Offers a detailed analysis of the most recent events collected in IAEA databases and other bibliographical sources. The publication provides the technical background for the recently revised IAEA Safety Guide on fire protection and a collection of lessons learned useful for practical fire safety enhancement in operating plants.

This Safety Guide provides specific recommendations on protection against internal and external hazards in the operation of nuclear power plants. It provides new or updated recommendations derived from enhanced understanding of operational aspects of hazards and combinations of hazards. Operating experience gained from incidents and accidents in nuclear power plants around the world has demonstrated that fire can be an important risk contributor in many Member States. However, there are other internal and external hazards that have also to be considered in the design and operation of nuclear power plants. This Safety Guide supersedes and expands the scope of lAEA Safety Standards Series No. NS- G-2. 1, Fire Safety in the Operation of Nuclear Power Plants, to include recommendations on these other hazards.

The comprehensive industrial safety standards and codes that exist today have evolved from lessons learned through past experience, research results, and improvements in technological capabilities. The current requirements for fire safety features of commercial nuclear power stations operated in the US are a notable example of this practice. Although fire protection has always been an important design requirement, from the aftermath of a serious fire that occurred in 1975 at the Browns Ferry plant, it was learned that the life safety and property protection concerns of the major fire insurance underwriters may not sufficiently encompass nuclear safety issues, particularly with regard to the potential for fire damage to result in the common mode failure of redundant trains of systems, and components important to the safe shutdown of the reactor. Following its investigations into the Browns Ferry fire, the Nuclear Regulatory Commission (NRC) promulgated guidance documents, which ultimately developed into mandatory regulations, necessary to assure the implementation of a fire protection program that would address nuclear safety concerns. The new criteria that evolved, contain prescriptive design features, as well as personnel and administrative requirements the Commission determined to be necessary to provide a defense-in-depth level of protection against the hazards of fire and its associated effects on safety related equipment. These criteria are primarily contained in Appendix R of Title 10 to the Code of Federal Regulations (10 CFR 50). Since 1983, various members of the Department of Nuclear Energy (DNE) at Brookhaven National Laboratory (BNL) have provided technical assistance to the Nuclear Regulatory Commission (NRC) in support of its evaluations of fire protection features implemented at commercial nuclear power stations operated in the US. This paper presents a discussion of the insights gained by the author during his active participation in this area.

Safety Guide NS-G-1.7 is a revision of an earlier Safety Guide, Safety Series No. 50-SG-D2. This and other new Safety Guides recommend how to meet the design requirements established in Safety Standards Series No. NS-R-1. Safety of Nuclear Power Plants: Design. Its technical conent is based on the most recent operational experience and has been extended to cover the design of plants in relation to internal explosions. The appendices provide guidance for the design and upgrading of fire detection and suppression systems.

The International Reporting System for Operating Experience (IRS) is an essential element of the international operating experience feedback system for nuclear power plants. Its fundamental objective is to contribute to improving safety of commercial nuclear power plants which are operated worldwide. IRS reports contain information on events of safety significance with important lessons learned which assist in reducing recurrence of events at other plants. This sixth publication, covering the period 2012 - 2014, follows the structure of the previous editions. It highlights important lessons based on a review of the approximately 240 event reports received from the participating countries over this period.