BS IEC/IEEE 63113:2021 pdf download – Nuclear facilities — Instrumentation important to safety — Spent fuel pool instrumentation.
1 Scope 1.1 General This document provides criteria for spent fuel pool instrumentation for nuclear power generating stations and other nuclear facilities. The document applies to water filled spent fuel pools where the water volume is necessary to prevent a release of fission products that exceeds allowed operational limits. 1.2 Purpose The purpose of this document is to establish design, performance, qualification, and display criteria for spent fuel pool instrumentation for normal operation, anticipated operational occurrences, design basis events, and design extension conditions (including severe accident conditions). 1.3 Application This document applies only to instrumentation for monitoring the condition of the spent fuel pool, i.e., pool level, pool temperature, and area radiation. It does not apply to control systems that are related to the spent fuel pool such as: the pool cooling systems, isolation valve control, crane instrumentation and control, or refuelling machine instrumentation and control. In some plant designs some of the instruments covered by this document also provide inputs to protection system functions. Such instruments must also comply with requirements for protection systems that are given elsewhere. The requirements applied to the systems and components performing these functions depend on how they contribute to the safety of the spent fuel poo l.
3 Terms and definitions For the purposes of this document, the following terms and definitions apply. ISO, IEC and IEEE maintain terminological databases for use in standardization at the following addresses: • IEC Electropedia: available at http://www.electropedia.org/ • ISO Online browsing platform: available at http://www.iso.org/obp • IEEE Standards Dictionary Online: available at http://dictionary.ieee.org 3.1 accident conditions deviations from normal operation that are less frequent and more severe than anticipated operational occurrences [SOURCE: IAEA Safety Glossary, 201 8 Edition] 3.2 anticipated operational occurrence deviation of an operational process from normal operation that is expected to occur at least once during the operating lifetime of a facility but which, in the view of appropriate design provisions, does not cause any significant damage to items important to safety or lead to accident conditions [SOURCE: IAEA Safety Glossary, 201 8 Edition] 3.3 common cause failure failures of two or more structures, systems or components due to a single event or cause Note 1 to entry: Common causes may be internal or external to an instrumentation and control (I&C) system. Note 2 to entry: The IEC definition differs from the IAEA in that the term “specific” was deleted because this additional word is not necessary to understand the definition. [SOURCE: IAEA Safety Glossary, 201 8 Edition, modified: see Note 2 to entry.] 3.4 design basis accident postulated accident leading to accident conditions for which a facility is designed in accordance with established design criteria and conservative methodology, and for which releases of radioactive material are kept within acceptable limits [SOURCE: IAEA Safety Glossary, 201 8 Edition]
3.5 design extension conditions postulated accident conditions that are not considered for design basis accidents, but that are considered in the design process of the facility in accordance with best estimate methodology, and for which releases of radioactive material are kept within acceptable limits [SOURCE: IAEA Safety Glossary, 201 8 Edition] 3.6 monitoring channel arrangement of components, from sensors to displays, as required to generate a signal from a plant condition and present the signal to the end user 3.7 operational states states defined under normal operation and anticipated operational occurrences Note 1 to entry: Some States and organizations use the term operating conditions (in contrast with accident conditions) for this concept. [SOURCE: IAEA Safety Glossary, 201 8 Edition] 3.8 periodic testing performance of tests at predetermined time points to demonstrate that the functional capabilities of the I&C systems and equipment important to safety are retained and that the characteristics relevant to the claims of safety analysis are satisfied [SOURCE: IEC 60671 :2007, 3.7] 3.9 pond sludge undesired debris material that originates from the storage of items in the spent fuel pool