Nuclear plant safety classification

Classification of on-site elements according to the Overall Provisions on Nuclear Plants Safety Assurance" ... 

IAEA Safety Standards Series no SSG-30, Safety Classifications of Structures, Systems Components in Nuclear Power Plants, International Atomic Energy Agency, 2014. 

Safety classification for I C systems in nuclear power plants... 

For further details. Clause 4.0 of Chapter XI may be referred to. We will now look into the various classifications of I C safety in nuclear plants. 

Developed based on details and idea from Safety Classification for I. C Systems in Nuclear Power Plants — Current Status. Difficulties CORDEL digital instrumentation. control task force World Nuclear Association. 

INTERNATIONAL STANDARDS/ ORGANIZATION SAFETY CLASSIFICATION OF 1 C FUNCTIONS SYSTEMS IN NUCLEAR PLANTS ... 

In Part G of these reference levels, the safety classification of Structures, Systems and Components (SSCs) is described. The goal is to identify all safety related SSC and to classify them according to their importance for safety. Part Q reflects changes in a Nuclear Power Plant (NPP) and it is requested that no change reduces the abihty of the reactor for safe operation in any form. In addition, national regulations and international agreements within the European Union are supplemented by a directive of the European Commission (2009b) which had to be implemented by July 2011 into national... 

When a computerized I C system is part of a backfit or an upgrade, its function in ensuring the safety of the nuclear power plant should be considered. The safety classification of the I C system should be established according to the criteria given in Section 2. Requirements for system reliability, qualification and quality assurance and other requirements will be defined in accordance with the safety classification. 

The safety classification methodology was derived from the standard, ANSI/ANS-51.1, "Nuclear Safety Criteria for the Design of Stationary Pressurized Water Reactor Plants" (Reference 2). The plan describes three safety-related classes and one nonnuclear safety class. The definitions for Safety Classes 1, 2, and 3 were found to comply with the standard definitions contained in 10 CFR 50.55a and NRC Regulatory Guide 1.26 (References 3 and 4). The definition for the nonnuclear safety class was included, but is outside the scope of this evaluation. 

Pantex uses its Facility Hazard Classification as the basis for determining if a facility is nuclear (which requires the development of Authorization Basis Documents) or if a facility requires control under the plant s PSM program because it is classified as an Explosive Manufacturing Operation or has threshold inventories of Highly Hazardous Chemieals. The Preliminary Hazard Analysis serves as the safety basis for facilities that are not classified as nuelear or eoveied by PSM. 

Safety systems for Nuclear Power Plants are governed by strong requirements, which cannot be fulfilled by products designed for normal industrial applications. That s why in all countries, safety classified systems and non-safety classified systems for NPPs use different technologies even if the classification standards give several definitions and gradations for systems. 

The use of safety categorisation and classification processes to assign appropriate codes and standards to plant design, qualification, and through life management, in accordance with their importance to nuclear safety. 

Nuclear Power Plants-Instrumentation and Control Functions Important for Safety-Use of Probabilistic Safety Assessment for the Classification, lEC TR 61838, International Electrotechnical Commission (lEC), Geneva, Switzerland, 2001. 

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