document(including
any amendments) applies.
IEC 60515;2007，Nuclear power plants – Instrumentation important to safety – Radiationdetectors – Characteristics and test methods
IEC 60568:2006, Nuclear power plants – Instrumentation important to safety – ln-coreinstrumentation for neutron fluence rate (flux) measurements in power reactors
IEC/IEEE 60780-323;2016,Nuclear facilities – Electrical equipment important to safety -Qualification
IEC 61226，Nuclear power plants – Instrumentation, control and electrical power systemsimportant to safety -Categorisation of functions and classification of systems
IEC 61513,Nuclear power plants – Instrumentation and control important to safety – Generalrequirements for systems
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
background-compensation
method employed for compensation of background contribution to the self-powered neutron detector current
Note 1 to entry: This is usually accomplished by placing an “emitterless” background detector in the in-core assembly, or by using detectors with an internal compensating lead wire.
Note 2 to entry: An equivalent term is “lead-compensation”.
3.2
beta decay
radioactive decay process in which mass number A remains unchanged, but the atomic number Z changes
Note 1 to entry: Processes include electron emission (b– decay), electron capture, and positron emission (b+ decay).